CSY/reowolf Changeset - 699bec97a862 · Centrum Wiskunde & Informatica (CWI)

Changeset - 699bec97a862

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mh - 4 years ago 2021-12-21 15:39:08
contact@maxhenger.nl

Fix longstanding variable scoping bug, add select statement test

2 files changed with 32 insertions and 14 deletions:

src/protocol/parser/pass_validation_linking.rs

src/protocol/tests/parser_validation.rs

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src/protocol/parser/pass_validation_linking.rs

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 /*
  * pass_validation_linking.rs
+ *
  * The pass that will validate properties of the AST statements (one is not
  * allowed to nest synchronous statements, instantiating components occurs in
  * the right places, etc.) and expressions (assignments may not occur in
  * arbitrary expressions).
+ *
  * Furthermore, this pass will also perform "linking", in the sense of: some AST
  * nodes have something to do with one another, so we link them up in this pass
  * (e.g. setting the parents of expressions, linking the control flow statements
  * like `continue` and `break` up to the respective loop statement, etc.).
+ *
  * There are several "confusing" parts about this pass:
+ *
  * Setting expression parents: this is the simplest one. The pass struct acts
  * like a little state machine. When visiting an expression it will set the
  * "parent expression" field of the pass to itself, then visit its child. The
  * child will look at this "parent expression" field to determine its parent.
+ *
  * Setting the `next` statement: the AST is a tree, but during execution we walk
  * a linear path through all statements. So where appropriate a statement may
  * set the "previous statement" field of the pass to itself. When visiting the
  * subsequent statement it will check this "previous statement", and if set, it
  * will link this previous statement up to itself. Not every statement has a
  * previous statement. Hence there are two patterns that occur: assigning the
  * `next` value, then clearing the "previous statement" field. And assigning the
  * `next` value, and then putting the current statement's ID in the "previous
  * statement" field. Because it is so common, this file contain two macros that
  * perform that operation.
+ *
  * To make storing types for polymorphic procedures simpler and more efficient,
  * we assign to each expression in the procedure a unique ID. This is what the
  * "next expression index" field achieves. Each expression simply takes the
  * current value, and then increments this counter.
  */
 use crate::collections::{ScopedBuffer};
 use crate::protocol::ast::*;
 use crate::protocol::input_source::*;
 use crate::protocol::parser::symbol_table::*;
 use crate::protocol::parser::type_table::*;
 use super::visitor::{
     BUFFER_INIT_CAPACITY,
     Ctx,
     Visitor,
     VisitorResult
 };
 use crate::protocol::parser::ModuleCompilationPhase;
 #[derive(PartialEq, Eq)]
 enum DefinitionType {
     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(),
+        }
+    }
+}
 struct ControlFlowStatement {
     in_sync: SynchronousStatementId,
     in_while: WhileStatementId,
     in_scope: Scope,
     statement: StatementId, // of 'break', 'continue' or 'goto'
+}
 /// 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 main idea is, because we're visiting nodes in a tree, to do as much as
 /// we can while we have the memory in cache.
 pub(crate) struct PassValidationLinking {
     // Traversal state, all valid IDs if inside a certain AST element. Otherwise
     // `id.is_invalid()` returns true.
     in_sync: SynchronousStatementId,
     in_while: WhileStatementId, // to resolve labeled continue/break
     in_select_guard: SelectStatementId, // for detection/rejection of builtin calls
     in_select_arm: u32,
     in_test_expr: StatementId, // wrapping if/while stmt id
     in_binding_expr: BindingExpressionId, // to resolve variable expressions
     in_binding_expr_lhs: bool,
     // Traversal state, current scope (which can be used to find the parent
     // scope) and the definition variant we are considering.
     cur_scope: Scope,
     def_type: DefinitionType,
     // "Trailing" traversal state, set be child/prev stmt/expr used by next one
     prev_stmt: StatementId,
     expr_parent: ExpressionParent,
     // Set by parent to indicate that child expression must be assignable. The
     // child will throw an error if it is not assignable. The stored span is
     // used for the error's position
     must_be_assignable: Option<InputSpan>,
     // Keeping track of relative positions and unique IDs.
     relative_pos_in_block: i32, // of statements: to determine when variables are visible
     next_expr_index: i32, // to arrive at a unique ID for all expressions within a definition
     // Control flow statements that require label resolving
     control_flow_stmts: Vec<ControlFlowStatement>,
     // Various temporary buffers for traversal. Essentially working around
     // Rust's borrowing rules since it cannot understand we're modifying AST
     // members but not the AST container.
     variable_buffer: ScopedBuffer<VariableId>,
     definition_buffer: ScopedBuffer<DefinitionId>,
     statement_buffer: ScopedBuffer<StatementId>,
     expression_buffer: ScopedBuffer<ExpressionId>,
+}
 impl PassValidationLinking {
     pub(crate) fn new() -> Self {
         Self{
             in_sync: SynchronousStatementId::new_invalid(),
             in_while: WhileStatementId::new_invalid(),
             in_select_guard: SelectStatementId::new_invalid(),
             in_select_arm: 0,
             in_test_expr: StatementId::new_invalid(),
             in_binding_expr: BindingExpressionId::new_invalid(),
             in_binding_expr_lhs: false,
             cur_scope: Scope::new_invalid(),
             prev_stmt: StatementId::new_invalid(),
             expr_parent: ExpressionParent::None,
             def_type: DefinitionType::Function(FunctionDefinitionId::new_invalid()),
             must_be_assignable: None,
             relative_pos_in_block: 0,
             next_expr_index: 0,
             control_flow_stmts: Vec::with_capacity(32),
             variable_buffer: ScopedBuffer::with_capacity(128),
             definition_buffer: ScopedBuffer::with_capacity(128),
             statement_buffer: ScopedBuffer::with_capacity(BUFFER_INIT_CAPACITY),
             expression_buffer: ScopedBuffer::with_capacity(BUFFER_INIT_CAPACITY),
+        }
+    }
     fn reset_state(&mut self) {
         self.in_sync = SynchronousStatementId::new_invalid();
         self.in_while = WhileStatementId::new_invalid();
         self.in_select_guard = SelectStatementId::new_invalid();
         self.in_test_expr = StatementId::new_invalid();
         self.in_binding_expr = BindingExpressionId::new_invalid();
         self.in_binding_expr_lhs = false;
         self.cur_scope = Scope::new_invalid();
         self.def_type = DefinitionType::Function(FunctionDefinitionId::new_invalid());
         self.prev_stmt = StatementId::new_invalid();
         self.expr_parent = ExpressionParent::None;
         self.must_be_assignable = None;
         self.relative_pos_in_block = 0;
         self.next_expr_index = 0;
         self.control_flow_stmts.clear();
+    }
+}
 macro_rules! assign_then_erase_next_stmt {
     ($self:ident, $ctx:ident, $stmt_id:expr) => {
         if !$self.prev_stmt.is_invalid() {
             $ctx.heap[$self.prev_stmt].link_next($stmt_id);
             $self.prev_stmt = StatementId::new_invalid();
+        }
+    }
+}
 macro_rules! assign_and_replace_next_stmt {
     ($self:ident, $ctx:ident, $stmt_id:expr) => {
         if !$self.prev_stmt.is_invalid() {
             $ctx.heap[$self.prev_stmt].link_next($stmt_id);
+        }
         $self.prev_stmt = $stmt_id;
+    }
+}
 impl Visitor for PassValidationLinking {
     fn visit_module(&mut self, ctx: &mut Ctx) -> VisitorResult {
         debug_assert_eq!(ctx.module().phase, ModuleCompilationPhase::TypesAddedToTable);
         let root = &ctx.heap[ctx.module().root_id];
         let section = self.definition_buffer.start_section_initialized(&root.definitions);
         for definition_id in section.iter_copied() {
             self.visit_definition(ctx, definition_id)?;
+        }
         section.forget();
         ctx.module_mut().phase = ModuleCompilationPhase::ValidatedAndLinked;
         Ok(())
+    }
     //--------------------------------------------------------------------------
     // 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 = Scope::Definition(id.upcast());
         self.expr_parent = ExpressionParent::None;
         // Visit parameters and assign a unique scope ID
         let definition = &ctx.heap[id];
         let body_id = definition.body;
         let section = self.variable_buffer.start_section_initialized(&definition.parameters);
         for variable_idx in 0..section.len() {
             let variable_id = section[variable_idx];
             let variable = &mut ctx.heap[variable_id];
             variable.unique_id_in_scope = variable_idx as i32;
+        }
         section.forget();
         // Visit statements in component body
         self.visit_block_stmt(ctx, body_id)?;
         // Assign total number of expressions and assign an in-block unique ID
         // to each of the locals in the procedure.
         ctx.heap[id].num_expressions_in_body = self.next_expr_index;
         self.visit_definition_and_assign_local_ids(ctx, id.upcast());
         self.resolve_pending_control_flow_targets(ctx)?;
         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 = Scope::Definition(id.upcast());
         self.expr_parent = ExpressionParent::None;
         // Visit parameters and assign a unique scope ID
         let definition = &ctx.heap[id];
         let body_id = definition.body;
         let section = self.variable_buffer.start_section_initialized(&definition.parameters);
         for variable_idx in 0..section.len() {
             let variable_id = section[variable_idx];
             let variable = &mut ctx.heap[variable_id];
             variable.unique_id_in_scope = variable_idx as i32;
+        }
         section.forget();
         // Visit statements in function body
         self.visit_block_stmt(ctx, body_id)?;
         // Assign total number of expressions and assign an in-block unique ID
         // to each of the locals in the procedure.
         ctx.heap[id].num_expressions_in_body = self.next_expr_index;
         self.visit_definition_and_assign_local_ids(ctx, id.upcast());
         self.resolve_pending_control_flow_targets(ctx)?;
         Ok(())
+    }
     //--------------------------------------------------------------------------
     // Statement visitors
     //--------------------------------------------------------------------------
     fn visit_block_stmt(&mut self, ctx: &mut Ctx, id: BlockStatementId) -> VisitorResult {
         let old_scope = self.push_statement_scope(ctx, Scope::Regular(id));
         // Set end of block
         let block_stmt = &ctx.heap[id];
         let end_block_id = block_stmt.end_block;
         // Copy statement IDs into buffer
         // Traverse statements in block
         let statement_section = self.statement_buffer.start_section_initialized(&block_stmt.statements);
         assign_and_replace_next_stmt!(self, ctx, id.upcast());
         for stmt_idx in 0..statement_section.len() {
             self.relative_pos_in_block = stmt_idx as i32;
             self.visit_stmt(ctx, statement_section[stmt_idx])?;
+        }
         statement_section.forget();
         assign_and_replace_next_stmt!(self, ctx, end_block_id.upcast());
         self.pop_statement_scope(old_scope);
         Ok(())
+    }
     fn visit_local_memory_stmt(&mut self, ctx: &mut Ctx, id: MemoryStatementId) -> VisitorResult {
         let stmt = &ctx.heap[id];
         let expr_id = stmt.initial_expr;
         let variable_id = stmt.variable;
         self.checked_add_local(ctx, self.cur_scope, self.relative_pos_in_block, variable_id)?;
         assign_and_replace_next_stmt!(self, ctx, id.upcast().upcast());
         debug_assert_eq!(self.expr_parent, ExpressionParent::None);
         self.expr_parent = ExpressionParent::Memory(id);
         self.visit_assignment_expr(ctx, expr_id)?;
         self.expr_parent = ExpressionParent::None;
         Ok(())
+    }
     fn visit_local_channel_stmt(&mut self, ctx: &mut Ctx, id: ChannelStatementId) -> VisitorResult {
         let stmt = &ctx.heap[id];
         let from_id = stmt.from;
         let to_id = stmt.to;
         self.checked_add_local(ctx, self.cur_scope, self.relative_pos_in_block, from_id)?;
         self.checked_add_local(ctx, self.cur_scope, self.relative_pos_in_block, to_id)?;
         assign_and_replace_next_stmt!(self, ctx, id.upcast().upcast());
         Ok(())
+    }
     fn visit_labeled_stmt(&mut self, ctx: &mut Ctx, id: LabeledStatementId) -> VisitorResult {
         let stmt = &ctx.heap[id];
         let body_id = stmt.body;
         self.checked_add_label(ctx, self.relative_pos_in_block, self.in_sync, id)?;
         self.visit_stmt(ctx, body_id)?;
         Ok(())
+    }
     fn visit_if_stmt(&mut self, ctx: &mut Ctx, id: IfStatementId) -> VisitorResult {
         let if_stmt = &ctx.heap[id];
         let end_if_id = if_stmt.end_if;
         let test_expr_id = if_stmt.test;
         let true_stmt_id = if_stmt.true_body;
         let false_stmt_id = if_stmt.false_body;
         // Visit test expression
         debug_assert_eq!(self.expr_parent, ExpressionParent::None);
         debug_assert!(self.in_test_expr.is_invalid());
         self.in_test_expr = id.upcast();
         self.expr_parent = ExpressionParent::If(id);
         self.visit_expr(ctx, test_expr_id)?;
         self.in_test_expr = StatementId::new_invalid();
         self.expr_parent = ExpressionParent::None;
         // Visit true and false branch. Executor chooses next statement based on
         // test expression, not on if-statement itself. Hence the if statement
         // does not have a static subsequent statement.
         assign_then_erase_next_stmt!(self, ctx, id.upcast());
         self.visit_block_stmt(ctx, true_stmt_id)?;
         assign_then_erase_next_stmt!(self, ctx, end_if_id.upcast());
         if let Some(false_id) = false_stmt_id {
             self.visit_block_stmt(ctx, false_id)?;
             assign_then_erase_next_stmt!(self, ctx, end_if_id.upcast());
+        }
         self.prev_stmt = end_if_id.upcast();
         Ok(())
+    }
     fn visit_while_stmt(&mut self, ctx: &mut Ctx, id: WhileStatementId) -> VisitorResult {
         let stmt = &ctx.heap[id];
         let end_while_id = stmt.end_while;
         let test_expr_id = stmt.test;
         let body_stmt_id = stmt.body;
         let old_while = self.in_while;
         self.in_while = id;
         // Visit test expression
         debug_assert_eq!(self.expr_parent, ExpressionParent::None);
         debug_assert!(self.in_test_expr.is_invalid());
         self.in_test_expr = id.upcast();
         self.expr_parent = ExpressionParent::While(id);
         self.visit_expr(ctx, test_expr_id)?;
         self.in_test_expr = StatementId::new_invalid();
         // Link up to body statement
         assign_then_erase_next_stmt!(self, ctx, id.upcast());
         self.expr_parent = ExpressionParent::None;
         self.visit_block_stmt(ctx, body_stmt_id)?;
         self.in_while = old_while;
         // Link final entry in while's block statement back to the while. The
         // executor will go to the end-while statement if the test expression
         // is false, so put that in as the new previous stmt
         assign_then_erase_next_stmt!(self, ctx, id.upcast());
         self.prev_stmt = end_while_id.upcast();
         Ok(())
+    }
     fn visit_break_stmt(&mut self, ctx: &mut Ctx, id: BreakStatementId) -> VisitorResult {
         self.control_flow_stmts.push(ControlFlowStatement{
             in_sync: self.in_sync,
             in_while: self.in_while,
             in_scope: self.cur_scope,
             statement: id.upcast()
         });
         assign_then_erase_next_stmt!(self, ctx, id.upcast());
         Ok(())
+    }
     fn visit_continue_stmt(&mut self, ctx: &mut Ctx, id: ContinueStatementId) -> VisitorResult {
         self.control_flow_stmts.push(ControlFlowStatement{
             in_sync: self.in_sync,
             in_while: self.in_while,
             in_scope: self.cur_scope,
             statement: id.upcast()
         });
         assign_then_erase_next_stmt!(self, ctx, id.upcast());
         Ok(())
+    }
     fn visit_synchronous_stmt(&mut self, ctx: &mut Ctx, id: SynchronousStatementId) -> VisitorResult {
         // Check for validity of synchronous statement
         let sync_stmt = &ctx.heap[id];
         let end_sync_id = sync_stmt.end_sync;
         let cur_sync_span = sync_stmt.span;
         if !self.in_sync.is_invalid() {
             // Nested synchronous statement
             let old_sync_span = ctx.heap[self.in_sync].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, "It is nested in this synchronous statement"
             ));
+        }
         if !self.def_type.is_primitive() {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, cur_sync_span,
                 "synchronous statements may only be used in primitive components"
             ));
+        }
         // Synchronous statement implicitly moves to its block
         assign_then_erase_next_stmt!(self, ctx, id.upcast());
         // Visit block statement. Note that we explicitly push the scope here
         // (and the `visit_block_stmt` will also push, but without effect) to
         // ensure the scope contains the sync ID.
         let sync_body = ctx.heap[id].body;
         debug_assert!(self.in_sync.is_invalid());
         self.in_sync = id;
         let old_scope = self.push_statement_scope(ctx, Scope::Synchronous(id, sync_body));
         self.visit_block_stmt(ctx, sync_body)?;
         self.pop_statement_scope(old_scope);
         assign_and_replace_next_stmt!(self, ctx, end_sync_id.upcast());
         self.in_sync = SynchronousStatementId::new_invalid();
         Ok(())
+    }
     fn visit_fork_stmt(&mut self, ctx: &mut Ctx, id: ForkStatementId) -> VisitorResult {
         let fork_stmt = &ctx.heap[id];
         let end_fork_id = fork_stmt.end_fork;
         let left_body_id = fork_stmt.left_body;
         let right_body_id = fork_stmt.right_body;
         // Fork statements may only occur inside sync blocks
         if self.in_sync.is_invalid() {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, fork_stmt.span,
                 "Forking may only occur inside sync blocks"
             ));
+        }
         // Visit the respective bodies. Like the if statement, a fork statement
         // does not have a single static subsequent statement. It forks and then
         // each fork has a different next statement.
         assign_then_erase_next_stmt!(self, ctx, id.upcast());
         self.visit_block_stmt(ctx, left_body_id)?;
         assign_then_erase_next_stmt!(self, ctx, end_fork_id.upcast());
         if let Some(right_body_id) = right_body_id {
             self.visit_block_stmt(ctx, right_body_id)?;
             assign_then_erase_next_stmt!(self, ctx, end_fork_id.upcast());
+        }
         self.prev_stmt = end_fork_id.upcast();
         Ok(())
+    }
     fn visit_select_stmt(&mut self, ctx: &mut Ctx, id: SelectStatementId) -> VisitorResult {
         let select_stmt = &ctx.heap[id];
         let end_select_id = select_stmt.end_select;
         // Select statements may only occur inside sync blocks
         if self.in_sync.is_invalid() {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, select_stmt.span,
                 "select statements may only occur inside sync blocks"
             ));
+        }
         if !self.def_type.is_primitive() {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, select_stmt.span,
                 "select statements may only be used in primitive components"
             ));
+        }
         // Visit the various arms in the select block
         let mut case_stmt_ids = self.statement_buffer.start_section();
         let num_cases = select_stmt.cases.len();
         for case in &select_stmt.cases {
             // Note: we add both to the buffer, retrieve them later in indexed
             // fashion
             case_stmt_ids.push(case.guard);
             case_stmt_ids.push(case.block.upcast());
+        }
         assign_then_erase_next_stmt!(self, ctx, id.upcast());
         for idx in 0..num_cases {
             let base_idx = 2 * idx;
             let guard_id     = case_stmt_ids[base_idx    ];
             let arm_block_id = case_stmt_ids[base_idx + 1];
             debug_assert_eq!(ctx.heap[arm_block_id].as_block().this.upcast(), arm_block_id); // backwards way of saying arm_block_id is a BlockStatementId
             let arm_block_id = BlockStatementId(arm_block_id);
             // The guard statement ends up belonging to the block statement
             // following the arm. The reason we parse it separately is to
             // extract all of the "get" calls.
             let old_scope = self.push_statement_scope(ctx, Scope::Regular(arm_block_id));
             // Visit the guard of this arm
             debug_assert!(self.in_select_guard.is_invalid());
             self.in_select_guard = id;
             self.in_select_arm = idx as u32;
             self.visit_stmt(ctx, guard_id)?;
             self.in_select_guard = SelectStatementId::new_invalid();
             // Visit the code associated with the guard
             self.visit_block_stmt(ctx, arm_block_id)?;
             self.pop_statement_scope(old_scope);
             // Link up last statement in block to EndSelect
             assign_then_erase_next_stmt!(self, ctx, end_select_id.upcast());
+        }
         self.in_select_guard = SelectStatementId::new_invalid();
         self.prev_stmt = end_select_id.upcast();
         Ok(())
+    }
     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.def_type.is_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
         assign_then_erase_next_stmt!(self, ctx, id.upcast());
         debug_assert_eq!(self.expr_parent, ExpressionParent::None);
         debug_assert_eq!(ctx.heap[id].expressions.len(), 1);
         self.expr_parent = ExpressionParent::Return(id);
         self.visit_expr(ctx, ctx.heap[id].expressions[0])?;
         self.expr_parent = ExpressionParent::None;
         Ok(())
+    }
     fn visit_goto_stmt(&mut self, ctx: &mut Ctx, id: GotoStatementId) -> VisitorResult {
         self.control_flow_stmts.push(ControlFlowStatement{
             in_sync: self.in_sync,
             in_while: self.in_while,
             in_scope: self.cur_scope,
             statement: id.upcast(),
         });
         assign_then_erase_next_stmt!(self, ctx, id.upcast());
         Ok(())
+    }
     fn visit_new_stmt(&mut self, ctx: &mut Ctx, id: NewStatementId) -> VisitorResult {
         // Make sure the new statement occurs inside a composite component
         if !self.def_type.is_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;
         assign_and_replace_next_stmt!(self, ctx, id.upcast());
         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 {
         let expr_id = ctx.heap[id].expression;
         assign_and_replace_next_stmt!(self, ctx, id.upcast());
         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 {
         let upcast_id = id.upcast();
         let assignment_expr = &mut ctx.heap[id];
         // Although we call assignment an expression to simplify the compiler's
         // code (mainly typechecking), we disallow nested use in expressions
         match self.expr_parent {
             // Look at us: lying through our teeth while providing error messages.
             ExpressionParent::Memory(_) => {},
             ExpressionParent::ExpressionStmt(_) => {},
             _ => {
                 let assignment_span = assignment_expr.full_span;
                 return Err(ParseError::new_error_str_at_span(
                     &ctx.module().source, assignment_span,
                     "assignments are statements, and cannot be used in expressions"
                 ))
             },
+        }
         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;
         assignment_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
         self.must_be_assignable = Some(assignment_expr.operator_span);
         self.visit_expr(ctx, left_expr_id)?;
         self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
         self.must_be_assignable = None;
         self.visit_expr(ctx, right_expr_id)?;
         self.expr_parent = old_expr_parent;
         Ok(())
+    }
     fn visit_binding_expr(&mut self, ctx: &mut Ctx, id: BindingExpressionId) -> VisitorResult {
         let upcast_id = id.upcast();
         // Check for valid context of binding expression
         if let Some(span) = self.must_be_assignable {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, span, "cannot assign to the result from a binding expression"
             ));
+        }
         if self.in_test_expr.is_invalid() {
             let binding_expr = &ctx.heap[id];
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, binding_expr.full_span,
                 "binding expressions can only be used inside the testing expression of 'if' and 'while' statements"
             ));
+        }
         if !self.in_binding_expr.is_invalid() {
             let binding_expr = &ctx.heap[id];
             let previous_expr = &ctx.heap[self.in_binding_expr];
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, binding_expr.full_span,
                 "nested binding expressions are not allowed"
             ).with_info_str_at_span(
                 &ctx.module().source, previous_expr.operator_span,
                 "the outer binding expression is found here"
             ));
+        }
         let mut seeking_parent = self.expr_parent;
         loop {
             // Perform upward search to make sure only LogicalAnd is applied to
             // the binding expression
             let valid = match seeking_parent {
                 ExpressionParent::If(_) | ExpressionParent::While(_) => {
                     // Every parent expression (if any) were LogicalAnd.
                     break;
+                }
                 ExpressionParent::Expression(parent_id, _) => {
                     let parent_expr = &ctx.heap[parent_id];
                     match parent_expr {
                         Expression::Binary(parent_expr) => {
                             // Set new parent to continue the search. Otherwise
                             // halt and provide an error using the current
                             // parent.
                             if parent_expr.operation == BinaryOperator::LogicalAnd {
                                 seeking_parent = parent_expr.parent;
                                 true
                             } else {
                                 false
+                            }
                         },
                         _ => false,
+                    }
                 },
                 _ => unreachable!(), // nested under if/while, so always expressions as parents
             };
             if !valid {
                 let binding_expr = &ctx.heap[id];
                 let parent_expr = &ctx.heap[seeking_parent.as_expression()];
                 return Err(ParseError::new_error_str_at_span(
                     &ctx.module().source, binding_expr.full_span,
                     "only the logical-and operator (&&) may be applied to binding expressions"
                 ).with_info_str_at_span(
                     &ctx.module().source, parent_expr.operation_span(),
                     "this was the disallowed operation applied to the result from a binding expression"
                 ));
+            }
+        }
         // Perform all of the index/parent assignment magic
         let binding_expr = &mut ctx.heap[id];
         let old_expr_parent = self.expr_parent;
         binding_expr.parent = old_expr_parent;
         binding_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         self.in_binding_expr = id;
         // Perform preliminary check on children: binding expressions only make
         // sense if the left hand side is just a variable expression, or if it
         // is a literal of some sort. The typechecker will take care of the rest
         let bound_to_id = binding_expr.bound_to;
         let bound_from_id = binding_expr.bound_from;
         match &ctx.heap[bound_to_id] {
             // Variables may not be binding variables, and literals may
             // actually not contain binding variables. But in that case we just
             // perform an equality check.
             Expression::Variable(_) => {}
             Expression::Literal(_) => {},
             _ => {
                 let binding_expr = &ctx.heap[id];
                 return Err(ParseError::new_error_str_at_span(
                     &ctx.module().source, binding_expr.operator_span,
                     "the left hand side of a binding expression may only be a variable or a literal expression"
                 ));
             },
+        }
         // Visit the children themselves
         self.in_binding_expr_lhs = true;
         self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
         self.visit_expr(ctx, bound_to_id)?;
         self.in_binding_expr_lhs = false;
         self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
         self.visit_expr(ctx, bound_from_id)?;
         self.expr_parent = old_expr_parent;
         self.in_binding_expr = BindingExpressionId::new_invalid();
         Ok(())
+    }
     fn visit_conditional_expr(&mut self, ctx: &mut Ctx, id: ConditionalExpressionId) -> VisitorResult {
         let upcast_id = id.upcast();
         let conditional_expr = &mut ctx.heap[id];
         if let Some(span) = self.must_be_assignable {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, span, "cannot assign to the result from a conditional expression"
             ))
+        }
         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;
         conditional_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         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 {
         let upcast_id = id.upcast();
         let binary_expr = &mut ctx.heap[id];
         if let Some(span) = self.must_be_assignable {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, span, "cannot assign to the result from a binary expression"
             ))
+        }
         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;
         binary_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         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 {
         let unary_expr = &mut ctx.heap[id];
         let expr_id = unary_expr.expression;
         if let Some(span) = self.must_be_assignable {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, span, "cannot assign to the result from a unary expression"
             ))
+        }
         let old_expr_parent = self.expr_parent;
         unary_expr.parent = old_expr_parent;
         unary_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         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 {
         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;
         indexing_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
         self.visit_expr(ctx, subject_expr_id)?;
         let old_assignable = self.must_be_assignable.take();
         self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
         self.visit_expr(ctx, index_expr_id)?;
         self.must_be_assignable = old_assignable;
         self.expr_parent = old_expr_parent;
         Ok(())
+    }
     fn visit_slicing_expr(&mut self, ctx: &mut Ctx, id: SlicingExpressionId) -> VisitorResult {
         let upcast_id = id.upcast();
         let slicing_expr = &mut ctx.heap[id];
         if let Some(span) = self.must_be_assignable {
             // TODO: @Slicing
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, span, "assignment to slices should be valid in the final language, but is currently not implemented"
             ));
+        }
         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;
         slicing_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
         self.visit_expr(ctx, subject_expr_id)?;
         let old_assignable = self.must_be_assignable.take();
         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.must_be_assignable = old_assignable;
         self.expr_parent = old_expr_parent;
         Ok(())
+    }
     fn visit_select_expr(&mut self, ctx: &mut Ctx, id: SelectExpressionId) -> VisitorResult {
         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;
         select_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         self.expr_parent = ExpressionParent::Expression(id.upcast(), 0);
         self.visit_expr(ctx, expr_id)?;
         self.expr_parent = old_expr_parent;
         Ok(())
+    }
     fn visit_literal_expr(&mut self, ctx: &mut Ctx, id: LiteralExpressionId) -> VisitorResult {
         let literal_expr = &mut ctx.heap[id];
         let old_expr_parent = self.expr_parent;
         literal_expr.parent = old_expr_parent;
         literal_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         if let Some(span) = self.must_be_assignable {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, span, "cannot assign to a literal expression"
             ))
+        }
         match &mut literal_expr.value {
             Literal::Null | Literal::True | Literal::False |
             Literal::Character(_) | Literal::String(_) | Literal::Integer(_) => {
                 // Just the parent has to be set, done above
             },
             Literal::Struct(literal) => {
                 let upcast_id = id.upcast();
                 // Retrieve type definition
                 let type_definition = ctx.types.get_base_definition(&literal.definition).unwrap();
                 let struct_definition = type_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(struct_definition.fields.len(), false);
                 for field in &mut literal.fields {
                     // Find field in the struct definition
                     let field_idx = struct_definition.fields.iter().position(|v| v.identifier == field.identifier);
                     if field_idx.is_none() {
                         let field_span = field.identifier.span;
                         let literal = ctx.heap[id].value.as_struct();
                         let ast_definition = &ctx.heap[literal.definition];
                         return Err(ParseError::new_error_at_span(
                             &ctx.module().source, field_span, format!(
                                 "This field does not exist on the struct '{}'",
                                 ast_definition.identifier().value.as_str()
+                            )
                         ));
+                    }
                     field.field_idx = field_idx.unwrap();
                     // Check if specified more than once
                     if specified[field.field_idx] {
                         let field_span = field.identifier.span;
                         return Err(ParseError::new_error_str_at_span(
                             &ctx.module().source, field_span,
                             "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 = &struct_definition.fields[def_field_idx].identifier;
                             not_specified.push_str(field_ident.value.as_str());
                             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)
                     };
                     let literal_span = literal.parser_type.full_span;
                     return Err(ParseError::new_error_at_span(
                         &ctx.module().source, literal_span, msg
                     ));
+                }
                 // Need to traverse fields expressions in struct and evaluate
                 // the poly args
                 let mut expr_section = self.expression_buffer.start_section();
                 for field in &literal.fields {
                     expr_section.push(field.value);
+                }
                 for expr_idx in 0..expr_section.len() {
                     let expr_id = expr_section[expr_idx];
                     self.expr_parent = ExpressionParent::Expression(upcast_id, expr_idx as u32);
                     self.visit_expr(ctx, expr_id)?;
+                }
                 expr_section.forget();
             },
             Literal::Enum(literal) => {
                 // Make sure the variant exists
                 let type_definition = ctx.types.get_base_definition(&literal.definition).unwrap();
                 let enum_definition = type_definition.definition.as_enum();
                 let variant_idx = enum_definition.variants.iter().position(|v| {
                     v.identifier == literal.variant
                 });
                 if variant_idx.is_none() {
                     let literal = ctx.heap[id].value.as_enum();
                     let ast_definition = ctx.heap[literal.definition].as_enum();
                     return Err(ParseError::new_error_at_span(
                         &ctx.module().source, literal.parser_type.full_span, format!(
                             "the variant '{}' does not exist on the enum '{}'",
                             literal.variant.value.as_str(), ast_definition.identifier.value.as_str()
+                        )
                     ));
+                }
                 literal.variant_idx = variant_idx.unwrap();
             },
             Literal::Union(literal) => {
                 // Make sure the variant exists
                 let type_definition = ctx.types.get_base_definition(&literal.definition).unwrap();
                 let union_definition = type_definition.definition.as_union();
                 let variant_idx = union_definition.variants.iter().position(|v| {
                     v.identifier == literal.variant
                 });
                 if variant_idx.is_none() {
                     let literal = ctx.heap[id].value.as_union();
                     let ast_definition = ctx.heap[literal.definition].as_union();
                     return Err(ParseError::new_error_at_span(
                         &ctx.module().source, literal.parser_type.full_span, format!(
                             "the variant '{}' does not exist on the union '{}'",
                             literal.variant.value.as_str(), ast_definition.identifier.value.as_str()
+                        )
                     ));
+                }
                 literal.variant_idx = variant_idx.unwrap();
                 // 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() {
                     let literal = ctx.heap[id].value.as_union();
                     let ast_definition = ctx.heap[literal.definition].as_union();
                     return Err(ParseError::new_error_at_span(
                         &ctx.module().source, literal.parser_type.full_span, format!(
                             "The variant '{}' of union '{}' expects {} embedded values, but {} were specified",
                             literal.variant.value.as_str(), ast_definition.identifier.value.as_str(),
                             union_variant.embedded.len(), literal.values.len()
                         ),
                     ))
+                }
                 // Traverse embedded values of union (if any) and evaluate the
                 // polymorphic arguments
                 let upcast_id = id.upcast();
                 let mut expr_section = self.expression_buffer.start_section();
                 for value in &literal.values {
                     expr_section.push(*value);
+                }
                 for expr_idx in 0..expr_section.len() {
                     let expr_id = expr_section[expr_idx];
                     self.expr_parent = ExpressionParent::Expression(upcast_id, expr_idx as u32);
                     self.visit_expr(ctx, expr_id)?;
+                }
                 expr_section.forget();
             },
             Literal::Array(literal) | Literal::Tuple(literal) => {
                 // Visit all expressions in the array
                 let upcast_id = id.upcast();
                 let expr_section = self.expression_buffer.start_section_initialized(literal);
                 for expr_idx in 0..expr_section.len() {
                     let expr_id = expr_section[expr_idx];
                     self.expr_parent = ExpressionParent::Expression(upcast_id, expr_idx as u32);
                     self.visit_expr(ctx, expr_id)?;
+                }
                 expr_section.forget();
+            }
+        }
         self.expr_parent = old_expr_parent;
         Ok(())
+    }
     fn visit_cast_expr(&mut self, ctx: &mut Ctx, id: CastExpressionId) -> VisitorResult {
         let cast_expr = &mut ctx.heap[id];
         if let Some(span) = self.must_be_assignable {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, span, "cannot assign to the result from a cast expression"
             ))
+        }
         let upcast_id = id.upcast();
         let old_expr_parent = self.expr_parent;
         cast_expr.parent = old_expr_parent;
         cast_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         // Recurse into the thing that we're casting
         self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
         let subject_id = cast_expr.subject;
         self.visit_expr(ctx, subject_id)?;
         self.expr_parent = old_expr_parent;
         Ok(())
+    }
     fn visit_call_expr(&mut self, ctx: &mut Ctx, id: CallExpressionId) -> VisitorResult {
         let call_expr = &ctx.heap[id];
         if let Some(span) = self.must_be_assignable {
             return Err(ParseError::new_error_str_at_span(
                 &ctx.module().source, span, "cannot assign to the result from a call expression"
             ))
+        }
         // Check whether the method is allowed to be called within the code's
         // context (in sync, definition type, etc.)
         let mut expecting_wrapping_new_stmt = false;
         let mut expecting_primitive_def = false;
         let mut expecting_wrapping_sync_stmt = false;
         let mut expecting_no_select_stmt = false;
         match call_expr.method {
             Method::Get => {
                 expecting_primitive_def = true;
                 expecting_wrapping_sync_stmt = true;
                 if !self.in_select_guard.is_invalid() {
                     // In a select guard. Take the argument (i.e. the port we're
                     // retrieving from) and add it to the list of involved ports
                     // of the guard
                     if call_expr.arguments.len() == 1 {
                         // We're checking the number of arguments later, for now
                         // assume it is correct.
                         let argument = call_expr.arguments[0];
                         let select_stmt = &mut ctx.heap[self.in_select_guard];
                         let select_case = &mut select_stmt.cases[self.in_select_arm as usize];
                         select_case.involved_ports.push((id, argument));
+                    }
+                }
             },
             Method::Put => {
                 expecting_primitive_def = true;
                 expecting_wrapping_sync_stmt = true;
                 expecting_no_select_stmt = true;
             },
             Method::Fires => {
                 expecting_primitive_def = true;
                 expecting_wrapping_sync_stmt = true;
             },
             Method::Create => {},
             Method::Length => {},
             Method::Assert => {
                 expecting_wrapping_sync_stmt = true;
                 expecting_no_select_stmt = true;
                 if self.def_type.is_function() {
                     let call_span = call_expr.func_span;
                     return Err(ParseError::new_error_str_at_span(
                         &ctx.module().source, call_span,
                         "assert statement may only occur in components"
                     ));
+                }
             },
             Method::Print => {},
             Method::UserFunction => {},
             Method::UserComponent => {
                 expecting_wrapping_new_stmt = true;
             },
+        }
         let call_expr = &mut ctx.heap[id];
         fn get_span_and_name<'a>(ctx: &'a Ctx, id: CallExpressionId) -> (InputSpan, String) {
             let call = &ctx.heap[id];
             let span = call.func_span;
             let name = String::from_utf8_lossy(ctx.module().source.section_at_span(span)).to_string();
             return (span, name);
+        }
         if expecting_primitive_def {
             if !self.def_type.is_primitive() {
                 let (call_span, func_name) = get_span_and_name(ctx, id);
                 return Err(ParseError::new_error_at_span(
                     &ctx.module().source, call_span,
                     format!("a call to '{}' may only occur in primitive component definitions", func_name)
                 ));
+            }
+        }
         if expecting_wrapping_sync_stmt {
             if self.in_sync.is_invalid() {
                 let (call_span, func_name) = get_span_and_name(ctx, id);
                 return Err(ParseError::new_error_at_span(
                     &ctx.module().source, call_span,
                     format!("a call to '{}' may only occur inside synchronous blocks", func_name)
                 ))
+            }
+        }
         if expecting_no_select_stmt {
             if !self.in_select_guard.is_invalid() {
                 let (call_span, func_name) = get_span_and_name(ctx, id);
                 return Err(ParseError::new_error_at_span(
                     &ctx.module().source, call_span,
                     format!("a call to '{}' may not occur in a select statement's guard", func_name)
                 ));
+            }
+        }
         if expecting_wrapping_new_stmt {
             if !self.expr_parent.is_new() {
                 let call_span = call_expr.func_span;
                 return Err(ParseError::new_error_str_at_span(
                     &ctx.module().source, call_span,
                     "cannot call a component, it can only be instantiated by using 'new'"
                 ));
+            }
         } else {
             if self.expr_parent.is_new() {
                 let call_span = call_expr.func_span;
                 return Err(ParseError::new_error_str_at_span(
                     &ctx.module().source, call_span,
                     "only components can be instantiated, this is a function"
                 ));
+            }
+        }
         // 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.type_class()),
         };
         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" };
             let call_span = call_expr.full_span;
             return Err(ParseError::new_error_at_span(
                 &ctx.module().source, call_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 section = self.expression_buffer.start_section_initialized(&call_expr.arguments);
         let old_expr_parent = self.expr_parent;
         call_expr.parent = old_expr_parent;
         call_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         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)?;
+        }
         section.forget();
         self.expr_parent = old_expr_parent;
         Ok(())
+    }
     fn visit_variable_expr(&mut self, ctx: &mut Ctx, id: VariableExpressionId) -> VisitorResult {
         let var_expr = &ctx.heap[id];
         // Check if declaration was already resolved (this occurs for the
         // variable expr that is on the LHS of the assignment expr that is
         // associated with a variable declaration)
         let mut variable_id = var_expr.declaration;
         let mut is_binding_target = false;
         // Otherwise try to find it
         if variable_id.is_none() {
             variable_id = self.find_variable(ctx, self.relative_pos_in_block, &var_expr.identifier);
+        }
         // Otherwise try to see if is a variable introduced by a binding expr
         let variable_id = if let Some(variable_id) = variable_id {
             variable_id
         } else {
             if self.in_binding_expr.is_invalid() || !self.in_binding_expr_lhs {
                 return Err(ParseError::new_error_str_at_span(
                     &ctx.module().source, var_expr.identifier.span, "unresolved variable"
                 ));
+            }
             // This is a binding variable, but it may only appear in very
             // specific locations.
             let is_valid_binding = match self.expr_parent {
                 ExpressionParent::Expression(expr_id, idx) => {
                     match &ctx.heap[expr_id] {
                         Expression::Binding(_binding_expr) => {
                             // Nested binding is disallowed, and because of
                             // the check above we know we're directly at the
                             // LHS of the binding expression
                             debug_assert_eq!(_binding_expr.this, self.in_binding_expr);
                             debug_assert_eq!(idx, 0);
                             true
+                        }
                         Expression::Literal(lit_expr) => {
                             // Only struct, unions, tuples and arrays can
                             // have subexpressions, so we're always fine
                             if cfg!(debug_assertions) {
                                 match lit_expr.value {
                                     Literal::Struct(_) | Literal::Union(_) | Literal::Array(_) | Literal::Tuple(_) => {},
                                     _ => unreachable!(),
+                                }
+                            }
                             true
                         },
                         _ => false,
+                    }
                 },
                 _ => {
                     false
+                }
             };
             if !is_valid_binding {
                 let binding_expr = &ctx.heap[self.in_binding_expr];
                 return Err(ParseError::new_error_str_at_span(
                     &ctx.module().source, var_expr.identifier.span,
                     "illegal location for binding variable: binding variables may only be nested under a binding expression, or a struct, union or array literal"
                 ).with_info_at_span(
                     &ctx.module().source, binding_expr.operator_span, format!(
                         "'{}' was interpreted as a binding variable because the variable is not declared and it is nested under this binding expression",
                         var_expr.identifier.value.as_str()
+                    )
                 ));
+            }
             // By now we know that this is a valid binding expression. Given
             // that a binding expression must be nested under an if/while
             // statement, we now add the variable to the (implicit) block
             // statement following the if/while statement.
             let bound_identifier = var_expr.identifier.clone();
             let bound_variable_id = ctx.heap.alloc_variable(|this| Variable {
                 this,
                 kind: VariableKind::Binding,
                 parser_type: ParserType {
                     elements: vec![ParserTypeElement {
                         element_span: bound_identifier.span,
                         variant: ParserTypeVariant::Inferred
                     }],
                     full_span: bound_identifier.span
                 },
                 identifier: bound_identifier,
                 relative_pos_in_block: 0,
                 unique_id_in_scope: -1,
             });
             let body_stmt_id = match &ctx.heap[self.in_test_expr] {
                 Statement::If(stmt) => stmt.true_body,
                 Statement::While(stmt) => stmt.body,
                 _ => unreachable!(),
             };
             let body_scope = Scope::Regular(body_stmt_id);
             self.checked_at_single_scope_add_local(ctx, body_scope, -1, bound_variable_id)?; // add at -1 such that first statement can access
             is_binding_target = true;
             bound_variable_id
         };
         let var_expr = &mut ctx.heap[id];
         var_expr.declaration = Some(variable_id);
         var_expr.used_as_binding_target = is_binding_target;
         var_expr.parent = self.expr_parent;
         var_expr.unique_id_in_definition = self.next_expr_index;
         self.next_expr_index += 1;
         Ok(())
+    }
+}
 impl PassValidationLinking {
     //--------------------------------------------------------------------------
     // Special traversal
     //--------------------------------------------------------------------------
     /// Pushes a new scope associated with a particular statement. If that
     /// statement already has an associated scope (i.e. scope associated with
     /// sync statement or select statement's arm) then we won't do anything.
     /// In all cases the caller must call `pop_statement_scope` with the scope
     /// and relative scope position returned by this function.
     fn push_statement_scope(&mut self, ctx: &mut Ctx, new_scope: Scope) -> (Scope, i32) {
         let old_scope = self.cur_scope.clone();
         debug_assert!(new_scope.is_block()); // never call for Definition scope
         let is_new_block = if old_scope.is_block() {
             old_scope.to_block() != new_scope.to_block()
         } else {
             true
         };
         if !is_new_block {
             // No need to push, but still return old scope, we pretend like we
             // replaced it.
             debug_assert!(!ctx.heap[new_scope.to_block()].scope_node.parent.is_invalid());
             return (old_scope, self.relative_pos_in_block);
+        }
         // This is a new block, so link it up
         if old_scope.is_block() {
             let parent_block = &mut ctx.heap[old_scope.to_block()];
             parent_block.scope_node.nested.push(new_scope);
+        }
         self.cur_scope = new_scope;
         let cur_block = &mut ctx.heap[new_scope.to_block()];
         cur_block.scope_node.parent = old_scope;
         cur_block.scope_node.relative_pos_in_parent = self.relative_pos_in_block;
         let old_relative_pos = self.relative_pos_in_block;
         self.relative_pos_in_block = -1;
         return (old_scope, old_relative_pos)
+    }
     fn pop_statement_scope(&mut self, scope_to_restore: (Scope, i32)) {
         self.cur_scope = scope_to_restore.0;
         self.relative_pos_in_block = scope_to_restore.1;
+    }
     fn visit_definition_and_assign_local_ids(&mut self, ctx: &mut Ctx, definition_id: DefinitionId) {
         let mut var_counter = 0;
         // Set IDs on parameters
         let (param_section, body_id) = match &ctx.heap[definition_id] {
             Definition::Function(func_def) => (
                 self.variable_buffer.start_section_initialized(&func_def.parameters),
                 func_def.body
             ),
             Definition::Component(comp_def) => (
                 self.variable_buffer.start_section_initialized(&comp_def.parameters),
                 comp_def.body
             ),
             _ => unreachable!(),
         } ;
         for var_id in param_section.iter_copied() {
             let var = &mut ctx.heap[var_id];
             var.unique_id_in_scope = var_counter;
             var_counter += 1;
+        }
         param_section.forget();
         // Recurse into body
         self.visit_block_and_assign_local_ids(ctx, body_id, var_counter);
+    }
     fn visit_block_and_assign_local_ids(&mut self, ctx: &mut Ctx, block_id: BlockStatementId, mut var_counter: i32) {
         let block_stmt = &mut ctx.heap[block_id];
         block_stmt.first_unique_id_in_scope = var_counter;
         let var_section = self.variable_buffer.start_section_initialized(&block_stmt.locals);
         let mut scope_section = self.statement_buffer.start_section();
         for child_scope in &block_stmt.scope_node.nested {
             debug_assert!(child_scope.is_block(), "found a child scope that is not a block statement");
             scope_section.push(child_scope.to_block().upcast());
+        }
         let mut var_idx = 0;
         let mut scope_idx = 0;
         while var_idx < var_section.len() || scope_idx < scope_section.len() {
             let relative_var_pos = if var_idx < var_section.len() {
                 ctx.heap[var_section[var_idx]].relative_pos_in_block
             } else {
                 i32::MAX
             };
             let relative_scope_pos = if scope_idx < scope_section.len() {
                 ctx.heap[scope_section[scope_idx]].as_block().scope_node.relative_pos_in_parent
             } else {
                 i32::MAX
             };
             debug_assert!(!(relative_var_pos == i32::MAX && relative_scope_pos == i32::MAX));
             // In certain cases the relative variable position is the same as
             // the scope position (insertion of binding variables). In that case
             // the variable should be treated first
             if relative_var_pos <= relative_scope_pos {
                 let var = &mut ctx.heap[var_section[var_idx]];
                 var.unique_id_in_scope = var_counter;
                 var_counter += 1;
                 var_idx += 1;
             } else {
                 // Boy oh boy
                 let block_id = ctx.heap[scope_section[scope_idx]].as_block().this;
                 self.visit_block_and_assign_local_ids(ctx, block_id, var_counter);
                 scope_idx += 1;
+            }
+        }
         var_section.forget();
         scope_section.forget();
         // Done assigning all IDs, assign the last ID to the block statement scope
         let block_stmt = &mut ctx.heap[block_id];
         block_stmt.next_unique_id_in_scope = var_counter;
+    }
     fn resolve_pending_control_flow_targets(&mut self, ctx: &mut Ctx) -> Result<(), ParseError> {
         for entry in &self.control_flow_stmts {
             let stmt = &ctx.heap[entry.statement];
             match stmt {
                 Statement::Break(stmt) => {
                     let stmt_id = stmt.this;
                     let target_while_id = Self::resolve_break_or_continue_target(ctx, entry, stmt.span, &stmt.label)?;
                     let target_while_stmt = &ctx.heap[target_while_id];
                     let target_end_while_id = target_while_stmt.end_while;
                     debug_assert!(!target_end_while_id.is_invalid());
                     let break_stmt = &mut ctx.heap[stmt_id];
                     break_stmt.target = target_end_while_id;
                 },
                 Statement::Continue(stmt) => {
                     let stmt_id = stmt.this;
                     let target_while_id = Self::resolve_break_or_continue_target(ctx, entry, stmt.span, &stmt.label)?;
                     let continue_stmt = &mut ctx.heap[stmt_id];
                     continue_stmt.target = target_while_id;
                 },
                 Statement::Goto(stmt) => {
                     let stmt_id = stmt.this;
                     let target_id = Self::find_label(entry.in_scope, ctx, &stmt.label)?;
                     let target_stmt = &ctx.heap[target_id];
                     if entry.in_sync != target_stmt.in_sync {
                         // Nested sync not allowed. And goto can only go to
                         // outer scopes, so we must be escaping from a sync.
                         debug_assert!(target_stmt.in_sync.is_invalid());    // target not in sync
                         debug_assert!(!entry.in_sync.is_invalid()); // but the goto is in sync
                         let goto_stmt = &ctx.heap[stmt_id];
                         let sync_stmt = &ctx.heap[entry.in_sync];
                         return Err(
                             ParseError::new_error_str_at_span(&ctx.module().source, goto_stmt.span, "goto may not escape the surrounding synchronous block")
                             .with_info_str_at_span(&ctx.module().source, target_stmt.label.span, "this is the target of the goto statement")
                             .with_info_str_at_span(&ctx.module().source, sync_stmt.span, "which will jump past this statement")
                         );
+                    }
                     let goto_stmt = &mut ctx.heap[stmt_id];
                     goto_stmt.target = target_id;
                 },
                 _ => unreachable!("cannot resolve control flow target for {:?}", stmt),
+            }
+        }
         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_add_local(&mut self, ctx: &mut Ctx, target_scope: Scope, relative_pos: i32, id: VariableId) -> Result<(), ParseError> {
+    fn checked_add_local(&mut self, ctx: &mut Ctx, target_scope: Scope, target_relative_pos: i32, id: VariableId) -> Result<(), ParseError> {
         debug_assert!(target_scope.is_block());
         let local = &ctx.heap[id];
         println!("DEBUG: Adding local '{}' at relative_pos {} in scope {:?}", local.identifier.value.as_str(), relative_pos, target_scope);
         let mut scope = target_scope;
         println!("DEBUG: Adding local '{}' at relative_pos {} in scope {:?}", local.identifier.value.as_str(), target_relative_pos, target_scope);
         // We immediately go to the parent scope. We check the target scope
         // in the call at the end. That is also where we check for collisions
         // with symbols.
         let block = &ctx.heap[target_scope.to_block()];
         let mut scope = block.scope_node.parent;
         let mut cur_relative_pos = block.scope_node.relative_pos_in_parent;
         loop {
             // We immediately go to the parent scope. We check the current scope
             // in the call at the end. Likewise for checking the symbol table.
             let block = &ctx.heap[scope.to_block()];
             scope = block.scope_node.parent;
             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_str_at_span(
                                 &ctx.module().source, local.identifier.span, "Local variable name conflicts with parameter"
                             ).with_info_str_at_span(
                                 &ctx.module().source, parameter.identifier.span, "Parameter definition is found here"
+                            )
                         );
+                    }
+                }
                 // No collisions
                 break;
+            }
             // If here then the parent scope is a block scope
-            let local_relative_pos = ctx.heap[scope.to_block()].scope_node.relative_pos_in_parent;
+            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 &&
+                    cur_relative_pos >= other_local.relative_pos_in_block &&
                     local.identifier == other_local.identifier {
                     // Collision within this scope
                     return Err(
                         ParseError::new_error_str_at_span(
                             &ctx.module().source, local.identifier.span, "Local variable name conflicts with another variable"
                         ).with_info_str_at_span(
                             &ctx.module().source, other_local.identifier.span, "Previous variable is found here"
+                        )
                     );
+                }
+            }
             scope = block.scope_node.parent;
             cur_relative_pos = block.scope_node.relative_pos_in_parent;
+        }
         // No collisions in any of the parent scope, attempt to add to scope
-        self.checked_at_single_scope_add_local(ctx, target_scope, relative_pos, id)
+        self.checked_at_single_scope_add_local(ctx, target_scope, target_relative_pos, id)
+    }
     /// Adds a local variable to the specified scope. Will check the specified
     /// scope for variable conflicts and the symbol table for global conflicts.
     /// Will NOT check parent scopes of the specified scope.
     fn checked_at_single_scope_add_local(
         &mut self, ctx: &mut Ctx, scope: Scope, relative_pos: i32, id: VariableId
     ) -> Result<(), ParseError> {
         // Check the symbol table for conflicts
+        {
             let cur_scope = SymbolScope::Definition(self.def_type.definition_id());
             let ident = &ctx.heap[id].identifier;
             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, ident.span,
                     "local variable declaration conflicts with symbol"
                 ).with_info_str_at_span(
                     &ctx.module().source, symbol.variant.span_of_introduction(&ctx.heap), "the conflicting symbol is introduced here"
                 ));
+            }
+        }
         // Check the specified scope for conflicts
         let local = &ctx.heap[id];
         debug_assert!(scope.is_block());
         let block = &ctx.heap[scope.to_block()];
         for other_local_id in &block.locals {
             let other_local = &ctx.heap[*other_local_id];
             if local.this != other_local.this &&
                 // relative_pos >= other_local.relative_pos_in_block &&
                 local.identifier == other_local.identifier {
                 // Collision
                 return Err(
                     ParseError::new_error_str_at_span(
                         &ctx.module().source, local.identifier.span, "Local variable name conflicts with another variable"
                     ).with_info_str_at_span(
                         &ctx.module().source, other_local.identifier.span, "Previous variable is found here"
+                    )
                 );
+            }
+        }
         // No collisions
         let block = &mut ctx.heap[scope.to_block()];
         block.locals.push(id);
         let local = &mut ctx.heap[id];
         local.relative_pos_in_block = relative_pos;
         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: i32, identifier: &Identifier) -> Option<VariableId> {
         println!("DEBUG: Calling find_variable for '{}' at relative_pos {}", identifier.value.as_str(), relative_pos);
         debug_assert!(self.cur_scope.is_block());
         // No need to use iterator over namespaces if here
         let mut scope = &self.cur_scope;
         loop {
             debug_assert!(scope.is_block());
             let block = &ctx.heap[scope.to_block()];
             println!("DEBUG: > Looking in block {:?} at relative_pos {}", scope.to_block().0, relative_pos);
             for local_id in &block.locals {
                 let local = &ctx.heap[*local_id];
                 if local.relative_pos_in_block < relative_pos && identifier == &local.identifier {
                     println!("DEBUG: > Matched at local with relative_pos {}", local.relative_pos_in_block);
                     return Some(*local_id);
+                }
+            }
             scope = &block.scope_node.parent;
             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 == &parameter.identifier {
                                 return Some(*parameter_id);
+                            }
+                        }
                     },
                     _ => unreachable!(),
+                }
                 // Variable could not be found
                 return None
             } else {
                 relative_pos = block.scope_node.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_add_label(&mut self, ctx: &mut Ctx, relative_pos: i32, in_sync: SynchronousStatementId, id: LabeledStatementId) -> Result<(), ParseError> {
         debug_assert!(self.cur_scope.is_block());
         // Make sure label is not defined within the current scope or any of the
         // parent scope.
         let label = &mut ctx.heap[id];
         label.relative_pos_in_block = relative_pos;
         label.in_sync = in_sync;
         let label = &ctx.heap[id];
         let mut scope = &self.cur_scope;
         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_str_at_span(
                         &ctx.module().source, label.label.span, "label name is used more than once"
                     ).with_info_str_at_span(
                         &ctx.module().source, other_label.label.span, "the other label is found here"
                     ));
+                }
+            }
             scope = &block.scope_node.parent;
             if !scope.is_block() {
                 break;
+            }
+        }
         // No collisions
         let block = &mut ctx.heap[self.cur_scope.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(mut scope: Scope, ctx: &Ctx, identifier: &Identifier) -> Result<LabeledStatementId, ParseError> {
         debug_assert!(scope.is_block());
         loop {
             debug_assert!(scope.is_block(), "scope is not a block");
             let relative_scope_pos = ctx.heap[scope.to_block()].scope_node.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_str_at_span(&ctx.module().source, identifier.span, "this target label skips over a variable declaration")
                                 .with_info_str_at_span(&ctx.module().source, label.label.span, "because it jumps to this label")
                                 .with_info_str_at_span(&ctx.module().source, local.identifier.span, "which skips over this variable")
                             );
+                        }
+                    }
                     return Ok(*label_id);
+                }
+            }
             scope = block.scope_node.parent;
             if !scope.is_block() {
                 return Err(ParseError::new_error_str_at_span(
                     &ctx.module().source, identifier.span, "could not find this label"
                 ));
+            }
+        }
+    }
     /// 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(mut scope: Scope, ctx: &Ctx, id: WhileStatementId) -> bool {
         let while_stmt = &ctx.heap[id];
         loop {
             debug_assert!(scope.is_block());
             let block = scope.to_block();
             if while_stmt.body == block {
                 return true;
+            }
             let block = &ctx.heap[block];
             scope = block.scope_node.parent;
             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(ctx: &Ctx, control_flow: &ControlFlowStatement, span: InputSpan, label: &Option<Identifier>) -> Result<WhileStatementId, ParseError> {
         let target = match label {
             Some(label) => {
                 let target_id = Self::find_label(control_flow.in_scope, 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(control_flow.in_scope, ctx, target_stmt.this) {
                         return Err(ParseError::new_error_str_at_span(
                             &ctx.module().source, label.span, "break statement is not nested under the target label's while statement"
                         ).with_info_str_at_span(
                             &ctx.module().source, target.label.span, "the targeted label is found here"
                         ));
+                    }
                     target_stmt.this
                 } else {
                     return Err(ParseError::new_error_str_at_span(
                         &ctx.module().source, label.span, "incorrect break target label, it must target a while loop"
                     ).with_info_str_at_span(
                         &ctx.module().source, target.label.span, "The targeted label is found here"
                     ));
+                }
             },
             None => {
                 // Use the enclosing while statement, the break must be
                 // nested within that while statement
                 if control_flow.in_while.is_invalid() {
                     return Err(ParseError::new_error_str_at_span(
                         &ctx.module().source, span, "Break statement is not nested under a while loop"
                     ));
+                }
                 control_flow.in_while
+            }
         };
         // 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 != control_flow.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!(!control_flow.in_sync.is_invalid());
                 let sync_stmt = &ctx.heap[control_flow.in_sync];
                 return Err(
                     ParseError::new_error_str_at_span(&ctx.module().source, span, "break may not escape the surrounding synchronous block")
                         .with_info_str_at_span(&ctx.module().source, target_while.span, "the break escapes out of this loop")
                         .with_info_str_at_span(&ctx.module().source, sync_stmt.span, "And would therefore escape this synchronous block")
                 );
+            }
+        }
         Ok(target)
+    }
+}
@@ \ No newline at end of file @@

src/protocol/tests/parser_validation.rs

➞

Show inline comments

 /// parser_validation.rs
 ///
 /// Simple tests for the validation phase
 use super::*;
 #[test]
 fn test_correct_struct_instance() {
     Tester::new_single_source_expect_ok(
         "single field",
+        "
         struct Foo { s32 a }
         func bar(s32 arg) -> Foo { return Foo{ a: arg }; }
+        "
     );
     Tester::new_single_source_expect_ok(
         "multiple fields",
+        "
         struct Foo { s32 a, s32 b }
         func bar(s32 arg) -> Foo { return Foo{ a: arg, b: arg }; }
+        "
     );
     Tester::new_single_source_expect_ok(
         "single field, explicit polymorph",
+        "
         struct Foo<T>{ T field }
         func bar(s32 arg) -> Foo<s32> { return Foo<s32>{ field: arg }; }
+        "
     );
     Tester::new_single_source_expect_ok(
         "single field, implicit polymorph",
+        "
         struct Foo<T>{ T field }
         func bar(s32 arg) -> s32 {
             auto thingo = Foo{ field: arg };
             return arg;
+        }
+        "
     );
     Tester::new_single_source_expect_ok(
         "multiple fields, same explicit polymorph",
+        "
         struct Pair<T1, T2>{ T1 first, T2 second }
         func bar(s32 arg) -> s32 {
             auto qux = Pair<s32, s32>{ first: arg, second: arg };
             return arg;
+        }
+        "
     );
     Tester::new_single_source_expect_ok(
         "multiple fields, same implicit polymorph",
+        "
         struct Pair<T1, T2>{ T1 first, T2 second }
         func bar(s32 arg) -> s32 {
             auto wup = Pair{ first: arg, second: arg };
             return arg;
+        }
+        "
     );
     Tester::new_single_source_expect_ok(
         "multiple fields, different explicit polymorph",
+        "
         struct Pair<T1, T2>{ T1 first, T2 second }
         func bar(s32 arg1, s8 arg2) -> s32 {
             auto shoo = Pair<s32, s8>{ first: arg1, second: arg2 };
             return arg1;
+        }
+        "
     );
     Tester::new_single_source_expect_ok(
         "multiple fields, different implicit polymorph",
+        "
         struct Pair<T1, T2>{ T1 first, T2 second }
         func bar(s32 arg1, s8 arg2) -> s32 {
             auto shrubbery = Pair{ first: arg1, second: arg2 };
             return arg1;
+        }
+        "
     );
+}
 #[test]
 fn test_incorrect_struct_instance() {
     Tester::new_single_source_expect_err(
         "reused field in definition",
         "struct Foo{ s32 a, s8 a }"
     ).error(|e| { e
         .assert_num(2)
         .assert_occurs_at(0, "a }")
         .assert_msg_has(0, "defined more than once")
         .assert_occurs_at(1, "a, ")
         .assert_msg_has(1, "other struct field");
     });
     Tester::new_single_source_expect_err(
         "reused field in instance",
+        "
         struct Foo{ s32 a, s32 b }
         func bar() -> s32 {
             auto foo = Foo{ a: 5, a: 3 };
             return 0;
+        }
+        "
     ).error(|e| { e
         .assert_occurs_at(0, "a: 3")
         .assert_msg_has(0, "field is specified more than once");
     });
     Tester::new_single_source_expect_err(
         "missing field",
+        "
         struct Foo { s32 a, s32 b }
         func bar() -> s32 {
             auto foo = Foo{ a: 2 };
             return 0;
+        }
+        "
     ).error(|e| { e
         .assert_occurs_at(0, "Foo{")
         .assert_msg_has(0, "'b' is missing");
     });
     Tester::new_single_source_expect_err(
         "missing fields",
+        "
         struct Foo { s32 a, s32 b, s32 c }
         func bar() -> s32 {
             auto foo = Foo{ a: 2 };
             return 0;
+        }
+        "
     ).error(|e| { e
         .assert_occurs_at(0, "Foo{")
         .assert_msg_has(0, "[b, c] are missing");
     });
+}
 #[test]
 fn test_correct_enum_instance() {
     Tester::new_single_source_expect_ok(
         "single variant",
+        "
         enum Foo { A }
         func bar() -> Foo { return Foo::A; }
+        "
     );
     Tester::new_single_source_expect_ok(
         "multiple variants",
+        "
         enum Foo { A=15, B = 0xF }
         func bar() -> Foo { auto a = Foo::A; return Foo::B; }
+        "
     );
     Tester::new_single_source_expect_ok(
         "explicit single polymorph",
+        "
         enum Foo<T>{ A }
         func bar() -> Foo<s32> { return Foo::A; }
+        "
     );
     Tester::new_single_source_expect_ok(
         "explicit multi-polymorph",
+        "
         enum Foo<A, B>{ A, B }
         func bar() -> Foo<s8, s32> { return Foo::B; }
+        "
     );
+}
 #[test]
 fn test_incorrect_enum_instance() {
     Tester::new_single_source_expect_err(
         "variant name reuse",
+        "
         enum Foo { A, A }
         func bar() -> Foo { return Foo::A; }
+        "
     ).error(|e| { e
         .assert_num(2)
         .assert_occurs_at(0, "A }")
         .assert_msg_has(0, "defined more than once")
         .assert_occurs_at(1, "A, ")
         .assert_msg_has(1, "other enum variant is defined here");
     });
     Tester::new_single_source_expect_err(
         "undefined variant",
+        "
         enum Foo { A }
         func bar() -> Foo { return Foo::B; }
+        "
     ).error(|e| { e
         .assert_num(1)
         .assert_msg_has(0, "variant 'B' does not exist on the enum 'Foo'");
     });
+}
 #[test]
 fn test_correct_union_instance() {
     Tester::new_single_source_expect_ok(
         "single tag",
+        "
         union Foo { A }
         func bar() -> Foo { return Foo::A; }
+        "
     );
     Tester::new_single_source_expect_ok(
         "multiple tags",
+        "
         union Foo { A, B }
         func bar() -> Foo { return Foo::B; }
+        "
     );
     Tester::new_single_source_expect_ok(
         "single embedded",
+        "
         union Foo { A(s32) }
         func bar() -> Foo { return Foo::A(5); }
+        "
     );
     Tester::new_single_source_expect_ok(
         "multiple embedded",
+        "
         union Foo { A(s32), B(s8) }
         func bar() -> Foo { return Foo::B(2); }
+        "
     );
     Tester::new_single_source_expect_ok(
         "multiple values in embedded",
+        "
         union Foo { A(s32, s8) }
         func bar() -> Foo { return Foo::A(0, 2); }
+        "
     );
     Tester::new_single_source_expect_ok(
         "mixed tag/embedded",
+        "
         union OptionInt { None, Some(s32) }
         func bar() -> OptionInt { return OptionInt::Some(3); }
+        "
     );
     Tester::new_single_source_expect_ok(
         "single polymorphic var",
+        "
         union Option<T> { None, Some(T) }
         func bar() -> Option<s32> { return Option::Some(3); }"
     );
     Tester::new_single_source_expect_ok(
         "multiple polymorphic vars",
+        "
         union Result<T, E> { Ok(T), Err(E), }
         func bar() -> Result<s32, s8> { return Result::Ok(3); }
+        "
     );
     Tester::new_single_source_expect_ok(
         "multiple polymorphic in one variant",
+        "
         union MaybePair<T1, T2>{ None, Some(T1, T2) }
         func bar() -> MaybePair<s8, s32> { return MaybePair::Some(1, 2); }
+        "
     );
+}
 #[test]
 fn test_incorrect_union_instance() {
     Tester::new_single_source_expect_err(
         "tag-variant name reuse",
+        "
         union Foo{ A, A }
+        "
     ).error(|e| { e
         .assert_num(2)
         .assert_occurs_at(0, "A }")
         .assert_msg_has(0, "union variant is defined more than once")
         .assert_occurs_at(1, "A, ")
         .assert_msg_has(1, "other union variant");
     });
     Tester::new_single_source_expect_err(
         "embedded-variant name reuse",
+        "
         union Foo{ A(s32), A(s8) }
+        "
     ).error(|e| { e
         .assert_num(2)
         .assert_occurs_at(0, "A(s8)")
         .assert_msg_has(0, "union variant is defined more than once")
         .assert_occurs_at(1, "A(s32)")
         .assert_msg_has(1, "other union variant");
     });
     Tester::new_single_source_expect_err(
         "undefined variant",
+        "
         union Silly{ Thing(s8) }
         func bar() -> Silly { return Silly::Undefined(5); }
+        "
     ).error(|e| { e
         .assert_msg_has(0, "variant 'Undefined' does not exist on the union 'Silly'");
     });
     Tester::new_single_source_expect_err(
         "using tag instead of embedded",
+        "
         union Foo{ A(s32) }
         func bar() -> Foo { return Foo::A; }
+        "
     ).error(|e| { e
         .assert_msg_has(0, "variant 'A' of union 'Foo' expects 1 embedded values, but 0 were");
     });
     Tester::new_single_source_expect_err(
         "using embedded instead of tag",
+        "
         union Foo{ A }
         func bar() -> Foo { return Foo::A(3); }
+        "
     ).error(|e| { e
         .assert_msg_has(0, "The variant 'A' of union 'Foo' expects 0");
     });
     Tester::new_single_source_expect_err(
         "wrong embedded value",
+        "
         union Foo{ A(s32) }
         func bar() -> Foo { return Foo::A(false); }
+        "
     ).error(|e| { e
         .assert_occurs_at(0, "Foo::A")
         .assert_msg_has(0, "failed to fully resolve")
         .assert_occurs_at(1, "false")
         .assert_msg_has(1, "has been resolved to 's32'")
         .assert_msg_has(1, "has been resolved to 'bool'");
     });
+}
 #[test]
 fn test_correct_tuple_members() {
     // Tuples with zero members
     Tester::new_single_source_expect_ok(
         "single zero-tuple",
         "struct Foo{ () bar }"
     ).for_struct("Foo", |s| { s
         .for_field("bar", |f| { f.assert_parser_type("()"); })
         .assert_size_alignment("Foo", 0, 1);
     });
     Tester::new_single_source_expect_ok(
         "triple zero-tuple",
         "struct Foo{ () bar, () baz, () qux }"
     ).for_struct("Foo", |s| { s
         .assert_size_alignment("Foo", 0, 1);
     });
     // Tuples with one member (which are elided, because due to ambiguity
     // between a one-tuple literal and a parenthesized expression, we're not
     // going to be able to construct one-tuples).
     Tester::new_single_source_expect_ok(
         "single elided one-tuple",
         "struct Foo{ (u32) bar }"
     ).for_struct("Foo", |s| { s
         .for_field("bar", |f| { f.assert_parser_type("u32"); })
         .assert_size_alignment("Foo", 4, 4);
     });
     Tester::new_single_source_expect_ok(
         "triple elided one-tuple",
         "struct Foo{ (u8) bar, (u16) baz, (u32) qux }"
     ).for_struct("Foo", |s| { s
         .assert_size_alignment("Foo", 8, 4);
     });
     // Tuples with three members
     Tester::new_single_source_expect_ok(
         "single three-tuple",
         "struct Foo{ (u8, u16, u32) bar }"
     ).for_struct("Foo", |s| { s
         .for_field("bar", |f| { f.assert_parser_type("(u8,u16,u32)"); })
         .assert_size_alignment("Foo", 8, 4);
     });
     Tester::new_single_source_expect_ok(
         "double three-tuple",
         "struct Foo{ (u8,u16,u32,) bar, (s8,s16,s32,) baz }"
     ).for_struct("Foo", |s| { s
         .for_field("bar", |f| { f.assert_parser_type("(u8,u16,u32)"); })
         .for_field("baz", |f| { f.assert_parser_type("(s8,s16,s32)"); })
         .assert_size_alignment("Foo", 16, 4);
     });
+}
 #[test]
 fn test_incorrect_tuple_member() {
     // Test not really necessary, but hey, what's a test between friends
     Tester::new_single_source_expect_err(
         "unknown tuple member",
         "struct Foo{ (u32, u32, u32, YouThirstySchmoo) field }"
     ).error(|e| { e
         .assert_num(1)
         .assert_msg_has(0, "unknown type")
         .assert_occurs_at(0, "YouThirstySchmoo");
     });
+}
 #[test]
 fn test_correct_tuple_polymorph_args() {
     Tester::new_single_source_expect_ok(
         "single tuple arg",
+        "
         union Option<T>{ Some(T), None }
         func thing() -> u32 {
             auto a = Option<()>::None;
             auto b = Option<(u32, u64)>::None;
             auto c = Option<(Option<(u8, s8)>, Option<(s8, u8)>)>::None;
             return 0;
+        }
+        "
     ).for_union("Option", |u| { u
         .assert_has_monomorph("Option<()>")
         .assert_has_monomorph("Option<(u32,u64)>")
         .assert_has_monomorph("Option<(Option<(u8,s8)>,Option<(s8,u8)>)>")
         .assert_size_alignment("Option<()>", 1, 1, 0, 0)
         .assert_size_alignment("Option<(u32,u64)>", 24, 8, 0, 0) // (u32, u64) becomes size 16, alignment 8. Hence union tag is aligned to 8
         .assert_size_alignment("Option<(Option<(u8,s8)>,Option<(s8,u8)>)>", 7, 1, 0, 0); // inner unions are size 3, alignment 1. Two of those with a tag is size 7
     });
+}
 #[test]
 fn test_incorrect_tuple_polymorph_args() {
     // Do some mismatching brackets. I don't know what else to test
     Tester::new_single_source_expect_err(
         "mismatch angle bracket",
+        "
         union Option<T>{ Some(T), None }
         func f() -> u32 {
             auto a = Option<(u32>)::None;
             return 0;
         }"
     ).error(|e| { e
         .assert_num(2)
         .assert_msg_has(0, "closing '>'").assert_occurs_at(0, ">)::None")
         .assert_msg_has(1, "match this '('").assert_occurs_at(1, "(u32>");
     });
     Tester::new_single_source_expect_err(
         "wrongly placed angle",
+        "
         union O<T>{ S(T), N }
         func f() -> u32 {
             auto a = O<(<u32>)>::None;
             return 0;
+        }
+        "
     ).error(|e| { e
         .assert_num(1)
         .assert_msg_has(0, "expected typename")
         .assert_occurs_at(0, "<u32");
     });
+}
 #[test]
 fn test_incorrect_tuple_member_access() {
     Tester::new_single_source_expect_err(
         "zero-tuple",
         "func foo() -> () { () a = (); auto b = a.0; return a; }"
     ).error(|e| { e
         .assert_num(1)
         .assert_msg_has(0, "out of bounds")
         .assert_occurs_at(0, "a.0");
     });
     // Make the type checker do some shenanigans before we can decide the tuple
     // type.
     Tester::new_single_source_expect_err(
         "sized tuple",
+        "
         func determinator<A,B>((A,B,A) v) -> B { return v.1; }
         func tester() -> u64 {
             auto v = (0,1,2);
             u32 a_u32 = 5;
             v.2 = a_u32;
             v.8 = 5;
             return determinator(v);
+        }
+        "
     ).error(|e| { e
         .assert_num(1)
         .assert_msg_has(0, "out of bounds")
         .assert_occurs_at(0, "v.8");
     });
+}
 #[test]
 fn test_polymorph_array_types() {
     Tester::new_single_source_expect_ok(
         "array of polymorph in struct",
+        "
         struct Foo<T> { T[] hello }
         struct Bar { Foo<u32>[] world }
+        "
     ).for_struct("Bar", |s| { s
         .for_field("world", |f| { f.assert_parser_type("Foo<u32>[]"); });
     });
     Tester::new_single_source_expect_ok(
         "array of port in struct",
+        "
         struct Bar { in<u32>[] inputs }
+        "
     ).for_struct("Bar", |s| { s
         .for_field("inputs", |f| { f.assert_parser_type("in<u32>[]"); });
     });
+}
 #[test]
 fn test_correct_modifying_operators() {
     // Not testing the types, just that it parses
     Tester::new_single_source_expect_ok(
         "valid uses",
+        "
         func f() -> u32 {
             auto a = 5;
             a += 2; a -= 2; a *= 2; a /= 2; a %= 2;
             a <<= 2; a >>= 2;
             a |= 2; a &= 2; a ^= 2;
             return a;
+        }
+        "
     );
+}
 #[test]
 fn test_incorrect_modifying_operators() {
     Tester::new_single_source_expect_err(
         "wrong declaration",
         "func f() -> u8 { auto a += 2; return a; }"
     ).error(|e| { e.assert_msg_has(0, "expected '='"); });
     Tester::new_single_source_expect_err(
         "inside function",
         "func f(u32 a) -> u32 { auto b = 0; auto c = f(a += 2); }"
     ).error(|e| { e.assert_msg_has(0, "assignments are statements"); });
     Tester::new_single_source_expect_err(
         "inside tuple",
         "func f(u32 a) -> u32 { auto b = (a += 2, a /= 2); return 0; }"
     ).error(|e| { e.assert_msg_has(0, "assignments are statements"); });
+}
 #[test]
 fn test_variable_introduction_in_scope() {
     Tester::new_single_source_expect_err(
         "variable use before declaration",
         "func f() -> u8 { return thing; auto thing = 5; }"
     ).error(|e| { e.assert_msg_has(0, "unresolved variable"); });
     Tester::new_single_source_expect_err(
         "variable use in declaration",
         "func f() -> u8 { auto thing = 5 + thing; return thing; }"
     ).error(|e| { e.assert_msg_has(0, "unresolved variable"); });
     Tester::new_single_source_expect_ok(
         "variable use after declaration",
         "func f() -> u8 { auto thing = 5; return thing; }"
     );
     Tester::new_single_source_expect_err(
         "variable use of closed scope",
         "func f() -> u8 { { auto thing = 5; } return thing; }"
     ).error(|e| { e.assert_msg_has(0, "unresolved variable"); });
+}
 #[test]
 fn test_correct_select_statement() {
     Tester::new_single_source_expect_ok(
         "guard variable decl",
+        "
         primitive f() {
             channel<u32> unused -> input;
             u32 outer_value = 0;
             sync select {
                 auto in_same_guard = get(input) -> {} // decl A1
                 auto in_same_gaurd = get(input) -> {} // decl A2
                 auto in_guard_and_block = get(input) -> {} // decl B1
                 outer_value = get(input) -> { auto in_guard_and_block = outer_value; } // decl B2
+            }
+        }
+        "
     );
     Tester::new_single_source_expect_ok(
         "empty select",
         "primitive f() { sync select {} }"
     );
     Tester::new_single_source_expect_ok(
         "mixed uses", "
         primitive f() {
             channel unused_output -> input;
             u32 outer_value = 0;
             sync select {
                 outer_value = get(input) -> outer_value = 0;
                 auto new_value = get(input) -> {
                     outer_value = new_value;
+                }
                 get(input) + get(input) ->
                     outer_value = 8;
                 get(input) ->
                     {}
                 outer_value %= get(input) -> {
                     outer_value *= outer_value;
                     auto new_value = get(input);
                     outer_value += new_value;
+                }
+            }
+        }
+        "
     );
+}
 #[test]
 fn test_incorrect_select_statement() {
     Tester::new_single_source_expect_err(
         "outside sync",
         "primitive f() { select {} }"
     ).error(|e| { e
         .assert_num(1)
         .assert_occurs_at(0, "select")
         .assert_msg_has(0, "inside sync blocks");
     });
-    Tester::new_single_source_expect_ok(
+    Tester::new_single_source_expect_err(
         "variable in previous block",
         "primitive f() {
             channel<u32> tx -> rx;
             u32 a = 0; // this one will be shadowed
             sync select { auto a = get(rx) -> {} }
         }"
     );
     ).error(|e| { e
         .assert_num(2)
         .assert_occurs_at(0, "a = get").assert_msg_has(0, "variable name conflicts")
         .assert_occurs_at(1, "a = 0").assert_msg_has(1, "Previous variable");
     });
     Tester::new_single_source_expect_err(
         "put inside arm",
         "primitive f() {
             channel<u32> a -> b;
             sync select { put(a) -> {} }
         }"
     ).error(|e| { e
         .assert_occurs_at(0, "put")
         .assert_msg_has(0, "may not occur");
     });
+}
 #[test]
 fn test_incorrect_goto_statement() {
     Tester::new_single_source_expect_err(
         "goto missing var in same scope",
         "func f() -> u32 {
             goto exit;
             auto v = 5;
             exit: return 0;
         }"
     ).error(|e| { e
         .assert_num(3)
         .assert_occurs_at(0, "exit;").assert_msg_has(0, "skips over a variable")
         .assert_occurs_at(1, "exit:").assert_msg_has(1, "jumps to this label")
         .assert_occurs_at(2, "v = 5").assert_msg_has(2, "skips over this variable");
     });
     Tester::new_single_source_expect_err(
         "goto missing var in outer scope",
         "func f() -> u32 {
             if (true) {
                 goto exit;
+            }
             auto v = 0;
             exit: return 1;
         }"
     ).error(|e| { e
         .assert_num(3)
         .assert_occurs_at(0, "exit;").assert_msg_has(0, "skips over a variable")
         .assert_occurs_at(1, "exit:").assert_msg_has(1, "jumps to this label")
         .assert_occurs_at(2, "v = 0").assert_msg_has(2, "skips over this variable");
     });
     Tester::new_single_source_expect_err(
         "goto jumping into scope",
         "func f() -> u32 {
             goto nested;
+            {
                 nested: return 0;
+            }
             return 1;
         }"
     ).error(|e| { e
         .assert_num(1)
         .assert_occurs_at(0, "nested;")
         .assert_msg_has(0, "could not find this label");
     });
     Tester::new_single_source_expect_err(
         "goto jumping outside sync",
         "primitive f() {
             sync { goto exit; }
             exit: u32 v = 0;
         }"
     ).error(|e| { e
         .assert_num(3)
         .assert_occurs_at(0, "goto exit;").assert_msg_has(0, "not escape the surrounding sync")
         .assert_occurs_at(1, "exit: u32 v").assert_msg_has(1, "target of the goto")
         .assert_occurs_at(2, "sync {").assert_msg_has(2, "jump past this");
     })
+}
 #[test]
 fn test_incorrect_while_statement() {
     // Just testing the error cases caught at compile-time. Other ones need
     // evaluation testing
     Tester::new_single_source_expect_err(
         "break wrong earlier loop",
         "func f() -> u32 {
             target: while (true) {}
             while (true) { break target; }
             return 0;
         }"
     ).error(|e| { e
         .assert_num(2)
         .assert_occurs_at(0, "target; }").assert_msg_has(0, "not nested under the target")
         .assert_occurs_at(1, "target: while").assert_msg_has(1, "is found here");
     });
     Tester::new_single_source_expect_err(
         "break wrong later loop",
         "func f() -> u32 {
             while (true) { break target; }
             target: while (true) {}
             return 0;
         }"
     ).error(|e| { e
         .assert_num(2)
         .assert_occurs_at(0, "target; }").assert_msg_has(0, "not nested under the target")
         .assert_occurs_at(1, "target: while").assert_msg_has(1, "is found here");
     });
     Tester::new_single_source_expect_err(
         "break outside of sync",
         "primitive f() {
             outer: while (true) { //mark
                 sync while(true) { break outer; }
+            }
         }"
     ).error(|e| { e
         .assert_num(3)
         .assert_occurs_at(0, "break outer;").assert_msg_has(0, "may not escape the surrounding")
         .assert_occurs_at(1, "while (true) { //mark").assert_msg_has(1, "escapes out of this loop")
         .assert_occurs_at(2, "sync while").assert_msg_has(2, "escape this synchronous block");
     });
+}
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