Changeset - 6af17d60c197
[Not reviewed]
1 6 1
MH - 4 years ago 2021-04-29 16:52:10
contact@maxhenger.nl
Cleaning up validation/linking pass
7 files changed with 312 insertions and 731 deletions:
0 comments (0 inline, 0 general)
src/collections/scoped_buffer.rs
Show inline comments
 
/// scoped_buffer.rs
 
///
 
/// Solves the common pattern where we are performing some kind of recursive
 
/// pattern while using a temporary buffer. At the start, or during the
 
/// procedure, we push stuff into the buffer. At the end we take out what we
 
/// have put in.
 
///
 
/// It is unsafe because we're using pointers to circumvent borrowing rules in
 
/// the name of code cleanliness. The correctness of use is checked in debug
 
/// mode.
 

	
 
/// The buffer itself. This struct should be the shared buffer. The type `T` is
 
/// intentionally `Copy` such that it can be copied out and the underlying
 
/// container can be truncated.
 
pub(crate) struct ScopedBuffer<T: Sized + Copy> {
 
    pub inner: Vec<T>,
 
}
 

	
 
/// A section of the buffer. Keeps track of where we started the section. When
 
/// done with the section one must call `into_vec` or `forget` to remove the
 
/// section from the underlying buffer.
 
pub(crate) struct ScopedSection<T: Sized + Copy> {
 
    inner: *mut Vec<T>,
 
    start_size: u32,
 
    #[cfg(debug_assertions)] cur_size: u32,
 
}
 

	
 
impl<T: Sized + Copy> ScopedBuffer<T> {
 
    pub(crate) fn new_reserved(capacity: usize) -> Self {
 
        Self{ inner: Vec::with_capacity(capacity) }
 
    }
 

	
 
    pub(crate) fn start_section(&mut self) -> ScopedSection<T> {
 
        let start_size = self.inner.len() as u32;
 
        ScopedSection{
 
            inner: &mut self.inner,
 
            start_size,
 
            cur_size: start_size
 
        }
 
    }
 

	
 
    pub(crate) fn start_section_initialized(&mut self, initialize_with: &[T]) -> ScopedSection<T> {
 
        let start_size = self.inner.len() as u32;
 
        let data_size = initialize_with.len() as u32;
 
        self.inner.extend_from_slice(initialize_with);
 
        ScopedSection{
 
            inner: &mut self.inner,
 
            start_size,
 
            cur_size: start_size + data_size,
 
        }
 
    }
 
}
 

	
 
#[cfg(debug_assertions)]
 
impl<T: Sized + Copy> Drop for ScopedBuffer<T> {
 
    fn drop(&mut self) {
 
        // Make sure that everyone cleaned up the buffer neatly
 
        debug_assert!(self.inner.is_empty(), "dropped non-empty scoped buffer");
 
    }
 
}
 

	
 
impl<T: Sized + Copy> ScopedSection<T> {
 
    #[inline]
 
    pub(crate) fn push(&mut self, value: T) {
 
        let vec = unsafe{&mut *self.inner};
 
        debug_assert_eq!(vec.len(), self.cur_size as usize, "trying to push onto section, but size is larger than expected");
 
        vec.push(value);
 
        if cfg!(debug_assertions) { self.cur_size += 1; }
 
    }
 

	
 
    pub(crate) fn len(&self) -> usize {
 
        let vec = unsafe{&mut *self.inner};
 
        debug_assert_eq!(vec.len(), self.cur_size as usize, "trying to get section length, but size is larger than expected");
 
        return vec.len() - self.start_size;
 
    }
 

	
 
    #[inline]
 
    pub(crate) fn forget(self) {
 
        let vec = unsafe{&mut *self.inner};
 
        debug_assert_eq!(vec.len(), self.cur_size as usize, "trying to forget section, but size is larger than expected");
 
        vec.truncate(self.start_size as usize);
 
    }
 

	
 
    #[inline]
 
    pub(crate) fn into_vec(self) -> Vec<T> {
 
        let vec = unsafe{&mut *self.inner};
 
        debug_assert_eq!(vec.len(), self.cur_size as usize, "trying to turn section into vec, but size is larger than expected");
 
        let section = Vec::from(&vec[self.start_size as usize..]);
 
        vec.truncate(self.start_size as usize);
 
        section
 
    }
 
}
 

	
 
impl<T: Sized + Copy> std::ops::Index<usize> for ScopedSection<T> {
 
    type Output = T;
 

	
 
    fn index(&self, idx: usize) -> &Self::Output {
 
        let vec = unsafe{&*self.inner};
 
        return vec[self.start_size as usize + idx]
 
    }
 
}
 

	
 
#[cfg(debug_assertions)]
 
impl<T: Sized + Copy> Drop for ScopedBuffer<T> {
 
    fn drop(&mut self) {
 
        // Make sure that the data was actually taken out of the scoped section
 
        let vec = unsafe{&*self.inner};
 
        debug_assert_eq!(vec.len(), self.start_size as usize);
 
    }
 
}
 
\ No newline at end of file
src/protocol/ast.rs
Show inline comments
 
// TODO: @cleanup, rigorous cleanup of dead code and silly object-oriented
 
//  trait impls where I deem them unfit.
 

	
 
use std::fmt;
 
use std::fmt::{Debug, Display, Formatter};
 
use std::ops::{Index, IndexMut};
 

	
 
use super::arena::{Arena, Id};
 
use crate::collections::StringRef;
 
use crate::protocol::inputsource::*;
 
use crate::protocol::input_source2::{InputPosition2, InputSpan};
 

	
 
/// Global limits to the AST, should be checked by lexer and parser. Some are
 
/// arbitrary
 
const MAX_LEVEL: usize = 128;
 
const MAX_NAMESPACES: usize = 64;
 

	
 
/// Helper macro that defines a type alias for a AST element ID. In this case 
 
/// only used to alias the `Id<T>` types.
 
macro_rules! define_aliased_ast_id {
 
    // Variant where we just defined the alias, without any indexing
 
    ($name:ident, $parent:ty) => {
 
        pub type $name = $parent;
 
    };
 
    // Variant where we define the type, and the Index and IndexMut traits
 
    (
 
        $name:ident, $parent:ty, 
 
        index($indexed_type:ty, $indexed_arena:ident)
 
    ) => {
 
        define_aliased_ast_id!($name, $parent);
 
        impl Index<$name> for Heap {
 
            type Output = $indexed_type;
 
            fn index(&self, index: $name) -> &Self::Output {
 
                &self.$indexed_arena[index]
 
            }
 
        }
 

	
 
        impl IndexMut<$name> for Heap {
 
            fn index_mut(&mut self, index: $name) -> &mut Self::Output {
 
                &mut self.$indexed_arena[index]
 
            }
 
        }
 
    };
 
    // Variant where we define type, Index(Mut) traits and an allocation function
 
    (
 
        $name:ident, $parent:ty,
 
        index($indexed_type:ty, $indexed_arena:ident),
 
        alloc($fn_name:ident)
 
    ) => {
 
        define_aliased_ast_id!($name, $parent, index($indexed_type, $indexed_arena));
 
        impl Heap {
 
            pub fn $fn_name(&mut self, f: impl FnOnce($name) -> $indexed_type) -> $name {
 
                self.$indexed_arena.alloc_with_id(|id| f(id))
 
            }
 
        }
 
    };
 
}
 

	
 
/// Helper macro that defines a wrapper type for a particular variant of an AST
 
/// element ID. Only used to define single-wrapping IDs.
 
macro_rules! define_new_ast_id {
 
    // Variant where we just defined the new type, without any indexing
 
    ($name:ident, $parent:ty) => {
 
        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 
        pub struct $name (pub(crate) $parent);
 

	
 
        impl $name {
 
            pub(crate) fn new_invalid() -> Self     { Self($parent::new_invalid()) }
 
            pub(crate) fn is_invalid(&self) -> bool { self.0.is_invalid() }
 
            pub fn upcast(self) -> $parent          { self.0 }
 
        }
 
    };
 
    // Variant where we define the type, and the Index and IndexMut traits
 
    (
 
        $name:ident, $parent:ty, 
 
        index($indexed_type:ty, $wrapper_type:path, $indexed_arena:ident)
 
    ) => {
 
        define_new_ast_id!($name, $parent);
 
        impl Index<$name> for Heap {
 
            type Output = $indexed_type;
 
            fn index(&self, index: $name) -> &Self::Output {
 
                if let $wrapper_type(v) = &self.$indexed_arena[index.0] {
 
                    v
 
                } else {
 
                    unreachable!()
 
                }
 
            }
 
        }
 

	
 
        impl IndexMut<$name> for Heap {
 
            fn index_mut(&mut self, index: $name) -> &mut Self::Output {
 
                if let $wrapper_type(v) = &mut self.$indexed_arena[index.0] {
 
                    v
 
                } else {
 
                    unreachable!()
 
                }
 
            }
 
        }
 
    };
 
    // Variant where we define the type, the Index and IndexMut traits, and an allocation function
 
    (
 
        $name:ident, $parent:ty, 
 
        index($indexed_type:ty, $wrapper_type:path, $indexed_arena:ident),
 
        alloc($fn_name:ident)
 
    ) => {
 
        define_new_ast_id!($name, $parent, index($indexed_type, $wrapper_type, $indexed_arena));
 
        impl Heap {
 
            pub fn $fn_name(&mut self, f: impl FnOnce($name) -> $indexed_type) -> $name {
 
                $name(
 
                    self.$indexed_arena.alloc_with_id(|id| {
 
                        $wrapper_type(f($name(id)))
 
                    })
 
                )
 
            }
 
        }
 
    }
 
}
 

	
 
define_aliased_ast_id!(RootId, Id<Root>, index(Root, protocol_descriptions), alloc(alloc_protocol_description));
 
define_aliased_ast_id!(PragmaId, Id<Pragma>, index(Pragma, pragmas), alloc(alloc_pragma));
 
define_aliased_ast_id!(ImportId, Id<Import>, index(Import, imports), alloc(alloc_import));
 
define_aliased_ast_id!(ParserTypeId, Id<ParserType>, index(ParserType, parser_types), alloc(alloc_parser_type));
 

	
 
define_aliased_ast_id!(VariableId, Id<Variable>, index(Variable, variables));
 
define_new_ast_id!(ParameterId, VariableId, index(Parameter, Variable::Parameter, variables), alloc(alloc_parameter));
 
define_new_ast_id!(LocalId, VariableId, index(Local, Variable::Local, variables), alloc(alloc_local));
 

	
 
define_aliased_ast_id!(DefinitionId, Id<Definition>, index(Definition, definitions));
 
define_new_ast_id!(StructDefinitionId, DefinitionId, index(StructDefinition, Definition::Struct, definitions), alloc(alloc_struct_definition));
 
define_new_ast_id!(EnumDefinitionId, DefinitionId, index(EnumDefinition, Definition::Enum, definitions), alloc(alloc_enum_definition));
 
define_new_ast_id!(UnionDefinitionId, DefinitionId, index(UnionDefinition, Definition::Union, definitions), alloc(alloc_union_definition));
 
define_new_ast_id!(ComponentDefinitionId, DefinitionId, index(ComponentDefinition, Definition::Component, definitions), alloc(alloc_component_definition));
 
define_new_ast_id!(FunctionDefinitionId, DefinitionId, index(FunctionDefinition, Definition::Function, definitions), alloc(alloc_function_definition));
 

	
 
define_aliased_ast_id!(StatementId, Id<Statement>, index(Statement, statements));
 
define_new_ast_id!(BlockStatementId, StatementId, index(BlockStatement, Statement::Block, statements), alloc(alloc_block_statement));
 
define_new_ast_id!(LocalStatementId, StatementId, index(LocalStatement, Statement::Local, statements), alloc(alloc_local_statement));
 
define_new_ast_id!(MemoryStatementId, LocalStatementId);
 
define_new_ast_id!(ChannelStatementId, LocalStatementId);
 
define_new_ast_id!(LabeledStatementId, StatementId, index(LabeledStatement, Statement::Labeled, statements), alloc(alloc_labeled_statement));
 
define_new_ast_id!(IfStatementId, StatementId, index(IfStatement, Statement::If, statements), alloc(alloc_if_statement));
 
define_new_ast_id!(EndIfStatementId, StatementId, index(EndIfStatement, Statement::EndIf, statements), alloc(alloc_end_if_statement));
 
define_new_ast_id!(WhileStatementId, StatementId, index(WhileStatement, Statement::While, statements), alloc(alloc_while_statement));
 
define_new_ast_id!(EndWhileStatementId, StatementId, index(EndWhileStatement, Statement::EndWhile, statements), alloc(alloc_end_while_statement));
 
define_new_ast_id!(BreakStatementId, StatementId, index(BreakStatement, Statement::Break, statements), alloc(alloc_break_statement));
 
define_new_ast_id!(ContinueStatementId, StatementId, index(ContinueStatement, Statement::Continue, statements), alloc(alloc_continue_statement));
 
define_new_ast_id!(SynchronousStatementId, StatementId, index(SynchronousStatement, Statement::Synchronous, statements), alloc(alloc_synchronous_statement));
 
define_new_ast_id!(EndSynchronousStatementId, StatementId, index(EndSynchronousStatement, Statement::EndSynchronous, statements), alloc(alloc_end_synchronous_statement));
 
define_new_ast_id!(ReturnStatementId, StatementId, index(ReturnStatement, Statement::Return, statements), alloc(alloc_return_statement));
 
define_new_ast_id!(AssertStatementId, StatementId, index(AssertStatement, Statement::Assert, statements), alloc(alloc_assert_statement));
 
define_new_ast_id!(GotoStatementId, StatementId, index(GotoStatement, Statement::Goto, statements), alloc(alloc_goto_statement));
 
define_new_ast_id!(NewStatementId, StatementId, index(NewStatement, Statement::New, statements), alloc(alloc_new_statement));
 
define_new_ast_id!(ExpressionStatementId, StatementId, index(ExpressionStatement, Statement::Expression, statements), alloc(alloc_expression_statement));
 

	
 
define_aliased_ast_id!(ExpressionId, Id<Expression>, index(Expression, expressions));
 
define_new_ast_id!(AssignmentExpressionId, ExpressionId, index(AssignmentExpression, Expression::Assignment, expressions), alloc(alloc_assignment_expression));
 
define_new_ast_id!(BindingExpressionId, ExpressionId, index(BindingExpression, Expression::Binding, expressions), alloc(alloc_binding_expression));
 
define_new_ast_id!(ConditionalExpressionId, ExpressionId, index(ConditionalExpression, Expression::Conditional, expressions), alloc(alloc_conditional_expression));
 
define_new_ast_id!(BinaryExpressionId, ExpressionId, index(BinaryExpression, Expression::Binary, expressions), alloc(alloc_binary_expression));
 
define_new_ast_id!(UnaryExpressionId, ExpressionId, index(UnaryExpression, Expression::Unary, expressions), alloc(alloc_unary_expression));
 
define_new_ast_id!(IndexingExpressionId, ExpressionId, index(IndexingExpression, Expression::Indexing, expressions), alloc(alloc_indexing_expression));
 
define_new_ast_id!(SlicingExpressionId, ExpressionId, index(SlicingExpression, Expression::Slicing, expressions), alloc(alloc_slicing_expression));
 
define_new_ast_id!(SelectExpressionId, ExpressionId, index(SelectExpression, Expression::Select, expressions), alloc(alloc_select_expression));
 
define_new_ast_id!(LiteralExpressionId, ExpressionId, index(LiteralExpression, Expression::Literal, expressions), alloc(alloc_literal_expression));
 
define_new_ast_id!(CallExpressionId, ExpressionId, index(CallExpression, Expression::Call, expressions), alloc(alloc_call_expression));
 
define_new_ast_id!(VariableExpressionId, ExpressionId, index(VariableExpression, Expression::Variable, expressions), alloc(alloc_variable_expression));
 

	
 
// TODO: @cleanup - pub qualifiers can be removed once done
 
#[derive(Debug)]
 
pub struct Heap {
 
    // Root arena, contains the entry point for different modules. Each root
 
    // contains lists of IDs that correspond to the other arenas.
 
    pub(crate) protocol_descriptions: Arena<Root>,
 
    // Contents of a file, these are the elements the `Root` elements refer to
 
    pragmas: Arena<Pragma>,
 
    pub(crate) imports: Arena<Import>,
 
    pub(crate) parser_types: Arena<ParserType>,
 
    pub(crate) variables: Arena<Variable>,
 
    pub(crate) definitions: Arena<Definition>,
 
    pub(crate) statements: Arena<Statement>,
 
    pub(crate) expressions: Arena<Expression>,
 
}
 

	
 
impl Heap {
 
    pub fn new() -> Heap {
 
        Heap {
 
            // string_alloc: StringAllocator::new(),
 
            protocol_descriptions: Arena::new(),
 
            pragmas: Arena::new(),
 
            imports: Arena::new(),
 
            parser_types: Arena::new(),
 
            variables: Arena::new(),
 
            definitions: Arena::new(),
 
            statements: Arena::new(),
 
            expressions: Arena::new(),
 
        }
 
    }
 
    pub fn alloc_memory_statement(
 
        &mut self,
 
        f: impl FnOnce(MemoryStatementId) -> MemoryStatement,
 
    ) -> MemoryStatementId {
 
        MemoryStatementId(LocalStatementId(self.statements.alloc_with_id(|id| {
 
            Statement::Local(LocalStatement::Memory(
 
                f(MemoryStatementId(LocalStatementId(id)))
 
            ))
 
        })))
 
    }
 
    pub fn alloc_channel_statement(
 
        &mut self,
 
        f: impl FnOnce(ChannelStatementId) -> ChannelStatement,
 
    ) -> ChannelStatementId {
 
        ChannelStatementId(LocalStatementId(self.statements.alloc_with_id(|id| {
 
            Statement::Local(LocalStatement::Channel(
 
                f(ChannelStatementId(LocalStatementId(id)))
 
            ))
 
        })))
 
    }
 
}
 

	
 
impl Index<MemoryStatementId> for Heap {
 
    type Output = MemoryStatement;
 
    fn index(&self, index: MemoryStatementId) -> &Self::Output {
 
        &self.statements[index.0.0].as_memory()
 
    }
 
}
 

	
 
impl Index<ChannelStatementId> for Heap {
 
    type Output = ChannelStatement;
 
    fn index(&self, index: ChannelStatementId) -> &Self::Output {
 
        &self.statements[index.0.0].as_channel()
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct Root {
 
    pub this: RootId,
 
    // Phase 1: parser
 
    // pub position: InputPosition,
 
    pub pragmas: Vec<PragmaId>,
 
    pub imports: Vec<ImportId>,
 
    pub definitions: Vec<DefinitionId>,
 
}
 

	
 
impl Root {
 
    // TODO: @Cleanup
 
    pub fn get_definition_ident(&self, h: &Heap, id: &[u8]) -> Option<DefinitionId> {
 
        for &def in self.definitions.iter() {
 
            if h[def].identifier().value == id {
 
            if h[def].identifier().value.as_bytes() == id {
 
                return Some(def);
 
            }
 
        }
 
        None
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Pragma {
 
    Version(PragmaVersion),
 
    Module(PragmaModule),
 
}
 

	
 
impl Pragma {
 
    pub(crate) fn as_module(&self) -> &PragmaModule {
 
        match self {
 
            Pragma::Module(pragma) => pragma,
 
            _ => unreachable!("Tried to obtain {:?} as PragmaModule", self),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct PragmaVersion {
 
    pub this: PragmaId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of full pragma
 
    pub version: u64,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct PragmaModule {
 
    pub this: PragmaId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of full pragma
 
    pub value: Identifier,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Import {
 
    Module(ImportModule),
 
    Symbols(ImportSymbols)
 
}
 

	
 
impl Import {
 
    pub(crate) fn span(&self) -> InputSpan {
 
        match self {
 
            Import::Module(v) => v.span,
 
            Import::Symbols(v) => v.span,
 
        }
 
    }
 

	
 
    pub(crate) fn as_module(&self) -> &ImportModule {
 
        match self {
 
            Import::Module(m) => m,
 
            _ => unreachable!("Unable to cast 'Import' to 'ImportModule'")
 
        }
 
    }
 
    pub(crate) fn as_symbols(&self) -> &ImportSymbols {
 
        match self {
 
            Import::Symbols(m) => m,
 
            _ => unreachable!("Unable to cast 'Import' to 'ImportSymbols'")
 
        }
 
    }
 
    pub(crate) fn as_symbols_mut(&mut self) -> &mut ImportSymbols {
 
        match self {
 
            Import::Symbols(m) => m,
 
            _ => unreachable!("Unable to cast 'Import' to 'ImportSymbols'")
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ImportModule {
 
    pub this: ImportId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub module: Identifier,
 
    pub alias: Identifier,
 
    pub module_id: RootId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct AliasedSymbol {
 
    pub name: Identifier,
 
    pub alias: Option<Identifier>,
 
    pub definition_id: DefinitionId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ImportSymbols {
 
    pub this: ImportId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub module: Identifier,
 
    pub module_id: RootId,
 
    pub symbols: Vec<AliasedSymbol>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct Identifier {
 
    pub span: InputSpan,
 
    pub value: StringRef<'static>,
 
}
 

	
 
impl PartialEq for Identifier {
 
    fn eq(&self, other: &Self) -> bool {
 
        return self.value == other.value
 
    }
 
}
 

	
 
impl Display for Identifier {
 
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
 
        write!(f, "{}", self.value.as_str())
 
    }
 
}
 

	
 
#[derive(Debug, Clone, PartialOrd, Ord)]
 
pub enum ParserTypeVariant {
 
    // Basic builtin
 
    Message,
 
    Bool,
 
    UInt8, UInt16, UInt32, UInt64,
 
    SInt8, SInt16, SInt32, SInt64,
 
    Character, String,
 
    // Literals (need to get concrete builtin type during typechecking)
 
    IntegerLiteral,
 
    // Marker for inference
 
    Inferred,
 
    // Builtins expecting one subsequent type
 
    Array,
 
    Input,
 
    Output,
 
    // User-defined types
 
    PolymorphicArgument(DefinitionId, usize), // usize = index into polymorphic variables
 
    Definition(DefinitionId, usize), // usize = number of following subtypes
 
}
 

	
 
impl ParserTypeVariant {
 
    pub(crate) fn num_embedded(&self) -> usize {
 
        match self {
 
            x if *x <= ParserTypeVariant::Inferred => 0,
 
            x if *x <= ParserTypeVariant::Output => 1,
 
            ParserTypeVariant::PolymorphicArgument(_, _) => 0,
 
            ParserTypeVariant::Definition(_, num) => num,
 
            _ => { debug_assert!(false); 0 },
 
        }
 
    }
 
}
 

	
 
pub struct ParserTypeElement {
 
    // TODO: @cleanup, do we ever need the span of a user-defined type after
 
    //  constructing it?
 
    pub full_span: InputSpan, // full span of type, including any polymorphic arguments
 
    pub variant: ParserTypeVariant,
 
}
 

	
 
/// ParserType is a specification of a type during the parsing phase and initial
 
/// linker/validator phase of the compilation process. These types may be
 
/// (partially) inferred or represent literals (e.g. a integer whose bytesize is
 
/// not yet determined).
 
#[derive(Debug, Clone)]
 
pub struct ParserType {
 
    pub elements: Vec<ParserTypeElement>
 
}
 

	
 
/// Specifies whether the symbolic type points to an actual user-defined type,
 
/// or whether it points to a polymorphic argument within the definition (e.g.
 
/// a defined variable `T var` within a function `int func<T>()`
 
#[derive(Debug, Clone)]
 
pub enum SymbolicParserTypeVariant {
 
    Definition(DefinitionId),
 
    // TODO: figure out if I need the DefinitionId here
 
    PolyArg(DefinitionId, usize), // index of polyarg in the definition
 
}
 

	
 
/// ConcreteType is the representation of a type after resolving symbolic types
 
/// and performing type inference
 
#[derive(Debug, Clone, Copy, Eq, PartialEq)]
 
pub enum ConcreteTypePart {
 
    // Markers for the use of polymorphic types within a procedure's body that
 
    // refer to polymorphic variables on the procedure's definition. Different
 
    // from markers in the `InferenceType`, these will not contain nested types.
 
    Marker(usize),
 
    // Special types (cannot be explicitly constructed by the programmer)
 
    Void,
 
    // Builtin types without nested types
 
    Message,
 
    Bool,
 
    Byte,
 
    Short,
 
    Int,
 
    Long,
 
    String,
 
    // Builtin types with one nested type
 
    Array,
 
    Slice,
 
    Input,
 
    Output,
 
    // User defined type with any number of nested types
 
    Instance(DefinitionId, usize),
 
}
 

	
 
#[derive(Debug, Clone, Eq, PartialEq)]
 
pub struct ConcreteType {
 
    pub(crate) parts: Vec<ConcreteTypePart>
 
}
 

	
 
impl Default for ConcreteType {
 
    fn default() -> Self {
 
        Self{ parts: Vec::new() }
 
    }
 
}
 

	
 
impl ConcreteType {
 
    pub(crate) fn has_marker(&self) -> bool {
 
        self.parts
 
            .iter()
 
            .any(|p| {
 
                if let ConcreteTypePart::Marker(_) = p { true } else { false }
 
            })
 
    }
 
}
 

	
 
// TODO: Remove at some point
 
#[derive(Debug, Clone, PartialEq, Eq)]
 
pub enum PrimitiveType {
 
    Unassigned,
 
    Input,
 
    Output,
 
    Message,
 
    Boolean,
 
    Byte,
 
    Short,
 
    Int,
 
    Long,
 
}
 

	
 
#[derive(Debug, Clone, PartialEq, Eq)]
 
pub struct Type {
 
    pub primitive: PrimitiveType,
 
    pub array: bool,
 
}
 

	
 
#[allow(dead_code)]
 
impl Type {
 
    pub const UNASSIGNED: Type = Type { primitive: PrimitiveType::Unassigned, array: false };
 

	
 
    pub const INPUT: Type = Type { primitive: PrimitiveType::Input, array: false };
 
    pub const OUTPUT: Type = Type { primitive: PrimitiveType::Output, array: false };
 
    pub const MESSAGE: Type = Type { primitive: PrimitiveType::Message, array: false };
 
    pub const BOOLEAN: Type = Type { primitive: PrimitiveType::Boolean, array: false };
 
    pub const BYTE: Type = Type { primitive: PrimitiveType::Byte, array: false };
 
    pub const SHORT: Type = Type { primitive: PrimitiveType::Short, array: false };
 
    pub const INT: Type = Type { primitive: PrimitiveType::Int, array: false };
 
    pub const LONG: Type = Type { primitive: PrimitiveType::Long, array: false };
 

	
 
    pub const INPUT_ARRAY: Type = Type { primitive: PrimitiveType::Input, array: true };
 
    pub const OUTPUT_ARRAY: Type = Type { primitive: PrimitiveType::Output, array: true };
 
    pub const MESSAGE_ARRAY: Type = Type { primitive: PrimitiveType::Message, array: true };
 
    pub const BOOLEAN_ARRAY: Type = Type { primitive: PrimitiveType::Boolean, array: true };
 
    pub const BYTE_ARRAY: Type = Type { primitive: PrimitiveType::Byte, array: true };
 
    pub const SHORT_ARRAY: Type = Type { primitive: PrimitiveType::Short, array: true };
 
    pub const INT_ARRAY: Type = Type { primitive: PrimitiveType::Int, array: true };
 
    pub const LONG_ARRAY: Type = Type { primitive: PrimitiveType::Long, array: true };
 
}
 

	
 
impl Display for Type {
 
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
 
        match &self.primitive {
 
            PrimitiveType::Unassigned => {
 
                write!(f, "unassigned")?;
 
            }
 
            PrimitiveType::Input => {
 
                write!(f, "in")?;
 
            }
 
            PrimitiveType::Output => {
 
                write!(f, "out")?;
 
            }
 
            PrimitiveType::Message => {
 
                write!(f, "msg")?;
 
            }
 
            PrimitiveType::Boolean => {
 
                write!(f, "boolean")?;
 
            }
 
            PrimitiveType::Byte => {
 
                write!(f, "byte")?;
 
            }
 
            PrimitiveType::Short => {
 
                write!(f, "short")?;
 
            }
 
            PrimitiveType::Int => {
 
                write!(f, "int")?;
 
            }
 
            PrimitiveType::Long => {
 
                write!(f, "long")?;
 
            }
 
        }
 
        if self.array {
 
            write!(f, "[]")
 
        } else {
 
            Ok(())
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Field {
 
    Length,
 
    Symbolic(FieldSymbolic),
 
}
 
impl Field {
 
    pub fn is_length(&self) -> bool {
 
        match self {
 
            Field::Length => true,
 
            _ => false,
 
        }
 
    }
 

	
 
    pub fn as_symbolic(&self) -> &FieldSymbolic {
 
        match self {
 
            Field::Symbolic(v) => v,
 
            _ => unreachable!("attempted to get Field::Symbolic from {:?}", self)
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct FieldSymbolic {
 
    // Phase 1: Parser
 
    pub(crate) identifier: Identifier,
 
    // Phase 3: Typing
 
    pub(crate) definition: Option<DefinitionId>,
 
    pub(crate) field_idx: usize,
 
}
 

	
 
#[derive(Debug, Clone, Copy)]
 
pub enum Scope {
 
    Definition(DefinitionId),
 
    Regular(BlockStatementId),
 
    Synchronous((SynchronousStatementId, BlockStatementId)),
 
}
 

	
 
impl Scope {
 
    pub fn is_block(&self) -> bool {
 
        match &self {
 
            Scope::Definition(_) => false,
 
            Scope::Regular(_) => true,
 
            Scope::Synchronous(_) => true,
 
        }
 
    }
 
    pub fn to_block(&self) -> BlockStatementId {
 
        match &self {
 
            Scope::Regular(id) => *id,
 
            Scope::Synchronous((_, id)) => *id,
 
            _ => panic!("unable to get BlockStatement from Scope")
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Variable {
 
    Parameter(Parameter),
 
    Local(Local),
 
}
 

	
 
impl Variable {
 
    pub fn identifier(&self) -> &Identifier {
 
        match self {
 
            Variable::Parameter(var) => &var.identifier,
 
            Variable::Local(var) => &var.identifier,
 
        }
 
    }
 
    pub fn is_parameter(&self) -> bool {
 
        match self {
 
            Variable::Parameter(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub fn as_parameter(&self) -> &Parameter {
 
        match self {
 
            Variable::Parameter(result) => result,
 
            _ => panic!("Unable to cast `Variable` to `Parameter`"),
 
        }
 
    }
 
    pub fn as_local(&self) -> &Local {
 
        match self {
 
            Variable::Local(result) => result,
 
            _ => panic!("Unable to cast `Variable` to `Local`"),
 
        }
 
    }
 
    pub fn as_local_mut(&mut self) -> &mut Local {
 
        match self {
 
            Variable::Local(result) => result,
 
            _ => panic!("Unable to cast 'Variable' to 'Local'"),
 
        }
 
    }
 
}
 

	
 
/// TODO: Remove distinction between parameter/local and add an enum to indicate
 
///     the distinction between the two
 
#[derive(Debug, Clone)]
 
pub struct Parameter {
 
    pub this: ParameterId,
 
    // Phase 2: parser
 
    pub span: InputSpan,
 
    pub parser_type: ParserType,
 
    pub identifier: Identifier,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct Local {
 
    pub this: LocalId,
 
    // Phase 1: parser
 
    pub identifier: Identifier,
 
    pub parser_type: ParserType,
 
    // Phase 2: linker
 
    pub relative_pos_in_block: u32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Definition {
 
    Struct(StructDefinition),
 
    Enum(EnumDefinition),
 
    Union(UnionDefinition),
 
    Component(ComponentDefinition),
 
    Function(FunctionDefinition),
 
}
 

	
 
impl Definition {
 
    pub fn is_struct(&self) -> bool {
 
        match self {
 
            Definition::Struct(_) => true,
 
            _ => false
 
        }
 
    }
 
    pub(crate) fn as_struct(&self) -> &StructDefinition {
 
        match self {
 
            Definition::Struct(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'StructDefinition'"),
 
        }
 
    }
 
    pub(crate) fn as_struct_mut(&mut self) -> &mut StructDefinition {
 
        match self {
 
            Definition::Struct(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'StructDefinition'"),
 
        }
 
    }
 
    pub fn is_enum(&self) -> bool {
 
        match self {
 
            Definition::Enum(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_enum(&self) -> &EnumDefinition {
 
        match self {
 
            Definition::Enum(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'EnumDefinition'"),
 
        }
 
    }
 
    pub(crate) fn as_enum_mut(&mut self) -> &mut EnumDefinition {
 
        match self {
 
            Definition::Enum(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'EnumDefinition'"),
 
        }
 
    }
 
    pub fn is_union(&self) -> bool {
 
        match self {
 
            Definition::Union(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_union(&self) -> &UnionDefinition {
 
        match self {
 
            Definition::Union(result) => result, 
 
            _ => panic!("Unable to cast 'Definition' to 'UnionDefinition'"),
 
        }
 
    }
 
    pub(crate) fn as_union_mut(&mut self) -> &mut UnionDefinition {
 
        match self {
 
            Definition::Union(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'UnionDefinition'"),
 
        }
 
    }
 
    pub fn is_component(&self) -> bool {
 
        match self {
 
            Definition::Component(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_component(&self) -> &ComponentDefinition {
 
        match self {
 
            Definition::Component(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Component`"),
 
        }
 
    }
 
    pub(crate) fn as_component_mut(&mut self) -> &mut ComponentDefinition {
 
        match self {
 
            Definition::Component(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Component`"),
 
        }
 
    }
 
    pub fn is_function(&self) -> bool {
 
        match self {
 
            Definition::Function(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_function(&self) -> &FunctionDefinition {
 
        match self {
 
            Definition::Function(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Function`"),
 
        }
 
    }
 
    pub(crate) fn as_function_mut(&mut self) -> &mut FunctionDefinition {
 
        match self {
 
            Definition::Function(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Function`"),
 
        }
 
    }
 
    pub fn defined_in(&self) -> RootId {
 
        match self {
 
            Definition::Struct(def) => def.defined_in,
 
            Definition::Enum(def) => def.defined_in,
 
            Definition::Union(def) => def.defined_in,
 
            Definition::Component(def) => def.defined_in,
 
            Definition::Function(def) => def.defined_in,
 
        }
 
    }
 
    pub fn identifier(&self) -> &Identifier {
 
        match self {
 
            Definition::Struct(def) => &def.identifier,
 
            Definition::Enum(def) => &def.identifier,
 
            Definition::Union(def) => &def.identifier,
 
            Definition::Component(def) => &def.identifier,
 
            Definition::Function(def) => &def.identifier,
 
        }
 
    }
 
    pub fn parameters(&self) -> &Vec<ParameterId> {
 
        // TODO: Fix this
 
        static EMPTY_VEC: Vec<ParameterId> = Vec::new();
 
        match self {
 
            Definition::Component(com) => &com.parameters,
 
            Definition::Function(fun) => &fun.parameters,
 
            _ => &EMPTY_VEC,
 
        }
 
    }
 
    pub fn body(&self) -> BlockStatementId {
 
        match self {
 
            Definition::Component(com) => com.body,
 
            Definition::Function(fun) => fun.body,
 
            _ => panic!("cannot retrieve body (for EnumDefinition/UnionDefinition or StructDefinition)")
 
        }
 
    }
 
    pub fn poly_vars(&self) -> &Vec<Identifier> {
 
        match self {
 
            Definition::Struct(def) => &def.poly_vars,
 
            Definition::Enum(def) => &def.poly_vars,
 
            Definition::Union(def) => &def.poly_vars,
 
            Definition::Component(def) => &def.poly_vars,
 
            Definition::Function(def) => &def.poly_vars,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct StructFieldDefinition {
 
    pub span: InputSpan,
 
    pub field: Identifier,
 
    pub parser_type: ParserType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct StructDefinition {
 
    pub this: StructDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub fields: Vec<StructFieldDefinition>
 
}
 

	
 
impl StructDefinition {
 
    pub(crate) fn new_empty(
 
        this: StructDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ this, defined_in, span, identifier, poly_vars, fields: Vec::new() }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum EnumVariantValue {
 
    None,
 
    Integer(i64),
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EnumVariantDefinition {
 
    pub identifier: Identifier,
 
    pub value: EnumVariantValue,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EnumDefinition {
 
    pub this: EnumDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub variants: Vec<EnumVariantDefinition>,
 
}
 

	
 
impl EnumDefinition {
 
    pub(crate) fn new_empty(
 
        this: EnumDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ this, defined_in, span, identifier, poly_vars, variants: Vec::new() }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum UnionVariantValue {
 
    None,
 
    Embedded(Vec<ParserType>),
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnionVariantDefinition {
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub value: UnionVariantValue,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnionDefinition {
 
    pub this: UnionDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub variants: Vec<UnionVariantDefinition>,
 
}
 

	
 
impl UnionDefinition {
 
    pub(crate) fn new_empty(
 
        this: UnionDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ this, defined_in, span, identifier, poly_vars, variants: Vec::new() }
 
    }
 
}
 

	
 
#[derive(Debug, Clone, Copy)]
 
pub enum ComponentVariant {
 
    Primitive,
 
    Composite,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ComponentDefinition {
 
    pub this: ComponentDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub span: InputSpan,
 
    pub variant: ComponentVariant,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub parameters: Vec<ParameterId>,
 
    pub body: BlockStatementId,
 
}
 

	
 
impl ComponentDefinition {
 
    pub(crate) fn new_empty(
 
        this: ComponentDefinitionId, defined_in: RootId, span: InputSpan,
 
        variant: ComponentVariant, identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ 
 
            this, defined_in, span, variant, identifier, poly_vars,
 
            parameters: Vec::new(), 
 
            body: BlockStatementId::new_invalid()
 
        }
 
    }
 
}
 

	
 
// Note that we will have function definitions for builtin functions as well. In
 
// that case the span, the identifier span and the body are all invalid.
 
#[derive(Debug, Clone)]
 
pub struct FunctionDefinition {
 
    pub this: FunctionDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub builtin: bool,
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub return_types: Vec<ParserType>,
 
    pub parameters: Vec<ParameterId>,
 
    pub body: BlockStatementId,
 
}
 

	
 
impl FunctionDefinition {
 
    pub(crate) fn new_empty(
 
        this: FunctionDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self {
 
            this, defined_in,
 
            builtin: false,
 
            span, identifier, poly_vars,
 
            return_types: Vec::new(),
 
            parameters: Vec::new(),
 
            body: BlockStatementId::new_invalid(),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Statement {
 
    Block(BlockStatement),
 
    Local(LocalStatement),
 
    Labeled(LabeledStatement),
 
    If(IfStatement),
 
    EndIf(EndIfStatement),
 
    While(WhileStatement),
 
    EndWhile(EndWhileStatement),
 
    Break(BreakStatement),
 
    Continue(ContinueStatement),
 
    Synchronous(SynchronousStatement),
 
    EndSynchronous(EndSynchronousStatement),
 
    Return(ReturnStatement),
 
    Goto(GotoStatement),
 
    New(NewStatement),
 
    Expression(ExpressionStatement),
 
}
 

	
 
impl Statement {
 
    pub fn is_block(&self) -> bool {
 
        match self {
 
            Statement::Block(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub fn as_block(&self) -> &BlockStatement {
 
        match self {
 
            Statement::Block(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `BlockStatement`"),
 
        }
 
    }
 
    pub fn as_block_mut(&mut self) -> &mut BlockStatement {
 
        match self {
 
            Statement::Block(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `BlockStatement`"),
 
        }
 
    }
 
    pub fn as_local(&self) -> &LocalStatement {
 
        match self {
 
            Statement::Local(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `LocalStatement`"),
 
        }
 
    }
 
    pub fn as_memory(&self) -> &MemoryStatement {
 
        self.as_local().as_memory()
 
    }
 
    pub fn as_channel(&self) -> &ChannelStatement {
 
        self.as_local().as_channel()
 
    }
 
    pub fn as_skip(&self) -> &SkipStatement {
 
        match self {
 
            Statement::Skip(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `SkipStatement`"),
 
        }
 
    }
 
    pub fn as_labeled(&self) -> &LabeledStatement {
 
        match self {
 
            Statement::Labeled(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `LabeledStatement`"),
 
        }
 
    }
 
    pub fn as_labeled_mut(&mut self) -> &mut LabeledStatement {
 
        match self {
 
            Statement::Labeled(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `LabeledStatement`"),
 
        }
 
    }
 
    pub fn as_if(&self) -> &IfStatement {
 
        match self {
 
            Statement::If(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `IfStatement`"),
 
        }
 
    }
 
    pub fn as_if_mut(&mut self) -> &mut IfStatement {
 
        match self {
 
            Statement::If(result) => result,
 
            _ => panic!("Unable to cast 'Statement' to 'IfStatement'"),
 
        }
 
    }
 
    pub fn as_end_if(&self) -> &EndIfStatement {
 
        match self {
 
            Statement::EndIf(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `EndIfStatement`"),
 
        }
 
    }
 
    pub fn is_while(&self) -> bool {
 
        match self {
 
            Statement::While(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub fn as_while(&self) -> &WhileStatement {
 
        match self {
 
            Statement::While(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `WhileStatement`"),
 
        }
 
    }
 
    pub fn as_while_mut(&mut self) -> &mut WhileStatement {
 
        match self {
 
            Statement::While(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `WhileStatement`"),
 
        }
 
    }
 
    pub fn as_end_while(&self) -> &EndWhileStatement {
 
        match self {
 
            Statement::EndWhile(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `EndWhileStatement`"),
 
        }
 
    }
 
    pub fn as_break(&self) -> &BreakStatement {
 
        match self {
 
            Statement::Break(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `BreakStatement`"),
 
        }
 
    }
 
    pub fn as_break_mut(&mut self) -> &mut BreakStatement {
 
        match self {
 
            Statement::Break(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `BreakStatement`"),
 
        }
 
    }
 
    pub fn as_continue(&self) -> &ContinueStatement {
 
        match self {
 
            Statement::Continue(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `ContinueStatement`"),
 
        }
 
    }
 
    pub fn as_continue_mut(&mut self) -> &mut ContinueStatement {
 
        match self {
 
            Statement::Continue(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `ContinueStatement`"),
 
        }
 
    }
 
    pub fn as_synchronous(&self) -> &SynchronousStatement {
 
        match self {
 
            Statement::Synchronous(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `SynchronousStatement`"),
 
        }
 
    }
 
    pub fn as_synchronous_mut(&mut self) -> &mut SynchronousStatement {
 
        match self {
 
            Statement::Synchronous(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `SynchronousStatement`"),
 
        }
 
    }
 
    pub fn as_end_synchronous(&self) -> &EndSynchronousStatement {
 
        match self {
 
            Statement::EndSynchronous(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `EndSynchronousStatement`"),
 
        }
 
    }
 
    pub fn as_return(&self) -> &ReturnStatement {
 
        match self {
 
            Statement::Return(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `ReturnStatement`"),
 
        }
 
    }
 
    pub fn as_goto(&self) -> &GotoStatement {
 
        match self {
 
            Statement::Goto(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `GotoStatement`"),
 
        }
 
    }
 
    pub fn as_goto_mut(&mut self) -> &mut GotoStatement {
 
        match self {
 
            Statement::Goto(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `GotoStatement`"),
 
        }
 
    }
 
    pub fn as_new(&self) -> &NewStatement {
 
        match self {
 
            Statement::New(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `NewStatement`"),
 
        }
 
    }
 
    pub fn as_expression(&self) -> &ExpressionStatement {
 
        match self {
 
            Statement::Expression(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `ExpressionStatement`"),
 
        }
 
    }
 
    pub fn span(&self) -> InputSpan {
 
        match self {
 
            Statement::Block(v) => v.span,
 
            Statement::Local(v) => v.span(),
 
            Statement::Labeled(v) => v.label.span,
 
            Statement::If(v) => v.span,
 
            Statement::While(v) => v.span,
 
            Statement::Break(v) => v.span,
 
            Statement::Continue(v) => v.span,
 
            Statement::Synchronous(v) => v.span,
 
            Statement::Return(v) => v.span,
 
            Statement::Goto(v) => v.span,
 
            Statement::New(v) => v.span,
 
            Statement::Expression(v) => v.span,
 
            Statement::EndIf(_) | Statement::EndWhile(_) | Statement::EndSynchronous(_) => unreachable!(),
 
        }
 
    }
 
    pub fn link_next(&mut self, next: StatementId) {
 
        match self {
 
            Statement::Block(_) => todo!(),
 
            Statement::Local(stmt) => match stmt {
 
                LocalStatement::Channel(stmt) => stmt.next = Some(next),
 
                LocalStatement::Memory(stmt) => stmt.next = Some(next),
 
            },
 
            Statement::EndIf(stmt) => stmt.next = Some(next),
 
            Statement::EndWhile(stmt) => stmt.next = Some(next),
 
            Statement::EndSynchronous(stmt) => stmt.next = Some(next),
 
            Statement::New(stmt) => stmt.next = Some(next),
 
            Statement::Expression(stmt) => stmt.next = Some(next),
 
            Statement::Return(_)
 
            | Statement::Break(_)
 
            | Statement::Continue(_)
 
            | Statement::Synchronous(_)
 
            | Statement::Goto(_)
 
            | Statement::While(_)
 
            | Statement::Labeled(_)
 
            | Statement::If(_) => unreachable!(),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BlockStatement {
 
    pub this: BlockStatementId,
 
    // Phase 1: parser
 
    pub is_implicit: bool,
 
    pub span: InputSpan, // of the complete block
 
    pub statements: Vec<StatementId>,
 
    // Phase 2: linker
 
    pub parent_scope: Option<Scope>,
 
    pub relative_pos_in_parent: u32,
 
    pub locals: Vec<LocalId>,
 
    pub labels: Vec<LabeledStatementId>,
 
}
 

	
 
impl BlockStatement {
 
    pub fn parent_block(&self, h: &Heap) -> Option<BlockStatementId> {
 
        let parent = self.parent_scope.unwrap();
 
        match parent {
 
            Scope::Definition(_) => {
 
                // If the parent scope is a definition, then there is no
 
                // parent block.
 
                None
 
            }
 
            Scope::Synchronous((parent, _)) => {
 
                // It is always the case that when this function is called,
 
                // the parent of a synchronous statement is a block statement:
 
                // nested synchronous statements are flagged illegal,
 
                // and that happens before resolving variables that
 
                // creates the parent_scope references in the first place.
 
                Some(h[parent].parent_scope(h).unwrap().to_block())
 
            }
 
            Scope::Regular(parent) => {
 
                // A variable scope is either a definition, sync, or block.
 
                Some(parent)
 
            }
 
        }
 
    }
 
    pub fn first(&self) -> StatementId {
 
        // It is an invariant (guaranteed by the lexer) that block statements have at least one stmt
 
        *self.statements.first().unwrap()
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum LocalStatement {
 
    Memory(MemoryStatement),
 
    Channel(ChannelStatement),
 
}
 

	
 
impl LocalStatement {
 
    pub fn this(&self) -> LocalStatementId {
 
        match self {
 
            LocalStatement::Memory(stmt) => stmt.this.upcast(),
 
            LocalStatement::Channel(stmt) => stmt.this.upcast(),
 
        }
 
    }
 
    pub fn as_memory(&self) -> &MemoryStatement {
 
        match self {
 
            LocalStatement::Memory(result) => result,
 
            _ => panic!("Unable to cast `LocalStatement` to `MemoryStatement`"),
 
        }
 
    }
 
    pub fn as_channel(&self) -> &ChannelStatement {
 
        match self {
 
            LocalStatement::Channel(result) => result,
 
            _ => panic!("Unable to cast `LocalStatement` to `ChannelStatement`"),
 
        }
 
    }
 
    pub fn span(&self) -> InputSpan {
 
        match self {
 
            LocalStatement::Channel(v) => v.span,
 
            LocalStatement::Memory(v) => v.span,
 
        }
 
    }
 
    pub fn next(&self) -> Option<StatementId> {
 
        match self {
 
            LocalStatement::Memory(stmt) => stmt.next,
 
            LocalStatement::Channel(stmt) => stmt.next,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct MemoryStatement {
 
    pub this: MemoryStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub variable: LocalId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
/// ChannelStatement is the declaration of an input and output port associated
 
/// with the same channel. Note that the polarity of the ports are from the
 
/// point of view of the component. So an output port is something that a
 
/// component uses to send data over (i.e. it is the "input end" of the
 
/// channel), and vice versa.
 
#[derive(Debug, Clone)]
 
pub struct ChannelStatement {
 
    pub this: ChannelStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "channel" keyword
 
    pub from: LocalId, // output
 
    pub to: LocalId,   // input
 
    // Phase 2: linker
 
    pub relative_pos_in_block: u32,
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LabeledStatement {
 
    pub this: LabeledStatementId,
 
    // Phase 1: parser
 
    pub label: Identifier,
 
    pub body: StatementId,
 
    // Phase 2: linker
 
    pub relative_pos_in_block: u32,
 
    pub in_sync: Option<SynchronousStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct IfStatement {
 
    pub this: IfStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "if" keyword
 
    pub test: ExpressionId,
 
    pub true_body: BlockStatementId,
 
    pub false_body: Option<BlockStatementId>,
 
    // Phase 2: linker
 
    pub end_if: Option<EndIfStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndIfStatement {
 
    pub this: EndIfStatementId,
 
    pub start_if: IfStatementId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct WhileStatement {
 
    pub this: WhileStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "while" keyword
 
    pub test: ExpressionId,
 
    pub body: BlockStatementId,
 
    // Phase 2: linker
 
    pub end_while: Option<EndWhileStatementId>,
 
    pub in_sync: Option<SynchronousStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndWhileStatement {
 
    pub this: EndWhileStatementId,
 
    pub start_while: WhileStatementId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BreakStatement {
 
    pub this: BreakStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "break" keyword
 
    pub label: Option<Identifier>,
 
    // Phase 2: linker
 
    pub target: Option<EndWhileStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ContinueStatement {
 
    pub this: ContinueStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "continue" keyword
 
    pub label: Option<Identifier>,
 
    // Phase 2: linker
 
    pub target: Option<WhileStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SynchronousStatement {
 
    pub this: SynchronousStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "sync" keyword
 
    pub body: BlockStatementId,
 
    // Phase 2: linker
 
    pub end_sync: Option<EndSynchronousStatementId>,
 
    pub parent_scope: Option<Scope>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndSynchronousStatement {
 
    pub this: EndSynchronousStatementId,
 
    pub start_sync: SynchronousStatementId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ReturnStatement {
 
    pub this: ReturnStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "return" keyword
 
    pub expressions: Vec<ExpressionId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct GotoStatement {
 
    pub this: GotoStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "goto" keyword
 
    pub label: Identifier,
 
    // Phase 2: linker
 
    pub target: Option<LabeledStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct NewStatement {
 
    pub this: NewStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "new" keyword
 
    pub expression: CallExpressionId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ExpressionStatement {
 
    pub this: ExpressionStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub expression: ExpressionId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
 
pub enum ExpressionParent {
 
    None, // only set during initial parsing
 
    If(IfStatementId),
 
    While(WhileStatementId),
 
    Return(ReturnStatementId),
 
    Assert(AssertStatementId),
 
    New(NewStatementId),
 
    ExpressionStmt(ExpressionStatementId),
 
    Expression(ExpressionId, u32) // index within expression (e.g LHS or RHS of expression)
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Expression {
 
    Assignment(AssignmentExpression),
 
    Binding(BindingExpression),
 
    Conditional(ConditionalExpression),
 
    Binary(BinaryExpression),
 
    Unary(UnaryExpression),
 
    Indexing(IndexingExpression),
 
    Slicing(SlicingExpression),
 
    Select(SelectExpression),
 
    Array(ArrayExpression),
 
    Literal(LiteralExpression),
 
    Call(CallExpression),
 
    Variable(VariableExpression),
 
}
 

	
 
impl Expression {
 
    pub fn as_assignment(&self) -> &AssignmentExpression {
 
        match self {
 
            Expression::Assignment(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `AssignmentExpression`"),
 
        }
 
    }
 
    pub fn as_conditional(&self) -> &ConditionalExpression {
 
        match self {
 
            Expression::Conditional(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `ConditionalExpression`"),
 
        }
 
    }
 
    pub fn as_binary(&self) -> &BinaryExpression {
 
        match self {
 
            Expression::Binary(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `BinaryExpression`"),
 
        }
 
    }
 
    pub fn as_unary(&self) -> &UnaryExpression {
 
        match self {
 
            Expression::Unary(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `UnaryExpression`"),
 
        }
 
    }
 
    pub fn as_indexing(&self) -> &IndexingExpression {
 
        match self {
 
            Expression::Indexing(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `IndexingExpression`"),
 
        }
 
    }
 
    pub fn as_slicing(&self) -> &SlicingExpression {
 
        match self {
 
            Expression::Slicing(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `SlicingExpression`"),
 
        }
 
    }
 
    pub fn as_select(&self) -> &SelectExpression {
 
        match self {
 
            Expression::Select(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `SelectExpression`"),
 
        }
 
    }
 
    pub fn as_array(&self) -> &ArrayExpression {
 
        match self {
 
            Expression::Array(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `ArrayExpression`"),
 
        }
 
    }
 
    pub fn as_constant(&self) -> &LiteralExpression {
 
        match self {
 
            Expression::Literal(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `ConstantExpression`"),
 
        }
 
    }
 
    pub fn as_call(&self) -> &CallExpression {
 
        match self {
 
            Expression::Call(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `CallExpression`"),
 
        }
 
    }
 
    pub fn as_call_mut(&mut self) -> &mut CallExpression {
 
        match self {
 
            Expression::Call(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `CallExpression`"),
 
        }
 
    }
 
    pub fn as_variable(&self) -> &VariableExpression {
 
        match self {
 
            Expression::Variable(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `VariableExpression`"),
 
        }
 
    }
 
    pub fn as_variable_mut(&mut self) -> &mut VariableExpression {
 
        match self {
 
            Expression::Variable(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `VariableExpression`"),
 
        }
 
    }
 
    // TODO: @cleanup
 
    pub fn parent(&self) -> &ExpressionParent {
 
        match self {
 
            Expression::Assignment(expr) => &expr.parent,
 
            Expression::Binding(expr) => &expr.parent,
 
            Expression::Conditional(expr) => &expr.parent,
 
            Expression::Binary(expr) => &expr.parent,
 
            Expression::Unary(expr) => &expr.parent,
 
            Expression::Indexing(expr) => &expr.parent,
 
            Expression::Slicing(expr) => &expr.parent,
 
            Expression::Select(expr) => &expr.parent,
 
            Expression::Array(expr) => &expr.parent,
 
            Expression::Literal(expr) => &expr.parent,
 
            Expression::Call(expr) => &expr.parent,
 
            Expression::Variable(expr) => &expr.parent,
 
        }
 
    }
 
    // TODO: @cleanup
 
    pub fn parent_expr_id(&self) -> Option<ExpressionId> {
 
        if let ExpressionParent::Expression(id, _) = self.parent() {
 
            Some(*id)
 
        } else {
 
            None
 
        }
 
    }
 
    // TODO: @cleanup
 
    pub fn set_parent(&mut self, parent: ExpressionParent) {
 
        match self {
 
            Expression::Assignment(expr) => expr.parent = parent,
 
            Expression::Binding(expr) => expr.parent = parent,
 
            Expression::Conditional(expr) => expr.parent = parent,
 
            Expression::Binary(expr) => expr.parent = parent,
 
            Expression::Unary(expr) => expr.parent = parent,
 
            Expression::Indexing(expr) => expr.parent = parent,
 
            Expression::Slicing(expr) => expr.parent = parent,
 
            Expression::Select(expr) => expr.parent = parent,
 
            Expression::Array(expr) => expr.parent = parent,
 
            Expression::Literal(expr) => expr.parent = parent,
 
            Expression::Call(expr) => expr.parent = parent,
 
            Expression::Variable(expr) => expr.parent = parent,
 
        }
 
    }
 
    pub fn get_type(&self) -> &ConcreteType {
 
        match self {
 
            Expression::Assignment(expr) => &expr.concrete_type,
 
            Expression::Binding(expr) => &expr.concrete_type,
 
            Expression::Conditional(expr) => &expr.concrete_type,
 
            Expression::Binary(expr) => &expr.concrete_type,
 
            Expression::Unary(expr) => &expr.concrete_type,
 
            Expression::Indexing(expr) => &expr.concrete_type,
 
            Expression::Slicing(expr) => &expr.concrete_type,
 
            Expression::Select(expr) => &expr.concrete_type,
 
            Expression::Array(expr) => &expr.concrete_type,
 
            Expression::Literal(expr) => &expr.concrete_type,
 
            Expression::Call(expr) => &expr.concrete_type,
 
            Expression::Variable(expr) => &expr.concrete_type,
 
        }
 
    }
 

	
 
    // TODO: @cleanup
 
    pub fn get_type_mut(&mut self) -> &mut ConcreteType {
 
        match self {
 
            Expression::Assignment(expr) => &mut expr.concrete_type,
 
            Expression::Binding(expr) => &mut expr.concrete_type,
 
            Expression::Conditional(expr) => &mut expr.concrete_type,
 
            Expression::Binary(expr) => &mut expr.concrete_type,
 
            Expression::Unary(expr) => &mut expr.concrete_type,
 
            Expression::Indexing(expr) => &mut expr.concrete_type,
 
            Expression::Slicing(expr) => &mut expr.concrete_type,
 
            Expression::Select(expr) => &mut expr.concrete_type,
 
            Expression::Array(expr) => &mut expr.concrete_type,
 
            Expression::Literal(expr) => &mut expr.concrete_type,
 
            Expression::Call(expr) => &mut expr.concrete_type,
 
            Expression::Variable(expr) => &mut expr.concrete_type,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum AssignmentOperator {
 
    Set,
 
    Multiplied,
 
    Divided,
 
    Remained,
 
    Added,
 
    Subtracted,
 
    ShiftedLeft,
 
    ShiftedRight,
 
    BitwiseAnded,
 
    BitwiseXored,
 
    BitwiseOred,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct AssignmentExpression {
 
    pub this: AssignmentExpressionId,
 
    // Phase 2: parser
 
    pub span: InputSpan, // of the operator
 
    pub left: ExpressionId,
 
    pub operation: AssignmentOperator,
 
    pub right: ExpressionId,
 
    // Phase 3: linker
 
    pub parent: ExpressionParent,
 
    // Phase 4: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BindingExpression {
 
    pub this: BindingExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub left: LiteralExpressionId,
 
    pub right: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ConditionalExpression {
 
    pub this: ConditionalExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of question mark operator
 
    pub test: ExpressionId,
 
    pub true_expression: ExpressionId,
 
    pub false_expression: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone, PartialEq, Eq)]
 
pub enum BinaryOperator {
 
    Concatenate,
 
    LogicalOr,
 
    LogicalAnd,
 
    BitwiseOr,
 
    BitwiseXor,
 
    BitwiseAnd,
 
    Equality,
 
    Inequality,
 
    LessThan,
 
    GreaterThan,
 
    LessThanEqual,
 
    GreaterThanEqual,
 
    ShiftLeft,
 
    ShiftRight,
 
    Add,
 
    Subtract,
 
    Multiply,
 
    Divide,
 
    Remainder,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BinaryExpression {
 
    pub this: BinaryExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the operator
 
    pub left: ExpressionId,
 
    pub operation: BinaryOperator,
 
    pub right: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone, PartialEq, Eq)]
 
pub enum UnaryOperation {
 
    Positive,
 
    Negative,
 
    BitwiseNot,
 
    LogicalNot,
 
    PreIncrement,
 
    PreDecrement,
 
    PostIncrement,
 
    PostDecrement,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnaryExpression {
 
    pub this: UnaryExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the operator
 
    pub operation: UnaryOperation,
 
    pub expression: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct IndexingExpression {
 
    pub this: IndexingExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub subject: ExpressionId,
 
    pub index: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SlicingExpression {
 
    pub this: SlicingExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // from '[' to ']';
 
    pub subject: ExpressionId,
 
    pub from_index: ExpressionId,
 
    pub to_index: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SelectExpression {
 
    pub this: SelectExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the '.'
 
    pub subject: ExpressionId,
 
    pub field: Field,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct CallExpression {
 
    pub this: CallExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub parser_type: ParserType, // of the function call
 
    pub method: Method,
 
    pub arguments: Vec<ExpressionId>,
 
    pub definition: DefinitionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Method {
 
    // Builtin
 
    Get,
 
    Put,
 
    Fires,
 
    Create,
 
    Length,
 
    Assert,
 
    UserFunction,
 
    UserComponent,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct MethodSymbolic {
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) definition: DefinitionId
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralExpression {
 
    pub this: LiteralExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub value: Literal,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Literal {
 
    Null, // message
 
    True,
 
    False,
 
    Character(char),
 
    String(StringRef<'static>),
 
    Integer(LiteralInteger),
 
    Struct(LiteralStruct),
 
    Enum(LiteralEnum),
 
    Union(LiteralUnion),
 
    Array(Vec<ExpressionId>),
 
}
 

	
 
impl Literal {
 
    pub(crate) fn as_struct(&self) -> &LiteralStruct {
 
        if let Literal::Struct(literal) = self{
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Struct", self)
 
        }
 
    }
 

	
 
    pub(crate) fn as_struct_mut(&mut self) -> &mut LiteralStruct {
 
        if let Literal::Struct(literal) = self{
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Struct", self)
 
        }
 
    }
 

	
 
    pub(crate) fn as_enum(&self) -> &LiteralEnum {
 
        if let Literal::Enum(literal) = self {
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Enum", self)
 
        }
 
    }
 

	
 
    pub(crate) fn as_union(&self) -> &LiteralUnion {
 
        if let Literal::Union(literal) = self {
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Union", self)
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralInteger {
 
    pub(crate) unsigned_value: u64,
 
    pub(crate) negated: bool, // for constant expression evaluation, TODO
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralStructField {
 
    // Phase 1: parser
 
    pub(crate) identifier: Identifier,
 
    pub(crate) value: ExpressionId,
 
    // Phase 2: linker
 
    pub(crate) field_idx: usize, // in struct definition
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralStruct {
 
    // Phase 1: parser
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) fields: Vec<LiteralStructField>,
 
    pub(crate) definition: DefinitionId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralEnum {
 
    // Phase 1: parser
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) variant: Identifier,
 
    pub(crate) definition: DefinitionId,
 
    // Phase 2: linker
 
    pub(crate) variant_idx: usize, // as present in the type table
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralUnion {
 
    // Phase 1: parser
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) variant: Identifier,
 
    pub(crate) values: Vec<ExpressionId>,
 
    pub(crate) definition: DefinitionId,
 
    // Phase 2: linker
 
    pub(crate) variant_idx: usize, // as present in type table
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct VariableExpression {
 
    pub this: VariableExpressionId,
 
    // Phase 1: parser
 
    pub identifier: Identifier,
 
    // Phase 2: linker
 
    pub declaration: Option<VariableId>,
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 
\ No newline at end of file
src/protocol/parser/mod.rs
Show inline comments
 
mod depth_visitor;
 
pub(crate) mod symbol_table;
 
pub(crate) mod symbol_table2;
 
pub(crate) mod type_table;
 
pub(crate) mod tokens;
 
pub(crate) mod token_parsing;
 
pub(crate) mod pass_tokenizer;
 
pub(crate) mod pass_symbols;
 
pub(crate) mod pass_imports;
 
pub(crate) mod pass_definitions;
 
mod type_resolver;
 
mod visitor;
 
mod visitor_linker;
 
mod pass_validation_linking;
 
mod utils;
 

	
 
use depth_visitor::*;
 
use tokens::*;
 
use crate::collections::*;
 
use symbol_table2::SymbolTable;
 
use visitor::Visitor2;
 
use visitor_linker::ValidityAndLinkerVisitor;
 
use pass_validation_linking::PassValidationLinking;
 
use type_resolver::{TypeResolvingVisitor, ResolveQueue};
 
use type_table::{TypeTable, TypeCtx};
 

	
 
use crate::protocol::ast::*;
 
use crate::protocol::input_source2::{InputSource2 as InputSource};
 
use crate::protocol::lexer::*;
 

	
 
use std::collections::HashMap;
 
use crate::protocol::ast_printer::ASTWriter;
 

	
 
#[derive(PartialEq, Eq)]
 
pub enum ModuleCompilationPhase {
 
    Source,                 // only source is set
 
    Tokenized,              // source is tokenized
 
    SymbolsScanned,         // all definitions are linked to their type class
 
    ImportsResolved,        // all imports are added to the symbol table
 
    DefinitionsParsed,      // produced the AST for the entire module
 
    TypesParsed,            // added all definitions to the type table
 
    ValidatedAndLinked,     // AST is traversed and has linked the required AST nodes
 
    Typed,                  // Type inference and checking has been performed
 
}
 

	
 
pub struct Module {
 
    // Buffers
 
    source: InputSource,
 
    tokens: TokenBuffer,
 
    // Identifiers
 
    root_id: RootId,
 
    name: Option<(PragmaId, StringRef<'static>)>,
 
    version: Option<(PragmaId, i64)>,
 
    phase: ModuleCompilationPhase,
 
}
 

	
 
pub struct PassCtx<'a> {
 
    heap: &'a mut Heap,
 
    symbols: &'a mut SymbolTable,
 
    pool: &'a mut StringPool,
 
}
 

	
 
// TODO: @fixme, pub qualifier
 
pub(crate) struct LexedModule {
 
    pub(crate) source: InputSource,
 
    module_name: Vec<u8>,
 
    version: Option<u64>,
 
    pub(crate) root_id: RootId,
 
}
 

	
 
pub struct Parser {
 
    pub(crate) heap: Heap,
 
    pub(crate) modules: Vec<LexedModule>,
 
    pub(crate) module_lookup: HashMap<Vec<u8>, usize>, // from (optional) module name to `modules` idx
 
    pub(crate) symbol_table: SymbolTable,
 
    pub(crate) type_table: TypeTable,
 
}
 

	
 
impl Parser {
 
    pub fn new() -> Self {
 
        Parser{
 
            heap: Heap::new(),
 
            modules: Vec::new(),
 
            module_lookup: HashMap::new(),
 
            symbol_table: SymbolTable::new(),
 
            type_table: TypeTable::new(),
 
        }
 
    }
 

	
 
    pub fn feed(&mut self, mut source: InputSource) -> Result<RootId, ParseError> {
 
        // Lex the input source
 
        let mut lex = Lexer::new(&mut source);
 
        let pd = lex.consume_protocol_description(&mut self.heap)?;
 

	
 
        // Seek the module name and version
 
        let root = &self.heap[pd];
 
        let mut module_name_pos = InputPosition::default();
 
        let mut module_name = Vec::new();
 
        let mut module_version_pos = InputPosition::default();
 
        let mut module_version = None;
 

	
 
        for pragma in &root.pragmas {
 
            match &self.heap[*pragma] {
 
                Pragma::Module(module) => {
 
                    if !module_name.is_empty() {
 
                        return Err(
 
                            ParseError::new_error(&source, module.position, "Double definition of module name in the same file")
 
                                .with_postfixed_info(&source, module_name_pos, "Previous definition was here")
 
                        )
 
                    }
 

	
 
                    module_name_pos = module.position.clone();
 
                    module_name = module.value.clone();
 
                },
 
                Pragma::Version(version) => {
 
                    if module_version.is_some() {
 
                        return Err(
 
                            ParseError::new_error(&source, version.position, "Double definition of module version")
 
                                .with_postfixed_info(&source, module_version_pos, "Previous definition was here")
 
                        )
 
                    }
 

	
 
                    module_version_pos = version.position.clone();
 
                    module_version = Some(version.version);
 
                },
 
            }
 
        }
 

	
 
        // Add module to list of modules and prevent naming conflicts
 
        let cur_module_idx = self.modules.len();
 
        if let Some(prev_module_idx) = self.module_lookup.get(&module_name) {
 
            // Find `#module` statement in other module again
 
            let prev_module = &self.modules[*prev_module_idx];
 
            let prev_module_pos = self.heap[prev_module.root_id].pragmas
 
                .iter()
 
                .find_map(|p| {
 
                    match &self.heap[*p] {
 
                        Pragma::Module(module) => Some(module.position.clone()),
 
                        _ => None
 
                    }
 
                })
 
                .unwrap_or(InputPosition::default());
 

	
 
            let module_name_msg = if module_name.is_empty() {
 
                format!("a nameless module")
 
            } else {
 
                format!("module '{}'", String::from_utf8_lossy(&module_name))
 
            };
 

	
 
            return Err(
 
                ParseError::new_error(&source, module_name_pos, &format!("Double definition of {} across files", module_name_msg))
 
                    .with_postfixed_info(&prev_module.source, prev_module_pos, "Other definition was here")
 
            );
 
        }
 

	
 
        self.modules.push(LexedModule{
 
            source,
 
            module_name: module_name.clone(),
 
            version: module_version,
 
            root_id: pd
 
        });
 
        self.module_lookup.insert(module_name, cur_module_idx);
 
        Ok(pd)
 
    }
 

	
 
    fn resolve_symbols_and_types(&mut self) -> Result<(), ParseError> {
 
        // Construct the symbol table to resolve any imports and/or definitions,
 
        // then use the symbol table to actually annotate all of the imports.
 
        // If the type table is constructed correctly then all imports MUST be
 
        // resolvable.
 
        self.symbol_table.build(&self.heap, &self.modules)?;
 

	
 
        // Not pretty, but we need to work around rust's borrowing rules, it is
 
        // totally safe to mutate the contents of an AST element that we are
 
        // not borrowing anywhere else.
 
        let mut module_index = 0;
 
        let mut import_index = 0;
 
        loop {
 
            if module_index >= self.modules.len() {
 
                break;
 
            }
 

	
 
            let module_root_id = self.modules[module_index].root_id;
 
            let import_id = {
 
                let root = &self.heap[module_root_id];
 
                if import_index >= root.imports.len() {
 
                    module_index += 1;
 
                    import_index = 0;
 
                    continue
 
                }
 
                root.imports[import_index]
 
            };
 

	
 
            let import = &mut self.heap[import_id];
 
            match import {
 
                Import::Module(import) => {
 
                    debug_assert!(import.module_id.is_none(), "module import already resolved");
 
                    let target_module_id = self.symbol_table.resolve_module(&import.module)
 
                        .expect("module import is resolved by symbol table");
 
                    import.module_id = Some(target_module_id)
 
                },
 
                Import::Symbols(import) => {
 
                    debug_assert!(import.module_id.is_none(), "module of symbol import already resolved");
 
                    let target_module_id = self.symbol_table.resolve_module(&import.module)
 
                        .expect("symbol import's module is resolved by symbol table");
 
                    import.module_id = Some(target_module_id);
 

	
 
                    for symbol in &mut import.symbols {
 
                        debug_assert!(symbol.definition_id.is_none(), "symbol import already resolved");
 
                        let (_, target_definition_id) = self.symbol_table.resolve_identifier(module_root_id, &symbol.alias)
 
                            .expect("symbol import is resolved by symbol table")
 
                            .as_definition()
 
                            .expect("symbol import does not resolve to namespace symbol");
 
                        symbol.definition_id = Some(target_definition_id);
 
                    }
 
                }
 
            }
 

	
 
            import_index += 1;
 
        }
 

	
 
        // All imports in the AST are now annotated. We now use the symbol table
 
        // to construct the type table.
 
        let mut type_ctx = TypeCtx::new(&self.symbol_table, &mut self.heap, &self.modules);
 
        self.type_table.build_base_types(&mut type_ctx)?;
 

	
 
        Ok(())
 
    }
 

	
 
    pub fn parse(&mut self) -> Result<(), ParseError> {
 
        self.resolve_symbols_and_types()?;
 

	
 
        // Validate and link all modules
 
        let mut visit = ValidityAndLinkerVisitor::new();
 
        let mut visit = PassValidationLinking::new();
 
        for module in &self.modules {
 
            let mut ctx = visitor::Ctx{
 
                heap: &mut self.heap,
 
                module,
 
                symbols: &mut self.symbol_table,
 
                types: &mut self.type_table,
 
            };
 
            visit.visit_module(&mut ctx)?;
 
        }
 

	
 
        // Perform typechecking on all modules
 
        let mut visit = TypeResolvingVisitor::new();
 
        let mut queue = ResolveQueue::new();
 
        for module in &self.modules {
 
            let ctx = visitor::Ctx{
 
                heap: &mut self.heap,
 
                module,
 
                symbols: &mut self.symbol_table,
 
                types: &mut self.type_table,
 
            };
 
            TypeResolvingVisitor::queue_module_definitions(&ctx, &mut queue);   
 
        };
 
        while !queue.is_empty() {
 
            let top = queue.pop().unwrap();
 
            let mut ctx = visitor::Ctx{
 
                heap: &mut self.heap,
 
                module: &self.modules[top.root_id.index as usize],
 
                symbols: &mut self.symbol_table,
 
                types: &mut self.type_table,
 
            };
 
            visit.handle_module_definition(&mut ctx, &mut queue, top)?;
 
        }
 

	
 
        // Perform remaining steps
 
        // TODO: Phase out at some point
 
        for module in &self.modules {
 
            let root_id = module.root_id;
 
            if let Err((position, message)) = Self::parse_inner(&mut self.heap, root_id) {
 
                return Err(ParseError::new_error(&self.modules[0].source, position, &message))
 
            }
 
        }
 

	
 
        // let mut writer = ASTWriter::new();
 
        // let mut file = std::fs::File::create(std::path::Path::new("ast.txt")).unwrap();
 
        // writer.write_ast(&mut file, &self.heap);
 

	
 
        Ok(())
 
    }
 

	
 
    pub fn parse_inner(h: &mut Heap, pd: RootId) -> VisitorResult {
 
        // TODO: @cleanup, slowly phasing out old compiler
 
        // NestedSynchronousStatements::new().visit_protocol_description(h, pd)?;
 
        // ChannelStatementOccurrences::new().visit_protocol_description(h, pd)?;
 
        // FunctionStatementReturns::new().visit_protocol_description(h, pd)?;
 
        // ComponentStatementReturnNew::new().visit_protocol_description(h, pd)?;
 
        // CheckBuiltinOccurrences::new().visit_protocol_description(h, pd)?;
 
        // BuildSymbolDeclarations::new().visit_protocol_description(h, pd)?;
 
        // LinkCallExpressions::new().visit_protocol_description(h, pd)?;
 
        // BuildScope::new().visit_protocol_description(h, pd)?;
 
        // ResolveVariables::new().visit_protocol_description(h, pd)?;
 
        LinkStatements::new().visit_protocol_description(h, pd)?;
 
        // BuildLabels::new().visit_protocol_description(h, pd)?;
 
        // ResolveLabels::new().visit_protocol_description(h, pd)?;
 
        AssignableExpressions::new().visit_protocol_description(h, pd)?;
 
        IndexableExpressions::new().visit_protocol_description(h, pd)?;
 
        SelectableExpressions::new().visit_protocol_description(h, pd)?;
 

	
 
        Ok(())
 
    }
 
}
 
\ No newline at end of file
src/protocol/parser/pass_definitions.rs
Show inline comments
 
use crate::protocol::ast::*;
 
use super::symbol_table2::*;
 
use super::{Module, ModuleCompilationPhase, PassCtx};
 
use super::tokens::*;
 
use super::token_parsing::*;
 
use crate::protocol::input_source2::{InputSource2 as InputSource, InputPosition2 as InputPosition, InputSpan, ParseError};
 
use crate::collections::*;
 

	
 
/// Parses all the tokenized definitions into actual AST nodes.
 
pub(crate) struct PassDefinitions {
 
    // State
 
    cur_definition: DefinitionId,
 
    // Temporary buffers of various kinds
 
    buffer: String,
 
    identifiers: Vec<Identifier>,
 
    struct_fields: Vec<StructFieldDefinition>,
 
    enum_variants: Vec<EnumVariantDefinition>,
 
    union_variants: Vec<UnionVariantDefinition>,
 
    parameters: ScopedBuffer<ParameterId>,
 
    expressions: ScopedBuffer<ExpressionId>,
 
    statements: ScopedBuffer<StatementId>,
 
    parser_types: Vec<ParserType>,
 
}
 

	
 
impl PassDefinitions {
 
    pub(crate) fn parse(&mut self, modules: &mut [Module], module_idx: usize, ctx: &mut PassCtx) -> Result<(), ParseError> {
 
        let module = &modules[module_idx];
 
        let module_range = &module.tokens.ranges[0];
 
        debug_assert_eq!(module.phase, ModuleCompilationPhase::ImportsResolved);
 
        debug_assert_eq!(module_range.range_kind, TokenRangeKind::Module);
 

	
 
        // Although we only need to parse the definitions, we want to go through
 
        // code ranges as well such that we can throw errors if we get
 
        // unexpected tokens at the module level of the source.
 
        let mut range_idx = module_range.first_child_idx;
 
        loop {
 
            let range_idx_usize = range_idx as usize;
 
            let cur_range = &module.tokens.ranges[range_idx_usize];
 

	
 
            match cur_range.range_kind {
 
                TokenRangeKind::Module => unreachable!(), // should not be reachable
 
                TokenRangeKind::Pragma | TokenRangeKind::Import => continue, // already fully parsed
 
                TokenRangeKind::Definition | TokenRangeKind::Code => {}
 
            }
 

	
 
            self.visit_range(modules, module_idx, ctx, range_idx_usize)?;
 

	
 
            match cur_range.next_sibling_idx {
 
                Some(idx) => { range_idx = idx; },
 
                None => { break; },
 
            }
 
        }
 

	
 

	
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_range(
 
        &mut self, modules: &[Module], module_idx: usize, ctx: &mut PassCtx, range_idx: usize
 
    ) -> Result<(), ParseError> {
 
        let module = &modules[module_idx];
 
        let cur_range = &module.tokens.ranges[range_idx];
 
        debug_assert!(cur_range.range_kind == TokenRangeKind::Definition || cur_range.range_kind == TokenRangeKind::Code);
 

	
 
        // Detect which definition we're parsing
 
        let mut iter = module.tokens.iter_range(cur_range);
 
        loop {
 
            let next = iter.next();
 
            if next.is_none() {
 
                return Ok(())
 
            }
 

	
 
            // Token was not None, so peek_ident returns None if not an ident
 
            let ident = peek_ident(&module.source, &mut iter);
 
            match ident {
 
                Some(KW_STRUCT) => self.visit_struct_definition(module, &mut iter, ctx)?,
 
                Some(KW_ENUM) => self.visit_enum_definition(module, &mut iter, ctx)?,
 
                Some(KW_FUNCTION) => self.visit_function_definition(module, &mut iter, ctx)?,
 
                Some(KW_PRIMITIVE) | Some(KW_COMPOSITE) => self.visit_component_definition(module, &mut iter, ctx)?,
 
                _ => return Err(ParseError::new_error_str_at_pos(
 
                    &module.source, iter.last_valid_pos(),
 
                    "unexpected symbol, expected some kind of type or procedure definition"
 
                )),
 
            }
 
        }
 
    }
 

	
 
    fn visit_struct_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        consume_exact_ident(&module.source, iter, KW_STRUCT)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        // Parse struct definition
 
        consume_polymorphic_vars_spilled(source, iter)?;
 
        debug_assert!(self.struct_fields.is_empty());
 
        consume_comma_separated(
 
            TokenKind::OpenCurly, TokenKind::CloseCurly, source, iter,
 
            |source, iter| {
 
                let start_pos = iter.last_valid_pos();
 
                let parser_type = consume_parser_type(
 
                    source, iter, &ctx.symbols, &ctx.heap, poly_vars, module_scope,
 
                    definition_id, false, 0
 
                )?;
 
                let field = consume_ident_interned(source, iter, ctx)?;
 
                Ok(StructFieldDefinition{
 
                    span: InputSpan::from_positions(start_pos, field.span.end),
 
                    field, parser_type
 
                })
 
            },
 
            &mut self.struct_fields, "a struct field", "a list of struct fields", None
 
        )?;
 

	
 
        // Transfer to preallocated definition
 
        let struct_def = ctx.heap[definition_id].as_struct_mut();
 
        struct_def.fields.clone_from(&self.struct_fields);
 
        self.struct_fields.clear();
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_enum_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        consume_exact_ident(&module.source, iter, KW_ENUM)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        // Parse enum definition
 
        consume_polymorphic_vars_spilled(source, iter)?;
 
        debug_assert!(self.enum_variants.is_empty());
 
        consume_comma_separated(
 
            TokenKind::OpenCurly, TokenKind::CloseCurly, source, iter,
 
            |source, iter| {
 
                let identifier = consume_ident_interned(source, iter, ctx)?;
 
                let value = if iter.next() == Some(TokenKind::Equal) {
 
                    iter.consume();
 
                    let (variant_number, _) = consume_integer_literal(source, iter, &mut self.buffer)?;
 
                    EnumVariantValue::Integer(variant_number as i64) // TODO: @int
 
                } else {
 
                    EnumVariantValue::None
 
                };
 
                Ok(EnumVariantDefinition{ identifier, value })
 
            },
 
            &mut self.enum_variants, "an enum variant", "a list of enum variants", None
 
        )?;
 

	
 
        // Transfer to definition
 
        let enum_def = ctx.heap[definition_id].as_enum_mut();
 
        enum_def.variants.clone_from(&self.enum_variants);
 
        self.enum_variants.clear();
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_union_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        consume_exact_ident(&module.source, iter, KW_UNION)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        // Parse union definition
 
        consume_polymorphic_vars_spilled(source, iter)?;
 
        debug_assert!(self.union_variants.is_empty());
 
        consume_comma_separated(
 
            TokenKind::OpenCurly, TokenKind::CloseCurly, source, iter,
 
            |source, iter| {
 
                let identifier = consume_ident_interned(source, iter, ctx)?;
 
                let mut close_pos = identifier.span.end;
 
                let has_embedded = maybe_consume_comma_separated(
 
                    TokenKind::OpenParen, TokenKind::CloseParen, source, iter,
 
                    |source, iter| {
 
                        consume_parser_type(
 
                            source, iter, &ctx.symbols, &ctx.heap, poly_vars,
 
                            module_scope, definition_id, false, 0
 
                        )
 
                    },
 
                    &mut self.parser_types, "an embedded type", Some(&mut close_pos)
 
                )?;
 
                let value = if has_embedded {
 
                    UnionVariantValue::Embedded(self.parser_types.clone())
 
                } else {
 
                    UnionVariantValue::None
 
                };
 
                self.parser_types.clear();
 

	
 
                Ok(UnionVariantDefinition{
 
                    span: InputSpan::from_positions(identifier.span.begin, close_pos),
 
                    identifier,
 
                    value
 
                })
 
            },
 
            &mut self.union_variants, "a union variant", "a list of union variants", None
 
        )?;
 

	
 
        // Transfer to AST
 
        let union_def = ctx.heap[definition_id].as_union_mut();
 
        union_def.variants.clone_from(&self.union_variants);
 
        self.union_variants.clear();
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_function_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        consume_exact_ident(&module.source, iter, KW_FUNCTION)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        // Parse function's argument list
 
        let mut parameter_section = self.parameters.start_section();
 
        consume_parameter_list(
 
            source, iter, ctx, &mut parameter_section, poly_vars, module_scope, definition_id
 
        )?;
 
        let parameters = parameter_section.into_vec();
 

	
 
        // Consume return types
 
        consume_token(&module.source, iter, TokenKind::ArrowRight)?;
 
        let mut open_curly_pos = iter.last_valid_pos();
 
        consume_comma_separated_until(
 
            TokenKind::OpenCurly, &module.source, iter,
 
            |source, iter| {
 
                consume_parser_type(source, iter, &ctx.symbols, &ctx.heap, poly_vars, module_scope, definition_id, false, 0)
 
            },
 
            &mut self.parser_types, "a return type", Some(&mut open_curly_pos)
 
        )?;
 
        let return_types = self.parser_types.clone();
 

	
 
        // TODO: @ReturnValues
 
        match return_types.len() {
 
            0 => return Err(ParseError::new_error_str_at_pos(&module.source, open_curly_pos, "expected a return type")),
 
            1 => {},
 
            _ => return Err(ParseError::new_error_str_at_pos(&module.source, open_curly_pos, "multiple return types are not (yet) allowed")),
 
        }
 

	
 
        // Consume block
 
        let body = self.consume_block_statement_without_leading_curly(module, iter, ctx, open_curly_pos)?;
 

	
 
        // Assign everything in the preallocated AST node
 
        let function = ctx.heap[definition_id].as_function_mut();
 
        function.return_types = return_types;
 
        function.parameters = parameters;
 
        function.body = body;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_component_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        let (_variant_text, _) = consume_any_ident(&module.source, iter)?;
 
        debug_assert!(variant_text == KW_PRIMITIVE || variant_text == KW_COMPOSITE);
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated definition
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        // Parse component's argument list
 
        let mut parameter_section = self.parameters.start_section();
 
        consume_parameter_list(
 
            source, iter, ctx, &mut parameter_section, poly_vars, module_scope, definition_id
 
        )?;
 
        let parameters = parameter_section.into_vec();
 

	
 
        // Consume block
 
        let body = self.consume_block_statement(module, iter, ctx)?;
 

	
 
        // Assign everything in the AST node
 
        let component = ctx.heap[definition_id].as_component_mut();
 
        component.parameters = parameters;
 
        component.body = body;
 

	
 
        Ok(())
 
    }
 

	
 
    /// Consumes a block statement. If the resulting statement is not a block
 
    /// (e.g. for a shorthand "if (expr) single_statement") then it will be
 
    /// wrapped in one
 
    fn consume_block_or_wrapped_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<BlockStatementId, ParseError> {
 
        if Some(TokenKind::OpenCurly) == iter.next() {
 
            // This is a block statement
 
            self.consume_block_statement(module, iter, ctx)
 
        } else {
 
            // Not a block statement, so wrap it in one
 
            let mut statements = self.statements.start_section();
 
            let wrap_begin_pos = iter.last_valid_pos();
 
            self.consume_statement(module, iter, ctx, &mut statements)?;
 
            let wrap_end_pos = iter.last_valid_pos();
 

	
 
            debug_assert_eq!(statements.len(), 1);
 
            let statements = statements.into_vec();
 

	
 
            ctx.heap.alloc_block_statement(|this| BlockStatement{
 
                this,
 
                is_implicit: true,
 
                span: InputSpan::from_positions(wrap_begin_pos, wrap_end_pos), // TODO: @Span
 
                statements,
 
                parent_scope: None,
 
                relative_pos_in_parent: 0,
 
                locals: Vec::new(),
 
                labels: Vec::new()
 
            })
 
        }
 
    }
 

	
 
    /// Consumes a statement and returns a boolean indicating whether it was a
 
    /// block or not.
 
    fn consume_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, section: &mut ScopedSection<StatementId>
 
    ) -> Result<(), ParseError> {
 
        let next = iter.next().expect("consume_statement has a next token");
 

	
 
        if next == TokenKind::OpenCurly {
 
            let id = self.consume_block_statement(module, iter, ctx)?;
 
            section.push(id.upcast());
 
        } else if next == TokenKind::Ident {
 
            let (ident, _) = consume_any_ident(source, iter)?;
 
            if ident == KW_STMT_IF {
 
                // Consume if statement and place end-if statement directly
 
                // after it.
 
                let id = self.consume_if_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 

	
 
                let end_if = ctx.heap.alloc_end_if_statement(|this| EndIfStatement{
 
                    this, start_if: id, next: None
 
                });
 
                section.push(id.upcast());
 

	
 
                let if_stmt = &mut ctx.heap[id];
 
                if_stmt.end_if = Some(end_if);
 
            } else if ident == KW_STMT_WHILE {
 
                let id = self.consume_while_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 

	
 
                let end_while = ctx.heap.alloc_end_while_statement(|this| EndWhileStatement{
 
                    this, start_while: id, next: None
 
                });
 
                section.push(id.upcast());
 

	
 
                let while_stmt = &mut ctx.heap[id];
 
                while_stmt.end_while = Some(end_while);
 
            } else if ident == KW_STMT_BREAK {
 
                let id = self.consume_break_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_CONTINUE {
 
                let id = self.consume_continue_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_SYNC {
 
                let id = self.consume_synchronous_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 

	
 
                let end_sync = ctx.heap.alloc_end_synchronous_statement(|this| EndSynchronousStatement{
 
                    this, start_sync: id, next: None
 
                });
 

	
 
                let sync_stmt = &mut ctx.heap[id];
 
                sync_stmt.end_sync = Some(end_sync);
 
            } else if ident == KW_STMT_RETURN {
 
                let id = self.consume_return_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_GOTO {
 
                let id = self.consume_goto_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_NEW {
 
                let id = self.consume_new_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_CHANNEL {
 
                let id = self.consume_channel_statement(module, iter, ctx)?;
 
                section.push(id.upcast().upcast());
 
            } else if iter.peek() == Some(TokenKind::Colon) {
 
                self.consume_labeled_statement(module, iter, ctx, section)?;
 
            } else {
 
                // Two fallback possibilities: the first one is a memory
 
                // declaration, the other one is to parse it as a regular
 
                // expression. This is a bit ugly
 
                if let Some((memory_stmt_id, assignment_stmt_id)) = self.maybe_consume_memory_statement(module, iter, ctx)? {
 
                    section.push(memory_stmt_id.upcast().upcast());
 
                    section.push(assignment_stmt_id.upcast());
 
                } else {
 
                    let id = self.consume_expression_statement(module, iter, ctx)?;
 
                    section.push(id.upcast());
 
                }
 
            }
 
        };
 

	
 
        return Ok(());
 
    }
 

	
 
    fn consume_block_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<BlockStatementId, ParseError> {
 
        let open_span = consume_token(source, iter, TokenKind::OpenCurly)?;
 
        self.consume_block_statement_without_leading_curly(module, iter, ctx, open_span.begin)
 
    }
 

	
 
    fn consume_block_statement_without_leading_curly(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, open_curly_pos: InputPosition
 
    ) -> Result<BlockStatementId, ParseError> {
 
        let mut statements = Vec::new();
 
        let mut next = iter.next();
 
        while next.is_some() && next != Some(TokenKind::CloseCurly) {
 

	
 
        }
 

	
 
        let mut block_span = consume_token(&module.source, iter, TokenKind::CloseCurly)?;
 
        block_span.begin = open_curly_pos;
 

	
 
        Ok(ctx.heap.alloc_block_statement(|this| BlockStatement{
 
            this,
 
            is_implicit: false,
 
            span: block_span,
 
            statements,
 
            parent_scope: None,
 
            relative_pos_in_parent: 0,
 
            locals: Vec::new(),
 
            labels: Vec::new(),
 
        }))
 
    }
 

	
 
    fn consume_if_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<IfStatementId, ParseError> {
 
        let if_span = consume_exact_ident(&module.source, iter, KW_STMT_IF)?;
 
        consume_token(&module.source, iter, TokenKind::OpenParen)?;
 
        let test = self.consume_expression(module, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::CloseParen)?;
 
        let true_body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 

	
 
        let false_body = if has_ident(source, iter, KW_STMT_ELSE) {
 
            iter.consume();
 
            let false_body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 
            Some(false_body)
 
        } else {
 
            None
 
        };
 

	
 
        Ok(ctx.heap.alloc_if_statement(|this| IfStatement{
 
            this,
 
            span: if_span,
 
            test,
 
            true_body,
 
            false_body,
 
            end_if: None,
 
        }))
 
    }
 

	
 
    fn consume_while_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<WhileStatementId, ParseError> {
 
        let while_span = consume_exact_ident(&module.source, iter, KW_STMT_WHILE)?;
 
        consume_token(&module.source, iter, TokenKind::OpenParen)?;
 
        let test = self.consume_expression(module, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::CloseParen)?;
 
        let body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 

	
 
        Ok(ctx.heap.alloc_while_statement(|this| WhileStatement{
 
            this,
 
            span: while_span,
 
            test,
 
            body,
 
            end_while: None,
 
            in_sync: None,
 
        }))
 
    }
 

	
 
    fn consume_break_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<BreakStatementId, ParseError> {
 
        let break_span = consume_exact_ident(&module.source, iter, KW_STMT_BREAK)?;
 
        let label = if Some(TokenKind::Ident) == iter.next() {
 
            let label = consume_ident_interned(&module.source, iter, ctx)?;
 
            Some(label)
 
        } else {
 
            None
 
        };
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 
        Ok(ctx.heap.alloc_break_statement(|this| BreakStatement{
 
            this,
 
            span: break_span,
 
            label,
 
            target: None,
 
        }))
 
    }
 

	
 
    fn consume_continue_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ContinueStatementId, ParseError> {
 
        let continue_span = consume_exact_ident(&module.source, iter, KW_STMT_CONTINUE)?;
 
        let label=  if Some(TokenKind::Ident) == iter.next() {
 
            let label = consume_ident_interned(&module.source, iter, ctx)?;
 
            Some(label)
 
        } else {
 
            None
 
        };
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 
        Ok(ctx.heap.alloc_continue_statement(|this| ContinueStatement{
 
            this,
 
            span: continue_span,
 
            label,
 
            target: None
 
        }))
 
    }
 

	
 
    fn consume_synchronous_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<SynchronousStatementId, ParseError> {
 
        let synchronous_span = consume_exact_ident(&module.source, iter, KW_STMT_SYNC)?;
 
        let body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 

	
 
        Ok(ctx.heap.alloc_synchronous_statement(|this| SynchronousStatement{
 
            this,
 
            span: synchronous_span,
 
            body,
 
            end_sync: None,
 
            parent_scope: None,
 
        }))
 
    }
 

	
 
    fn consume_return_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ReturnStatementId, ParseError> {
 
        let return_span = consume_exact_ident(&module.source, iter, KW_STMT_RETURN)?;
 
        let mut scoped_section = self.expressions.start_section();
 

	
 
        consume_comma_separated_until(
 
            TokenKind::SemiColon, &module.source, iter,
 
            |source, iter| self.consume_expression(module, iter, ctx),
 
            &mut scoped_section, "a return expression", None
 
        )?;
 
        let expressions = scoped_section.into_vec();
 

	
 
        if expressions.is_empty() {
 
            return Err(ParseError::new_error_str_at_span(&module.source, return_span, "expected at least one return value"));
 
        }
 

	
 
        Ok(ctx.heap.alloc_return_statement(|this| ReturnStatement{
 
            this,
 
            span: return_span,
 
            expressions
 
        }))
 
    }
 

	
 
    fn consume_goto_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<GotoStatementId, ParseError> {
 
        let goto_span = consume_exact_ident(&module.source, iter, KW_STMT_GOTO)?;
 
        let label = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 
        Ok(ctx.heap.alloc_goto_statement(|this| GotoStatement{
 
            this,
 
            span: goto_span,
 
            label,
 
            target: None
 
        }))
 
    }
 

	
 
    fn consume_new_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<NewStatementId, ParseError> {
 
        let new_span = consume_exact_ident(&module.source, iter, KW_STMT_NEW)?;
 

	
 
        // TODO: @Cleanup, should just call something like consume_component_expression-ish
 
        let start_pos = iter.last_valid_pos();
 
        let expression_id = self.consume_primary_expression(module, iter, ctx)?;
 
        let expression = &ctx.heap[expression_id];
 
        let mut valid = false;
 

	
 
        let mut call_id = CallExpressionId.new_invalid();
 
        if let Expression::Call(expression) = expression {
 
            if expression.method == Method::UserComponent {
 
            // Allow both components and functions, as it makes more sense to
 
            // check their correct use in the validation and linking pass
 
            if expression.method == Method::UserComponent || expression.method == Method::UserFunction {
 
                call_id = expression.this;
 
                valid = true;
 
            }
 
        }
 

	
 
        if !valid {
 
            return Err(ParseError::new_error_str_at_span(
 
                source, InputSpan::from_positions(start_pos, iter.last_valid_pos()),
 
                "expected a call to a component"
 
                "expected a call expression"
 
            ));
 
        }
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
        debug_assert!(!call_id.is_invalid());
 
        Ok(ctx.heap.alloc_new_statement(|this| NewStatement{
 
            this,
 
            span: new_span,
 
            expression: call_id,
 
            next: None
 
        }))
 
    }
 

	
 
    fn consume_channel_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ChannelStatementId, ParseError> {
 
        // Consume channel specification
 
        let channel_span = consume_exact_ident(&module.source, iter, KW_STMT_CHANNEL)?;
 
        let channel_type = if Some(TokenKind::OpenAngle) = iter.next() {
 
            // Retrieve the type of the channel, we're cheating a bit here by
 
            // consuming the first '<' and setting the initial angle depth to 1
 
            // such that our final '>' will be consumed as well.
 
            iter.consume();
 
            consume_parser_type(
 
                &module.source, iter, &ctx.symbols, &ctx.heap,
 
                poly_vars, SymbolScope::Module(module.root_id), definition_id,
 
                true, 1
 
            )?
 
        } else {
 
            // Assume inferred
 
            ParserType{ elements: vec![ParserTypeElement{
 
                full_span: channel_span, // TODO: @Span fix
 
                variant: ParserTypeVariant::Inferred
 
            }]}
 
        };
 

	
 
        let from_identifier = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::ArrowRight)?;
 
        let to_identifier = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
        // Construct ports
 
        let from = ctx.heap.alloc_local(|this| Local{
 
            this,
 
            identifier: from_identifier,
 
            parser_type: channel_type.clone(),
 
            relative_pos_in_block: 0,
 
        });
 
        let to = ctx.heap.alloc_local(|this| Local{
 
            this,
 
            identifier: to_identifier,
 
            parser_type: channel_type,
 
            relative_pos_in_block: 0,
 
        });
 

	
 
        // Construct the channel
 
        Ok(ctx.heap.alloc_channel_statement(|this| ChannelStatement{
 
            this,
 
            span: channel_span,
 
            from, to,
 
            relative_pos_in_block: 0,
 
            next: None,
 
        }))
 
    }
 

	
 
    fn consume_labeled_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, section: &mut ScopedSection<StatementId>
 
    ) -> Result<(), ParseError> {
 
        let label = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::Colon)?;
 

	
 
        // Not pretty: consume_statement may produce more than one statement.
 
        // The values in the section need to be in the correct order if some
 
        // kind of outer block is consumed, so we take another section, push
 
        // the expressions in that one, and then allocate the labeled statement.
 
        let mut inner_section = self.statements.start_section();
 
        self.consume_statement(module, iter, ctx, &mut inner_section)?;
 
        debug_assert!(inner_section.len() >= 1);
 

	
 
        let stmt_id = ctx.heap.alloc_labeled_statement(|this| LabeledStatement {
 
            this,
 
            label,
 
            body: *inner_section[0],
 
            relative_pos_in_block: 0,
 
            in_sync: None,
 
        });
 

	
 
        if inner_section.len() == 1 {
 
            // Produce the labeled statement pointing to the first statement.
 
            // This is by far the most common case.
 
            inner_section.forget();
 
            section.push(stmt_id.upcast());
 
        } else {
 
            // Produce the labeled statement using the first statement, and push
 
            // the remaining ones at the end.
 
            let inner_statements = inner_section.into_vec();
 
            section.push(stmt_id.upcast());
 
            for idx in 1..inner_statements.len() {
 
                section.push(inner_statements[idx])
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn maybe_consume_memory_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<Option<(MemoryStatementId, ExpressionStatementId)>, ParseError> {
 
        // This is a bit ugly. It would be nicer if we could somehow
 
        // consume the expression with a type hint if we do get a valid
 
        // type, but we don't get an identifier following it
 
        let iter_state = iter.save();
 
        let definition_id = self.cur_definition;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        let parser_type = consume_parser_type(
 
            &module.source, iter, &ctx.symbols, &ctx.heap, poly_vars,
 
            SymbolScope::Definition(definition_id), definition_id, true, 0
 
        );
 

	
 
        if let Ok(parser_type) = parser_type {
 
            if Some(TokenKind::Ident) == iter.next() {
 
                // Assume this is a proper memory statement
 
                let identifier = consume_ident_interned(&module.source, iter, ctx)?;
 
                let memory_span = InputSpan::from_positions(parser_type.elements[0].full_span.begin, identifier.span.end);
 
                let assign_span = consume_token(&module.source, iter, TokenKind::Equal)?;
 

	
 
                let initial_expr_begin_pos = iter.last_valid_pos();
 
                let initial_expr_id = self.consume_expression(module, iter, ctx)?;
 
                let initial_expr_end_pos = iter.last_valid_pos();
 
                consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
                // Allocate the memory statement with the variable
 
                let local_id = ctx.heap.alloc_local(|this| Local{
 
                    this,
 
                    identifier: identifier.clone(),
 
                    parser_type,
 
                    relative_pos_in_block: 0,
 
                });
 
                let memory_stmt_id = ctx.heap.alloc_memory_statement(|this| MemoryStatement{
 
                    this,
 
                    span: memory_span,
 
                    variable: local_id,
 
                    next: None
 
                });
 

	
 
                // Allocate the initial assignment
 
                let variable_expr_id = ctx.heap.alloc_variable_expression(|this| VariableExpression{
 
                    this,
 
                    identifier,
 
                    declaration: None,
 
                    parent: ExpressionParent::None,
 
                    concrete_type: Default::default()
 
                });
 
                let assignment_expr_id = ctx.heap.alloc_assignment_expression(|this| AssignmentExpression{
 
                    this,
 
                    span: assign_span,
 
                    left: variable_expr_id.upcast(),
 
                    operation: AssignmentOperator::Set,
 
                    right: initial_expr_id,
 
                    parent: ExpressionParent::None,
 
                    concrete_type: Default::default(),
 
                });
 
                let assignment_stmt_id = ctx.heap.alloc_expression_statement(|this| ExpressionStatement{
 
                    this,
 
                    span: InputSpan::from_positions(initial_expr_begin_pos, initial_expr_end_pos),
 
                    expression: assignment_expr_id.upcast(),
 
                    next: None,
 
                });
 

	
 
                return Ok(Some((memory_stmt_id, assignment_stmt_id)))
 
            }
 
        }
 

	
 
        // If here then one of the preconditions for a memory statement was not
 
        // met. So recover the iterator and return
 
        iter.load(iter_state);
 
        Ok(None)
 
    }
 

	
 
    fn consume_expression_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionStatementId, ParseError> {
 
        let start_pos = iter.last_valid_pos();
 
        let expression = self.consume_expression(module, iter, ctx)?;
 
        let end_pos = iter.last_valid_pos();
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
        Ok(ctx.heap.alloc_expression_statement(|this| ExpressionStatement{
 
            this,
 
            span: InputSpan::from_positions(start_pos, end_pos),
 
            expression,
 
            next: None,
 
        }))
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Expression Parsing
 
    //--------------------------------------------------------------------------
 

	
 
    fn consume_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_assignment_expression(module, iter, ctx)
 
    }
 

	
 
    fn consume_assignment_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        // Utility to convert token into assignment operator
 
        fn parse_assignment_operator(token: Option<TokenKind>) -> Option<AssignmentOperator> {
 
            use TokenKind as TK;
 
            use AssignmentOperator as AO;
 

	
 
            if token.is_none() {
 
                return None
 
            }
 

	
 
            match token.unwrap() {
 
                TK::Equal               => Some(AO::Set),
 
                TK::StarEquals          => Some(AO::Multiplied),
 
                TK::SlashEquals         => Some(AO::Divided),
 
                TK::PercentEquals       => Some(AO::Remained),
 
                TK::PlusEquals          => Some(AO::Added),
 
                TK::MinusEquals         => Some(AO::Subtracted),
 
                TK::ShiftLeftEquals     => Some(AO::ShiftedLeft),
 
                TK::ShiftRightEquals    => Some(AO::ShiftedRight),
 
                TK::AndEquals           => Some(AO::BitwiseAnded),
 
                TK::CaretEquals         => Some(AO::BitwiseXored),
 
                TK::OrEquals            => Some(AO::BitwiseOred),
 
                _                       => None
 
            }
 
        }
 

	
 
        let expr = self.consume_conditional_expression(module, iter, ctx)?;
 
        if let Some(operation) = parse_assignment_operator(iter.next()) {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let left = expr;
 
            let right = self.consume_expression(module, iter, ctx)?;
 

	
 
            Ok(ctx.heap.alloc_assignment_expression(|this| AssignmentExpression{
 
                this, span, left, operation, right,
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast())
 
        } else {
 
            Ok(expr)
 
        }
 
    }
 

	
 
    fn consume_conditional_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        let result = self.consume_concat_expression(module, iter, ctx)?;
 
        if let Some(TokenKind::Question) = iter.next() {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let test = result;
 
            let true_expression = self.consume_expression(module, iter, ctx)?;
 
            consume_token(source, iter, TokenKind::Colon)?;
 
            let false_expression = self.consume_expression(module, iter, ctx)?;
 
            Ok(ctx.heap.alloc_conditional_expression(|this| ConditionalExpression{
 
                this, span, test, true_expression, false_expression,
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast())
 
        } else {
 
            Ok(result)
 
        }
 
    }
 

	
 
    fn consume_concat_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::At) => Some(BinaryOperator::Concatenate),
 
                _ => None
 
            },
 
            Self::consume_logical_or_expression
 
        )
 
    }
 

	
 
    fn consume_logical_or_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::OrOr) => Some(BinaryOperator::LogicalOr),
 
                _ => None
 
            },
 
            Self::consume_logical_and_expression
 
        )
 
    }
 

	
 
    fn consume_logical_and_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::AndAnd) => Some(BinaryOperator::LogicalAnd),
 
                _ => None
 
            },
 
            Self::consume_bitwise_or_expression
 
        )
 
    }
 

	
 
    fn consume_bitwise_or_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Or) => Some(BinaryOperator::BitwiseOr),
 
                _ => None
 
            },
 
            Self::consume_bitwise_xor_expression
 
        )
 
    }
 

	
 
    fn consume_bitwise_xor_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Caret) => Some(BinaryOperator::BitwiseXor),
 
                _ => None
 
            },
 
            Self::consume_bitwise_and_expression
 
        )
 
    }
 

	
 
    fn consume_bitwise_and_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::And) => Some(BinaryOperator::BitwiseAnd),
 
                _ => None
 
            },
 
            Self::consume_equality_expression
 
        )
 
    }
 

	
 
    fn consume_equality_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::EqualEqual) => Some(BinaryOperator::Equality),
 
                Some(TokenKind::NotEqual) => Some(BinaryOperator::Inequality),
 
                _ => None
 
            },
 
            Self::consume_relational_expression
 
        )
 
    }
 

	
 
    fn consume_relational_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::OpenAngle) => Some(BinaryOperator::LessThan),
 
                Some(TokenKind::CloseAngle) => Some(BinaryOperator::GreaterThan),
 
                Some(TokenKind::LessEquals) => Some(BinaryOperator::LessThanEqual),
 
                Some(TokenKind::GreaterEquals) => Some(BinaryOperator::GreaterThanEqual),
 
                _ => None
 
            },
 
            Self::consume_shift_expression
 
        )
 
    }
 

	
 
    fn consume_shift_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::ShiftLeft) => Some(BinaryOperator::ShiftLeft),
 
                Some(TokenKind::ShiftRight) => Some(BinaryOperator::ShiftRight),
 
                _ => None
 
            },
 
            Self::consume_add_or_subtract_expression
 
        )
 
    }
 

	
 
    fn consume_add_or_subtract_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Plus) => Some(BinaryOperator::Add),
 
                Some(TokenKind::Minus) => Some(BinaryOperator::Subtract),
 
                _ => None,
 
            },
 
            Self::consume_multiply_divide_or_modulus_expression
 
        )
 
    }
 

	
 
    fn consume_multiply_divide_or_modulus_expression(
 
        &mut self, module: &Module, iter: &mut Tokeniter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Star) => Some(BinaryOperator::Multiply),
 
                Some(TokenKind::Slash) => Some(BinaryOperator::Divide),
 
                Some(TokenKind::Percent) => Some(BinaryOperator::Remainder),
 
                _ => None
 
            },
 
            Self::consume_prefix_expression
 
        )
 
    }
 

	
 
    fn consume_prefix_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        fn parse_prefix_token(token: Option<TokenKind>) -> Some(UnaryOperation) {
 
            use TokenKind as TK;
 
            use UnaryOperation as UO;
 
            match token {
 
                Some(TK::Plus) => Some(UO::Positive),
 
                Some(TK::Minus) => Some(UO::Negative),
 
                Some(TK::PlusPlus) => Some(UO::PreIncrement),
 
                Some(TK::MinusMinus) => Some(UO::PreDecrement),
 
                Some(TK::Tilde) => Some(UO::BitwiseNot),
 
                Some(TK::Exclamation) => Some(UO::LogicalNot),
 
                _ => None
 
            }
 
        }
 

	
 
        if let Some(operation) = parse_prefix_token(iter.next()) {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let expression = self.consume_prefix_expression(module, iter, ctx)?;
 
            Ok(ctx.heap.alloc_unary_expression(|this| UnaryExpression {
 
                this, span, operation, expression,
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default()
 
            }).upcast())
 
        } else {
 
            self.consume_postfix_expression(module, iter, ctx)
 
        }
 
    }
 

	
 
    fn consume_postfix_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        fn has_matching_postfix_token(token: Option<TokenKind>) -> bool {
 
            use TokenKind as TK;
 

	
 
            if token.is_none() { return false; }
 
            match token.unwrap() {
 
                TK::PlusPlus | TK::MinusMinus | TK::OpenSquare | TK::Dot => true,
 
                _ => false
 
            }
 
        }
 

	
 
        let mut result = self.consume_primary_expression(module, iter, ctx)?;
 
        let mut next = iter.next();
 
        while has_matching_postfix_token(next) {
 
            let token = next.unwrap();
 
            let mut span = iter.next_span();
 
            iter.consume();
 

	
 
            if token == TokenKind::PlusPlus {
 
                result = ctx.heap.alloc_unary_expression(|this| UnaryExpression{
 
                    this, span,
 
                    operation: UnaryOperation::PostIncrement,
 
                    expression: result,
 
                    parent: ExpressionParent::None,
 
                    concrete_type: ConcreteType::default()
 
                }).upcast();
 
            } else if token == TokenKind::MinusMinus {
 
                result = ctx.heap.alloc_unary_expression(|this| UnaryExpression{
 
                    this, span,
 
                    operation: UnaryOperation::PostDecrement,
 
                    expression: result,
 
                    parent: ExpressionParent::None,
 
                    concrete_type: ConcreteType::default()
 
                }).upcast();
 
            } else if token == TokenKind::OpenSquare {
 
                let subject = result;
 
                let from_index = self.consume_expression(module, iter, ctx)?;
 

	
 
                // Check if we have an indexing or slicing operation
 
                next = iter.next();
 
                if Some(TokenKind::DotDot) = next {
 
                    iter.consume();
 

	
 
                    let to_index = self.consume_expression(module, iter, ctx)?;
 
                    let end_span = consume_token(&module.source, iter, TokenKind::CloseSquare)?;
 
                    span.end = end_span.end;
 

	
 
                    result = ctx.heap.alloc_slicing_expression(|this| SlicingExpression{
 
                        this, span, subject, from_index, to_index,
 
                        parent: ExpressionParent::None,
 
                        concrete_type: ConcreteType::default()
 
                    }).upcast();
 
                } else if Some(TokenKind::CloseSquare) {
 
                    let end_span = consume_token(&module.source, iter, TokenKind::CloseSquare)?;
 
                    span.end = end_span.end;
 

	
 
                    result = ctx.heap.alloc_indexing_expression(|this| IndexingExpression{
 
                        this, span, subject,
 
                        index: from_index,
 
                        parent: ExpressionParent::None,
 
                        concrete_type: ConcreteType::default()
 
                    }).upcast();
 
                } else {
 
                    return Err(ParseError::new_error_str_at_pos(
 
                        &module.source, iter.last_valid_pos(), "unexpected token: expected ']' or '..'"
 
                    ));
 
                }
 
            } else {
 
                debug_assert_eq!(token, TokenKind::Dot);
 
                let subject = result;
 
                let (field_text, field_span) = consume_ident(&module.source, iter)?;
 
                let field = if field_text == b"length" {
 
                    Field::Length
 
                } else {
 
                    let value = ctx.pool.intern(field_text);
 
                    let identifier = Identifier{ value, span: field_span };
 
                    Field::Symbolic(FieldSymbolic{ identifier, definition: None, field_idx: 0 });
 
                };
 

	
 
                result = ctx.heap.alloc_select_expression(|this| SelectExpression{
 
                    this, span, subject, field,
 
                    parent: ExpressionParent::None,
 
                    concrete_type: ConcreteType::default()
 
                }).upcast();
 
            }
 

	
 
            next = iter.next();
 
        }
 

	
 
        Ok(result)
 
    }
 

	
 
    fn consume_primary_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        let next = iter.next();
 

	
 
        let result = if next == Some(TokenKind::OpenParen) {
 
            // Expression between parentheses
 
            iter.consume();
 
            let result = self.consume_expression(module, iter, ctx)?;
 
            consume_token(&module.source, iter, TokenKind::CloseParen)?;
 

	
 
            result
 
        } else if next == Some(TokenKind::OpenCurly) {
 
            // Array literal
 
            let (start_pos, mut end_pos) = iter.next_positions();
 
            let mut scoped_section = self.expressions.start_section();
 
            consume_comma_separated(
 
                TokenKind::OpenCurly, TokenKind::CloseCurly, &module.source, iter,
 
                |source, iter| self.consume_expression(module, iter, ctx),
 
                &mut scoped_section, "an expression", "a list of expressions", Some(&mut end_pos)
 
            )?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this,
 
                span: InputSpan::from_positions(start_pos, end_pos),
 
                value: Literal::Array(scoped_section.into_vec()),
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast()
 
        } else if next == Some(TokenKind::Integer) {
 
            let (literal, span) = consume_integer_literal(&module.source, iter, &mut self.buffer)?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::Integer(LiteralInteger{ unsigned_value: literal, negated: false }),
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast()
 
        } else if next == Some(TokenKind::String) {
 
            let span = consume_string_literal(&module.source, iter, &mut self.buffer)?;
 
            let interned = ctx.pool.intern(self.buffer.as_bytes());
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::String(interned),
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast()
 
        } else if next == Some(TokenKind::Character) {
 
            let (character, span) = consume_character_literal(&module.source, iter)?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::Character(character),
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast()
 
        } else if next == Some(TokenKind::Ident) {
 
            // May be a variable, a type instantiation or a function call. If we
 
            // have a single identifier that we cannot find in the type table
 
            // then we're going to assume that we're dealing with a variable.
 
            let ident_span = iter.next_span();
 
            let ident_text = module.source.section_at_span(ident_span);
 
            let symbol = ctx.symbols.get_symbol_by_name(SymbolScope::Module(module.root_id), ident_text);
 

	
 
            if symbol.is_some() {
 
                // The first bit looked like a symbol, so we're going to follow
 
                // that all the way through, assume we arrive at some kind of
 
                // function call or type instantiation
 
                use ParserTypeVariant as PTV;
 

	
 
                let symbol_scope = SymbolScope::Definition(self.cur_definition);
 
                let poly_vars = ctx.heap[self.cur_definition].poly_vars();
 
                let parser_type = consume_parser_type(
 
                    &module.source, iter, &ctx.symbols, &ctx.heap, poly_vars, symbol_scope,
 
                    self.cur_definition, true, 0
 
                )?;
 
                debug_assert!(!parser_type.elements.is_empty());
 
                match parser_type.elements[0].variant {
 
                    PTV::Definition(target_definition_id, _) => {
 
                        let definition = &ctx.heap[target_definition_id];
 
                        match definition {
 
                            Definition::Struct(_) => {
 
                                // Struct literal
 
                                let mut last_token = iter.last_valid_pos();
 
                                let mut struct_fields = Vec::new();
 
                                consume_comma_separated(
 
                                    TokenKind::OpenCurly, TokenKind::CloseCurly, &module.source, iter,
 
                                    |source, iter| {
 
                                        let identifier = consume_ident_interned(source, iter, ctx)?;
 
                                        consume_token(source, iter, TokenKind::Colon)?;
 
                                        let value = self.consume_expression(module, iter, ctx)?;
 
                                        Ok(LiteralStructField{ identifier, value, field_idx: 0 })
 
                                    },
 
                                    &mut struct_fields, "a struct field", "a list of struct field", Some(&mut last_token)
 
                                )?;
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, last_token),
 
                                    value: Literal::Struct(LiteralStruct{
 
                                        parser_type,
 
                                        fields: struct_fields,
 
                                        definition: target_definition_id,
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default(),
 
                                }).upcast()
 
                            },
 
                            Definition::Enum(_) => {
 
                                // Enum literal: consume the variant
 
                                consume_token(&module.source, iter, TokenKind::ColonColon)?;
 
                                let variant = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, variant.span.end),
 
                                    value: Literal::Enum(LiteralEnum{
 
                                        parser_type,
 
                                        variant,
 
                                        definition: target_definition_id,
 
                                        variant_idx: 0
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default()
 
                                }).upcast()
 
                            },
 
                            Definition::Union(_) => {
 
                                // Union literal: consume the variant
 
                                consume_token(&module.source, iter, TokenKind::ColonColon)?;
 
                                let variant = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                                // Consume any possible embedded values
 
                                let mut end_pos = iter.last_valid_pos();
 
                                let values = self.consume_expression_list(module, iter, ctx, Some(&mut end_pos))?;
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, end_pos),
 
                                    value: Literal::Union(LiteralUnion{
 
                                        parser_type, variant, values,
 
                                        definition: target_definition_id,
 
                                        variant_idx: 0,
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default()
 
                                }).upcast()
 
                            },
 
                            Definition::Component(_) => {
 
                                // Component instantiation
 
                                let arguments = self.consume_expression_list(module, iter, ctx, None)?;
 

	
 
                                ctx.heap.alloc_call_expression(|this| CallExpression{
 
                                    this,
 
                                    span: parser_type.elements[0].full_span, // TODO: @Span fix
 
                                    parser_type,
 
                                    method: Method::UserComponent,
 
                                    arguments,
 
                                    definition: target_definition_id,
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default(),
 
                                }).upcast()
 
                            },
 
                            Definition::Function(function_definition) => {
 
                                // Function call: consume the arguments
 
                                let arguments = self.consume_expression_list(module, iter, ctx, None)?;
 

	
 
                                // Check whether it is a builtin function
 
                                let method = if function_definition.builtin {
 
                                    match function_definition.identifier.value.as_str() {
 
                                        "get" => Method::Get,
 
                                        "put" => Method::Put,
 
                                        "fires" => Method::Fires,
 
                                        "create" => Method::Create,
 
                                        "length" => Method::Length,
 
                                        "assert" => Method::Assert,
 
                                        _ => unreachable!(),
 
                                    }
 
                                } else {
 
                                    Method::UserFunction
 
                                };
 

	
 
                                ctx.heap.alloc_call_expression(|this| CallExpression{
 
                                    this,
 
                                    span: parser_type.elements[0].full_span, // TODO: @Span fix
 
                                    parser_type,
 
                                    method,
 
                                    arguments,
 
                                    definition: target_definition_id,
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default(),
 
                                }).upcast()
 
                            }
 
                        }
 
                    },
 
                    _ => {
 
                        // TODO: Casting expressions
 
                        return Err(ParseError::new_error_str_at_span(
 
                            &module.source, parser_type.elements[0].full_span,
 
                            "unexpected type in expression, note that casting expressions are not yet implemented"
 
                        ))
 
                    }
 
                }
 
            } else {
 
                // Check for builtin keywords or builtin functions
 
                if ident_text == KW_LIT_NULL || ident_text == KW_LIT_TRUE || ident_text == KW_LIT_FALSE {
 
                    // Parse builtin literal
 
                    let value = match ident_text {
 
                        KW_LIT_NULL => Literal::Null,
 
                        KW_LIT_TRUE => Literal::True,
 
                        KW_LIT_FALSE => Literal::False,
 
                        _ => unreachable!(),
 
                    };
 

	
 
                    ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                        this,
 
                        span: ident_span,
src/protocol/parser/pass_validation_linking.rs
Show inline comments
 
file renamed from src/protocol/parser/visitor_linker.rs to src/protocol/parser/pass_validation_linking.rs
 
use crate::collections::{ScopedBuffer};
 
use crate::protocol::ast::*;
 
use crate::protocol::inputsource::*;
 
use crate::protocol::input_source2::{InputSource2 as InputSource, ParseError};
 
use crate::protocol::parser::{
 
    symbol_table::*, 
 
    symbol_table2::*,
 
    type_table::*,
 
    utils::*,
 
};
 

	
 
use super::visitor::{
 
    STMT_BUFFER_INIT_CAPACITY,
 
    EXPR_BUFFER_INIT_CAPACITY,
 
    TYPE_BUFFER_INIT_CAPACITY,
 
    Ctx, 
 
    Visitor2, 
 
    VisitorResult
 
};
 

	
 
#[derive(PartialEq, Eq)]
 
enum DefinitionType {
 
    None,
 
    Primitive(ComponentDefinitionId),
 
    Composite(ComponentDefinitionId),
 
    Function(FunctionDefinitionId)
 
}
 

	
 
impl DefinitionType {
 
    fn is_primitive(&self) -> bool { if let Self::Primitive(_) = self { true } else { false } }
 
    fn is_composite(&self) -> bool { if let Self::Composite(_) = self { true } else { false } }
 
    fn is_function(&self) -> bool { if let Self::Function(_) = self { true } else { false } }
 
    fn definition_id(&self) -> DefinitionId {
 
        match self {
 
            DefinitionType::Primitive(v) => v.upcast(),
 
            DefinitionType::Composite(v) => v.upcast(),
 
            DefinitionType::Function(v) => v.upcast(),
 
        }
 
    }
 
}
 

	
 
/// This particular visitor will go through the entire AST in a recursive manner
 
/// and check if all statements and expressions are legal (e.g. no "return"
 
/// statements in component definitions), and will link certain AST nodes to
 
/// their appropriate targets (e.g. goto statements, or function calls).
 
///
 
/// This visitor will not perform control-flow analysis (e.g. making sure that
 
/// each function actually returns) and will also not perform type checking. So
 
/// the linking of function calls and component instantiations will be checked
 
/// and linked to the appropriate definitions, but the return types and/or
 
/// arguments will not be checked for validity.
 
///
 
/// The visitor visits each statement in a block in a breadth-first manner
 
/// first. We are thereby sure that we have found all variables/labels in a
 
/// particular block. In this phase nodes may queue statements for insertion
 
/// (e.g. the insertion of an `EndIf` statement for a particular `If`
 
/// statement). These will be inserted after visiting every node, after which
 
/// the visitor recurses into each statement in a block.
 
///
 
/// Because of this scheme expressions will not be visited in the breadth-first
 
/// pass.
 
pub(crate) struct ValidityAndLinkerVisitor {
 
pub(crate) struct PassValidationLinking {
 
    /// `in_sync` is `Some(id)` if the visitor is visiting the children of a
 
    /// synchronous statement. A single value is sufficient as nested
 
    /// synchronous statements are not allowed
 
    in_sync: Option<SynchronousStatementId>,
 
    /// `in_while` contains the last encountered `While` statement. This is used
 
    /// to resolve unlabeled `Continue`/`Break` statements.
 
    in_while: Option<WhileStatementId>,
 
    // Traversal state: current scope (which can be used to find the parent
 
    // scope), the definition variant we are considering, and whether the
 
    // visitor is performing breadthwise block statement traversal.
 
    cur_scope: Option<Scope>,
 
    def_type: DefinitionType,
 
    performing_breadth_pass: bool,
 
    // Parent expression (the previous stmt/expression we visited that could be
 
    // used as an expression parent)
 
    expr_parent: ExpressionParent,
 
    // Keeping track of relative position in block in the breadth-first pass.
 
    // May not correspond to block.statement[index] if any statements are
 
    // inserted after the breadth-pass
 
    relative_pos_in_block: u32,
 
    // Single buffer of statement IDs that we want to traverse in a block.
 
    // Required to work around Rust borrowing rules and to prevent constant
 
    // cloning of vectors.
 
    statement_buffer: Vec<StatementId>,
 
    statement_buffer: ScopedBuffer<StatementId>,
 
    // Another buffer, now with expression IDs, to prevent constant cloning of
 
    // vectors while working around rust's borrowing rules
 
    expression_buffer: Vec<ExpressionId>,
 
    // Yet another buffer, now with parser type IDs, similar to above
 
    parser_type_buffer: Vec<ParserTypeId>,
 
    expression_buffer: ScopedBuffer<ExpressionId>,
 
}
 

	
 
impl ValidityAndLinkerVisitor {
 
impl PassValidationLinking {
 
    pub(crate) fn new() -> Self {
 
        Self{
 
            in_sync: None,
 
            in_while: None,
 
            cur_scope: None,
 
            expr_parent: ExpressionParent::None,
 
            def_type: DefinitionType::None,
 
            performing_breadth_pass: false,
 
            relative_pos_in_block: 0,
 
            statement_buffer: Vec::with_capacity(STMT_BUFFER_INIT_CAPACITY),
 
            expression_buffer: Vec::with_capacity(EXPR_BUFFER_INIT_CAPACITY),
 
            parser_type_buffer: Vec::with_capacity(TYPE_BUFFER_INIT_CAPACITY),
 
            statement_buffer: ScopedBuffer::new_reserved(STMT_BUFFER_INIT_CAPACITY),
 
            expression_buffer: ScopedBuffer::new_reserved(EXPR_BUFFER_INIT_CAPACITY),
 
        }
 
    }
 

	
 
    fn reset_state(&mut self) {
 
        self.in_sync = None;
 
        self.in_while = None;
 
        self.cur_scope = None;
 
        self.expr_parent = ExpressionParent::None;
 
        self.def_type = DefinitionType::None;
 
        self.relative_pos_in_block = 0;
 
        self.performing_breadth_pass = false;
 
        self.statement_buffer.clear();
 
        self.expression_buffer.clear();
 
        self.parser_type_buffer.clear();
 
    }
 

	
 
    /// Debug call to ensure that we didn't make any mistakes in any of the
 
    /// employed buffers
 
    fn check_post_definition_state(&self) {
 
        debug_assert!(self.statement_buffer.is_empty());
 
        debug_assert!(self.expression_buffer.is_empty());
 
        debug_assert!(self.parser_type_buffer.is_empty());
 
    }
 
}
 

	
 
impl Visitor2 for ValidityAndLinkerVisitor {
 
impl Visitor2 for PassValidationLinking {
 
    //--------------------------------------------------------------------------
 
    // Definition visitors
 
    //--------------------------------------------------------------------------
 

	
 
    fn visit_component_definition(&mut self, ctx: &mut Ctx, id: ComponentDefinitionId) -> VisitorResult {
 
        self.reset_state();
 

	
 
        self.def_type = match &ctx.heap[id].variant {
 
            ComponentVariant::Primitive => DefinitionType::Primitive(id),
 
            ComponentVariant::Composite => DefinitionType::Composite(id),
 
        };
 
        self.cur_scope = Some(Scope::Definition(id.upcast()));
 
        self.expr_parent = ExpressionParent::None;
 

	
 
        // Visit types of parameters
 
        debug_assert!(self.parser_type_buffer.is_empty());
 
        let comp_def = &ctx.heap[id];
 
        self.parser_type_buffer.extend(
 
            comp_def.parameters
 
                .iter()
 
                .map(|id| ctx.heap[*id].parser_type)
 
        );
 

	
 
        let num_types = self.parser_type_buffer.len();
 
        for idx in 0..num_types {
 
            self.visit_parser_type(ctx, self.parser_type_buffer[idx])?;
 
        }
 

	
 
        self.parser_type_buffer.clear();
 

	
 
        // Visit statements in component body
 
        let body_id = ctx.heap[id].body;
 
        self.performing_breadth_pass = true;
 
        self.visit_block_stmt(ctx, body_id)?;
 
        self.performing_breadth_pass = false;
 
        self.visit_block_stmt(ctx, body_id)?;
 

	
 
        self.check_post_definition_state();
 
        Ok(())
 
    }
 

	
 
    fn visit_function_definition(&mut self, ctx: &mut Ctx, id: FunctionDefinitionId) -> VisitorResult {
 
        self.reset_state();
 

	
 
        // Set internal statement indices
 
        self.def_type = DefinitionType::Function(id);
 
        self.cur_scope = Some(Scope::Definition(id.upcast()));
 
        self.expr_parent = ExpressionParent::None;
 

	
 
        // Visit types of parameters
 
        debug_assert!(self.parser_type_buffer.is_empty());
 
        let func_def = &ctx.heap[id];
 
        self.parser_type_buffer.extend(
 
            func_def.parameters
 
                .iter()
 
                .map(|id| ctx.heap[*id].parser_type)
 
        );
 
        self.parser_type_buffer.push(func_def.return_type);
 

	
 
        let num_types = self.parser_type_buffer.len();
 
        for idx in 0..num_types {
 
            self.visit_parser_type(ctx, self.parser_type_buffer[idx])?;
 
        }
 

	
 
        self.parser_type_buffer.clear();
 

	
 
        // Visit statements in function body
 
        let body_id = ctx.heap[id].body;
 
        self.performing_breadth_pass = true;
 
        self.visit_block_stmt(ctx, body_id)?;
 
        self.performing_breadth_pass = false;
 
        self.visit_block_stmt(ctx, body_id)?;
 

	
 
        self.check_post_definition_state();
 
        Ok(())
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Statement visitors
 
    //--------------------------------------------------------------------------
 

	
 
    fn visit_block_stmt(&mut self, ctx: &mut Ctx, id: BlockStatementId) -> VisitorResult {
 
        self.visit_block_stmt_with_hint(ctx, id, None)
 
    }
 

	
 
    fn visit_local_memory_stmt(&mut self, ctx: &mut Ctx, id: MemoryStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let variable_id = ctx.heap[id].variable;
 
            self.checked_local_add(ctx, self.relative_pos_in_block, variable_id)?;
 
        } else {
 
            let variable_id = ctx.heap[id].variable;
 
            let parser_type_id = ctx.heap[variable_id].parser_type;
 
            self.visit_parser_type(ctx, parser_type_id)?;
 

	
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
        }
 

	
 
    fn visit_local_memory_stmt(&mut self, _ctx: &mut Ctx, _id: MemoryStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 

	
 
    fn visit_local_channel_stmt(&mut self, ctx: &mut Ctx, id: ChannelStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let (from_id, to_id) = {
 
                let stmt = &ctx.heap[id];
 
                (stmt.from, stmt.to)
 
            };
 
            self.checked_local_add(ctx, self.relative_pos_in_block, from_id)?;
 
            self.checked_local_add(ctx, self.relative_pos_in_block, to_id)?;
 
        } else {
 
            let chan_stmt = &ctx.heap[id];
 
            let from_type_id = ctx.heap[chan_stmt.from].parser_type;
 
            let to_type_id = ctx.heap[chan_stmt.to].parser_type;
 
            self.visit_parser_type(ctx, from_type_id)?;
 
            self.visit_parser_type(ctx, to_type_id)?;
 
        }
 

	
 
    fn visit_local_channel_stmt(&mut self, _ctx: &mut Ctx, _id: ChannelStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 

	
 
    fn visit_labeled_stmt(&mut self, ctx: &mut Ctx, id: LabeledStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            // Add label to block lookup
 
            self.checked_label_add(ctx, id)?;
 

	
 
            // Modify labeled statement itself
 
            let labeled = &mut ctx.heap[id];
 
            labeled.relative_pos_in_block = self.relative_pos_in_block;
 
            labeled.in_sync = self.in_sync.clone();
 
        }
 

	
 
        let body_id = ctx.heap[id].body;
 
        self.visit_stmt(ctx, body_id)?;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_if_stmt(&mut self, ctx: &mut Ctx, id: IfStatementId) -> VisitorResult {
 
        if !self.performing_breadth_pass {
 
            // Traverse expression and bodies
 
            let (test_id, true_id, false_id) = {
 
                let stmt = &ctx.heap[id];
 
                (stmt.test, stmt.true_body, stmt.false_body)
 
            };
 

	
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::If(id);
 
            self.visit_expr(ctx, test_id)?;
 
            self.expr_parent = ExpressionParent::None;
 

	
 
            self.visit_stmt(ctx, true_id)?;
 
            self.visit_stmt(ctx, false_id)?;
 
        // Traverse expression and bodies
 
        let (test_id, true_id, false_id) = {
 
            let stmt = &ctx.heap[id];
 
            (stmt.test, stmt.true_body, stmt.false_body)
 
        };
 

	
 
        debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
        self.expr_parent = ExpressionParent::If(id);
 
        self.visit_expr(ctx, test_id)?;
 
        self.expr_parent = ExpressionParent::None;
 

	
 
        self.visit_block_stmt(ctx, true_id)?;
 
        if let Some(false_id) = false_id {
 
            self.visit_block_stmt(ctx, false_id)?;
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_while_stmt(&mut self, ctx: &mut Ctx, id: WhileStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let stmt = &mut ctx.heap[id];
 
            stmt.in_sync = self.in_sync.clone();
 
        } else {
 
            let (test_id, body_id) = {
 
                let stmt = &ctx.heap[id];
 
                (stmt.test, stmt.body)
 
            };
 
            let old_while = self.in_while.replace(id);
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::While(id);
 
            self.visit_expr(ctx, test_id)?;
 
            self.expr_parent = ExpressionParent::None;
 

	
 
            self.visit_stmt(ctx, body_id)?;
 
            self.in_while = old_while;
 
        }
 
        let (test_id, body_id) = {
 
            let stmt = &ctx.heap[id];
 
            (stmt.test, stmt.body)
 
        };
 
        let old_while = self.in_while.replace(id);
 
        debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
        self.expr_parent = ExpressionParent::While(id);
 
        self.visit_expr(ctx, test_id)?;
 
        self.expr_parent = ExpressionParent::None;
 

	
 
        self.visit_block_stmt(ctx, body_id)?;
 
        self.in_while = old_while;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_break_stmt(&mut self, ctx: &mut Ctx, id: BreakStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            // Should be able to resolve break statements with a label in the
 
            // breadth pass, no need to do after resolving all labels
 
            let target_end_while = {
 
                let stmt = &ctx.heap[id];
 
                let target_while_id = self.resolve_break_or_continue_target(ctx, stmt.position, &stmt.label)?;
 
                let target_while = &ctx.heap[target_while_id];
 
                debug_assert!(target_while.end_while.is_some());
 
                target_while.end_while.unwrap()
 
            };
 

	
 
            let stmt = &mut ctx.heap[id];
 
            stmt.target = Some(target_end_while);
 
        }
 
        // Resolve break target
 
        let target_end_while = {
 
            let stmt = &ctx.heap[id];
 
            let target_while_id = self.resolve_break_or_continue_target(ctx, stmt.position, &stmt.label)?;
 
            let target_while = &ctx.heap[target_while_id];
 
            debug_assert!(target_while.end_while.is_some());
 
            target_while.end_while.unwrap()
 
        };
 

	
 
        let stmt = &mut ctx.heap[id];
 
        stmt.target = Some(target_end_while);
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_continue_stmt(&mut self, ctx: &mut Ctx, id: ContinueStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let target_while_id = {
 
                let stmt = &ctx.heap[id];
 
                self.resolve_break_or_continue_target(ctx, stmt.position, &stmt.label)?
 
            };
 

	
 
            let stmt = &mut ctx.heap[id];
 
            stmt.target = Some(target_while_id)
 
        }
 
        // Resolve continue target
 
        let target_while_id = {
 
            let stmt = &ctx.heap[id];
 
            self.resolve_break_or_continue_target(ctx, stmt.position, &stmt.label)?
 
        };
 

	
 
        let stmt = &mut ctx.heap[id];
 
        stmt.target = Some(target_while_id);
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_synchronous_stmt(&mut self, ctx: &mut Ctx, id: SynchronousStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            // Check for validity of synchronous statement
 
            let cur_sync_position = ctx.heap[id].position;
 
            if self.in_sync.is_some() {
 
                // Nested synchronous statement
 
                let old_sync = &ctx.heap[self.in_sync.unwrap()];
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, cur_sync_position, "Illegal nested synchronous statement")
 
                        .with_postfixed_info(&ctx.module.source, old_sync.position, "It is nested in this synchronous statement")
 
                );
 
            }
 

	
 
            if !self.def_type.is_primitive() {
 
                return Err(ParseError::new_error(
 
                    &ctx.module.source, cur_sync_position,
 
                    "Synchronous statements may only be used in primitive components"
 
                ));
 
            }
 
        } else {
 
            let sync_body = ctx.heap[id].body;
 
            let old = self.in_sync.replace(id);
 
            self.visit_stmt_with_hint(ctx, sync_body, Some(id))?;
 
            self.in_sync = old;
 
        // Check for validity of synchronous statement
 
        let cur_sync_span = ctx.heap[id].span;
 
        if self.in_sync.is_some() {
 
            // Nested synchronous statement
 
            let old_sync_span = &ctx.heap[self.in_sync.unwrap()].span;
 
            return Err(ParseError::new_error_str_at_span(
 
                &ctx.module.source, cur_sync_span, "Illegal nested synchronous statement"
 
            ).with_info_str_at_span(
 
                &ctx.module.source, old_sync_span.position, "It is nested in this synchronous statement"
 
            ));
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_return_stmt(&mut self, ctx: &mut Ctx, id: ReturnStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let stmt = &ctx.heap[id];
 
            if !self.def_type.is_function() {
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, stmt.position, "Return statements may only appear in function bodies")
 
                );
 
            }
 
        } else {
 
            // If here then we are within a function
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::Return(id);
 
            self.visit_expr(ctx, ctx.heap[id].expression)?;
 
            self.expr_parent = ExpressionParent::None;
 
        if self.def_type != DefinitionType::Primitive {
 
            return Err(ParseError::new_error_str_at_span(
 
                &ctx.module.source, cur_sync_span,
 
                "synchronous statements may only be used in primitive components"
 
            ));
 
        }
 

	
 
        let sync_body = ctx.heap[id].body;
 
        let old = self.in_sync.replace(id);
 
        self.visit_block_stmt_with_hint(ctx, sync_body, Some(id))?;
 
        self.in_sync = old;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_assert_stmt(&mut self, ctx: &mut Ctx, id: AssertStatementId) -> VisitorResult {
 
    fn visit_return_stmt(&mut self, ctx: &mut Ctx, id: ReturnStatementId) -> VisitorResult {
 
        // Check if "return" occurs within a function
 
        let stmt = &ctx.heap[id];
 
        if self.performing_breadth_pass {
 
            if self.def_type.is_function() {
 
                // TODO: We probably want to allow this. Mark the function as
 
                //  using asserts, and then only allow calls to these functions
 
                //  within components. Such a marker will cascade through any
 
                //  functions that then call an asserting function
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, stmt.position, "Illegal assert statement in a function")
 
                );
 
            }
 

	
 
            // We are in a component of some sort, but we also need to be within a
 
            // synchronous statement
 
            if self.in_sync.is_none() {
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, stmt.position, "Illegal assert statement outside of a synchronous block")
 
                );
 
            }
 
        } else {
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            let expr_id = stmt.expression;
 

	
 
            self.expr_parent = ExpressionParent::Assert(id);
 
            self.visit_expr(ctx, expr_id)?;
 
            self.expr_parent = ExpressionParent::None;
 
        if self.def_type != DefinitionType::Function {
 
            return Err(ParseError::new_error_str_at_span(
 
                &ctx.module.source, stmt.span,
 
                "return statements may only appear in function bodies"
 
            ));
 
        }
 

	
 
        // If here then we are within a function
 
        debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
        self.expr_parent = ExpressionParent::Return(id);
 
        self.visit_expr(ctx, ctx.heap[id].expression)?;
 
        self.expr_parent = ExpressionParent::None;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_goto_stmt(&mut self, ctx: &mut Ctx, id: GotoStatementId) -> VisitorResult {
 
        if !self.performing_breadth_pass {
 
            // Must perform goto label resolving after the breadth pass, this
 
            // way we are able to find all the labels in current and outer
 
            // scopes.
 
            let target_id = self.find_label(ctx, &ctx.heap[id].label)?;
 
            ctx.heap[id].target = Some(target_id);
 

	
 
            let target = &ctx.heap[target_id];
 
            if self.in_sync != target.in_sync {
 
                // We can only goto the current scope or outer scopes. Because
 
                // nested sync statements are not allowed so if the value does
 
                // not match, then we must be inside a sync scope
 
                debug_assert!(self.in_sync.is_some());
 
                let goto_stmt = &ctx.heap[id];
 
                let sync_stmt = &ctx.heap[self.in_sync.unwrap()];
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, goto_stmt.position, "Goto may not escape the surrounding synchronous block")
 
                        .with_postfixed_info(&ctx.module.source, target.position, "This is the target of the goto statement")
 
                        .with_postfixed_info(&ctx.module.source, sync_stmt.position, "Which will jump past this statement")
 
                );
 
            }
 
        let target_id = self.find_label(ctx, &ctx.heap[id].label)?;
 
        ctx.heap[id].target = Some(target_id);
 

	
 
        let target = &ctx.heap[target_id];
 
        if self.in_sync != target.in_sync {
 
            // We can only goto the current scope or outer scopes. Because
 
            // nested sync statements are not allowed so if the value does
 
            // not match, then we must be inside a sync scope
 
            debug_assert!(self.in_sync.is_some());
 
            let goto_stmt = &ctx.heap[id];
 
            let sync_stmt = &ctx.heap[self.in_sync.unwrap()];
 
            return Err(
 
                ParseError::new_error_str_at_span(&ctx.module.source, goto_stmt.span, "goto may not escape the surrounding synchronous block")
 
                .with_postfixed_info(&ctx.module.source, target.label.span, "this is the target of the goto statement")
 
                .with_postfixed_info(&ctx.module.source, sync_stmt.span, "which will jump past this statement")
 
            );
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_new_stmt(&mut self, ctx: &mut Ctx, id: NewStatementId) -> VisitorResult {
 
        // Link the call expression following the new statement
 
        if self.performing_breadth_pass {
 
            // TODO: Cleanup error messages, can be done cleaner
 
            // Make sure new statement occurs within a composite component
 
            let call_expr_id = ctx.heap[id].expression;
 
            if !self.def_type.is_composite() {
 
                let new_stmt = &ctx.heap[id];
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, new_stmt.position, "Instantiating components may only be done in composite components")
 
                );
 
            }
 

	
 
            // We make sure that we point to a symbolic method. Checking that it
 
            // points to a component is done in the depth pass.
 
            let call_expr = &ctx.heap[call_expr_id];
 
            if let Method::Symbolic(_) = &call_expr.method {
 
                // We're fine
 
            } else {
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, call_expr.position, "Must instantiate a component")
 
                );
 
            }
 
        } else {
 
            // Just call `visit_call_expr`. We do some extra work we don't have
 
            // to, but this prevents silly mistakes.
 
            let call_expr_id = ctx.heap[id].expression;
 

	
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::New(id);
 
            self.visit_call_expr(ctx, call_expr_id)?;
 
            self.expr_parent = ExpressionParent::None;
 
        // Make sure the new statement occurs inside a composite component
 
        if self.def_type != DefinitionType::Composite {
 
            let new_stmt = &ctx.heap[id];
 
            return Err(ParseError::new_error_str_at_span(
 
                &ctx.module.source, new_stmt.span,
 
                "instantiating components may only be done in composite components"
 
            ));
 
        }
 

	
 
        // Recurse into call expression (which will check the expression parent
 
        // to ensure that the "new" statment instantiates a component)
 
        let call_expr_id = ctx.heap[id].expression;
 

	
 
        debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
        self.expr_parent = ExpressionParent::New(id);
 
        self.visit_call_expr(ctx, call_expr_id)?;
 
        self.expr_parent = ExpressionParent::None;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_expr_stmt(&mut self, ctx: &mut Ctx, id: ExpressionStatementId) -> VisitorResult {
 
        if !self.performing_breadth_pass {
 
            let expr_id = ctx.heap[id].expression;
 
        let expr_id = ctx.heap[id].expression;
 

	
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::ExpressionStmt(id);
 
            self.visit_expr(ctx, expr_id)?;
 
            self.expr_parent = ExpressionParent::None;
 
        }
 
        debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
        self.expr_parent = ExpressionParent::ExpressionStmt(id);
 
        self.visit_expr(ctx, expr_id)?;
 
        self.expr_parent = ExpressionParent::None;
 

	
 
        Ok(())
 
    }
 

	
 

	
 
    //--------------------------------------------------------------------------
 
    // Expression visitors
 
    //--------------------------------------------------------------------------
 

	
 
    fn visit_assignment_expr(&mut self, ctx: &mut Ctx, id: AssignmentExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let upcast_id = id.upcast();
 
        let assignment_expr = &mut ctx.heap[id];
 

	
 
        let left_expr_id = assignment_expr.left;
 
        let right_expr_id = assignment_expr.right;
 
        let old_expr_parent = self.expr_parent;
 
        assignment_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
 
        self.visit_expr(ctx, left_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
 
        self.visit_expr(ctx, right_expr_id)?;
 
        self.expr_parent = old_expr_parent;
 
        Ok(())
 
    }
 

	
 
    fn visit_conditional_expr(&mut self, ctx: &mut Ctx, id: ConditionalExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 
        let upcast_id = id.upcast();
 
        let conditional_expr = &mut ctx.heap[id];
 

	
 
        let test_expr_id = conditional_expr.test;
 
        let true_expr_id = conditional_expr.true_expression;
 
        let false_expr_id = conditional_expr.false_expression;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        conditional_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
 
        self.visit_expr(ctx, test_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
 
        self.visit_expr(ctx, true_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 2);
 
        self.visit_expr(ctx, false_expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_binary_expr(&mut self, ctx: &mut Ctx, id: BinaryExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 
        let upcast_id = id.upcast();
 
        let binary_expr = &mut ctx.heap[id];
 
        let left_expr_id = binary_expr.left;
 
        let right_expr_id = binary_expr.right;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        binary_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
 
        self.visit_expr(ctx, left_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
 
        self.visit_expr(ctx, right_expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_unary_expr(&mut self, ctx: &mut Ctx, id: UnaryExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let unary_expr = &mut ctx.heap[id];
 
        let expr_id = unary_expr.expression;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        unary_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(id.upcast(), 0);
 
        self.visit_expr(ctx, expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_indexing_expr(&mut self, ctx: &mut Ctx, id: IndexingExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 
        let upcast_id = id.upcast();
 
        let indexing_expr = &mut ctx.heap[id];
 

	
 
        let subject_expr_id = indexing_expr.subject;
 
        let index_expr_id = indexing_expr.index;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        indexing_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
 
        self.visit_expr(ctx, subject_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
 
        self.visit_expr(ctx, index_expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_slicing_expr(&mut self, ctx: &mut Ctx, id: SlicingExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 
        let upcast_id = id.upcast();
 
        let slicing_expr = &mut ctx.heap[id];
 

	
 
        let subject_expr_id = slicing_expr.subject;
 
        let from_expr_id = slicing_expr.from_index;
 
        let to_expr_id = slicing_expr.to_index;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        slicing_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
 
        self.visit_expr(ctx, subject_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
 
        self.visit_expr(ctx, from_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 2);
 
        self.visit_expr(ctx, to_expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_select_expr(&mut self, ctx: &mut Ctx, id: SelectExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let select_expr = &mut ctx.heap[id];
 
        let expr_id = select_expr.subject;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        select_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(id.upcast(), 0);
 
        self.visit_expr(ctx, expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_array_expr(&mut self, ctx: &mut Ctx, id: ArrayExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let upcast_id = id.upcast();
 
        let array_expr = &mut ctx.heap[id];
 

	
 
        let old_num_exprs = self.expression_buffer.len();
 
        self.expression_buffer.extend(&array_expr.elements);
 
        let new_num_exprs = self.expression_buffer.len();
 

	
 
        let old_expr_parent = self.expr_parent;
 
        array_expr.parent = old_expr_parent;
 

	
 
        for field_expr_idx in old_num_exprs..new_num_exprs {
 
            let field_expr_id = self.expression_buffer[field_expr_idx];
 
            self.expr_parent = ExpressionParent::Expression(upcast_id, field_expr_idx as u32);
 
            self.visit_expr(ctx, field_expr_id)?;
 
        }
 

	
 
        self.expression_buffer.truncate(old_num_exprs);
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_literal_expr(&mut self, ctx: &mut Ctx, id: LiteralExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        const FIELD_NOT_FOUND_SENTINEL: usize = usize::max_value();
 

	
 
        let constant_expr = &mut ctx.heap[id];
 
        let literal_expr = &mut ctx.heap[id];
 
        let old_expr_parent = self.expr_parent;
 
        constant_expr.parent = old_expr_parent;
 
        literal_expr.parent = old_expr_parent;
 

	
 
        match &mut constant_expr.value {
 
        match &mut literal_expr.value {
 
            Literal::Null | Literal::True | Literal::False |
 
            Literal::Character(_) | Literal::Integer(_) => {
 
                // Just the parent has to be set, done above
 
            },
 
            Literal::Struct(literal) => {
 
                let upcast_id = id.upcast();
 

	
 
                // Retrieve and set the literal's definition
 
                let definition = self.find_symbol_of_type(
 
                    &ctx.module.source, ctx.module.root_id, &ctx.symbols, &ctx.types,
 
                    &literal.identifier, TypeClass::Struct
 
                )?;
 
                literal.definition = Some(definition.ast_definition);
 

	
 
                let definition = definition.definition.as_struct();
 

	
 
                // Make sure all fields are specified, none are specified twice
 
                // and all fields exist on the struct definition
 
                let mut specified = Vec::new(); // TODO: @performance
 
                specified.resize(definition.fields.len(), false);
 

	
 
                for field in &mut literal.fields {
 
                    // Find field in the struct definition
 
                    field.field_idx = FIELD_NOT_FOUND_SENTINEL;
 
                    for (def_field_idx, def_field) in definition.fields.iter().enumerate() {
 
                        if field.identifier == def_field.identifier {
 
                            field.field_idx = def_field_idx;
 
                            break;
 
                        }
 
                    }
 

	
 
                    // Check if not found
 
                    if field.field_idx == FIELD_NOT_FOUND_SENTINEL {
 
                        return Err(ParseError::new_error(
 
                            &ctx.module.source, field.identifier.position,
 
                            &format!(
 
                                "This field does not exist on the struct '{}'",
 
                                &String::from_utf8_lossy(&literal.identifier.value),
 
                            )
 
                        ));
 
                    }
 

	
 
                    // Check if specified more than once
 
                    if specified[field.field_idx] {
 
                        return Err(ParseError::new_error(
 
                            &ctx.module.source, field.identifier.position,
 
                            "This field is specified more than once"
 
                        ));
 
                    }
 

	
 
                    specified[field.field_idx] = true;
 
                }
 

	
 
                if !specified.iter().all(|v| *v) {
 
                    // Some fields were not specified
 
                    let mut not_specified = String::new();
 
                    let mut num_not_specified = 0;
 
                    for (def_field_idx, is_specified) in specified.iter().enumerate() {
 
                        if !is_specified {
 
                            if !not_specified.is_empty() { not_specified.push_str(", ") }
 
                            let field_ident = &definition.fields[def_field_idx].identifier;
 
                            not_specified.push_str(&String::from_utf8_lossy(&field_ident.value));
 
                            num_not_specified += 1;
 
                        }
 
                    }
 

	
 
                    debug_assert!(num_not_specified > 0);
 
                    let msg = if num_not_specified == 1 {
 
                        format!("Not all fields are specified, '{}' is missing", not_specified)
 
                    } else {
 
                        format!("Not all fields are specified, [{}] are missing", not_specified)
 
                    };
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, literal.identifier.position, &msg
 
                    ));
 
                }
 

	
 
                // Need to traverse fields expressions in struct and evaluate
 
                // the poly args
 
                let old_num_exprs = self.expression_buffer.len();
 
                self.expression_buffer.extend(literal.fields.iter().map(|v| v.value));
 
                let new_num_exprs = self.expression_buffer.len();
 

	
 
                self.visit_literal_poly_args(ctx, id)?;
 

	
 
                for expr_idx in old_num_exprs..new_num_exprs {
 
                    let expr_id = self.expression_buffer[expr_idx];
 
                    self.expr_parent = ExpressionParent::Expression(upcast_id, expr_idx as u32);
 
                    self.visit_expr(ctx, expr_id)?;
 
                }
 

	
 
                self.expression_buffer.truncate(old_num_exprs);
 
            },
 
            Literal::Enum(literal) => {
 
                // TODO: @tokenizer, remove this horrible hack once we have a 
 
                //  tokenizer and can distinguish types during AST-construction.
 
                //  For now see this horrible hack and weep!
 
                let (symbol, _) = ctx.symbols.resolve_namespaced_identifier(
 
                    ctx.module.root_id, &literal.identifier
 
                );
 
                if let Some(symbol) = symbol {
 
                    if let Symbol::Definition((_, definition_id)) = &symbol.symbol {
 
                        if let Some(defined_type) = ctx.types.get_base_definition(definition_id) {
 
                            if defined_type.definition.type_class() == TypeClass::Union {
 
                                // Transmute into union literal and call this function again
 
                                let old_identifier = literal.identifier.clone();
 
                                let lit_expr = &ctx.heap[id];
 
                                let old_position = lit_expr.position;
 

	
 
                                ctx.heap[id] = LiteralExpression{
 
                                    this: id,
 
                                    position: old_position,
 
                                    value: Literal::Union(LiteralUnion{
 
                                        identifier: old_identifier,
 
                                        values: vec!(),
 
                                        poly_args2: Vec::new(),
 
                                        definition: None,
 
                                        variant_idx: 0,
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default()
 
                                };
 

	
 
                                return self.visit_literal_expr(ctx, id);
 
                            }
 
                        }
 
                    }
 
                }
 

	
 
                // Retrieve and set definion of enumeration
 
                let (definition, ident_iter) = self.find_symbol_of_type_variant(
 
                    &ctx.module.source, ctx.module.root_id, &ctx.symbols, &ctx.types, 
 
                    &literal.identifier, TypeClass::Enum
 
                )?;
 
                literal.definition = Some(definition.ast_definition);
 

	
 
                // Make sure the variant exists
 
                let (variant_ident, _) = ident_iter.prev().unwrap();
 
                let enum_definition = definition.definition.as_enum();
 

	
 
                match enum_definition.variants.iter().position(|variant| {
 
                    variant.identifier.value == variant_ident
 
                }) {
 
                    Some(variant_idx) => {
 
                        literal.variant_idx = variant_idx;
 
                    },
 
                    None => {
 
                        // Reborrow
 
                        let variant = String::from_utf8_lossy(variant_ident).to_string();
 
                        let literal = ctx.heap[id].value.as_enum();
 
                        let enum_definition = ctx.heap[definition.ast_definition].as_enum();
 
                        return Err(ParseError::new_error(
 
                            &ctx.module.source, literal.identifier.position,
 
                            &format!(
 
                                "The variant '{}' does not exist on the enum '{}'",
 
                                &variant, &String::from_utf8_lossy(&enum_definition.identifier.value)
 
                            )
 
                        ));
 
                    }
 
                }
 

	
 
                self.visit_literal_poly_args(ctx, id)?;
 
            },
 
            Literal::Union(literal) => {
 
                let upcast_id = id.upcast();
 

	
 
                // Retrieve and set definition of union
 
                let (definition, ident_iter) = self.find_symbol_of_type_variant(
 
                    &ctx.module.source, ctx.module.root_id, &ctx.symbols, &ctx.types,
 
                    &literal.identifier, TypeClass::Union
 
                )?;
 
                literal.definition = Some(definition.ast_definition);
 
                
 
                // Make sure the variant exists
 
                let (variant_ident, _) = ident_iter.prev().unwrap();
 
                let union_definition = definition.definition.as_union();
 

	
 
                match union_definition.variants.iter().position(|variant| {
 
                    variant.identifier.value == variant_ident
 
                }) {
 
                    Some(variant_idx) => {
 
                        literal.variant_idx = variant_idx;
 
                    },
 
                    None => {
 
                        // Reborrow
 
                        let variant = String::from_utf8_lossy(variant_ident).to_string();
 
                        let literal = ctx.heap[id].value.as_union();
 
                        let union_definition = ctx.heap[definition.ast_definition].as_union();
 
                        return Err(ParseError::new_error(
 
                            &ctx.module.source, literal.identifier.position,
 
                            &format!(
 
                                "The variant '{}' does not exist on the union '{}'",
 
                                &variant, &String::from_utf8_lossy(&union_definition.identifier.value)
 
                            )
 
                        ));
 
                    }
 
                }
 

	
 
                // Make sure the number of specified values matches the expected
 
                // number of embedded values in the union variant.
 
                let union_variant = &union_definition.variants[literal.variant_idx];
 
                if union_variant.embedded.len() != literal.values.len() {
 
                    // Reborrow
 
                    let variant = String::from_utf8_lossy(variant_ident).to_string();
 
                    let literal = ctx.heap[id].value.as_union();
 
                    let union_definition = ctx.heap[definition.ast_definition].as_union();
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, literal.identifier.position,
 
                        &format!(
 
                            "The variant '{}' of union '{}' expects {} embedded values, but {} were specified",
 
                            variant, &String::from_utf8_lossy(&union_definition.identifier.value),
 
                            union_variant.embedded.len(), literal.values.len()
 
                        ),
 
                    ))
 
                }
 

	
 
                // Traverse embedded values of union (if any) and evaluate the
 
                // polymorphic arguments
 
                let old_num_exprs = self.expression_buffer.len();
 
                self.expression_buffer.extend(&literal.values);
 
                let new_num_exprs = self.expression_buffer.len();
 

	
 
                self.visit_literal_poly_args(ctx, id)?;
 

	
 
                for expr_idx in old_num_exprs..new_num_exprs {
 
                    let expr_id = self.expression_buffer[expr_idx];
 
                    self.expr_parent = ExpressionParent::Expression(upcast_id, expr_idx as u32);
 
                    self.visit_expr(ctx, expr_id)?;
 
                }
 

	
 
                self.expression_buffer.truncate(old_num_exprs);
 
            }
 
        }
 

	
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_call_expr(&mut self, ctx: &mut Ctx, id: CallExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let call_expr = &mut ctx.heap[id];
 
        let num_expr_args = call_expr.arguments.len();
 

	
 
        // Resolve the method to the appropriate definition and check the
 
        // legality of the particular method call.
 
        // TODO: @cleanup Unify in some kind of signature call, see similar
 
        //  cleanup comments with this `match` format.
 
        let num_definition_args;
 
        // Check whether the method is allowed to be called within the code's
 
        // context (in sync, definition type, etc.)
 
        let mut expected_wrapping_new_stmt = false;
 
        match &mut call_expr.method {
 
            Method::Create => {
 
                num_definition_args = 1;
 
            Method::Get => {
 
                if self.def_type != DefinitionType::Primitive {
 
                    return Err(ParseError::new_error_str_at_span(
 
                        &ctx.module.source, call_expr.span,
 
                        "a call to 'get' may only occur in primitive component definitions"
 
                    ));
 
                }
 
                if self.in_sync.is_none() {
 
                    return Err(ParseError::new_error_str_at_span(
 
                        &ctx.module.source, call_expr.span,
 
                        "a call to 'get' may only occur inside synchronous blocks"
 
                    ));
 
                }
 
            },
 
            Method::Fires => {
 
                if !self.def_type.is_primitive() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'fires' may only occur in primitive component definitions"
 
            Method::Put => {
 
                if self.def_type != DefinitionType::Primitive {
 
                    return Err(ParseError::new_error_str_at_span(
 
                        &ctx.module.source, call_expr.span,
 
                        "a call to 'put' may only occur in primitive component definitions"
 
                    ));
 
                }
 
                if self.in_sync.is_none() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'fires' may only occur inside synchronous blocks"
 
                    return Err(ParseError::new_error_str_at_span(
 
                        &ctx.module.source, call_expr.span,
 
                        "a call to 'put' may only occur inside synchronous blocks"
 
                    ));
 
                }
 
                num_definition_args = 1;
 
            },
 
            Method::Get => {
 
                if !self.def_type.is_primitive() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'get' may only occur in primitive component definitions"
 
            Method::Fires => {
 
                if self.def_type != DefinitionType::Primitive {
 
                    return Err(ParseError::new_error_str_at_span(
 
                        &ctx.module.source, call_expr.span,
 
                        "a call to 'fires' may only occur in primitive component definitions"
 
                    ));
 
                }
 
                if self.in_sync.is_none() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'get' may only occur inside synchronous blocks"
 
                    return Err(ParseError::new_error_str_at_span(
 
                        &ctx.module.source, call_expr.span,
 
                        "a call to 'fires' may only occur inside synchronous blocks"
 
                    ));
 
                }
 
                num_definition_args = 1;
 
            },
 
            Method::Put => {
 
                if !self.def_type.is_primitive() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'put' may only occur in primitive component definitions"
 
            Method::Create => {},
 
            Method::Length => {},
 
            Method::Assert => {
 
                if self.def_type == DefinitionType::Function {
 
                    return Err(ParseError::new_error_str_at_span(
 
                        &ctx.module.source, call_expr.span,
 
                        "assert statement may only occur in components"
 
                    ));
 
                }
 
                if self.in_sync.is_none() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'put' may only occur inside synchronous blocks"
 
                    return Err(ParseError::new_error_str_at_span(
 
                        &ctx.module.source, call_expr.span,
 
                        "assert statements may only occur inside synchronous blocks"
 
                    ));
 
                }
 
                num_definition_args = 2;
 
            }
 
            Method::Symbolic(symbolic) => {
 
                // Find symbolic procedure
 
                let expected_type = if let ExpressionParent::New(_) = self.expr_parent {
 
                    // Expect to find a component
 
                    TypeClass::Component
 
                } else {
 
                    // Expect to find a function
 
                    // TODO: @tokenizer, remove this ambiguity when tokenizer is implemented. Hacked
 
                    //  in here for now.
 
                    let (symbol, _) = ctx.symbols.resolve_namespaced_identifier(
 
                        ctx.module.root_id, &symbolic.identifier
 
                    );
 
                    if let Some(symbol) = symbol {
 
                        if let Symbol::Definition((_, definition_id)) = symbol.symbol {
 
                            if let Some(defined_type) = ctx.types.get_base_definition(&definition_id) {
 
                                if defined_type.definition.type_class() == TypeClass::Union {
 
                                    // Transmute into union literal and call the appropriate traverser
 
                                    let call_expr = &ctx.heap[id];
 
                                    let old_position = call_expr.position.clone();
 
                                    let old_arguments = call_expr.arguments.clone();
 
                                    let old_identifier = match &call_expr.method {
 
                                        Method::Symbolic(v) => v.identifier.clone(),
 
                                        _ => unreachable!(),
 
                                    };
 

	
 
                                    let expr_id = id.upcast();
 
                                    let lit_id = LiteralExpressionId(expr_id);
 
                                    ctx.heap[expr_id] = Expression::Literal(LiteralExpression{
 
                                        this: lit_id,
 
                                        position: old_position,
 
                                        value: Literal::Union(LiteralUnion{
 
                                            identifier: old_identifier,
 
                                            values: old_arguments,
 
                                            poly_args2: Vec::new(),
 
                                            definition: None,
 
                                            variant_idx: 0,
 
                                        }),
 
                                        parent: ExpressionParent::None,
 
                                        concrete_type: ConcreteType::default(),
 
                                    });
 
                                    
 
                                    return self.visit_literal_expr(ctx, lit_id);
 
                                }
 
                            }
 
                        }
 
                    }
 
                    TypeClass::Function
 
                };
 

	
 
                let definition = self.find_symbol_of_type(
 
                    &ctx.module.source, ctx.module.root_id, &ctx.symbols, &ctx.types,
 
                    &symbolic.identifier, expected_type
 
                )?;
 
            },
 
            Method::UserFunction => {},
 
            Method::UserComponent => {
 
                expected_wrapping_new_stmt = true;
 
            },
 
        }
 

	
 
                symbolic.definition = Some(definition.ast_definition);
 
                match &definition.definition {
 
                    DefinedTypeVariant::Function(definition) => {
 
                        num_definition_args = definition.arguments.len();
 
                    },
 
                    DefinedTypeVariant::Component(definition) => {
 
                        num_definition_args = definition.arguments.len();
 
                    }
 
                    _ => unreachable!(),
 
                }
 
        if expected_wrapping_new_stmt {
 
            if self.expr_parent != ExpressionParent::New {
 
                return Err(ParseError::new_error_str_at_span(
 
                    &ctx.module.source, call_expr.span,
 
                    "cannot call a component, it can only be instantiated by using 'new'"
 
                ));
 
            }
 
        } else {
 
            if self.expr_parent == ExpressionParent::New {
 
                return Err(ParseError::new_error_str_at_span(
 
                    &ctx.module.source, call_expr.span,
 
                    "only components can be instantiated"
 
                ));
 
            }
 
        }
 

	
 
        // Check the poly args and the number of variables in the call
 
        // expression
 
        self.visit_call_poly_args(ctx, id)?;
 
        let call_expr = &mut ctx.heap[id];
 
        if num_expr_args != num_definition_args {
 
            return Err(ParseError::new_error(
 
                &ctx.module.source, call_expr.position,
 
                &format!(
 
                    "This call expects {} arguments, but {} were provided",
 
                    num_definition_args, num_expr_args
 
        // Check the number of arguments
 
        let call_definition = ctx.types.get_base_definition(&call_expr.definition).unwrap();
 
        let num_expected_args = match &call_definition.definition {
 
            DefinedTypeVariant::Function(definition) => definition.arguments.len(),
 
            DefinedTypeVariant::Component(definition) => definition.arguments.len(),
 
            v => unreachable!("encountered {:?} type in call expression", v),
 
        };
 

	
 
        let num_provided_args = call_expr.arguments.len();
 
        if num_provided_args != num_expected_args {
 
            let argument_text = if num_expected_args == 1 { "argument" } else { "arguments" };
 
            return Err(ParseError::new_error_at_span(
 
                &ctx.module.source, call_expr.span, format!(
 
                    "expected {} {}, but {} were provided",
 
                    num_expected_args, argument_text, num_provided_args
 
                )
 
            ));
 
        }
 

	
 
        // Recurse into all of the arguments and set the expression's parent
 
        let upcast_id = id.upcast();
 

	
 
        let old_num_exprs = self.expression_buffer.len();
 
        self.expression_buffer.extend(&call_expr.arguments);
 
        let new_num_exprs = self.expression_buffer.len();
 

	
 
        let section = self.expression_buffer.start_section_initialized(&call_expr.arguments);
 
        let old_expr_parent = self.expr_parent;
 
        call_expr.parent = old_expr_parent;
 

	
 
        for arg_expr_idx in old_num_exprs..new_num_exprs {
 
            let arg_expr_id = self.expression_buffer[arg_expr_idx];
 
        for arg_expr_idx in 0..section.len() {
 
            let arg_expr_id = section[arg_expr_idx];
 
            self.expr_parent = ExpressionParent::Expression(upcast_id, arg_expr_idx as u32);
 
            self.visit_expr(ctx, arg_expr_id)?;
 
        }
 

	
 
        self.expression_buffer.truncate(old_num_exprs);
 
        section.forget();
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_variable_expr(&mut self, ctx: &mut Ctx, id: VariableExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let var_expr = &ctx.heap[id];
 
        let variable_id = self.find_variable(ctx, self.relative_pos_in_block, &var_expr.identifier)?;
 
        let var_expr = &mut ctx.heap[id];
 
        var_expr.declaration = Some(variable_id);
 
        var_expr.parent = self.expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // ParserType visitors
 
    //--------------------------------------------------------------------------
 

	
 
    fn visit_parser_type(&mut self, ctx: &mut Ctx, id: ParserTypeId) -> VisitorResult {
 
        let old_num_types = self.parser_type_buffer.len();
 
        match self.visit_parser_type_without_buffer_cleanup(ctx, id) {
 
            Ok(_) => {
 
                debug_assert_eq!(self.parser_type_buffer.len(), old_num_types);
 
                Ok(())
 
            },
 
            Err(err) => {
 
                self.parser_type_buffer.truncate(old_num_types);
 
                Err(err)
 
            }
 
        }
 
    }
 
}
 

	
 
impl ValidityAndLinkerVisitor {
 
impl PassValidationLinking {
 
    //--------------------------------------------------------------------------
 
    // Special traversal
 
    //--------------------------------------------------------------------------
 

	
 
    /// Will visit a statement with a hint about its wrapping statement. This is
 
    /// used to distinguish block statements with a wrapping synchronous
 
    /// statement from normal block statements.
 
    fn visit_stmt_with_hint(&mut self, ctx: &mut Ctx, id: StatementId, hint: Option<SynchronousStatementId>) -> VisitorResult {
 
        if let Statement::Block(block_stmt) = &ctx.heap[id] {
 
            let block_id = block_stmt.this;
 
            self.visit_block_stmt_with_hint(ctx, block_id, hint)
 
        } else {
 
            self.visit_stmt(ctx, id)
 
        }
 
    }
 

	
 
    fn visit_block_stmt_with_hint(&mut self, ctx: &mut Ctx, id: BlockStatementId, hint: Option<SynchronousStatementId>) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            // Performing a breadth pass, so don't traverse into the statements
 
            // of the block.
 
            return Ok(())
 
        }
 

	
 
        // Set parent scope and relative position in the parent scope. Remember
 
        // these values to set them back to the old values when we're done with
 
        // the traversal of the block's statements.
 
        let body = &mut ctx.heap[id];
 
        body.parent_scope = self.cur_scope.clone();
 
        body.relative_pos_in_parent = self.relative_pos_in_block;
 

	
 
        let old_scope = self.cur_scope.replace(match hint {
 
            Some(sync_id) => Scope::Synchronous((sync_id, id)),
 
            None => Scope::Regular(id),
 
        });
 
        let old_relative_pos = self.relative_pos_in_block;
 

	
 
        // Copy statement IDs into buffer
 
        let old_num_stmts = self.statement_buffer.len();
 
        {
 
            let body = &ctx.heap[id];
 
            self.statement_buffer.extend_from_slice(&body.statements);
 
        }
 
        let new_num_stmts = self.statement_buffer.len();
 
        let statement_section = self.statement_buffer.start_section_initialized(&body.statements);
 

	
 
        // Perform the breadth-first pass. Its main purpose is to find labeled
 
        // statements such that we can find the `goto`-targets immediately when
 
        // performing the depth pass
 
        self.performing_breadth_pass = true;
 
        for stmt_idx in old_num_stmts..new_num_stmts {
 
            self.relative_pos_in_block = (stmt_idx - old_num_stmts) as u32;
 
            self.visit_stmt(ctx, self.statement_buffer[stmt_idx])?;
 
        for stmt_idx in 0..statement_section.len() {
 
            self.relative_pos_in_block = stmt_idx as u32;
 
            self.visit_statement_for_locals_labels_and_in_sync(ctx, self.relative_pos_in_block, statement_section[stmt_idx])?;
 
        }
 

	
 
        // And the depth pass. Because we're not actually visiting any inserted
 
        // nodes because we're using the statement buffer, we may safely use the
 
        // relative_pos_in_block counter.
 
        self.performing_breadth_pass = false;
 
        for stmt_idx in old_num_stmts..new_num_stmts {
 
            self.relative_pos_in_block = (stmt_idx - old_num_stmts) as u32;
 
            self.visit_stmt(ctx, self.statement_buffer[stmt_idx])?;
 
        for stmt_idx in 0..statement_section.len() {
 
            self.relative_pos_in_block = stmt_idx as u32;
 
            self.visit_stmt(ctx, statement_section[stmt_idx])?;
 
        }
 

	
 
        self.cur_scope = old_scope;
 
        self.relative_pos_in_block = old_relative_pos;
 

	
 
        // Pop statement buffer
 
        self.statement_buffer.truncate(old_num_stmts);
 
        statement_section.forget();
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_statement_for_locals_labels_and_in_sync(&mut self, ctx: &mut Ctx, relative_pos: u32, id: StatementId) -> VisitorResult {
 
        let statement = &mut ctx.heap[id];
 
        match statement {
 
            Statement::Local(stmt) => {
 
                match stmt {
 
                    LocalStatement::Memory(local) => {
 
                        let variable_id = local.variable;
 
                        self.checked_local_add(ctx, relative_pos, variable_id)?;
 
                    },
 
                    LocalStatement::Channel(local) => {
 
                        let from_id = local.from;
 
                        let to_id = local.to;
 
                        self.checked_local_add(ctx, relative_pos, from_id)?;
 
                        self.checked_local_add(ctx, relative_pos, to_id)?;
 
                    }
 
                }
 
            }
 
            Statement::Labeled(stmt) => {
 
                let stmt_id = stmt.this;
 
                self.checked_label_add(ctx, relative_pos, self.in_sync, stmt_id)?;
 
                self.visit_statement_for_locals_labels_and_in_sync(ctx, relative_pos, stmt.body)?;
 
            },
 
            Statement::While(stmt) => {
 
                stmt.in_sync = self.in_sync;
 
            },
 
            _ => {},
 
        }
 

	
 
        return Ok(())
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Utilities
 
    //--------------------------------------------------------------------------
 

	
 
    /// Adds a local variable to the current scope. It will also annotate the
 
    /// `Local` in the AST with its relative position in the block.
 
    fn checked_local_add(&mut self, ctx: &mut Ctx, relative_pos: u32, id: LocalId) -> Result<(), ParseError> {
 
        debug_assert!(self.cur_scope.is_some());
 

	
 
        // Make sure we do not conflict with any global symbols
 
        let cur_scope = SymbolScope::Definition(self.def_type.definition_id())
 
        {
 
            let ident = &ctx.heap[id].identifier;
 
            if let Some(symbol) = ctx.symbols.resolve_symbol(ctx.module.root_id, &ident.value) {
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, ident.position, "Local variable declaration conflicts with symbol")
 
                        .with_postfixed_info(&ctx.module.source, symbol.position, "Conflicting symbol is found here")
 
                );
 
            if let Some(symbol) = ctx.symbols.get_symbol_by_name(cur_scope, &ident.value.as_bytes()) {
 
                return Err(ParseError::new_error_str_at_span(
 
                    &ctx.module.source, symbol.variant.span_of_introduction(&ctx.heap),
 
                    "local variable declaration conflicts with symbol"
 
                ).with_postfixed_info(
 
                    &ctx.module.source, symbol.position, "the conflicting symbol is introduced here"
 
                ));
 
            }
 
        }
 

	
 
        let local = &mut ctx.heap[id];
 
        local.relative_pos_in_block = relative_pos;
 

	
 
        // Make sure we do not shadow any variables in any of the scopes. Note
 
        // that variables in parent scopes may be declared later
 
        let local = &ctx.heap[id];
 
        let mut scope = self.cur_scope.as_ref().unwrap();
 
        let mut local_relative_pos = self.relative_pos_in_block;
 

	
 
        loop {
 
            debug_assert!(scope.is_block(), "scope is not a block");
 
            let block = &ctx.heap[scope.to_block()];
 
            for other_local_id in &block.locals {
 
                let other_local = &ctx.heap[*other_local_id];
 
                // Position check in case another variable with the same name
 
                // is defined in a higher-level scope, but later than the scope
 
                // in which the current variable resides.
 
                if local.this != *other_local_id &&
 
                    local_relative_pos >= other_local.relative_pos_in_block &&
 
                    local.identifier == other_local.identifier {
 
                    // Collision within this scope
 
                    return Err(
 
                        ParseError::new_error(&ctx.module.source, local.position, "Local variable name conflicts with another variable")
 
                            .with_postfixed_info(&ctx.module.source, other_local.position, "Previous variable is found here")
 
                    );
 
                }
 
            }
 

	
 
            // Current scope is fine, move to parent scope if any
 
            debug_assert!(block.parent_scope.is_some(), "block scope does not have a parent");
 
            scope = block.parent_scope.as_ref().unwrap();
 
            if let Scope::Definition(definition_id) = scope {
 
                // At outer scope, check parameters of function/component
 
                for parameter_id in ctx.heap[*definition_id].parameters() {
 
                    let parameter = &ctx.heap[*parameter_id];
 
                    if local.identifier == parameter.identifier {
 
                        return Err(
 
                            ParseError::new_error(&ctx.module.source, local.position, "Local variable name conflicts with parameter")
 
                                .with_postfixed_info(&ctx.module.source, parameter.position, "Parameter definition is found here")
 
                        );
 
                    }
 
                }
 

	
 
                break;
 
            }
 

	
 
            // If here, then we are dealing with a block-like parent block
 
            local_relative_pos = ctx.heap[scope.to_block()].relative_pos_in_parent;
 
        }
 

	
 
        // No collisions at all
 
        let block = &mut ctx.heap[self.cur_scope.as_ref().unwrap().to_block()];
 
        block.locals.push(id);
 

	
 
        Ok(())
 
    }
 

	
 
    /// Finds a variable in the visitor's scope that must appear before the
 
    /// specified relative position within that block.
 
    fn find_variable(&self, ctx: &Ctx, mut relative_pos: u32, identifier: &NamespacedIdentifier) -> Result<VariableId, ParseError> {
 
    fn find_variable(&self, ctx: &Ctx, mut relative_pos: u32, identifier: &Identifier) -> Result<VariableId, ParseError> {
 
        debug_assert!(self.cur_scope.is_some());
 
        debug_assert!(identifier.parts.len() == 1, "implement namespaced seeking of target associated with identifier");
 

	
 
        // TODO: May still refer to an alias of a global symbol using a single
 
        //  identifier in the namespace.
 
        // No need to use iterator over namespaces if here
 
        let mut scope = self.cur_scope.as_ref().unwrap();
 
        
 
        loop {
 
            debug_assert!(scope.is_block());
 
            let block = &ctx.heap[scope.to_block()];
 
            
 
            for local_id in &block.locals {
 
                let local = &ctx.heap[*local_id];
 
                
 
                if local.relative_pos_in_block < relative_pos && identifier.matches_identifier(&local.identifier) {
 
                    return Ok(local_id.upcast());
 
                }
 
            }
 

	
 
            debug_assert!(block.parent_scope.is_some());
 
            scope = block.parent_scope.as_ref().unwrap();
 
            if !scope.is_block() {
 
                // Definition scope, need to check arguments to definition
 
                match scope {
 
                    Scope::Definition(definition_id) => {
 
                        let definition = &ctx.heap[*definition_id];
 
                        for parameter_id in definition.parameters() {
 
                            let parameter = &ctx.heap[*parameter_id];
 
                            if identifier.matches_identifier(&parameter.identifier) {
 
                                return Ok(parameter_id.upcast());
 
                            }
 
                        }
 
                    },
 
                    _ => unreachable!(),
 
                }
 

	
 
                // Variable could not be found
 
                return Err(ParseError::new_error(
 
                    &ctx.module.source, identifier.position, "This variable is not declared"
 
                return Err(ParseError::new_error_str_at_span(
 
                    &ctx.module.source, identifier.span, "unresolved variable"
 
                ));
 
            } else {
 
                relative_pos = block.relative_pos_in_parent;
 
            }
 
        }
 
    }
 

	
 
    /// Adds a particular label to the current scope. Will return an error if
 
    /// there is another label with the same name visible in the current scope.
 
    fn checked_label_add(&mut self, ctx: &mut Ctx, id: LabeledStatementId) -> Result<(), ParseError> {
 
    fn checked_label_add(&mut self, ctx: &mut Ctx, relative_pos: u32, in_sync: Option<SynchronousStatementId>, id: LabeledStatementId) -> Result<(), ParseError> {
 
        debug_assert!(self.cur_scope.is_some());
 

	
 
        // Make sure label is not defined within the current scope or any of the
 
        // parent scope.
 
        let label = &ctx.heap[id];
 
        let label = &mut ctx.heap[id];
 
        label.relative_pos_in_block = relative_pos;
 
        label.in_sync = in_sync;
 

	
 
        let label = &*label;
 
        let mut scope = self.cur_scope.as_ref().unwrap();
 

	
 
        loop {
 
            debug_assert!(scope.is_block(), "scope is not a block");
 
            let block = &ctx.heap[scope.to_block()];
 
            for other_label_id in &block.labels {
 
                let other_label = &ctx.heap[*other_label_id];
 
                if other_label.label == label.label {
 
                    // Collision
 
                    return Err(
 
                        ParseError::new_error(&ctx.module.source, label.position, "Label name conflicts with another label")
 
                            .with_postfixed_info(&ctx.module.source, other_label.position, "Other label is found here")
 
                    );
 
                    return Err(ParseError::new_error_str_at_span(
 
                        &ctx.module.source, label.label.span, "label name is used more than once"
 
                    ).with_postfixed_info(
 
                        &ctx.module.source, other_label.label.span, "the other label is found here"
 
                    ));
 
                }
 
            }
 

	
 
            debug_assert!(block.parent_scope.is_some(), "block scope does not have a parent");
 
            scope = block.parent_scope.as_ref().unwrap();
 
            if !scope.is_block() {
 
                break;
 
            }
 
        }
 

	
 
        // No collisions
 
        let block = &mut ctx.heap[self.cur_scope.as_ref().unwrap().to_block()];
 
        block.labels.push(id);
 

	
 
        Ok(())
 
    }
 

	
 
    /// Finds a particular labeled statement by its identifier. Once found it
 
    /// will make sure that the target label does not skip over any variable
 
    /// declarations within the scope in which the label was found.
 
    fn find_label(&self, ctx: &Ctx, identifier: &Identifier) -> Result<LabeledStatementId, ParseError> {
 
        debug_assert!(self.cur_scope.is_some());
 

	
 
        let mut scope = self.cur_scope.as_ref().unwrap();
 
        loop {
 
            debug_assert!(scope.is_block(), "scope is not a block");
 
            let relative_scope_pos = ctx.heap[scope.to_block()].relative_pos_in_parent;
 

	
 
            let block = &ctx.heap[scope.to_block()];
 
            for label_id in &block.labels {
 
                let label = &ctx.heap[*label_id];
 
                if label.label == *identifier {
 
                    for local_id in &block.locals {
 
                        // TODO: Better to do this in control flow analysis, it
 
                        //  is legal to skip over a variable declaration if it
 
                        //  is not actually being used. I might be missing
 
                        //  something here when laying out the bytecode...
 
                        let local = &ctx.heap[*local_id];
 
                        if local.relative_pos_in_block > relative_scope_pos && local.relative_pos_in_block < label.relative_pos_in_block {
 
                            return Err(
 
                                ParseError::new_error(&ctx.module.source, identifier.position, "This target label skips over a variable declaration")
 
                                    .with_postfixed_info(&ctx.module.source, label.position, "Because it jumps to this label")
 
                                    .with_postfixed_info(&ctx.module.source, local.position, "Which skips over this variable")
 
                                ParseError::new_error_str_at_span(&ctx.module.source, identifier.span, "this target label skips over a variable declaration")
 
                                .with_postfixed_info(&ctx.module.source, label.label.span, "because it jumps to this label")
 
                                .with_postfixed_info(&ctx.module.source, local.identifier.span, "which skips over this variable")
 
                            );
 
                        }
 
                    }
 
                    return Ok(*label_id);
 
                }
 
            }
 

	
 
            debug_assert!(block.parent_scope.is_some(), "block scope does not have a parent");
 
            scope = block.parent_scope.as_ref().unwrap();
 
            if !scope.is_block() {
 
                return Err(ParseError::new_error(&ctx.module.source, identifier.position, "Could not find this label"));
 
                return Err(ParseError::new_error_str_at_span(
 
                    &ctx.module.source, identifier.span, "could not find this label"
 
                ));
 
            }
 

	
 
        }
 
    }
 

	
 
    /// Finds a particular symbol in the symbol table which must correspond to
 
    /// a definition of a particular type.
 
    // Note: root_id, symbols and types passed in explicitly to prevent
 
    //  borrowing errors
 
    fn find_symbol_of_type<'t>(
 
        &self, source: &InputSource, root_id: RootId, symbols: &SymbolTable, 
 
        types: &'t TypeTable, identifier: &NamespacedIdentifier, 
 
        expected_type_class: TypeClass
 
    ) -> Result<&'t DefinedType, ParseError> {
 
        // Find symbol associated with identifier
 
        let (find_result, _) = find_type_definition(symbols, types, root_id, identifier)
 
            .as_parse_error(source)?;
 

	
 
        let definition_type_class = find_result.definition.type_class();
 
        if expected_type_class != definition_type_class {
 
            return Err(ParseError::new_error(
 
                source, identifier.position,
 
                &format!(
 
                    "Expected to find a {}, this symbol points to a {}",
 
                    expected_type_class, definition_type_class
 
                )
 
            ))
 
        }
 

	
 
        Ok(find_result)
 
    }
 

	
 
    /// Finds a particular enum/union using a namespaced identifier. We allow 
 
    /// for one more element to exist in the namespaced identifier that 
 
    /// supposedly resolves to the enum/union variant.
 
    fn find_symbol_of_type_variant<'t, 'i>(
 
        &self, source: &InputSource, root_id: RootId, symbols: &SymbolTable,
 
        types: &'t TypeTable, identifier: &'i NamespacedIdentifier,
 
        expected_type_class: TypeClass
 
    ) -> Result<(&'t DefinedType, NamespacedIdentifierIter<'i>), ParseError> {
 
        debug_assert!(expected_type_class == TypeClass::Enum || expected_type_class == TypeClass::Union);
 
        let (symbol, mut ident_iter) = symbols.resolve_namespaced_identifier(root_id, identifier);
 

	
 
        if symbol.is_none() {
 
            return Err(ParseError::new_error(
 
                source, identifier.position, 
 
                "Could not resolve this identifier to a symbol"
 
            ));
 
        }
 

	
 
        let symbol = symbol.unwrap();
 
        match symbol.symbol {
 
            Symbol::Namespace(_) => {
 
                return Err(ParseError::new_error(
 
                    source, identifier.position, 
 
                    "This identifier was resolved to a namespace instead of a type"
 
                ))
 
            },
 
            Symbol::Definition((_, definition_id)) => {
 
                let definition = types.get_base_definition(&definition_id);
 
                debug_assert!(definition.is_some());
 
                let definition = definition.unwrap();
 

	
 
                let definition_type_class = definition.definition.type_class();
 
                if expected_type_class != definition_type_class {
 
                    return Err(ParseError::new_error(
 
                        source, identifier.position,
 
                        &format!(
 
                            "Expected to find a {}, this symbols points to a {}",
 
                            expected_type_class, definition_type_class
 
                        )
 
                    ));
 
                }
 

	
 
                // Make sure we have a variant (that doesn't contain any 
 
                // polymorphic args)
 
                let next_part = ident_iter.next();
 
                if next_part.is_none() {
 
                    return Err(ParseError::new_error(
 
                        source, identifier.position,
 
                        &format!(
 
                            "This identifier points to the type '{}', did you mean to instantiate a variant?",
 
                            String::from_utf8_lossy(&identifier.value)
 
                        )
 
                    ));
 
                }
 
                let (_, next_polyargs) = next_part.unwrap();
 

	
 
                // Now we make sure that there aren't even more identifiers, and
 
                // make sure that the variant does not contain any polymorphic
 
                // arguments. In that case we can simplify the later visit of
 
                // the (optional) polymorphic args of the enum.
 
                let returned_section = ident_iter.returned_section();
 
                if ident_iter.num_remaining() != 0 {
 
                    return Err(ParseError::new_error(
 
                        source, identifier.position,
 
                        &format!(
 
                            "Too many identifiers, did you mean to write '{}'",
 
                            &String::from_utf8_lossy(returned_section)
 
                        )
 
                    ));
 
                }
 

	
 
                if next_polyargs.is_some() {
 
                    return Err(ParseError::new_error(
 
                        source, identifier.position,
 
                        "Encountered polymorphic args to an enum variant. These can only be specified for the enum type."
 
                    ))
 
                }
 

	
 
                // We're absolutely fine
 
                Ok((definition, ident_iter))
 
            }
 
        }
 
    }
 

	
 
    /// This function will check if the provided while statement ID has a block
 
    /// statement that is one of our current parents.
 
    fn has_parent_while_scope(&self, ctx: &Ctx, id: WhileStatementId) -> bool {
 
        debug_assert!(self.cur_scope.is_some());
 
        let mut scope = self.cur_scope.as_ref().unwrap();
 
        let while_stmt = &ctx.heap[id];
 
        loop {
 
            debug_assert!(scope.is_block());
 
            let block = scope.to_block();
 
            if while_stmt.body == block.upcast() {
 
                return true;
 
            }
 

	
 
            let block = &ctx.heap[block];
 
            debug_assert!(block.parent_scope.is_some(), "block scope does not have a parent");
 
            scope = block.parent_scope.as_ref().unwrap();
 
            if !scope.is_block() {
 
                return false;
 
            }
 
        }
 
    }
 

	
 
    /// This function should be called while dealing with break/continue
 
    /// statements. It will try to find the targeted while statement, using the
 
    /// target label if provided. If a valid target is found then the loop's
 
    /// ID will be returned, otherwise a parsing error is constructed.
 
    /// The provided input position should be the position of the break/continue
 
    /// statement.
 
    fn resolve_break_or_continue_target(&self, ctx: &Ctx, position: InputPosition, label: &Option<Identifier>) -> Result<WhileStatementId, ParseError> {
 
        let target = match label {
 
            Some(label) => {
 
                let target_id = self.find_label(ctx, label)?;
 

	
 
                // Make sure break target is a while statement
 
                let target = &ctx.heap[target_id];
 
                if let Statement::While(target_stmt) = &ctx.heap[target.body] {
 
                    // Even though we have a target while statement, the break might not be
 
                    // present underneath this particular labeled while statement
 
                    if !self.has_parent_while_scope(ctx, target_stmt.this) {
 
                        ParseError::new_error(&ctx.module.source, label.position, "Break statement is not nested under the target label's while statement")
 
                            .with_postfixed_info(&ctx.module.source, target.position, "The targeted label is found here");
 
                    }
 

	
 
                    target_stmt.this
 
                } else {
 
                    return Err(
 
                        ParseError::new_error(&ctx.module.source, label.position, "Incorrect break target label, it must target a while loop")
 
                            .with_postfixed_info(&ctx.module.source, target.position, "The targeted label is found here")
 
                    );
 
                }
 
            },
 
            None => {
 
                // Use the enclosing while statement, the break must be
 
                // nested within that while statement
 
                if self.in_while.is_none() {
 
                    return Err(
 
                        ParseError::new_error(&ctx.module.source, position, "Break statement is not nested under a while loop")
 
                    );
 
                }
 

	
 
                self.in_while.unwrap()
 
            }
 
        };
 

	
 
        // We have a valid target for the break statement. But we need to
 
        // make sure we will not break out of a synchronous block
 
        {
 
            let target_while = &ctx.heap[target];
 
            if target_while.in_sync != self.in_sync {
 
                // Break is nested under while statement, so can only escape a
 
                // sync block if the sync is nested inside the while statement.
 
                debug_assert!(self.in_sync.is_some());
 
                let sync_stmt = &ctx.heap[self.in_sync.unwrap()];
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, position, "Break may not escape the surrounding synchronous block")
 
                        .with_postfixed_info(&ctx.module.source, target_while.position, "The break escapes out of this loop")
 
                        .with_postfixed_info(&ctx.module.source, sync_stmt.position, "And would therefore escape this synchronous block")
 
                );
 
            }
 
        }
 

	
 
        Ok(target)
 
    }
 

	
 
    fn visit_literal_poly_args(&mut self, ctx: &mut Ctx, lit_id: LiteralExpressionId) -> VisitorResult {
 
        // TODO: @token Revisit when tokenizer is implemented
 
        let literal_expr = &mut ctx.heap[lit_id];
 
        match &mut literal_expr.value {
 
            Literal::Struct(literal) => {
 
                literal.poly_args2.extend(&literal.identifier.poly_args);
 
            },
 
            Literal::Enum(literal) => {
 
                literal.poly_args2.extend(&literal.identifier.poly_args);
 
            },
 
            Literal::Union(literal) => {
 
                literal.poly_args2.extend(&literal.identifier.poly_args);
 
            }
 
            _ => {
 
                debug_assert!(false, "called visit_literal_poly_args on a non-polymorphic literal");
 
                unreachable!();
 
            }
 
        }
 

	
 
        let literal_expr = &ctx.heap[lit_id];
 
        let literal_pos = literal_expr.position;
 
        let (num_poly_args_to_infer, poly_args_to_visit) = match &literal_expr.value {
 
            Literal::Null | Literal::False | Literal::True |
 
            Literal::Character(_) | Literal::Integer(_) => {
 
                // Not really an error, but a programmer error as we're likely
 
                // doing work twice
 
                unreachable!();
 
            },
 
            Literal::Struct(literal) => {
 
                // Retrieve type and make sure number of specified polymorphic
 
                // arguments is correct.
 
                let defined_type = ctx.types.get_base_definition(literal.definition.as_ref().unwrap())
 
                    .unwrap();
 
                let maybe_poly_args = literal.identifier.get_poly_args();
 
                let num_to_infer = match_polymorphic_args_to_vars(
 
                    defined_type, maybe_poly_args, literal.identifier.position
 
                ).as_parse_error(&ctx.heap, &ctx.module.source)?;
 

	
 
                (num_to_infer, &literal.poly_args2)
 
            },
 
            Literal::Enum(literal) => {
 
                let defined_type = ctx.types.get_base_definition(literal.definition.as_ref().unwrap())
 
                    .unwrap();
 
                let maybe_poly_args = literal.identifier.get_poly_args();
 
                let num_to_infer = match_polymorphic_args_to_vars(
 
                    defined_type, maybe_poly_args, literal.identifier.position
 
                ).as_parse_error(&ctx.heap, &ctx.module.source)?;
 

	
 
                (num_to_infer, &literal.poly_args2)
 
            },
 
            Literal::Union(literal) => {
 
                let defined_type = ctx.types.get_base_definition(literal.definition.as_ref().unwrap())
 
                    .unwrap();
 
                let maybe_poly_args = literal.identifier.get_poly_args();
 
                let num_to_infer = match_polymorphic_args_to_vars(
 
                    defined_type, maybe_poly_args, literal.identifier.position
 
                ).as_parse_error(&ctx.heap, &ctx.module.source)?;
 

	
 
                (num_to_infer, &literal.poly_args2)
 
            }
 
        };
 

	
 
        // Visit all specified parser types in the polymorphic arguments
 
        let old_num_types = self.parser_type_buffer.len();
 
        self.parser_type_buffer.extend(poly_args_to_visit);
 
        while self.parser_type_buffer.len() > old_num_types {
 
            let parser_type_id = self.parser_type_buffer.pop().unwrap();
 
            self.visit_parser_type(ctx, parser_type_id)?;
 
        }
 
        self.parser_type_buffer.truncate(old_num_types);
 

	
 
        if num_poly_args_to_infer != 0 {
 
            for _ in 0..num_poly_args_to_infer {
 
                self.parser_type_buffer.push(ctx.heap.alloc_parser_type(|this| ParserType{
 
                    this, pos: literal_pos, variant: ParserTypeVariant::Inferred
 
                }));
 
            }
 

	
 
            let poly_args = match &mut ctx.heap[lit_id].value {
 
                Literal::Struct(literal) => &mut literal.poly_args2,
 
                Literal::Enum(literal) => &mut literal.poly_args2,
 
                Literal::Union(literal) => &mut literal.poly_args2,
 
                _ => unreachable!(),
 
            };
 
            poly_args.reserve(num_poly_args_to_infer);
 
            for _ in 0..num_poly_args_to_infer {
 
                poly_args.push(self.parser_type_buffer.pop().unwrap());
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 
}
 
\ No newline at end of file
src/protocol/parser/type_resolver.rs
Show inline comments
 
@@ -2001,1537 +2001,1537 @@ impl TypeResolvingVisitor {
 
            Literal::Character(_) => todo!("character literals"),
 
            Literal::Struct(data) => {
 
                let extra = self.extra_data.get_mut(&upcast_id).unwrap();
 
                for poly in &extra.poly_vars {
 
                    debug_log!(" * Poly: {}", poly.display_name(&ctx.heap));
 
                }
 
                let mut poly_progress = HashSet::new();
 
                debug_assert_eq!(extra.embedded.len(), data.fields.len());
 

	
 
                debug_log!(" * During (inferring types from fields and struct type):");
 

	
 
                // Mutually infer field signature/expression types
 
                for (field_idx, field) in data.fields.iter().enumerate() {
 
                    let field_expr_id = field.value;
 
                    let signature_type: *mut _ = &mut extra.embedded[field_idx];
 
                    let field_type: *mut _ = self.expr_types.get_mut(&field_expr_id).unwrap();
 
                    let (_, progress_arg) = Self::apply_equal2_signature_constraint(
 
                        ctx, upcast_id, Some(field_expr_id), extra, &mut poly_progress,
 
                        signature_type, 0, field_type, 0
 
                    )?;
 

	
 
                    debug_log!(
 
                        "   - Field {} type | sig: {}, field: {}", field_idx,
 
                        unsafe{&*signature_type}.display_name(&ctx.heap),
 
                        unsafe{&*field_type}.display_name(&ctx.heap)
 
                    );
 

	
 
                    if progress_arg {
 
                        self.expr_queued.insert(field_expr_id);
 
                    }
 
                }
 

	
 
                debug_log!("   - Field poly progress | {:?}", poly_progress);
 

	
 
                // Same for the type of the struct itself
 
                let signature_type: *mut _ = &mut extra.returned;
 
                let expr_type: *mut _ = self.expr_types.get_mut(&upcast_id).unwrap();
 
                let (_, progress_expr) = Self::apply_equal2_signature_constraint(
 
                    ctx, upcast_id, None, extra, &mut poly_progress,
 
                    signature_type, 0, expr_type, 0
 
                )?;
 

	
 
                debug_log!(
 
                    "   - Ret type | sig: {}, expr: {}",
 
                    unsafe{&*signature_type}.display_name(&ctx.heap),
 
                    unsafe{&*expr_type}.display_name(&ctx.heap)
 
                );
 
                debug_log!("   - Ret poly progress | {:?}", poly_progress);
 

	
 
                if progress_expr {
 
                    // TODO: @cleanup, cannot call utility self.queue_parent thingo
 
                    if let Some(parent_id) = ctx.heap[upcast_id].parent_expr_id() {
 
                        self.expr_queued.insert(parent_id);
 
                    }
 
                }
 

	
 
                // Check which expressions use the polymorphic arguments. If the
 
                // polymorphic variables have been progressed then we try to 
 
                // progress them inside the expression as well.
 
                debug_log!(" * During (reinferring from progressed polyvars):");
 

	
 
                // For all field expressions
 
                for field_idx in 0..extra.embedded.len() {
 
                    debug_assert_eq!(field_idx, data.fields[field_idx].field_idx, "confusing, innit?");
 
                    let signature_type: *mut _ = &mut extra.embedded[field_idx];
 
                    let field_expr_id = data.fields[field_idx].value;
 
                    let field_type: *mut _ = self.expr_types.get_mut(&field_expr_id).unwrap();
 

	
 
                    let progress_arg = Self::apply_equal2_polyvar_constraint(&ctx.heap,
 
                        extra, &poly_progress, signature_type, field_type
 
                    );
 

	
 
                    debug_log!(
 
                        "   - Field {} type | sig: {}, field: {}", field_idx,
 
                        unsafe{&*signature_type}.display_name(&ctx.heap),
 
                        unsafe{&*field_type}.display_name(&ctx.heap)
 
                    );
 
                    if progress_arg {
 
                        self.expr_queued.insert(field_expr_id);
 
                    }
 
                }
 
                
 
                // For the return type
 
                let signature_type: *mut _ = &mut extra.returned;
 
                let expr_type: *mut _ = self.expr_types.get_mut(&upcast_id).unwrap();
 

	
 
                let progress_expr = Self::apply_equal2_polyvar_constraint(
 
                    &ctx.heap, extra, &poly_progress, signature_type, expr_type
 
                );
 

	
 
                progress_expr
 
            },
 
            Literal::Enum(_) => {
 
                let extra = self.extra_data.get_mut(&upcast_id).unwrap();
 
                for poly in &extra.poly_vars {
 
                    debug_log!(" * Poly: {}", poly.display_name(&ctx.heap));
 
                }
 
                let mut poly_progress = HashSet::new();
 
                
 
                debug_log!(" * During (inferring types from return type)");
 

	
 
                let signature_type: *mut _ = &mut extra.returned;
 
                let expr_type: *mut _ = self.expr_types.get_mut(&upcast_id).unwrap();
 
                let (_, progress_expr) = Self::apply_equal2_signature_constraint(
 
                    ctx, upcast_id, None, extra, &mut poly_progress,
 
                    signature_type, 0, expr_type, 0
 
                )?;
 

	
 
                debug_log!(
 
                    "   - Ret type | sig: {}, expr: {}",
 
                    unsafe{&*signature_type}.display_name(&ctx.heap),
 
                    unsafe{&*expr_type}.display_name(&ctx.heap)
 
                );
 

	
 
                if progress_expr {
 
                    // TODO: @cleanup
 
                    if let Some(parent_id) = ctx.heap[upcast_id].parent_expr_id() {
 
                        self.expr_queued.insert(parent_id);
 
                    }
 
                }
 

	
 
                debug_log!(" * During (reinferring from progress polyvars):");
 
                let progress_expr = Self::apply_equal2_polyvar_constraint(
 
                    &ctx.heap, extra, &poly_progress, signature_type, expr_type
 
                );
 

	
 
                progress_expr
 
            },
 
            Literal::Union(data) => {
 
                let extra = self.extra_data.get_mut(&upcast_id).unwrap();
 
                for poly in &extra.poly_vars {
 
                    debug_log!(" * Poly: {}", poly.display_name(&ctx.heap));
 
                }
 
                let mut poly_progress = HashSet::new();
 
                debug_assert_eq!(extra.embedded.len(), data.values.len());
 

	
 
                debug_log!(" * During (inferring types from variant values and union type):");
 

	
 
                // Mutually infer union variant values
 
                for (value_idx, value_expr_id) in data.values.iter().enumerate() {
 
                    let value_expr_id = *value_expr_id;
 
                    let signature_type: *mut _ = &mut extra.embedded[value_idx];
 
                    let value_type: *mut _ = self.expr_types.get_mut(&value_expr_id).unwrap();
 
                    let (_, progress_arg) = Self::apply_equal2_signature_constraint(
 
                        ctx, upcast_id, Some(value_expr_id), extra, &mut poly_progress,
 
                        signature_type, 0, value_type, 0 
 
                    )?;
 

	
 
                    debug_log!(
 
                        "   - Value {} type | sig: {}, field: {}", value_idx,
 
                        unsafe{&*signature_type}.display_name(&ctx.heap),
 
                        unsafe{&*value_type}.display_name(&ctx.heap)
 
                    );
 

	
 
                    if progress_arg {
 
                        self.expr_queued.insert(value_expr_id);
 
                    }
 
                }
 

	
 
                debug_log!("   - Field poly progress | {:?}", poly_progress);
 

	
 
                // Infer type of union itself
 
                let signature_type: *mut _ = &mut extra.returned;
 
                let expr_type: *mut _ = self.expr_types.get_mut(&upcast_id).unwrap();
 
                let (_, progress_expr) = Self::apply_equal2_signature_constraint(
 
                    ctx, upcast_id, None, extra, &mut poly_progress,
 
                    signature_type, 0, expr_type, 0
 
                )?;
 

	
 
                debug_log!(
 
                    "   - Ret type | sig: {}, expr: {}",
 
                    unsafe{&*signature_type}.display_name(&ctx.heap),
 
                    unsafe{&*expr_type}.display_name(&ctx.heap)
 
                );
 
                debug_log!("   - Ret poly progress | {:?}", poly_progress);
 

	
 
                if progress_expr {
 
                    // TODO: @cleanup, borrowing rules
 
                    if let Some(parent_id) = ctx.heap[upcast_id].parent_expr_id() {
 
                        self.expr_queued.insert(parent_id);
 
                    }
 
                }
 

	
 
                debug_log!(" * During (reinferring from progress polyvars):");
 
            
 
                // For all embedded values of the union variant
 
                for value_idx in 0..extra.embedded.len() {
 
                    let signature_type: *mut _ = &mut extra.embedded[value_idx];
 
                    let value_expr_id = data.values[value_idx];
 
                    let value_type: *mut _ = self.expr_types.get_mut(&value_expr_id).unwrap();
 
                    
 
                    let progress_arg = Self::apply_equal2_polyvar_constraint(
 
                        &ctx.heap, extra, &poly_progress, signature_type, value_type
 
                    );
 

	
 
                    debug_log!(
 
                        "   - Value {} type | sig: {}, value: {}", value_idx,
 
                        unsafe{&*signature_type}.display_name(&ctx.heap),
 
                        unsafe{&*value_type}.display_name(&ctx.heap)
 
                    );
 
                    if progress_arg {
 
                        self.expr_queued.insert(value_expr_id);
 
                    }
 
                }
 

	
 
                // And for the union type itself
 
                let signature_type: *mut _ = &mut extra.returned;
 
                let expr_type: *mut _ = self.expr_types.get_mut(&upcast_id).unwrap();
 

	
 
                let progress_expr = Self::apply_equal2_polyvar_constraint(
 
                    &ctx.heap, extra, &poly_progress, signature_type, expr_type
 
                );
 

	
 
                progress_expr
 
            }
 
        };
 

	
 
        debug_log!(" * After:");
 
        debug_log!("   - Expr type: {}", self.expr_types.get(&upcast_id).unwrap().display_name(&ctx.heap));
 

	
 
        // TODO: FIX!!!!
 
        if progress_expr { self.queue_expr_parent(ctx, upcast_id); }
 

	
 
        Ok(())
 
    }
 

	
 
    // TODO: @cleanup, see how this can be cleaned up once I implement
 
    //  polymorphic struct/enum/union literals. These likely follow the same
 
    //  pattern as here.
 
    fn progress_call_expr(&mut self, ctx: &mut Ctx, id: CallExpressionId) -> Result<(), ParseError> {
 
        let upcast_id = id.upcast();
 
        let expr = &ctx.heap[id];
 
        let extra = self.extra_data.get_mut(&upcast_id).unwrap();
 

	
 
        debug_log!("Call expr '{}': {}", match &expr.method {
 
            Method::Create => String::from("create"),
 
            Method::Fires => String::from("fires"),
 
            Method::Get => String::from("get"),
 
            Method::Put => String::from("put"),
 
            Method::Symbolic(method) => String::from_utf8_lossy(&method.identifier.value).to_string()
 
        },upcast_id.index);
 
        debug_log!(" * Before:");
 
        debug_log!("   - Expr type: {}", self.expr_types.get(&upcast_id).unwrap().display_name(&ctx.heap));
 
        debug_log!(" * During (inferring types from arguments and return type):");
 

	
 
        // Check if we can make progress using the arguments and/or return types
 
        // while keeping track of the polyvars we've extended
 
        let mut poly_progress = HashSet::new();
 
        debug_assert_eq!(extra.embedded.len(), expr.arguments.len());
 

	
 
        for (arg_idx, arg_id) in expr.arguments.clone().into_iter().enumerate() {
 
            let signature_type: *mut _ = &mut extra.embedded[arg_idx];
 
            let argument_type: *mut _ = self.expr_types.get_mut(&arg_id).unwrap();
 
            let (_, progress_arg) = Self::apply_equal2_signature_constraint(
 
                ctx, upcast_id, Some(arg_id), extra, &mut poly_progress,
 
                signature_type, 0, argument_type, 0
 
            )?;
 

	
 
            debug_log!(
 
                "   - Arg {} type | sig: {}, arg: {}", arg_idx,
 
                unsafe{&*signature_type}.display_name(&ctx.heap), 
 
                unsafe{&*argument_type}.display_name(&ctx.heap));
 

	
 
            if progress_arg {
 
                // Progressed argument expression
 
                self.expr_queued.insert(arg_id);
 
            }
 
        }
 

	
 
        // Do the same for the return type
 
        let signature_type: *mut _ = &mut extra.returned;
 
        let expr_type: *mut _ = self.expr_types.get_mut(&upcast_id).unwrap();
 
        let (_, progress_expr) = Self::apply_equal2_signature_constraint(
 
            ctx, upcast_id, None, extra, &mut poly_progress,
 
            signature_type, 0, expr_type, 0
 
        )?;
 

	
 
        debug_log!(
 
            "   - Ret type | sig: {}, expr: {}", 
 
            unsafe{&*signature_type}.display_name(&ctx.heap), 
 
            unsafe{&*expr_type}.display_name(&ctx.heap)
 
        );
 

	
 
        if progress_expr {
 
            // TODO: @cleanup, cannot call utility self.queue_parent thingo
 
            if let Some(parent_id) = ctx.heap[upcast_id].parent_expr_id() {
 
                self.expr_queued.insert(parent_id);
 
            }
 
        }
 

	
 
        // If we did not have an error in the polymorph inference above, then
 
        // reapplying the polymorph type to each argument type and the return
 
        // type should always succeed.
 
        debug_log!(" * During (reinferring from progressed polyvars):");
 
        for (poly_idx, poly_var) in extra.poly_vars.iter().enumerate() {
 
            debug_log!("   - Poly {} | sig: {}", poly_idx, poly_var.display_name(&ctx.heap));
 
        }
 
        // TODO: @performance If the algorithm is changed to be more "on demand
 
        //  argument re-evaluation", instead of "all-argument re-evaluation",
 
        //  then this is no longer true
 
        for arg_idx in 0..extra.embedded.len() {
 
            let signature_type: *mut _ = &mut extra.embedded[arg_idx];
 
            let arg_expr_id = expr.arguments[arg_idx];
 
            let arg_type: *mut _ = self.expr_types.get_mut(&arg_expr_id).unwrap();
 
            
 
            let progress_arg = Self::apply_equal2_polyvar_constraint(&ctx.heap,
 
                extra, &poly_progress,
 
                signature_type, arg_type
 
            );
 
            
 
            debug_log!(
 
                "   - Arg {} type | sig: {}, arg: {}", arg_idx, 
 
                unsafe{&*signature_type}.display_name(&ctx.heap), 
 
                unsafe{&*arg_type}.display_name(&ctx.heap)
 
            );
 
            if progress_arg {
 
                self.expr_queued.insert(arg_expr_id);
 
            }
 
        }
 

	
 
        // Once more for the return type
 
        let signature_type: *mut _ = &mut extra.returned;
 
        let ret_type: *mut _ = self.expr_types.get_mut(&upcast_id).unwrap();
 

	
 
        let progress_ret = Self::apply_equal2_polyvar_constraint(&ctx.heap,
 
            extra, &poly_progress, signature_type, ret_type
 
        );
 
        debug_log!(
 
            "   - Ret type | sig: {}, arg: {}", 
 
            unsafe{&*signature_type}.display_name(&ctx.heap), 
 
            unsafe{&*ret_type}.display_name(&ctx.heap)
 
        );
 
        if progress_ret {
 
            self.queue_expr_parent(ctx, upcast_id);
 
        }
 

	
 
        debug_log!(" * After:");
 
        debug_log!("   - Expr type: {}", self.expr_types.get(&upcast_id).unwrap().display_name(&ctx.heap));
 

	
 
        Ok(())
 
    }
 

	
 
    fn progress_variable_expr(&mut self, ctx: &mut Ctx, id: VariableExpressionId) -> Result<(), ParseError> {
 
        let upcast_id = id.upcast();
 
        let var_expr = &ctx.heap[id];
 
        let var_id = var_expr.declaration.unwrap();
 

	
 
        debug_log!("Variable expr '{}': {}", &String::from_utf8_lossy(&ctx.heap[var_id].identifier().value), upcast_id.index);
 
        debug_log!(" * Before:");
 
        debug_log!("   - Var  type: {}", self.var_types.get(&var_id).unwrap().var_type.display_name(&ctx.heap));
 
        debug_log!("   - Expr type: {}", self.expr_types.get(&upcast_id).unwrap().display_name(&ctx.heap));
 

	
 
        // Retrieve shared variable type and expression type and apply inference
 
        let var_data = self.var_types.get_mut(&var_id).unwrap();
 
        let expr_type = self.expr_types.get_mut(&upcast_id).unwrap();
 

	
 
        let infer_res = unsafe{ InferenceType::infer_subtrees_for_both_types(
 
            &mut var_data.var_type as *mut _, 0, expr_type, 0
 
        ) };
 
        if infer_res == DualInferenceResult::Incompatible {
 
            let var_decl = &ctx.heap[var_id];
 
            return Err(ParseError::new_error(
 
                &ctx.module.source, var_decl.position(),
 
                &format!(
 
                    "Conflicting types for this variable, previously assigned the type '{}'",
 
                    var_data.var_type.display_name(&ctx.heap)
 
                )
 
            ).with_postfixed_info(
 
                &ctx.module.source, var_expr.position,
 
                &format!(
 
                    "But inferred to have incompatible type '{}' here",
 
                    expr_type.display_name(&ctx.heap)
 
                )
 
            ))
 
        }
 

	
 
        let progress_var = infer_res.modified_lhs();
 
        let progress_expr = infer_res.modified_rhs();
 

	
 
        if progress_var {
 
            // Let other variable expressions using this type progress as well
 
            for other_expr in var_data.used_at.iter() {
 
                if *other_expr != upcast_id {
 
                    self.expr_queued.insert(*other_expr);
 
                }
 
            }
 

	
 
            // Let a linked port know that our type has updated
 
            if let Some(linked_id) = var_data.linked_var {
 
                // Only perform one-way inference to prevent updating our type, this
 
                // would lead to an inconsistency
 
                let var_type: *mut _ = &mut var_data.var_type;
 
                let link_data = self.var_types.get_mut(&linked_id).unwrap();
 

	
 
                debug_assert!(
 
                    unsafe{&*var_type}.parts[0] == InferenceTypePart::Input ||
 
                    unsafe{&*var_type}.parts[0] == InferenceTypePart::Output
 
                );
 
                debug_assert!(
 
                    link_data.var_type.parts[0] == InferenceTypePart::Input ||
 
                    link_data.var_type.parts[0] == InferenceTypePart::Output
 
                );
 
                match InferenceType::infer_subtree_for_single_type(&mut link_data.var_type, 1, &unsafe{&*var_type}.parts, 1) {
 
                    SingleInferenceResult::Modified => {
 
                        for other_expr in &link_data.used_at {
 
                            self.expr_queued.insert(*other_expr);
 
                        }
 
                    },
 
                    SingleInferenceResult::Unmodified => {},
 
                    SingleInferenceResult::Incompatible => {
 
                        let var_data = self.var_types.get(&var_id).unwrap();
 
                        let link_data = self.var_types.get(&linked_id).unwrap();
 
                        let var_decl = &ctx.heap[var_id];
 
                        let link_decl = &ctx.heap[linked_id];
 

	
 
                        return Err(ParseError::new_error(
 
                            &ctx.module.source, var_decl.position(),
 
                            &format!(
 
                                "Conflicting types for this variable, assigned the type '{}'",
 
                                var_data.var_type.display_name(&ctx.heap)
 
                            )
 
                        ).with_postfixed_info(
 
                            &ctx.module.source, link_decl.position(),
 
                            &format!(
 
                                "Because it is incompatible with this variable, assigned the type '{}'",
 
                                link_data.var_type.display_name(&ctx.heap)
 
                            )
 
                        ));
 
                    }
 
                }
 
            }
 
        }
 
        if progress_expr { self.queue_expr_parent(ctx, upcast_id); }
 

	
 
        debug_log!(" * After:");
 
        debug_log!("   - Var  type [{}]: {}", progress_var, self.var_types.get(&var_id).unwrap().var_type.display_name(&ctx.heap));
 
        debug_log!("   - Expr type [{}]: {}", progress_expr, self.expr_types.get(&upcast_id).unwrap().display_name(&ctx.heap));
 

	
 

	
 
        Ok(())
 
    }
 

	
 
    fn queue_expr_parent(&mut self, ctx: &Ctx, expr_id: ExpressionId) {
 
        if let ExpressionParent::Expression(parent_expr_id, _) = &ctx.heap[expr_id].parent() {
 
            self.expr_queued.insert(*parent_expr_id);
 
        }
 
    }
 

	
 
    fn queue_expr(&mut self, expr_id: ExpressionId) {
 
        self.expr_queued.insert(expr_id);
 
    }
 

	
 
    /// Applies a forced type constraint: the type associated with the supplied
 
    /// expression will be molded into the provided "template". The template may
 
    /// be fully specified (e.g. a bool) or contain "inference" variables (e.g.
 
    /// an array of T)
 
    fn apply_forced_constraint(
 
        &mut self, ctx: &mut Ctx, expr_id: ExpressionId, template: &[InferenceTypePart]
 
    ) -> Result<bool, ParseError> {
 
        debug_assert_expr_ids_unique_and_known!(self, expr_id);
 
        let expr_type = self.expr_types.get_mut(&expr_id).unwrap();
 
        match InferenceType::infer_subtree_for_single_type(expr_type, 0, template, 0) {
 
            SingleInferenceResult::Modified => Ok(true),
 
            SingleInferenceResult::Unmodified => Ok(false),
 
            SingleInferenceResult::Incompatible => Err(
 
                self.construct_template_type_error(ctx, expr_id, template)
 
            )
 
        }
 
    }
 

	
 
    fn apply_forced_constraint_types(
 
        to_infer: *mut InferenceType, to_infer_start_idx: usize,
 
        template: &[InferenceTypePart], template_start_idx: usize
 
    ) -> Result<bool, ()> {
 
        match InferenceType::infer_subtree_for_single_type(
 
            unsafe{ &mut *to_infer }, to_infer_start_idx,
 
            template, template_start_idx
 
        ) {
 
            SingleInferenceResult::Modified => Ok(true),
 
            SingleInferenceResult::Unmodified => Ok(false),
 
            SingleInferenceResult::Incompatible => Err(()),
 
        }
 
    }
 

	
 
    /// Applies a type constraint that expects the two provided types to be
 
    /// equal. We attempt to make progress in inferring the types. If the call
 
    /// is successful then the composition of all types are made equal.
 
    /// The "parent" `expr_id` is provided to construct errors.
 
    fn apply_equal2_constraint(
 
        &mut self, ctx: &Ctx, expr_id: ExpressionId,
 
        arg1_id: ExpressionId, arg1_start_idx: usize,
 
        arg2_id: ExpressionId, arg2_start_idx: usize
 
    ) -> Result<(bool, bool), ParseError> {
 
        debug_assert_expr_ids_unique_and_known!(self, arg1_id, arg2_id);
 
        let arg1_type: *mut _ = self.expr_types.get_mut(&arg1_id).unwrap();
 
        let arg2_type: *mut _ = self.expr_types.get_mut(&arg2_id).unwrap();
 

	
 
        let infer_res = unsafe{ InferenceType::infer_subtrees_for_both_types(
 
            arg1_type, arg1_start_idx,
 
            arg2_type, arg2_start_idx
 
        ) };
 
        if infer_res == DualInferenceResult::Incompatible {
 
            return Err(self.construct_arg_type_error(ctx, expr_id, arg1_id, arg2_id));
 
        }
 

	
 
        Ok((infer_res.modified_lhs(), infer_res.modified_rhs()))
 
    }
 

	
 
    /// Applies an equal2 constraint between a signature type (e.g. a function
 
    /// argument or struct field) and an expression whose type should match that
 
    /// expression. If we make progress on the signature, then we try to see if
 
    /// any of the embedded polymorphic types can be progressed.
 
    ///
 
    /// `outer_expr_id` is the main expression we're progressing (e.g. a 
 
    /// function call), while `expr_id` is the embedded expression we're 
 
    /// matching against the signature. `expression_type` and 
 
    /// `expression_start_idx` belong to `expr_id`.
 
    fn apply_equal2_signature_constraint(
 
        ctx: &Ctx, outer_expr_id: ExpressionId, expr_id: Option<ExpressionId>,
 
        polymorph_data: &mut ExtraData, polymorph_progress: &mut HashSet<usize>,
 
        signature_type: *mut InferenceType, signature_start_idx: usize,
 
        expression_type: *mut InferenceType, expression_start_idx: usize
 
    ) -> Result<(bool, bool), ParseError> {
 
        // Safety: cannot mutually infer the same types
 
        //         polymorph_data containers may not be modified
 
        debug_assert_ptrs_distinct!(signature_type, expression_type);
 

	
 
        // Infer the signature and expression type
 
        let infer_res = unsafe { 
 
            InferenceType::infer_subtrees_for_both_types(
 
                signature_type, signature_start_idx,
 
                expression_type, expression_start_idx
 
            ) 
 
        };
 

	
 
        if infer_res == DualInferenceResult::Incompatible {
 
            // TODO: Check if I still need to use this
 
            let outer_position = ctx.heap[outer_expr_id].position();
 
            let (position_name, position) = match expr_id {
 
                Some(expr_id) => ("argument's", ctx.heap[expr_id].position()),
 
                None => ("type's", outer_position)
 
            };
 
            let (signature_display_type, expression_display_type) = unsafe { (
 
                (&*signature_type).display_name(&ctx.heap),
 
                (&*expression_type).display_name(&ctx.heap)
 
            ) };
 

	
 
            return Err(ParseError::new_error(
 
                &ctx.module.source, outer_position,
 
                "Failed to fully resolve the types of this expression"
 
            ).with_postfixed_info(
 
                &ctx.module.source, position,
 
                &format!(
 
                    "Because the {} signature has been resolved to '{}', but the expression has been resolved to '{}'",
 
                    position_name, signature_display_type, expression_display_type
 
                )
 
            ));
 
        }
 

	
 
        // Try to see if we can progress any of the polymorphic variables
 
        let progress_sig = infer_res.modified_lhs();
 
        let progress_expr = infer_res.modified_rhs();
 

	
 
        if progress_sig {
 
            let signature_type = unsafe{&mut *signature_type};
 
            debug_assert!(
 
                signature_type.has_body_marker, 
 
                "made progress on signature type, but it doesn't have a marker"
 
            );
 
            for (poly_idx, poly_section) in signature_type.body_marker_iter() {
 
                let polymorph_type = &mut polymorph_data.poly_vars[poly_idx];
 
                match Self::apply_forced_constraint_types(
 
                    polymorph_type, 0, poly_section, 0
 
                ) {
 
                    Ok(true) => { polymorph_progress.insert(poly_idx); },
 
                    Ok(false) => {},
 
                    Err(()) => { return Err(Self::construct_poly_arg_error(ctx, polymorph_data, outer_expr_id))}
 
                }
 
            }
 
        }
 
        Ok((progress_sig, progress_expr))
 
    }
 

	
 
    /// Applies equal2 constraints on the signature type for each of the 
 
    /// polymorphic variables. If the signature type is progressed then we 
 
    /// progress the expression type as well.
 
    ///
 
    /// This function assumes that the polymorphic variables have already been
 
    /// progressed as far as possible by calling 
 
    /// `apply_equal2_signature_constraint`. As such, we expect to not encounter
 
    /// any errors.
 
    ///
 
    /// This function returns true if the expression's type has been progressed
 
    fn apply_equal2_polyvar_constraint(
 
        heap: &Heap,
 
        polymorph_data: &ExtraData, _polymorph_progress: &HashSet<usize>,
 
        signature_type: *mut InferenceType, expr_type: *mut InferenceType
 
    ) -> bool {
 
        // Safety: all pointers should be distinct
 
        //         polymorph_data contains may not be modified
 
        debug_assert_ptrs_distinct!(signature_type, expr_type);
 
        let signature_type = unsafe{&mut *signature_type};
 
        let expr_type = unsafe{&mut *expr_type};
 

	
 
        // Iterate through markers in signature type to try and make progress
 
        // on the polymorphic variable        
 
        let mut seek_idx = 0;
 
        let mut modified_sig = false;
 
        
 
        while let Some((poly_idx, start_idx)) = signature_type.find_body_marker(seek_idx) {
 
            let end_idx = InferenceType::find_subtree_end_idx(&signature_type.parts, start_idx);
 
            // if polymorph_progress.contains(&poly_idx) {
 
                // Need to match subtrees
 
                let polymorph_type = &polymorph_data.poly_vars[poly_idx];
 
                debug_log!("   - DEBUG: Applying {} to '{}' from '{}'", polymorph_type.display_name(heap), InferenceType::partial_display_name(heap, &signature_type.parts[start_idx..]), signature_type.display_name(heap));
 
                let modified_at_marker = Self::apply_forced_constraint_types(
 
                    signature_type, start_idx, 
 
                    &polymorph_type.parts, 0
 
                ).expect("no failure when applying polyvar constraints");
 

	
 
                modified_sig = modified_sig || modified_at_marker;
 
            // }
 

	
 
            seek_idx = end_idx;
 
        }
 

	
 
        // If we made any progress on the signature's type, then we also need to
 
        // apply it to the expression that is supposed to match the signature.
 
        if modified_sig {
 
            match InferenceType::infer_subtree_for_single_type(
 
                expr_type, 0, &signature_type.parts, 0
 
            ) {
 
                SingleInferenceResult::Modified => true,
 
                SingleInferenceResult::Unmodified => false,
 
                SingleInferenceResult::Incompatible =>
 
                    unreachable!("encountered failure while reapplying modified signature to expression after polyvar inference")
 
            }
 
        } else {
 
            false
 
        }
 
    }
 

	
 
    /// Applies a type constraint that expects all three provided types to be
 
    /// equal. In case we can make progress in inferring the types then we
 
    /// attempt to do so. If the call is successful then the composition of all
 
    /// types is made equal.
 
    fn apply_equal3_constraint(
 
        &mut self, ctx: &Ctx, expr_id: ExpressionId,
 
        arg1_id: ExpressionId, arg2_id: ExpressionId,
 
        start_idx: usize
 
    ) -> Result<(bool, bool, bool), ParseError> {
 
        // Safety: all expression IDs are always distinct, and we do not modify
 
        //  the container
 
        debug_assert_expr_ids_unique_and_known!(self, expr_id, arg1_id, arg2_id);
 
        let expr_type: *mut _ = self.expr_types.get_mut(&expr_id).unwrap();
 
        let arg1_type: *mut _ = self.expr_types.get_mut(&arg1_id).unwrap();
 
        let arg2_type: *mut _ = self.expr_types.get_mut(&arg2_id).unwrap();
 

	
 
        let expr_res = unsafe{
 
            InferenceType::infer_subtrees_for_both_types(expr_type, start_idx, arg1_type, start_idx)
 
        };
 
        if expr_res == DualInferenceResult::Incompatible {
 
            return Err(self.construct_expr_type_error(ctx, expr_id, arg1_id));
 
        }
 

	
 
        let args_res = unsafe{
 
            InferenceType::infer_subtrees_for_both_types(arg1_type, start_idx, arg2_type, start_idx) };
 
        if args_res == DualInferenceResult::Incompatible {
 
            return Err(self.construct_arg_type_error(ctx, expr_id, arg1_id, arg2_id));
 
        }
 

	
 
        // If all types are compatible, but the second call caused the arg1_type
 
        // to be expanded, then we must also assign this to expr_type.
 
        let mut progress_expr = expr_res.modified_lhs();
 
        let mut progress_arg1 = expr_res.modified_rhs();
 
        let progress_arg2 = args_res.modified_rhs();
 

	
 
        if args_res.modified_lhs() { 
 
            unsafe {
 
                let end_idx = InferenceType::find_subtree_end_idx(&(*arg2_type).parts, start_idx);
 
                let subtree = &((*arg2_type).parts[start_idx..end_idx]);
 
                (*expr_type).replace_subtree(start_idx, subtree);
 
            }
 
            progress_expr = true;
 
            progress_arg1 = true;
 
        }
 

	
 
        Ok((progress_expr, progress_arg1, progress_arg2))
 
    }
 

	
 
    // TODO: @optimize Since we only deal with a single type this might be done
 
    //  a lot more efficiently, methinks (disregarding the allocations here)
 
    fn apply_equal_n_constraint(
 
        &mut self, ctx: &Ctx, expr_id: ExpressionId, args: &[ExpressionId],
 
    ) -> Result<Vec<bool>, ParseError> {
 
        // Early exit
 
        match args.len() {
 
            0 => return Ok(vec!()),         // nothing to progress
 
            1 => return Ok(vec![false]),    // only one type, so nothing to infer
 
            _ => {}
 
        }
 

	
 
        let mut progress = Vec::new();
 
        progress.resize(args.len(), false);
 

	
 
        // Do pairwise inference, keep track of the last entry we made progress
 
        // on. Once done we need to update everything to the most-inferred type.
 
        let mut arg_iter = args.iter();
 
        let mut last_arg_id = *arg_iter.next().unwrap();
 
        let mut last_lhs_progressed = 0;
 
        let mut lhs_arg_idx = 0;
 

	
 
        while let Some(next_arg_id) = arg_iter.next() {
 
            let arg1_type: *mut _ = self.expr_types.get_mut(&last_arg_id).unwrap();
 
            let arg2_type: *mut _ = self.expr_types.get_mut(next_arg_id).unwrap();
 

	
 
            let res = unsafe {
 
                InferenceType::infer_subtrees_for_both_types(arg1_type, 0, arg2_type, 0)
 
            };
 

	
 
            if res == DualInferenceResult::Incompatible {
 
                return Err(self.construct_arg_type_error(ctx, expr_id, last_arg_id, *next_arg_id));
 
            }
 

	
 
            if res.modified_lhs() {
 
                // We re-inferred something on the left hand side, so everything
 
                // up until now should be re-inferred.
 
                progress[lhs_arg_idx] = true;
 
                last_lhs_progressed = lhs_arg_idx;
 
            }
 
            progress[lhs_arg_idx + 1] = res.modified_rhs();
 

	
 
            last_arg_id = *next_arg_id;
 
            lhs_arg_idx += 1;
 
        }
 

	
 
        // Re-infer everything. Note that we do not need to re-infer the type
 
        // exactly at `last_lhs_progressed`, but only everything up to it.
 
        let last_type: *mut _ = self.expr_types.get_mut(args.last().unwrap()).unwrap();
 
        for arg_idx in 0..last_lhs_progressed {
 
            let arg_type: *mut _ = self.expr_types.get_mut(&args[arg_idx]).unwrap();
 
            unsafe{
 
                (*arg_type).replace_subtree(0, &(*last_type).parts);
 
            }
 
            progress[arg_idx] = true;
 
        }
 

	
 
        Ok(progress)
 
    }
 

	
 
    /// Determines the `InferenceType` for the expression based on the
 
    /// expression parent. Note that if the parent is another expression, we do
 
    /// not take special action, instead we let parent expressions fix the type
 
    /// of subexpressions before they have a chance to call this function.
 
    fn insert_initial_expr_inference_type(
 
        &mut self, ctx: &mut Ctx, expr_id: ExpressionId
 
    ) -> Result<(), ParseError> {
 
        use ExpressionParent as EP;
 
        use InferenceTypePart as ITP;
 

	
 
        let expr = &ctx.heap[expr_id];
 
        let inference_type = match expr.parent() {
 
            EP::None =>
 
                // Should have been set by linker
 
                unreachable!(),
 
            EP::ExpressionStmt(_) | EP::Expression(_, _) =>
 
                // Determined during type inference
 
                InferenceType::new(false, false, vec![ITP::Unknown]),
 
            EP::If(_) | EP::While(_) | EP::Assert(_) =>
 
            EP::If(_) | EP::While(_) =>
 
                // Must be a boolean
 
                InferenceType::new(false, true, vec![ITP::Bool]),
 
            EP::Return(_) =>
 
                // Must match the return type of the function
 
                if let DefinitionType::Function(func_id) = self.definition_type {
 
                    let return_parser_type_id = ctx.heap[func_id].return_type;
 
                    self.determine_inference_type_from_parser_type(ctx, return_parser_type_id, true)
 
                } else {
 
                    // Cannot happen: definition always set upon body traversal
 
                    // and "return" calls in components are illegal.
 
                    unreachable!();
 
                },
 
            EP::New(_) =>
 
                // Must be a component call, which we assign a "Void" return
 
                // type
 
                InferenceType::new(false, true, vec![ITP::Void]),
 
        };
 

	
 
        match self.expr_types.entry(expr_id) {
 
            Entry::Vacant(vacant) => {
 
                vacant.insert(inference_type);
 
            },
 
            Entry::Occupied(mut preexisting) => {
 
                // We already have an entry, this happens if our parent fixed
 
                // our type (e.g. we're used in a conditional expression's test)
 
                // but we have a different type.
 
                // TODO: Is this ever called? Seems like it can't
 
                debug_assert!(false, "I am actually called, my ID is {}", expr_id.index);
 
                let old_type = preexisting.get_mut();
 
                if let SingleInferenceResult::Incompatible = InferenceType::infer_subtree_for_single_type(
 
                    old_type, 0, &inference_type.parts, 0
 
                ) {
 
                    return Err(self.construct_expr_type_error(ctx, expr_id, expr_id))
 
                }
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn insert_initial_call_polymorph_data(
 
        &mut self, ctx: &mut Ctx, call_id: CallExpressionId
 
    ) {
 
        use InferenceTypePart as ITP;
 

	
 
        // Note: the polymorph variables may be partially specified and may
 
        // contain references to the wrapping definition's (i.e. the proctype
 
        // we are currently visiting) polymorphic arguments.
 
        //
 
        // The arguments of the call may refer to polymorphic variables in the
 
        // definition of the function we're calling, not of the wrapping
 
        // definition. We insert markers in these inferred types to be able to
 
        // map them back and forth to the polymorphic arguments of the function
 
        // we are calling.
 
        let call = &ctx.heap[call_id];
 

	
 
        // Handle the polymorphic variables themselves
 
        let mut poly_vars = Vec::with_capacity(call.poly_args.len());
 
        for poly_arg_type_id in call.poly_args.clone() { // TODO: @performance
 
            poly_vars.push(self.determine_inference_type_from_parser_type(ctx, poly_arg_type_id, true));
 
        }
 

	
 
        // Handle the arguments
 
        // TODO: @cleanup: Maybe factor this out for reuse in the validator/linker, should also
 
        //  make the code slightly more robust.
 
        let (embedded_types, return_type) = match &call.method {
 
            Method::Create => {
 
                // Not polymorphic
 
                (
 
                    vec![InferenceType::new(false, true, vec![ITP::Int])],
 
                    InferenceType::new(false, true, vec![ITP::Message, ITP::Byte])
 
                )
 
            },
 
            Method::Fires => {
 
                // bool fires<T>(PortLike<T> arg)
 
                (
 
                    vec![InferenceType::new(true, false, vec![ITP::PortLike, ITP::MarkerBody(0), ITP::Unknown])],
 
                    InferenceType::new(false, true, vec![ITP::Bool])
 
                )
 
            },
 
            Method::Get => {
 
                // T get<T>(input<T> arg)
 
                (
 
                    vec![InferenceType::new(true, false, vec![ITP::Input, ITP::MarkerBody(0), ITP::Unknown])],
 
                    InferenceType::new(true, false, vec![ITP::MarkerBody(0), ITP::Unknown])
 
                )
 
            },
 
            Method::Put => {
 
                // void Put<T>(output<T> port, T msg)
 
                (
 
                    vec![
 
                        InferenceType::new(true, false, vec![ITP::Output, ITP::MarkerBody(0), ITP::Unknown]),
 
                        InferenceType::new(true, false, vec![ITP::MarkerBody(0), ITP::Unknown])
 
                    ],
 
                    InferenceType::new(false, true, vec![ITP::Void])
 
                )
 
            }
 
            Method::Symbolic(symbolic) => {
 
                let definition = &ctx.heap[symbolic.definition.unwrap()];
 

	
 
                match definition {
 
                    Definition::Component(definition) => {
 
                        debug_assert_eq!(poly_vars.len(), definition.poly_vars.len());
 
                        let mut parameter_types = Vec::with_capacity(definition.parameters.len());
 
                        for param_id in definition.parameters.clone() {
 
                            let param = &ctx.heap[param_id];
 
                            let param_parser_type_id = param.parser_type;
 
                            parameter_types.push(self.determine_inference_type_from_parser_type(ctx, param_parser_type_id, false));
 
                        }
 

	
 
                        (parameter_types, InferenceType::new(false, true, vec![InferenceTypePart::Void]))
 
                    },
 
                    Definition::Function(definition) => {
 
                        debug_assert_eq!(poly_vars.len(), definition.poly_vars.len());
 
                        let mut parameter_types = Vec::with_capacity(definition.parameters.len());
 
                        for param_id in definition.parameters.clone() {
 
                            let param = &ctx.heap[param_id];
 
                            let param_parser_type_id = param.parser_type;
 
                            parameter_types.push(self.determine_inference_type_from_parser_type(ctx, param_parser_type_id, false));
 
                        }
 

	
 
                        let return_type = self.determine_inference_type_from_parser_type(ctx, definition.return_type, false);
 
                        (parameter_types, return_type)
 
                    },
 
                    Definition::Struct(_) | Definition::Enum(_) | Definition::Union(_) => {
 
                        unreachable!("insert initial polymorph data for struct/enum/union");
 
                    }
 
                }
 
            }
 
        };
 

	
 
        self.extra_data.insert(call_id.upcast(), ExtraData {
 
            poly_vars,
 
            embedded: embedded_types,
 
            returned: return_type
 
        });
 
    }
 

	
 
    fn insert_initial_struct_polymorph_data(
 
        &mut self, ctx: &mut Ctx, lit_id: LiteralExpressionId,
 
    ) {
 
        use InferenceTypePart as ITP;
 
        let literal = ctx.heap[lit_id].value.as_struct();
 

	
 
        // Handle polymorphic arguments
 
        let mut poly_vars = Vec::with_capacity(literal.poly_args2.len());
 
        let mut total_num_poly_parts = 0;
 
        for poly_arg_type_id in literal.poly_args2.clone() { // TODO: @performance
 
            let inference_type = self.determine_inference_type_from_parser_type(
 
                ctx, poly_arg_type_id, true
 
            ); 
 
            total_num_poly_parts += inference_type.parts.len();
 
            poly_vars.push(inference_type);
 
        }
 

	
 
        // Handle parser types on struct definition
 
        let definition = &ctx.heap[literal.definition.unwrap()];
 
        let definition = match definition {
 
            Definition::Struct(definition) => {
 
                debug_assert_eq!(poly_vars.len(), definition.poly_vars.len());
 
                definition
 
            },
 
            _ => unreachable!("definition for struct literal does not point to struct definition")
 
        };
 

	
 
        // Note: programmer is capable of specifying fields in a struct literal
 
        // in a different order than on the definition. We take the literal-
 
        // specified order to be leading.
 
        let mut embedded_types = Vec::with_capacity(definition.fields.len());
 
        for lit_field in literal.fields.iter() {
 
            let def_field = &definition.fields[lit_field.field_idx];
 
            let inference_type = self.determine_inference_type_from_parser_type(
 
                ctx, def_field.parser_type, false
 
            );
 
            embedded_types.push(inference_type);
 
        }
 

	
 
        // Return type is the struct type itself, with the appropriate 
 
        // polymorphic variables. So:
 
        // - 1 part for definition
 
        // - N_poly_arg marker parts for each polymorphic argument
 
        // - all the parts for the currently known polymorphic arguments 
 
        let parts_reserved = 1 + poly_vars.len() + total_num_poly_parts;
 
        let mut parts = Vec::with_capacity(parts_reserved);
 
        parts.push(ITP::Instance(definition.this.upcast(), poly_vars.len()));
 
        let mut return_type_done = true;
 
        for (poly_var_idx, poly_var) in poly_vars.iter().enumerate() {
 
            if !poly_var.is_done { return_type_done = false; }
 

	
 
            parts.push(ITP::MarkerBody(poly_var_idx));
 
            parts.extend(poly_var.parts.iter().cloned());
 
        }
 

	
 
        debug_assert_eq!(parts.len(), parts_reserved);
 
        let return_type = InferenceType::new(!poly_vars.is_empty(), return_type_done, parts);
 

	
 
        self.extra_data.insert(lit_id.upcast(), ExtraData{
 
            poly_vars, 
 
            embedded: embedded_types,
 
            returned: return_type,
 
        });
 
    }
 

	
 
    /// Inserts the extra polymorphic data struct for enum expressions. These
 
    /// can never be determined from the enum itself, but may be inferred from
 
    /// the use of the enum.
 
    fn insert_initial_enum_polymorph_data(
 
        &mut self, ctx: &Ctx, lit_id: LiteralExpressionId
 
    ) {
 
        use InferenceTypePart as ITP;
 
        let literal = ctx.heap[lit_id].value.as_enum();
 

	
 
        // Handle polymorphic arguments to the enum
 
        let mut poly_vars = Vec::with_capacity(literal.poly_args2.len());
 
        let mut total_num_poly_parts = 0;
 
        for poly_arg_type_id in literal.poly_args2.clone() { // TODO: @performance
 
            let inference_type = self.determine_inference_type_from_parser_type(
 
                ctx, poly_arg_type_id, true
 
            );
 
            total_num_poly_parts += inference_type.parts.len();
 
            poly_vars.push(inference_type);
 
        }
 

	
 
        // Handle enum type itself
 
        let parts_reserved = 1 + poly_vars.len() + total_num_poly_parts;
 
        let mut parts = Vec::with_capacity(parts_reserved);
 
        parts.push(ITP::Instance(literal.definition.unwrap(), poly_vars.len()));
 
        let mut enum_type_done = true;
 
        for (poly_var_idx, poly_var) in poly_vars.iter().enumerate() {
 
            if !poly_var.is_done { enum_type_done = false; }
 

	
 
            parts.push(ITP::MarkerBody(poly_var_idx));
 
            parts.extend(poly_var.parts.iter().cloned());
 
        }
 

	
 
        debug_assert_eq!(parts.len(), parts_reserved);
 
        let enum_type = InferenceType::new(!poly_vars.is_empty(), enum_type_done, parts);
 

	
 
        self.extra_data.insert(lit_id.upcast(), ExtraData{
 
            poly_vars,
 
            embedded: Vec::new(),
 
            returned: enum_type,
 
        });
 
    }
 

	
 
    /// Inserts the extra polymorphic data struct for unions. The polymorphic
 
    /// arguments may be partially determined from embedded values in the union.
 
    fn insert_initial_union_polymorph_data(
 
        &mut self, ctx: &Ctx, lit_id: LiteralExpressionId
 
    ) {
 
        use InferenceTypePart as ITP;
 
        let literal = ctx.heap[lit_id].value.as_union();
 

	
 
        // Construct the polymorphic variables
 
        let mut poly_vars = Vec::with_capacity(literal.poly_args2.len());
 
        let mut total_num_poly_parts = 0;
 
        for poly_arg_type_id in literal.poly_args2.clone() { // TODO: @performance
 
            let inference_type = self.determine_inference_type_from_parser_type(
 
                ctx, poly_arg_type_id, true
 
            );
 
            total_num_poly_parts += inference_type.parts.len();
 
            poly_vars.push(inference_type);
 
        }
 

	
 
        // Handle any of the embedded values in the variant, if specified
 
        let definition_id = literal.definition.unwrap();
 
        let union_definition = ctx.types.get_base_definition(&definition_id)
 
            .unwrap()
 
            .definition.as_union();
 
        let variant_definition = &union_definition.variants[literal.variant_idx];
 
        debug_assert_eq!(variant_definition.embedded.len(), literal.values.len());
 

	
 
        let mut embedded = Vec::with_capacity(variant_definition.embedded.len());
 
        for embedded_id in &variant_definition.embedded {
 
            let inference_type = self.determine_inference_type_from_parser_type(
 
                ctx, *embedded_id, false
 
            );
 
            embedded.push(inference_type);
 
        }
 

	
 
        // Handle the type of the union itself
 
        let parts_reserved = 1 + poly_vars.len() + total_num_poly_parts;
 
        let mut parts = Vec::with_capacity(parts_reserved);
 
        parts.push(ITP::Instance(definition_id, poly_vars.len()));
 
        let mut union_type_done = true;
 
        for (poly_var_idx, poly_var) in poly_vars.iter().enumerate() {
 
            if !poly_var.is_done { union_type_done = false; }
 

	
 
            parts.push(ITP::MarkerBody(poly_var_idx));
 
            
 
            parts.extend(poly_var.parts.iter().cloned());
 
        }
 

	
 
        debug_assert_eq!(parts_reserved, parts.len());
 
        let union_type = InferenceType::new(!poly_vars.is_empty(), union_type_done, parts);
 

	
 
        self.extra_data.insert(lit_id.upcast(), ExtraData{
 
            poly_vars,
 
            embedded,
 
            returned: union_type
 
        });
 
    }
 

	
 
    /// Inserts the extra polymorphic data struct. Assumes that the select
 
    /// expression's referenced (definition_id, field_idx) has been resolved.
 
    fn insert_initial_select_polymorph_data(
 
        &mut self, ctx: &Ctx, select_id: SelectExpressionId
 
    ) {
 
        use InferenceTypePart as ITP;
 

	
 
        // Retrieve relevant data
 
        let expr = &ctx.heap[select_id];
 
        let field = expr.field.as_symbolic();
 

	
 
        let definition_id = field.definition.unwrap();
 
        let definition = ctx.heap[definition_id].as_struct();
 
        let field_idx = field.field_idx;
 

	
 
        // Generate initial polyvar types and struct type
 
        let num_poly_vars = definition.poly_vars.len();
 
        let mut poly_vars = Vec::with_capacity(num_poly_vars);
 
        let struct_parts_reserved = 1 + 2 * num_poly_vars;
 
        let mut struct_parts = Vec::with_capacity(struct_parts_reserved);
 
        struct_parts.push(ITP::Instance(definition_id, num_poly_vars));        
 

	
 
        for poly_idx in 0..num_poly_vars {
 
            poly_vars.push(InferenceType::new(true, false, vec![
 
                ITP::MarkerBody(poly_idx), ITP::Unknown,
 
            ]));
 
            struct_parts.push(ITP::MarkerBody(poly_idx));
 
            struct_parts.push(ITP::Unknown);
 
        }
 
        debug_assert_eq!(struct_parts.len(), struct_parts_reserved);
 

	
 
        // Generate initial field type
 
        let field_type = self.determine_inference_type_from_parser_type(
 
            ctx, definition.fields[field_idx].parser_type, false
 
        );
 

	
 
        self.extra_data.insert(select_id.upcast(), ExtraData{
 
            poly_vars,
 
            embedded: vec![InferenceType::new(num_poly_vars != 0, num_poly_vars == 0, struct_parts)],
 
            returned: field_type
 
        });
 
    }
 

	
 
    /// Determines the initial InferenceType from the provided ParserType. This
 
    /// may be called with two kinds of intentions:
 
    /// 1. To resolve a ParserType within the body of a function, or on
 
    ///     polymorphic arguments to calls/instantiations within that body. This
 
    ///     means that the polymorphic variables are known and can be replaced
 
    ///     with the monomorph we're instantiating.
 
    /// 2. To resolve a ParserType on a called function's definition or on
 
    ///     an instantiated datatype's members. This means that the polymorphic
 
    ///     arguments inside those ParserTypes refer to the polymorphic
 
    ///     variables in the called/instantiated type's definition.
 
    /// In the second case we place InferenceTypePart::Marker instances such
 
    /// that we can perform type inference on the polymorphic variables.
 
    fn determine_inference_type_from_parser_type(
 
        &mut self, ctx: &Ctx, parser_type_id: ParserTypeId,
 
        parser_type_in_body: bool
 
    ) -> InferenceType {
 
        use ParserTypeVariant as PTV;
 
        use InferenceTypePart as ITP;
 

	
 
        let mut to_consider = VecDeque::with_capacity(16);
 
        to_consider.push_back(parser_type_id);
 

	
 
        let mut infer_type = Vec::new();
 
        let mut has_inferred = false;
 
        let mut has_markers = false;
 

	
 
        while !to_consider.is_empty() {
 
            let parser_type_id = to_consider.pop_front().unwrap();
 
            let parser_type = &ctx.heap[parser_type_id];
 
            match &parser_type.variant {
 
                PTV::Message => {
 
                    // TODO: @types Remove the Message -> Byte hack at some point...
 
                    infer_type.push(ITP::Message);
 
                    infer_type.push(ITP::Byte);
 
                },
 
                PTV::Bool => { infer_type.push(ITP::Bool); },
 
                PTV::Byte => { infer_type.push(ITP::Byte); },
 
                PTV::Short => { infer_type.push(ITP::Short); },
 
                PTV::Int => { infer_type.push(ITP::Int); },
 
                PTV::Long => { infer_type.push(ITP::Long); },
 
                PTV::String => { infer_type.push(ITP::String); },
 
                PTV::IntegerLiteral => { unreachable!("integer literal type on variable type"); },
 
                PTV::Inferred => {
 
                    infer_type.push(ITP::Unknown);
 
                    has_inferred = true;
 
                },
 
                PTV::Array(subtype_id) => {
 
                    infer_type.push(ITP::Array);
 
                    to_consider.push_front(*subtype_id);
 
                },
 
                PTV::Input(subtype_id) => {
 
                    infer_type.push(ITP::Input);
 
                    to_consider.push_front(*subtype_id);
 
                },
 
                PTV::Output(subtype_id) => {
 
                    infer_type.push(ITP::Output);
 
                    to_consider.push_front(*subtype_id);
 
                },
 
                PTV::Symbolic(symbolic) => {
 
                    debug_assert!(symbolic.variant.is_some(), "symbolic variant not yet determined");
 
                    match symbolic.variant.as_ref().unwrap() {
 
                        SymbolicParserTypeVariant::PolyArg(_, arg_idx) => {
 
                            let arg_idx = *arg_idx;
 
                            debug_assert!(symbolic.poly_args2.is_empty()); // TODO: @hkt
 

	
 
                            if parser_type_in_body {
 
                                // Polymorphic argument refers to definition's
 
                                // polymorphic variables
 
                                debug_assert!(arg_idx < self.poly_vars.len());
 
                                debug_assert!(!self.poly_vars[arg_idx].has_marker());
 
                                infer_type.push(ITP::MarkerDefinition(arg_idx));
 
                                for concrete_part in &self.poly_vars[arg_idx].parts {
 
                                    infer_type.push(ITP::from(*concrete_part));
 
                                }
 
                            } else {
 
                                // Polymorphic argument has to be inferred
 
                                has_markers = true;
 
                                has_inferred = true;
 
                                infer_type.push(ITP::MarkerBody(arg_idx));
 
                                infer_type.push(ITP::Unknown);
 
                            }
 
                        },
 
                        SymbolicParserTypeVariant::Definition(definition_id) => {
 
                            // TODO: @cleanup
 
                            if cfg!(debug_assertions) {
 
                                let definition = &ctx.heap[*definition_id];
 
                                debug_assert!(definition.is_struct() || definition.is_enum() || definition.is_union()); // TODO: @function_ptrs
 
                                let num_poly = match definition {
 
                                    Definition::Struct(v) => v.poly_vars.len(),
 
                                    Definition::Enum(v) => v.poly_vars.len(),
 
                                    Definition::Union(v) => v.poly_vars.len(),
 
                                    _ => unreachable!(),
 
                                };
 
                                debug_assert_eq!(symbolic.poly_args2.len(), num_poly);
 
                            }
 

	
 
                            infer_type.push(ITP::Instance(*definition_id, symbolic.poly_args2.len()));
 
                            let mut poly_arg_idx = symbolic.poly_args2.len();
 
                            while poly_arg_idx > 0 {
 
                                poly_arg_idx -= 1;
 
                                to_consider.push_front(symbolic.poly_args2[poly_arg_idx]);
 
                            }
 
                        }
 
                    }
 
                }
 
            }
 
        }
 

	
 
        InferenceType::new(has_markers, !has_inferred, infer_type)
 
    }
 

	
 
    /// Construct an error when an expression's type does not match. This
 
    /// happens if we infer the expression type from its arguments (e.g. the
 
    /// expression type of an addition operator is the type of the arguments)
 
    /// But the expression type was already set due to our parent (e.g. an
 
    /// "if statement" or a "logical not" always expecting a boolean)
 
    fn construct_expr_type_error(
 
        &self, ctx: &Ctx, expr_id: ExpressionId, arg_id: ExpressionId
 
    ) -> ParseError {
 
        // TODO: Expand and provide more meaningful information for humans
 
        let expr = &ctx.heap[expr_id];
 
        let arg_expr = &ctx.heap[arg_id];
 
        let expr_type = self.expr_types.get(&expr_id).unwrap();
 
        let arg_type = self.expr_types.get(&arg_id).unwrap();
 

	
 
        return ParseError::new_error(
 
            &ctx.module.source, expr.position(),
 
            &format!(
 
                "Incompatible types: this expression expected a '{}'", 
 
                expr_type.display_name(&ctx.heap)
 
            )
 
        ).with_postfixed_info(
 
            &ctx.module.source, arg_expr.position(),
 
            &format!(
 
                "But this expression yields a '{}'",
 
                arg_type.display_name(&ctx.heap)
 
            )
 
        )
 
    }
 

	
 
    fn construct_arg_type_error(
 
        &self, ctx: &Ctx, expr_id: ExpressionId,
 
        arg1_id: ExpressionId, arg2_id: ExpressionId
 
    ) -> ParseError {
 
        let expr = &ctx.heap[expr_id];
 
        let arg1 = &ctx.heap[arg1_id];
 
        let arg2 = &ctx.heap[arg2_id];
 

	
 
        let arg1_type = self.expr_types.get(&arg1_id).unwrap();
 
        let arg2_type = self.expr_types.get(&arg2_id).unwrap();
 

	
 
        return ParseError::new_error(
 
            &ctx.module.source, expr.position(),
 
            "Incompatible types: cannot apply this expression"
 
        ).with_postfixed_info(
 
            &ctx.module.source, arg1.position(),
 
            &format!(
 
                "Because this expression has type '{}'",
 
                arg1_type.display_name(&ctx.heap)
 
            )
 
        ).with_postfixed_info(
 
            &ctx.module.source, arg2.position(),
 
            &format!(
 
                "But this expression has type '{}'",
 
                arg2_type.display_name(&ctx.heap)
 
            )
 
        )
 
    }
 

	
 
    fn construct_template_type_error(
 
        &self, ctx: &Ctx, expr_id: ExpressionId, template: &[InferenceTypePart]
 
    ) -> ParseError {
 
        let expr = &ctx.heap[expr_id];
 
        let expr_type = self.expr_types.get(&expr_id).unwrap();
 

	
 
        return ParseError::new_error(
 
            &ctx.module.source, expr.position(),
 
            &format!(
 
                "Incompatible types: got a '{}' but expected a '{}'",
 
                expr_type.display_name(&ctx.heap), 
 
                InferenceType::partial_display_name(&ctx.heap, template)
 
            )
 
        )
 
    }
 

	
 
    /// Constructs a human interpretable error in the case that type inference
 
    /// on a polymorphic variable to a function call or literal construction 
 
    /// failed. This may only be caused by a pair of inference types (which may 
 
    /// come from arguments or the return type) having two different inferred 
 
    /// values for that polymorphic variable.
 
    ///
 
    /// So we find this pair and construct the error using it.
 
    ///
 
    /// We assume that the expression is a function call or a struct literal,
 
    /// and that an actual error has occurred.
 
    fn construct_poly_arg_error(
 
        ctx: &Ctx, poly_data: &ExtraData, expr_id: ExpressionId
 
    ) -> ParseError {
 
        // Helper function to check for polymorph mismatch between two inference
 
        // types.
 
        fn has_poly_mismatch<'a>(type_a: &'a InferenceType, type_b: &'a InferenceType) -> Option<(usize, &'a [InferenceTypePart], &'a [InferenceTypePart])> {
 
            if !type_a.has_body_marker || !type_b.has_body_marker {
 
                return None
 
            }
 

	
 
            for (marker_a, section_a) in type_a.body_marker_iter() {
 
                for (marker_b, section_b) in type_b.body_marker_iter() {
 
                    if marker_a != marker_b {
 
                        // Not the same polymorphic variable
 
                        continue;
 
                    }
 

	
 
                    if !InferenceType::check_subtrees(section_a, 0, section_b, 0) {
 
                        // Not compatible
 
                        return Some((marker_a, section_a, section_b))
 
                    }
 
                }
 
            }
 

	
 
            None
 
        }
 

	
 
        // Helpers function to retrieve polyvar name and definition name
 
        fn get_poly_var_and_func_name(ctx: &Ctx, poly_var_idx: usize, expr: &CallExpression) -> (String, String) {
 
            match &expr.method {
 
                Method::Create => unreachable!(),
 
                Method::Fires => (String::from('T'), String::from("fires")),
 
                Method::Get => (String::from('T'), String::from("get")),
 
                Method::Put => (String::from('T'), String::from("put")),
 
                Method::Symbolic(symbolic) => {
 
                    let definition = &ctx.heap[symbolic.definition.unwrap()];
 
                    let poly_var = match definition {
 
                        Definition::Struct(_) | Definition::Enum(_) | Definition::Union(_) => unreachable!(),
 
                        Definition::Function(definition) => {
 
                            String::from_utf8_lossy(&definition.poly_vars[poly_var_idx].value).to_string()
 
                        },
 
                        Definition::Component(definition) => {
 
                            String::from_utf8_lossy(&definition.poly_vars[poly_var_idx].value).to_string()
 
                        }
 
                    };
 
                    let func_name = String::from_utf8_lossy(&symbolic.identifier.value).to_string();
 
                    (poly_var, func_name)
 
                }
 
            }
 
        }
 

	
 
        fn get_poly_var_and_type_name(ctx: &Ctx, poly_var_idx: usize, definition_id: DefinitionId) -> (String, String) {
 
            let definition = &ctx.heap[definition_id];
 
            let (poly_var_name, type_name) = match definition {
 
                Definition::Function(_) | Definition::Component(_) =>
 
                    unreachable!("get_poly_var_and_type_name called on unsupported type"),
 
                Definition::Enum(definition) => (
 
                    &definition.poly_vars[poly_var_idx].value,
 
                    &definition.identifier.value
 
                ),
 
                Definition::Struct(definition) => (
 
                    &definition.poly_vars[poly_var_idx].value,
 
                    &definition.identifier.value
 
                ),
 
                Definition::Union(definition) => (
 
                    &definition.poly_vars[poly_var_idx].value,
 
                    &definition.identifier.value
 
                ),
 
            };
 

	
 
            (
 
                String::from_utf8_lossy(poly_var_name).to_string(),
 
                String::from_utf8_lossy(type_name).to_string()
 
            )
 
        }
 

	
 
        // Helper function to construct initial error
 
        fn construct_main_error(ctx: &Ctx, poly_var_idx: usize, expr: &Expression) -> ParseError {
 
            match expr {
 
                Expression::Call(expr) => {
 
                    let (poly_var, func_name) = get_poly_var_and_func_name(ctx, poly_var_idx, expr);
 
                    return ParseError::new_error(
 
                        &ctx.module.source, expr.position(),
 
                        &format!(
 
                            "Conflicting type for polymorphic variable '{}' of '{}'",
 
                            poly_var, func_name
 
                        )
 
                    )
 
                },
 
                Expression::Literal(expr) => {
 
                    let definition_id = match &expr.value {
 
                        Literal::Struct(v) => v.definition.unwrap(),
 
                        Literal::Enum(v) => v.definition.unwrap(),
 
                        Literal::Union(v) => v.definition.unwrap(),
 
                        _ => unreachable!(),
 
                    };
 

	
 
                    let (poly_var, struct_name) = get_poly_var_and_type_name(ctx, poly_var_idx, definition_id);
 
                    return ParseError::new_error(
 
                        &ctx.module.source, expr.position(),
 
                        &format!(
 
                            "Conflicting type for polymorphic variable '{}' of instantiation of '{}'",
 
                            poly_var, struct_name
 
                        )
 
                    )
 
                },
 
                Expression::Select(expr) => {
 
                    let field = expr.field.as_symbolic();
 
                    let (poly_var, struct_name) = get_poly_var_and_type_name(ctx, poly_var_idx, field.definition.unwrap());
 
                    return ParseError::new_error(
 
                        &ctx.module.source, expr.position(),
 
                        &format!(
 
                            "Conflicting type for polymorphic variable '{}' while accessing field '{}' of '{}'",
 
                            poly_var, &String::from_utf8_lossy(&field.identifier.value), struct_name
 
                        )
 
                    )
 
                }
 
                _ => unreachable!("called construct_poly_arg_error without a call/literal expression")
 
            }
 
        }
 

	
 
        // Actual checking
 
        let expr = &ctx.heap[expr_id];
 
        let (expr_args, expr_return_name) = match expr {
 
            Expression::Call(expr) => 
 
                (
 
                    expr.arguments.clone(),
 
                    "return type"
 
                ),
 
            Expression::Literal(expr) => {
 
                let expressions = match &expr.value {
 
                    Literal::Struct(v) => v.fields.iter()
 
                        .map(|f| f.value)
 
                        .collect(),
 
                    Literal::Enum(_) => Vec::new(),
 
                    Literal::Union(v) => v.values.clone(),
 
                    _ => unreachable!()
 
                };
 

	
 
                ( expressions, "literal" )
 
            },
 
            Expression::Select(expr) =>
 
                // Select expression uses the polymorphic variables of the 
 
                // struct it is accessing, so get the subject expression.
 
                (
 
                    vec![expr.subject],
 
                    "selected field"
 
                ),
 
            _ => unreachable!(),
 
        };
 

	
 
        // - check return type with itself
 
        if let Some((poly_idx, section_a, section_b)) = has_poly_mismatch(
 
            &poly_data.returned, &poly_data.returned
 
        ) {
 
            return construct_main_error(ctx, poly_idx, expr)
 
                .with_postfixed_info(
 
                    &ctx.module.source, expr.position(),
 
                    &format!(
 
                        "The {} inferred the conflicting types '{}' and '{}'",
 
                        expr_return_name,
 
                        InferenceType::partial_display_name(&ctx.heap, section_a),
 
                        InferenceType::partial_display_name(&ctx.heap, section_b)
 
                    )
 
                )
 
        }
 

	
 
        // - check arguments with each other argument and with return type
 
        for (arg_a_idx, arg_a) in poly_data.embedded.iter().enumerate() {
 
            for (arg_b_idx, arg_b) in poly_data.embedded.iter().enumerate() {
 
                if arg_b_idx > arg_a_idx {
 
                    break;
 
                }
 

	
 
                if let Some((poly_idx, section_a, section_b)) = has_poly_mismatch(&arg_a, &arg_b) {
 
                    let error = construct_main_error(ctx, poly_idx, expr);
 
                    if arg_a_idx == arg_b_idx {
 
                        // Same argument
 
                        let arg = &ctx.heap[expr_args[arg_a_idx]];
 
                        return error.with_postfixed_info(
 
                            &ctx.module.source, arg.position(),
 
                            &format!(
 
                                "This argument inferred the conflicting types '{}' and '{}'",
 
                                InferenceType::partial_display_name(&ctx.heap, section_a),
 
                                InferenceType::partial_display_name(&ctx.heap, section_b)
 
                            )
 
                        )
 
                    } else {
 
                        let arg_a = &ctx.heap[expr_args[arg_a_idx]];
 
                        let arg_b = &ctx.heap[expr_args[arg_b_idx]];
 
                        return error.with_postfixed_info(
 
                            &ctx.module.source, arg_a.position(),
 
                            &format!(
 
                                "This argument inferred it to '{}'",
 
                                InferenceType::partial_display_name(&ctx.heap, section_a)
 
                            )
 
                        ).with_postfixed_info(
 
                            &ctx.module.source, arg_b.position(),
 
                            &format!(
 
                                "While this argument inferred it to '{}'",
 
                                InferenceType::partial_display_name(&ctx.heap, section_b)
 
                            )
 
                        )
 
                    }
 
                }
 
            }
 

	
 
            // Check with return type
 
            if let Some((poly_idx, section_arg, section_ret)) = has_poly_mismatch(arg_a, &poly_data.returned) {
 
                let arg = &ctx.heap[expr_args[arg_a_idx]];
 
                return construct_main_error(ctx, poly_idx, expr)
 
                    .with_postfixed_info(
 
                        &ctx.module.source, arg.position(),
 
                        &format!(
 
                            "This argument inferred it to '{}'",
 
                            InferenceType::partial_display_name(&ctx.heap, section_arg)
 
                        )
 
                    )
 
                    .with_postfixed_info(
 
                        &ctx.module.source, expr.position(),
 
                        &format!(
 
                            "While the {} inferred it to '{}'",
 
                            expr_return_name,
 
                            InferenceType::partial_display_name(&ctx.heap, section_ret)
 
                        )
 
                    )
 
            }
src/protocol/parser/visitor.rs
Show inline comments
 
use crate::protocol::ast::*;
 
use crate::protocol::inputsource::*;
 
use crate::protocol::parser::{symbol_table::*, type_table::*, LexedModule};
 
use crate::protocol::input_source2::ParseError;
 
use crate::protocol::parser::{type_table::*, Module};
 
use crate::protocol::symbol_table2::{SymbolTable};
 

	
 
type Unit = ();
 
pub(crate) type VisitorResult = Result<Unit, ParseError>;
 

	
 
/// Globally configured vector capacity for statement buffers in visitor 
 
/// implementations
 
pub(crate) const STMT_BUFFER_INIT_CAPACITY: usize = 256;
 
/// Globally configured vector capacity for expression buffers in visitor
 
/// implementations
 
pub(crate) const EXPR_BUFFER_INIT_CAPACITY: usize = 256;
 
/// Globally configured vector capacity for parser type buffers in visitor
 
/// implementations
 
pub(crate) const TYPE_BUFFER_INIT_CAPACITY: usize = 128;
 

	
 
/// General context structure that is used while traversing the AST.
 
pub(crate) struct Ctx<'p> {
 
    pub heap: &'p mut Heap,
 
    pub module: &'p LexedModule,
 
    pub module: &'p Module,
 
    pub symbols: &'p mut SymbolTable,
 
    pub types: &'p mut TypeTable,
 
}
 

	
 
/// Visitor is a generic trait that will fully walk the AST. The default
 
/// implementation of the visitors is to not recurse. The exception is the
 
/// top-level `visit_definition`, `visit_stmt` and `visit_expr` methods, which
 
/// call the appropriate visitor function.
 
pub(crate) trait Visitor2 {
 
    // Entry point
 
    fn visit_module(&mut self, ctx: &mut Ctx) -> VisitorResult {
 
        let mut def_index = 0;
 
        loop {
 
            let definition_id = {
 
                let root = &ctx.heap[ctx.module.root_id];
 
                if def_index >= root.definitions.len() {
 
                    return Ok(())
 
                }
 

	
 
                root.definitions[def_index]
 
            };
 

	
 
            self.visit_definition(ctx, definition_id)?;
 
            def_index += 1;
 
        }
 
    }
 

	
 
    // Definitions
 
    // --- enum matching
 
    fn visit_definition(&mut self, ctx: &mut Ctx, id: DefinitionId) -> VisitorResult {
 
        match &ctx.heap[id] {
 
            Definition::Enum(def) => {
 
                let def = def.this;
 
                self.visit_enum_definition(ctx, def)
 
            },
 
            Definition::Union(def) => {
 
                let def = def.this;
 
                self.visit_union_definition(ctx, def)
 
            }
 
            Definition::Struct(def) => {
 
                let def = def.this;
 
                self.visit_struct_definition(ctx, def)
 
            },
 
            Definition::Component(def) => {
 
                let def = def.this;
 
                self.visit_component_definition(ctx, def)
 
            },
 
            Definition::Function(def) => {
 
                let def = def.this;
 
                self.visit_function_definition(ctx, def)
 
            }
 
        }
 
    }
 

	
 
    // --- enum variant handling
 
    fn visit_enum_definition(&mut self, _ctx: &mut Ctx, _id: EnumId) -> VisitorResult { Ok(()) }
 
    fn visit_union_definition(&mut self, _ctx: &mut Ctx, _id: UnionId) -> VisitorResult{ Ok(()) }
 
    fn visit_struct_definition(&mut self, _ctx: &mut Ctx, _id: StructId) -> VisitorResult { Ok(()) }
 
    fn visit_component_definition(&mut self, _ctx: &mut Ctx, _id: ComponentId) -> VisitorResult { Ok(()) }
 
    fn visit_function_definition(&mut self, _ctx: &mut Ctx, _id: FunctionId) -> VisitorResult { Ok(()) }
 
    fn visit_component_definition(&mut self, _ctx: &mut Ctx, _id: ComponentDefinitionId) -> VisitorResult { Ok(()) }
 
    fn visit_function_definition(&mut self, _ctx: &mut Ctx, _id: FunctionDefinitionId) -> VisitorResult { Ok(()) }
 

	
 
    // Statements
 
    // --- enum matching
 
    fn visit_stmt(&mut self, ctx: &mut Ctx, id: StatementId) -> VisitorResult {
 
        match &ctx.heap[id] {
 
            Statement::Block(stmt) => {
 
                let this = stmt.this;
 
                self.visit_block_stmt(ctx, this)
 
            },
 
            Statement::Local(stmt) => {
 
                let this = stmt.this();
 
                self.visit_local_stmt(ctx, this)
 
            },
 
            Statement::Skip(stmt) => {
 
                let this = stmt.this;
 
                self.visit_skip_stmt(ctx, this)
 
            },
 
            Statement::Labeled(stmt) => {
 
                let this = stmt.this;
 
                self.visit_labeled_stmt(ctx, this)
 
            },
 
            Statement::If(stmt) => {
 
                let this = stmt.this;
 
                self.visit_if_stmt(ctx, this)
 
            },
 
            Statement::EndIf(_stmt) => Ok(()),
 
            Statement::While(stmt) => {
 
                let this = stmt.this;
 
                self.visit_while_stmt(ctx, this)
 
            },
 
            Statement::EndWhile(_stmt) => Ok(()),
 
            Statement::Break(stmt) => {
 
                let this = stmt.this;
 
                self.visit_break_stmt(ctx, this)
 
            },
 
            Statement::Continue(stmt) => {
 
                let this = stmt.this;
 
                self.visit_continue_stmt(ctx, this)
 
            },
 
            Statement::Synchronous(stmt) => {
 
                let this = stmt.this;
 
                self.visit_synchronous_stmt(ctx, this)
 
            },
 
            Statement::EndSynchronous(_stmt) => Ok(()),
 
            Statement::Return(stmt) => {
 
                let this = stmt.this;
 
                self.visit_return_stmt(ctx, this)
 
            },
 
            Statement::Assert(stmt) => {
 
                let this = stmt.this;
 
                self.visit_assert_stmt(ctx, this)
 
            },
 
            Statement::Goto(stmt) => {
 
                let this = stmt.this;
 
                self.visit_goto_stmt(ctx, this)
 
            },
 
            Statement::New(stmt) => {
 
                let this = stmt.this;
 
                self.visit_new_stmt(ctx, this)
 
            },
 
            Statement::Expression(stmt) => {
 
                let this = stmt.this;
 
                self.visit_expr_stmt(ctx, this)
 
            }
 
        }
 
    }
 

	
 
    fn visit_local_stmt(&mut self, ctx: &mut Ctx, id: LocalStatementId) -> VisitorResult {
 
        match &ctx.heap[id] {
 
            LocalStatement::Channel(stmt) => {
 
                let this = stmt.this;
 
                self.visit_local_channel_stmt(ctx, this)
 
            },
 
            LocalStatement::Memory(stmt) => {
 
                let this = stmt.this;
 
                self.visit_local_memory_stmt(ctx, this)
 
            },
 
        }
 
    }
 

	
 
    // --- enum variant handling
 
    fn visit_block_stmt(&mut self, _ctx: &mut Ctx, _id: BlockStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_local_memory_stmt(&mut self, _ctx: &mut Ctx, _id: MemoryStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_local_channel_stmt(&mut self, _ctx: &mut Ctx, _id: ChannelStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_skip_stmt(&mut self, _ctx: &mut Ctx, _id: SkipStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_labeled_stmt(&mut self, _ctx: &mut Ctx, _id: LabeledStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_if_stmt(&mut self, _ctx: &mut Ctx, _id: IfStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_while_stmt(&mut self, _ctx: &mut Ctx, _id: WhileStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_break_stmt(&mut self, _ctx: &mut Ctx, _id: BreakStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_continue_stmt(&mut self, _ctx: &mut Ctx, _id: ContinueStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_synchronous_stmt(&mut self, _ctx: &mut Ctx, _id: SynchronousStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_return_stmt(&mut self, _ctx: &mut Ctx, _id: ReturnStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_assert_stmt(&mut self, _ctx: &mut Ctx, _id: AssertStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_goto_stmt(&mut self, _ctx: &mut Ctx, _id: GotoStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_new_stmt(&mut self, _ctx: &mut Ctx, _id: NewStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_expr_stmt(&mut self, _ctx: &mut Ctx, _id: ExpressionStatementId) -> VisitorResult { Ok(()) }
 

	
 
    // Expressions
 
    // --- enum matching
 
    fn visit_expr(&mut self, ctx: &mut Ctx, id: ExpressionId) -> VisitorResult {
 
        match &ctx.heap[id] {
 
            Expression::Assignment(expr) => {
 
                let this = expr.this;
 
                self.visit_assignment_expr(ctx, this)
 
            },
 
            Expression::Binding(expr) => {
 
                let this = expr.this;
 
                self.visit_binding_expr(ctx, this)
 
            }
 
            Expression::Conditional(expr) => {
 
                let this = expr.this;
 
                self.visit_conditional_expr(ctx, this)
 
            }
 
            Expression::Binary(expr) => {
 
                let this = expr.this;
 
                self.visit_binary_expr(ctx, this)
 
            }
 
            Expression::Unary(expr) => {
 
                let this = expr.this;
 
                self.visit_unary_expr(ctx, this)
 
            }
 
            Expression::Indexing(expr) => {
 
                let this = expr.this;
 
                self.visit_indexing_expr(ctx, this)
 
            }
 
            Expression::Slicing(expr) => {
 
                let this = expr.this;
 
                self.visit_slicing_expr(ctx, this)
 
            }
 
            Expression::Select(expr) => {
 
                let this = expr.this;
 
                self.visit_select_expr(ctx, this)
 
            }
 
            Expression::Array(expr) => {
 
                let this = expr.this;
 
                self.visit_array_expr(ctx, this)
 
            }
 
            Expression::Literal(expr) => {
 
                let this = expr.this;
 
                self.visit_literal_expr(ctx, this)
 
            }
 
            Expression::Call(expr) => {
 
                let this = expr.this;
 
                self.visit_call_expr(ctx, this)
 
            }
 
            Expression::Variable(expr) => {
 
                let this = expr.this;
 
                self.visit_variable_expr(ctx, this)
 
            }
 
        }
 
    }
 

	
 
    fn visit_assignment_expr(&mut self, _ctx: &mut Ctx, _id: AssignmentExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_binding_expr(&mut self, _ctx: &mut Ctx, _id: BindingExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_conditional_expr(&mut self, _ctx: &mut Ctx, _id: ConditionalExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_binary_expr(&mut self, _ctx: &mut Ctx, _id: BinaryExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_unary_expr(&mut self, _ctx: &mut Ctx, _id: UnaryExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_indexing_expr(&mut self, _ctx: &mut Ctx, _id: IndexingExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_slicing_expr(&mut self, _ctx: &mut Ctx, _id: SlicingExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_select_expr(&mut self, _ctx: &mut Ctx, _id: SelectExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_array_expr(&mut self, _ctx: &mut Ctx, _id: ArrayExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_literal_expr(&mut self, _ctx: &mut Ctx, _id: LiteralExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_call_expr(&mut self, _ctx: &mut Ctx, _id: CallExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_variable_expr(&mut self, _ctx: &mut Ctx, _id: VariableExpressionId) -> VisitorResult { Ok(()) }
 

	
 
    // Types
 
    fn visit_parser_type(&mut self, _ctx: &mut Ctx, _id: ParserTypeId) -> VisitorResult { Ok(()) }
 
}
 
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