Changeset - 8c870bc3cff3
[Not reviewed]
0 4 0
mh - 4 years ago 2021-12-15 16:21:15
contact@maxhenger.nl
Implement tuple element selection
4 files changed with 223 insertions and 102 deletions:
0 comments (0 inline, 0 general)
src/protocol/ast.rs
Show inline comments
 
@@ -1554,200 +1554,206 @@ pub struct ConditionalExpression {
 
    // Parsing
 
    pub operator_span: InputSpan,
 
    pub full_span: InputSpan,
 
    pub test: ExpressionId,
 
    pub true_expression: ExpressionId,
 
    pub false_expression: ExpressionId,
 
    // Validator/Linking
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

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

	
 
#[derive(Debug, Clone)]
 
pub struct BinaryExpression {
 
    pub this: BinaryExpressionId,
 
    // Parsing
 
    pub operator_span: InputSpan,
 
    pub full_span: InputSpan,
 
    pub left: ExpressionId,
 
    pub operation: BinaryOperator,
 
    pub right: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 
pub enum UnaryOperator {
 
    Positive,
 
    Negative,
 
    BitwiseNot,
 
    LogicalNot,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnaryExpression {
 
    pub this: UnaryExpressionId,
 
    // Parsing
 
    pub operator_span: InputSpan,
 
    pub full_span: InputSpan,
 
    pub operation: UnaryOperator,
 
    pub expression: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct IndexingExpression {
 
    pub this: IndexingExpressionId,
 
    // Parsing
 
    pub operator_span: InputSpan,
 
    pub full_span: InputSpan,
 
    pub subject: ExpressionId,
 
    pub index: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SlicingExpression {
 
    pub this: SlicingExpressionId,
 
    // Parsing
 
    pub slicing_span: InputSpan, // from '[' to ']'
 
    pub full_span: InputSpan, // includes subject
 
    pub subject: ExpressionId,
 
    pub from_index: ExpressionId,
 
    pub to_index: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum SelectKind {
 
    StructField(Identifier),
 
    TupleMember(u64), // u64 is overkill, but space is taken up by `StructField` variant anyway
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SelectExpression {
 
    pub this: SelectExpressionId,
 
    // Parsing
 
    pub operator_span: InputSpan, // of the '.'
 
    pub full_span: InputSpan, // includes subject and field
 
    pub subject: ExpressionId,
 
    pub field_name: Identifier,
 
    pub kind: SelectKind,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct CastExpression {
 
    pub this: CastExpressionId,
 
    // Parsing
 
    pub cast_span: InputSpan, // of the "cast" keyword,
 
    pub full_span: InputSpan, // includes the cast subject
 
    pub to_type: ParserType,
 
    pub subject: ExpressionId,
 
    // Validator/linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct CallExpression {
 
    pub this: CallExpressionId,
 
    // Parsing
 
    pub func_span: InputSpan, // of the function name
 
    pub full_span: InputSpan, // includes the arguments and parentheses
 
    pub parser_type: ParserType, // of the function call, not the return type
 
    pub method: Method,
 
    pub arguments: Vec<ExpressionId>,
 
    pub definition: DefinitionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

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

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

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralExpression {
 
    pub this: LiteralExpressionId,
 
    // Parsing
 
    pub span: InputSpan,
 
    pub value: Literal,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

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

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

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

	
src/protocol/ast_printer.rs
Show inline comments
 
@@ -556,193 +556,201 @@ impl ASTWriter {
 
            Statement::Expression(stmt) => {
 
                self.kv(indent).with_id(PREFIX_EXPR_STMT_ID, stmt.this.0.index)
 
                    .with_s_key("ExpressionStatement");
 
                self.write_expr(heap, stmt.expression, indent2);
 
                self.kv(indent2).with_s_key("Next").with_disp_val(&stmt.next.index);
 
            }
 
        }
 
    }
 

	
 
    fn write_expr(&mut self, heap: &Heap, expr_id: ExpressionId, indent: usize) {
 
        let expr = &heap[expr_id];
 
        let indent2 = indent + 1;
 
        let indent3 = indent2 + 1;
 

	
 
        match expr {
 
            Expression::Assignment(expr) => {
 
                self.kv(indent).with_id(PREFIX_ASSIGNMENT_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("AssignmentExpr");
 
                self.kv(indent2).with_s_key("Operation").with_debug_val(&expr.operation);
 
                self.kv(indent2).with_s_key("Left");
 
                self.write_expr(heap, expr.left, indent3);
 
                self.kv(indent2).with_s_key("Right");
 
                self.write_expr(heap, expr.right, indent3);
 
                self.kv(indent2).with_s_key("Parent")
 
                    .with_custom_val(|v| write_expression_parent(v, &expr.parent));
 
            },
 
            Expression::Binding(expr) => {
 
                self.kv(indent).with_id(PREFIX_BINARY_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("BindingExpr");
 
                self.kv(indent2).with_s_key("BindToExpression");
 
                self.write_expr(heap, expr.bound_to, indent3);
 
                self.kv(indent2).with_s_key("BindFromExpression");
 
                self.write_expr(heap, expr.bound_from, indent3);
 
                self.kv(indent2).with_s_key("Parent")
 
                    .with_custom_val(|v| write_expression_parent(v, &expr.parent));
 
            },
 
            Expression::Conditional(expr) => {
 
                self.kv(indent).with_id(PREFIX_CONDITIONAL_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("ConditionalExpr");
 
                self.kv(indent2).with_s_key("Condition");
 
                self.write_expr(heap, expr.test, indent3);
 
                self.kv(indent2).with_s_key("TrueExpression");
 
                self.write_expr(heap, expr.true_expression, indent3);
 
                self.kv(indent2).with_s_key("FalseExpression");
 
                self.write_expr(heap, expr.false_expression, indent3);
 
                self.kv(indent2).with_s_key("Parent")
 
                    .with_custom_val(|v| write_expression_parent(v, &expr.parent));
 
            },
 
            Expression::Binary(expr) => {
 
                self.kv(indent).with_id(PREFIX_BINARY_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("BinaryExpr");
 
                self.kv(indent2).with_s_key("Operation").with_debug_val(&expr.operation);
 
                self.kv(indent2).with_s_key("Left");
 
                self.write_expr(heap, expr.left, indent3);
 
                self.kv(indent2).with_s_key("Right");
 
                self.write_expr(heap, expr.right, indent3);
 
                self.kv(indent2).with_s_key("Parent")
 
                    .with_custom_val(|v| write_expression_parent(v, &expr.parent));
 
            },
 
            Expression::Unary(expr) => {
 
                self.kv(indent).with_id(PREFIX_UNARY_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("UnaryExpr");
 
                self.kv(indent2).with_s_key("Operation").with_debug_val(&expr.operation);
 
                self.kv(indent2).with_s_key("Argument");
 
                self.write_expr(heap, expr.expression, indent3);
 
                self.kv(indent2).with_s_key("Parent")
 
                    .with_custom_val(|v| write_expression_parent(v, &expr.parent));
 
            },
 
            Expression::Indexing(expr) => {
 
                self.kv(indent).with_id(PREFIX_INDEXING_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("IndexingExpr");
 
                self.kv(indent2).with_s_key("Subject");
 
                self.write_expr(heap, expr.subject, indent3);
 
                self.kv(indent2).with_s_key("Index");
 
                self.write_expr(heap, expr.index, indent3);
 
                self.kv(indent2).with_s_key("Parent")
 
                    .with_custom_val(|v| write_expression_parent(v, &expr.parent));
 
            },
 
            Expression::Slicing(expr) => {
 
                self.kv(indent).with_id(PREFIX_SLICING_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("SlicingExpr");
 
                self.kv(indent2).with_s_key("Subject");
 
                self.write_expr(heap, expr.subject, indent3);
 
                self.kv(indent2).with_s_key("FromIndex");
 
                self.write_expr(heap, expr.from_index, indent3);
 
                self.kv(indent2).with_s_key("ToIndex");
 
                self.write_expr(heap, expr.to_index, indent3);
 
                self.kv(indent2).with_s_key("Parent")
 
                    .with_custom_val(|v| write_expression_parent(v, &expr.parent));
 
            },
 
            Expression::Select(expr) => {
 
                self.kv(indent).with_id(PREFIX_SELECT_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("SelectExpr");
 
                self.kv(indent2).with_s_key("Subject");
 
                self.write_expr(heap, expr.subject, indent3);
 

	
 
                self.kv(indent2).with_s_key("Field").with_identifier_val(&expr.field_name);
 
                match &expr.kind {
 
                    SelectKind::StructField(field_name) => {
 
                        self.kv(indent2).with_s_key("StructField").with_identifier_val(field_name);
 
                    },
 
                    SelectKind::TupleMember(member_index) => {
 
                        self.kv(indent2).with_s_key("TupleMember").with_disp_val(member_index);
 
                    },
 
                }
 

	
 
                self.kv(indent2).with_s_key("Parent")
 
                    .with_custom_val(|v| write_expression_parent(v, &expr.parent));
 
            },
 
            Expression::Literal(expr) => {
 
                self.kv(indent).with_id(PREFIX_LITERAL_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("LiteralExpr");
 

	
 
                let val = self.kv(indent2).with_s_key("Value");
 
                match &expr.value {
 
                    Literal::Null => { val.with_s_val("null"); },
 
                    Literal::True => { val.with_s_val("true"); },
 
                    Literal::False => { val.with_s_val("false"); },
 
                    Literal::Character(data) => { val.with_disp_val(data); },
 
                    Literal::String(data) => {
 
                        // Stupid hack
 
                        let string = String::from(data.as_str());
 
                        val.with_disp_val(&string);
 
                    },
 
                    Literal::Integer(data) => { val.with_debug_val(data); },
 
                    Literal::Struct(data) => {
 
                        val.with_s_val("Struct");
 
                        let indent4 = indent3 + 1;
 

	
 
                        self.kv(indent3).with_s_key("ParserType")
 
                            .with_custom_val(|t| write_parser_type(t, heap, &data.parser_type));
 
                        self.kv(indent3).with_s_key("Definition").with_disp_val(&data.definition.index);
 

	
 
                        for field in &data.fields {
 
                            self.kv(indent3).with_s_key("Field");
 
                            self.kv(indent4).with_s_key("Name").with_identifier_val(&field.identifier);
 
                            self.kv(indent4).with_s_key("Index").with_disp_val(&field.field_idx);
 
                            self.kv(indent4).with_s_key("ParserType");
 
                            self.write_expr(heap, field.value, indent4 + 1);
 
                        }
 
                    },
 
                    Literal::Enum(data) => {
 
                        val.with_s_val("Enum");
 

	
 
                        self.kv(indent3).with_s_key("ParserType")
 
                            .with_custom_val(|t| write_parser_type(t, heap, &data.parser_type));
 
                        self.kv(indent3).with_s_key("Definition").with_disp_val(&data.definition.index);
 
                        self.kv(indent3).with_s_key("VariantIdx").with_disp_val(&data.variant_idx);
 
                    },
 
                    Literal::Union(data) => {
 
                        val.with_s_val("Union");
 
                        let indent4 = indent3 + 1;
 

	
 
                        self.kv(indent3).with_s_key("ParserType")
 
                            .with_custom_val(|t| write_parser_type(t, heap, &data.parser_type));
 
                        self.kv(indent3).with_s_key("Definition").with_disp_val(&data.definition.index);
 
                        self.kv(indent3).with_s_key("VariantIdx").with_disp_val(&data.variant_idx);
 

	
 
                        for value in &data.values {
 
                            self.kv(indent3).with_s_key("Value");
 
                            self.write_expr(heap, *value, indent4);
 
                        }
 
                    },
 
                    Literal::Array(data) => {
 
                        val.with_s_val("Array");
 
                        let indent4 = indent3 + 1;
 

	
 
                        self.kv(indent3).with_s_key("Elements");
 
                        for expr_id in data {
 
                            self.write_expr(heap, *expr_id, indent4);
 
                        }
 
                    },
 
                    Literal::Tuple(data) => {
 
                        val.with_s_val("Tuple");
 
                        let indent4 = indent3 + 1;
 
                        self.kv(indent3).with_s_key("Elements");
 
                        for expr_id in data {
 
                            self.write_expr(heap, *expr_id, indent4);
 
                        }
 
                    }
 
                }
 

	
 
                self.kv(indent2).with_s_key("Parent")
 
                    .with_custom_val(|v| write_expression_parent(v, &expr.parent));
 
            },
 
            Expression::Cast(expr) => {
 
                self.kv(indent).with_id(PREFIX_CAST_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("CallExpr");
 
                self.kv(indent2).with_s_key("ToType")
 
                    .with_custom_val(|t| write_parser_type(t, heap, &expr.to_type));
 
                self.kv(indent2).with_s_key("Subject");
 
                self.write_expr(heap, expr.subject, indent3);
 
                self.kv(indent2).with_s_key("Parent")
 
                    .with_custom_val(|v| write_expression_parent(v, &expr.parent));
 
            }
 
            Expression::Call(expr) => {
 
                self.kv(indent).with_id(PREFIX_CALL_EXPR_ID, expr.this.0.index)
 
                    .with_s_key("CallExpr");
 

	
 
                let definition = &heap[expr.definition];
 
                match definition {
 
                    Definition::Component(definition) => {
src/protocol/parser/pass_definitions.rs
Show inline comments
 
@@ -1224,201 +1224,224 @@ impl PassDefinitions {
 
            let operator_span = iter.next_span();
 
            iter.consume();
 

	
 
            let expression = self.consume_prefix_expression(module, iter, ctx)?;
 
            let full_span = InputSpan::from_positions(
 
                operator_span.begin, ctx.heap[expression].full_span().end,
 
            );
 
            Ok(ctx.heap.alloc_unary_expression(|this| UnaryExpression {
 
                this, operator_span, full_span, operation, expression,
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast())
 
        } else if next == Some(TokenKind::PlusPlus) {
 
            return Err(ParseError::new_error_str_at_span(
 
                &module.source, iter.next_span(), "prefix increment is not supported in the language"
 
            ));
 
        } else if next == Some(TokenKind::MinusMinus) {
 
            return Err(ParseError::new_error_str_at_span(
 
                &module.source, iter.next_span(), "prefix decrement is not supported in this language"
 
            ));
 
        } else {
 
            self.consume_postfix_expression(module, iter, ctx)
 
        }
 
    }
 

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

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

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

	
 
            if token == TokenKind::PlusPlus {
 
                return Err(ParseError::new_error_str_at_span(
 
                    &module.source, operator_span, "postfix increment is not supported in this language"
 
                ));
 
            } else if token == TokenKind::MinusMinus {
 
                return Err(ParseError::new_error_str_at_span(
 
                    &module.source, operator_span, "prefix increment is not supported in this language"
 
                ));
 
            } else if token == TokenKind::OpenSquare {
 
                let subject = result;
 
                let from_index = self.consume_expression(module, iter, ctx)?;
 

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

	
 
                    let to_index = self.consume_expression(module, iter, ctx)?;
 
                    let end_span = consume_token(&module.source, iter, TokenKind::CloseSquare)?;
 
                    operator_span.end = end_span.end;
 
                    let full_span = InputSpan::from_positions(
 
                        ctx.heap[subject].full_span().begin, operator_span.end
 
                    );
 

	
 
                    result = ctx.heap.alloc_slicing_expression(|this| SlicingExpression{
 
                        this,
 
                        slicing_span: operator_span,
 
                        full_span, subject, from_index, to_index,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast();
 
                } else if Some(TokenKind::CloseSquare) == next {
 
                    let end_span = consume_token(&module.source, iter, TokenKind::CloseSquare)?;
 
                    operator_span.end = end_span.end;
 

	
 
                    let full_span = InputSpan::from_positions(
 
                        ctx.heap[subject].full_span().begin, operator_span.end
 
                    );
 

	
 
                    result = ctx.heap.alloc_indexing_expression(|this| IndexingExpression{
 
                        this, operator_span, full_span, subject,
 
                        index: from_index,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast();
 
                } else {
 
                    return Err(ParseError::new_error_str_at_pos(
 
                        &module.source, iter.last_valid_pos(), "unexpected token: expected ']' or '..'"
 
                    ));
 
                }
 
            } else {
 
                // Can be a select expression for struct fields, or a select
 
                // for a tuple element.
 
                debug_assert_eq!(token, TokenKind::Dot);
 
                let subject = result;
 
                let field_name = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                let full_span = InputSpan::from_positions(
 
                    ctx.heap[subject].full_span().begin, field_name.span.end
 
                );
 
                let next = iter.next();
 
                let (select_kind, full_span) = if Some(TokenKind::Integer) == next {
 
                    // Tuple member
 
                    let (index, index_span) = consume_integer_literal(&module.source, iter, &mut self.buffer)?;
 
                    let full_span = InputSpan::from_positions(
 
                        ctx.heap[subject].full_span().begin, index_span.end
 
                    );
 

	
 
                    (SelectKind::TupleMember(index), full_span)
 
                } else if Some(TokenKind::Ident) == next {
 
                    // Struct field
 
                    let field_name = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                    let full_span = InputSpan::from_positions(
 
                        ctx.heap[subject].full_span().begin, field_name.span.end
 
                    );
 

	
 
                    (SelectKind::StructField(field_name), full_span)
 
                } else {
 
                    return Err(ParseError::new_error_str_at_pos(
 
                        &module.source, iter.last_valid_pos(), "unexpected token: expected integer or identifier"
 
                    ));
 
                };
 

	
 
                result = ctx.heap.alloc_select_expression(|this| SelectExpression{
 
                    this, operator_span, full_span, subject, field_name,
 
                    this, operator_span, full_span, subject,
 
                    kind: select_kind,
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                }).upcast();
 
            }
 

	
 
            next = iter.next();
 
        }
 

	
 
        Ok(result)
 
    }
 

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

	
 
        let result = if next == Some(TokenKind::OpenParen) {
 
            // Something parenthesized. This can mean several things: we have
 
            // a parenthesized expression or we have a tuple literal. They are
 
            // ambiguous when the tuple has one member. But like the tuple type
 
            // parsing we interpret all one-tuples as parenthesized expressions.
 
            //
 
            // Practically (to prevent unnecessary `consume_expression` calls)
 
            // we distinguish the zero-tuple, the parenthesized expression, and
 
            // the N-tuple (for N > 1).
 
            let open_paren_pos = iter.next_start_position();
 
            iter.consume();
 
            let result = if Some(TokenKind::CloseParen) == iter.next() {
 
                // Zero-tuple
 
                let (_, close_paren_pos) = iter.next_positions();
 
                iter.consume();
 

	
 
                let literal_id = ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                    this,
 
                    span: InputSpan::from_positions(open_paren_pos, close_paren_pos),
 
                    value: Literal::Tuple(Vec::new()),
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                });
 

	
 
                literal_id.upcast()
 
            } else {
 
                // Start by consuming one expression, then check for a comma
 
                let expr_id = self.consume_expression(module, iter, ctx)?;
 
                if Some(TokenKind::Comma) == iter.next() && Some(TokenKind::CloseParen) != iter.peek() {
 
                    // Must be an N-tuple
 
                    iter.consume(); // the comma
 
                    let mut scoped_section = self.expressions.start_section();
 
                    scoped_section.push(expr_id);
 

	
 
                    let mut close_paren_pos = open_paren_pos;
 
                    consume_comma_separated_until(
 
                        TokenKind::CloseParen, &module.source, iter, ctx,
 
                        |_source, iter, ctx| self.consume_expression(module, iter, ctx),
 
                        &mut scoped_section, "an expression", Some(&mut close_paren_pos)
 
                    )?;
 
                    debug_assert!(scoped_section.len() > 1); // peeked token wasn't CloseParen, must be expression
 

	
 
                    let literal_id = ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                        this,
 
                        span: InputSpan::from_positions(open_paren_pos, close_paren_pos),
 
                        value: Literal::Tuple(scoped_section.into_vec()),
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    });
 

	
 
                    literal_id.upcast()
 
                } else {
 
                    // Assume we're dealing with a normal expression
 
                    consume_token(&module.source, iter, TokenKind::CloseParen)?;
 

	
 
                    expr_id
 
                }
 
            };
 

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

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this,
 
                span: InputSpan::from_positions(start_pos, end_pos),
 
                value: Literal::Array(scoped_section.into_vec()),
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast()
 
        } else if next == Some(TokenKind::Integer) {
 
            let (literal, span) = consume_integer_literal(&module.source, iter, &mut self.buffer)?;
 

	
src/protocol/parser/pass_typing.rs
Show inline comments
 
@@ -1946,329 +1946,409 @@ impl PassTyping {
 
        debug_log!("   - Subject type: {}", self.debug_get_display_name(ctx, subject_id));
 
        debug_log!("   - Index   type: {}", self.debug_get_display_name(ctx, index_id));
 
        debug_log!("   - Expr    type: {}", self.debug_get_display_name(ctx, upcast_id));
 

	
 
        // Make sure subject is arraylike and index is integerlike
 
        let progress_subject_base = self.apply_template_constraint(ctx, subject_id, &ARRAYLIKE_TEMPLATE)?;
 
        let progress_index = self.apply_template_constraint(ctx, index_id, &INTEGERLIKE_TEMPLATE)?;
 

	
 
        // Make sure if output is of T then subject is Array<T>
 
        let (progress_expr, progress_subject) =
 
            self.apply_equal2_constraint(ctx, upcast_id, upcast_id, 0, subject_id, 1)?;
 

	
 
        debug_log!(" * After:");
 
        debug_log!("   - Subject type [{}]: {}", progress_subject_base || progress_subject, self.debug_get_display_name(ctx, subject_id));
 
        debug_log!("   - Index   type [{}]: {}", progress_index, self.debug_get_display_name(ctx, index_id));
 
        debug_log!("   - Expr    type [{}]: {}", progress_expr, self.debug_get_display_name(ctx, upcast_id));
 

	
 
        if progress_expr { self.queue_expr_parent(ctx, upcast_id); }
 
        if progress_subject_base || progress_subject { self.queue_expr(ctx, subject_id); }
 
        if progress_index { self.queue_expr(ctx, index_id); }
 

	
 
        Ok(())
 
    }
 

	
 
    fn progress_slicing_expr(&mut self, ctx: &mut Ctx, id: SlicingExpressionId) -> Result<(), ParseError> {
 
        let upcast_id = id.upcast();
 
        let expr = &ctx.heap[id];
 
        let subject_id = expr.subject;
 
        let from_id = expr.from_index;
 
        let to_id = expr.to_index;
 

	
 
        debug_log!("Slicing expr: {}", upcast_id.index);
 
        debug_log!(" * Before:");
 
        debug_log!("   - Subject type: {}", self.debug_get_display_name(ctx, subject_id));
 
        debug_log!("   - FromIdx type: {}", self.debug_get_display_name(ctx, from_id));
 
        debug_log!("   - ToIdx   type: {}", self.debug_get_display_name(ctx, to_id));
 
        debug_log!("   - Expr    type: {}", self.debug_get_display_name(ctx, upcast_id));
 

	
 
        // Make sure subject is arraylike and indices are of equal integerlike
 
        let progress_subject_base = self.apply_template_constraint(ctx, subject_id, &ARRAYLIKE_TEMPLATE)?;
 
        let progress_idx_base = self.apply_template_constraint(ctx, from_id, &INTEGERLIKE_TEMPLATE)?;
 
        let (progress_from, progress_to) = self.apply_equal2_constraint(ctx, upcast_id, from_id, 0, to_id, 0)?;
 

	
 
        let (progress_expr, progress_subject) = match self.type_is_certainly_or_certainly_not_string(ctx, subject_id) {
 
            (true, _) => {
 
                // Certainly a string
 
                (self.apply_forced_constraint(ctx, upcast_id, &STRING_TEMPLATE)?, false)
 
            },
 
            (_, true) => {
 
                // Certainly not a string
 
                let progress_expr_base = self.apply_template_constraint(ctx, upcast_id, &SLICE_TEMPLATE)?;
 
                let (progress_expr, progress_subject) =
 
                    self.apply_equal2_constraint(ctx, upcast_id, upcast_id, 1, subject_id, 1)?;
 

	
 
                (progress_expr_base || progress_expr, progress_subject)
 
            },
 
            _ => {
 
                // Could be anything, at least attempt to progress subtype
 
                let progress_expr_base = self.apply_template_constraint(ctx, upcast_id, &ARRAYLIKE_TEMPLATE)?;
 
                let (progress_expr, progress_subject) =
 
                    self.apply_equal2_constraint(ctx, upcast_id, upcast_id, 1, subject_id, 1)?;
 

	
 
                (progress_expr_base || progress_expr, progress_subject)
 
            }
 
        };
 

	
 
        debug_log!(" * After:");
 
        debug_log!("   - Subject type [{}]: {}", progress_subject_base || progress_subject, self.debug_get_display_name(ctx, subject_id));
 
        debug_log!("   - FromIdx type [{}]: {}", progress_idx_base || progress_from, self.debug_get_display_name(ctx, from_id));
 
        debug_log!("   - ToIdx   type [{}]: {}", progress_idx_base || progress_to, self.debug_get_display_name(ctx, to_id));
 
        debug_log!("   - Expr    type [{}]: {}", progress_expr, self.debug_get_display_name(ctx, upcast_id));
 

	
 
        if progress_expr { self.queue_expr_parent(ctx, upcast_id); }
 
        if progress_subject_base || progress_subject { self.queue_expr(ctx, subject_id); }
 
        if progress_idx_base || progress_from { self.queue_expr(ctx, from_id); }
 
        if progress_idx_base || progress_to { self.queue_expr(ctx, to_id); }
 

	
 
        Ok(())
 
    }
 

	
 
    fn progress_select_expr(&mut self, ctx: &mut Ctx, id: SelectExpressionId) -> Result<(), ParseError> {
 
        let upcast_id = id.upcast();
 
        
 
        debug_log!("Select expr: {}", upcast_id.index);
 
        debug_log!(" * Before:");
 
        debug_log!("   - Subject type: {}", self.debug_get_display_name(ctx, ctx.heap[id].subject));
 
        debug_log!("   - Expr    type: {}", self.debug_get_display_name(ctx, upcast_id));
 

	
 
        let subject_id = ctx.heap[id].subject;
 
        let subject_expr_idx = ctx.heap[subject_id].get_unique_id_in_definition();
 
        let select_expr = &ctx.heap[id];
 
        let expr_idx = select_expr.unique_id_in_definition;
 

	
 
        let infer_expr = &self.expr_types[expr_idx as usize];
 
        let extra_idx = infer_expr.extra_data_idx;
 

	
 
        fn determine_inference_type_instance<'a>(types: &'a TypeTable, infer_type: &InferenceType) -> Result<Option<&'a DefinedType>, ()> {
 
        fn try_get_definition_id_from_inference_type<'a>(types: &'a TypeTable, infer_type: &InferenceType) -> Result<Option<&'a DefinedType>, ()> {
 
            for part in &infer_type.parts {
 
                if part.is_marker() || !part.is_concrete() {
 
                    continue;
 
                }
 

	
 
                // Part is concrete, check if it is an instance of something
 
                if let InferenceTypePart::Instance(definition_id, _num_sub) = part {
 
                    // Lookup type definition and ensure the specified field 
 
                    // name exists on the struct
 
                    let definition = types.get_base_definition(definition_id);
 
                    debug_assert!(definition.is_some());
 
                    let definition = definition.unwrap();
 

	
 
                    return Ok(Some(definition))
 
                } else {
 
                    // Expected an instance of something
 
                    return Err(())
 
                }
 
            }
 

	
 
            // Nothing is concrete yet
 
            Ok(None)
 
        }
 

	
 
        if infer_expr.field_or_monomorph_idx < 0 {
 
            // We don't know the field or the definition it is pointing to yet
 
            // Not yet known, check if we can determine it
 
            let subject_type = &self.expr_types[subject_expr_idx as usize].expr_type;
 
            let type_def = determine_inference_type_instance(&ctx.types, subject_type);
 
        fn try_get_tuple_size_from_inference_type(infer_type: &InferenceType) -> Result<Option<u32>, ()> {
 
            for part in &infer_type.parts {
 
                if part.is_marker() || !part.is_concrete() {
 
                    continue;
 
                }
 

	
 
            match type_def {
 
                Ok(Some(type_def)) => {
 
                    // Subject type is known, check if it is a
 
                    // struct and the field exists on the struct
 
                    let struct_def = if let DefinedTypeVariant::Struct(struct_def) = &type_def.definition {
 
                        struct_def
 
                    } else {
 
                        return Err(ParseError::new_error_at_span(
 
                            &ctx.module().source, select_expr.field_name.span, format!(
 
                                "Can only apply field access to structs, got a subject of type '{}'",
 
                                subject_type.display_name(&ctx.heap)
 
                            )
 
                        ));
 
                    };
 
                if let InferenceTypePart::Tuple(size) = part {
 
                    return Ok(Some(*size));
 
                } else {
 
                    // Expected a tuple
 
                    return Err(());
 
                }
 
            }
 

	
 
                    let mut struct_def_id = None;
 
            // Type is not "defined enough" yet
 
            Ok(None)
 
        }
 

	
 
                    for (field_def_idx, field_def) in struct_def.fields.iter().enumerate() {
 
                        if field_def.identifier == select_expr.field_name {
 
                            // Set field definition and index
 
                            let infer_expr = &mut self.expr_types[expr_idx as usize];
 
                            infer_expr.field_or_monomorph_idx = field_def_idx as i32;
 
                            struct_def_id = Some(type_def.ast_definition);
 
                            break;
 
        let (progress_subject, progress_expr) = match &select_expr.kind {
 
            SelectKind::StructField(field_name) => {
 
                // Handle select of a struct's field
 
                if infer_expr.field_or_monomorph_idx < 0 {
 
                    // We don't know the field or the definition it is pointing to yet
 
                    // Not yet known, check if we can determine it
 
                    let subject_type = &self.expr_types[subject_expr_idx as usize].expr_type;
 
                    let type_def = try_get_definition_id_from_inference_type(&ctx.types, subject_type);
 

	
 
                    match type_def {
 
                        Ok(Some(type_def)) => {
 
                            // Subject type is known, check if it is a
 
                            // struct and the field exists on the struct
 
                            let struct_def = if let DefinedTypeVariant::Struct(struct_def) = &type_def.definition {
 
                                struct_def
 
                            } else {
 
                                return Err(ParseError::new_error_at_span(
 
                                    &ctx.module().source, field_name.span, format!(
 
                                        "Can only apply field access to structs, got a subject of type '{}'",
 
                                        subject_type.display_name(&ctx.heap)
 
                                    )
 
                                ));
 
                            };
 

	
 
                            let mut struct_def_id = None;
 

	
 
                            for (field_def_idx, field_def) in struct_def.fields.iter().enumerate() {
 
                                if field_def.identifier == *field_name {
 
                                    // Set field definition and index
 
                                    let infer_expr = &mut self.expr_types[expr_idx as usize];
 
                                    infer_expr.field_or_monomorph_idx = field_def_idx as i32;
 
                                    struct_def_id = Some(type_def.ast_definition);
 
                                    break;
 
                                }
 
                            }
 

	
 
                            if struct_def_id.is_none() {
 
                                let ast_struct_def = ctx.heap[type_def.ast_definition].as_struct();
 
                                return Err(ParseError::new_error_at_span(
 
                                    &ctx.module().source, field_name.span, format!(
 
                                        "this field does not exist on the struct '{}'",
 
                                        ast_struct_def.identifier.value.as_str()
 
                                    )
 
                                ))
 
                            }
 

	
 
                            // Encountered definition and field index for the
 
                            // first time
 
                            self.insert_initial_select_polymorph_data(ctx, id, struct_def_id.unwrap());
 
                        },
 
                        Ok(None) => {
 
                            // Type of subject is not yet known, so we
 
                            // cannot make any progress yet
 
                            return Ok(())
 
                        },
 
                        Err(()) => {
 
                            return Err(ParseError::new_error_at_span(
 
                                &ctx.module().source, field_name.span, format!(
 
                                    "Can only apply field access to structs, got a subject of type '{}'",
 
                                    subject_type.display_name(&ctx.heap)
 
                                )
 
                            ));
 
                        }
 
                    }
 
                }
 

	
 
                    if struct_def_id.is_none() {
 
                        let ast_struct_def = ctx.heap[type_def.ast_definition].as_struct();
 
                        return Err(ParseError::new_error_at_span(
 
                            &ctx.module().source, select_expr.field_name.span, format!(
 
                                "this field does not exist on the struct '{}'",
 
                                ast_struct_def.identifier.value.as_str()
 
                            )
 
                        ))
 
                    }
 
                // If here then field index is known, and the referenced struct type
 
                // information is inserted into `extra_data`. Check to see if we can
 
                // do some mutual inference.
 
                let poly_data = &mut self.extra_data[extra_idx as usize];
 
                let mut poly_progress = HashSet::new();
 

	
 
                    // Encountered definition and field index for the
 
                    // first time
 
                    self.insert_initial_select_polymorph_data(ctx, id, struct_def_id.unwrap());
 
                },
 
                Ok(None) => {
 
                    // Type of subject is not yet known, so we
 
                    // cannot make any progress yet
 
                    return Ok(())
 
                },
 
                Err(()) => {
 
                    return Err(ParseError::new_error_at_span(
 
                        &ctx.module().source, select_expr.field_name.span, format!(
 
                            "Can only apply field access to structs, got a subject of type '{}'",
 
                            subject_type.display_name(&ctx.heap)
 
                        )
 
                    ));
 
                // Apply to struct's type
 
                let signature_type: *mut _ = &mut poly_data.embedded[0];
 
                let subject_type: *mut _ = &mut self.expr_types[subject_expr_idx as usize].expr_type;
 

	
 
                let (_, progress_subject) = Self::apply_equal2_signature_constraint(
 
                    ctx, upcast_id, Some(subject_id), poly_data, &mut poly_progress,
 
                    signature_type, 0, subject_type, 0
 
                )?;
 

	
 
                if progress_subject {
 
                    self.expr_queued.push_back(subject_expr_idx);
 
                }
 
            }
 
        }
 

	
 
        // If here then field index is known, and the referenced struct type
 
        // information is inserted into `extra_data`. Check to see if we can
 
        // do some mutual inference.
 
        let poly_data = &mut self.extra_data[extra_idx as usize];
 
        let mut poly_progress = HashSet::new();
 
                // Apply to field's type
 
                let signature_type: *mut _ = &mut poly_data.returned;
 
                let expr_type: *mut _ = &mut self.expr_types[expr_idx as usize].expr_type;
 

	
 
        // Apply to struct's type
 
        let signature_type: *mut _ = &mut poly_data.embedded[0];
 
        let subject_type: *mut _ = &mut self.expr_types[subject_expr_idx as usize].expr_type;
 
                let (_, progress_expr) = Self::apply_equal2_signature_constraint(
 
                    ctx, upcast_id, None, poly_data, &mut poly_progress,
 
                    signature_type, 0, expr_type, 0
 
                )?;
 

	
 
        let (_, progress_subject) = Self::apply_equal2_signature_constraint(
 
            ctx, upcast_id, Some(subject_id), poly_data, &mut poly_progress,
 
            signature_type, 0, subject_type, 0
 
        )?;
 
                if progress_expr {
 
                    if let Some(parent_id) = ctx.heap[upcast_id].parent_expr_id() {
 
                        let parent_idx = ctx.heap[parent_id].get_unique_id_in_definition();
 
                        self.expr_queued.push_back(parent_idx);
 
                    }
 
                }
 

	
 
        if progress_subject {
 
            self.expr_queued.push_back(subject_expr_idx);
 
        }
 
                // Reapply progress in polymorphic variables to struct's type
 
                let signature_type: *mut _ = &mut poly_data.embedded[0];
 
                let subject_type: *mut _ = &mut self.expr_types[subject_expr_idx as usize].expr_type;
 

	
 
        // Apply to field's type
 
        let signature_type: *mut _ = &mut poly_data.returned;
 
        let expr_type: *mut _ = &mut self.expr_types[expr_idx as usize].expr_type;
 
                let progress_subject = Self::apply_equal2_polyvar_constraint(
 
                    poly_data, &poly_progress, signature_type, subject_type
 
                );
 

	
 
        let (_, progress_expr) = Self::apply_equal2_signature_constraint(
 
            ctx, upcast_id, None, poly_data, &mut poly_progress,
 
            signature_type, 0, expr_type, 0
 
        )?;
 
                let signature_type: *mut _ = &mut poly_data.returned;
 
                let expr_type: *mut _ = &mut self.expr_types[expr_idx as usize].expr_type;
 

	
 
        if progress_expr {
 
            if let Some(parent_id) = ctx.heap[upcast_id].parent_expr_id() {
 
                let parent_idx = ctx.heap[parent_id].get_unique_id_in_definition();
 
                self.expr_queued.push_back(parent_idx);
 
            }
 
        }
 
                let progress_expr = Self::apply_equal2_polyvar_constraint(
 
                    poly_data, &poly_progress, signature_type, expr_type
 
                );
 

	
 
        // Reapply progress in polymorphic variables to struct's type
 
        let signature_type: *mut _ = &mut poly_data.embedded[0];
 
        let subject_type: *mut _ = &mut self.expr_types[subject_expr_idx as usize].expr_type;
 
                (progress_subject, progress_expr)
 
            },
 
            SelectKind::TupleMember(member_index) => {
 
                let member_index = *member_index;
 

	
 
                if infer_expr.field_or_monomorph_idx < 0 {
 
                    // We don't know what kind of tuple we're accessing yet
 
                    let subject_type = &self.expr_types[subject_expr_idx as usize].expr_type;
 
                    let tuple_size = try_get_tuple_size_from_inference_type(subject_type);
 

	
 
                    match tuple_size {
 
                        Ok(Some(enum_size)) => {
 
                            // Make sure we don't access an element outside of
 
                            // the tuple's bounds
 
                            if member_index >= enum_size as u64 {
 
                                return Err(ParseError::new_error_at_span(
 
                                    &ctx.module().source, select_expr.full_span, format!(
 
                                        "element index {} is out of bounds, tuple has {} elements",
 
                                        member_index, enum_size
 
                                    )
 
                                ));
 
                            }
 

	
 
                            // Within bounds, so set the index (such that we
 
                            // will not perform this lookup again)
 
                            let infer_expr = &mut self.expr_types[expr_idx as usize];
 
                            infer_expr.field_or_monomorph_idx = member_index as i32;
 
                        },
 
                        Ok(None) => {
 
                            // Nothing is known about the tuple yet
 
                            return Ok(());
 
                        },
 
                        Err(()) => {
 
                            return Err(ParseError::new_error_at_span(
 
                                &ctx.module().source, select_expr.full_span, format!(
 
                                    "Can only apply tuple element selection to tuples, got a subject of type '{}'",
 
                                    subject_type.display_name(&ctx.heap)
 
                                )
 
                            ));
 
                        }
 
                    }
 
                }
 

	
 
        let progress_subject = Self::apply_equal2_polyvar_constraint(
 
            poly_data, &poly_progress, signature_type, subject_type
 
        );
 
                // If here then we know which member we're accessing. So seek
 
                // that member in the subject type and apply inference.
 
                let subject_type = &self.expr_types[subject_expr_idx as usize].expr_type;
 
                let mut member_start_idx = 1;
 
                for _ in 0..member_index {
 
                    member_start_idx = InferenceType::find_subtree_end_idx(&subject_type.parts, member_start_idx);
 
                }
 

	
 
        let signature_type: *mut _ = &mut poly_data.returned;
 
        let expr_type: *mut _ = &mut self.expr_types[expr_idx as usize].expr_type;
 
                let (progress_expr, progress_subject) = self.apply_equal2_constraint(
 
                    ctx, upcast_id, upcast_id, 0, subject_id, member_start_idx
 
                )?;
 

	
 
        let progress_expr = Self::apply_equal2_polyvar_constraint(
 
            poly_data, &poly_progress, signature_type, expr_type
 
        );
 
                (progress_subject, progress_expr)
 
            },
 
        };
 

	
 
        if progress_subject { self.queue_expr(ctx, subject_id); }
 
        if progress_expr { self.queue_expr_parent(ctx, upcast_id); }
 

	
 
        debug_log!(" * After:");
 
        debug_log!("   - Subject type [{}]: {}", progress_subject, self.debug_get_display_name(ctx, subject_id));
 
        debug_log!("   - Expr    type [{}]: {}", progress_expr, self.debug_get_display_name(ctx, upcast_id));
 

	
 
        Ok(())
 
    }
 

	
 
    fn progress_literal_expr(&mut self, ctx: &mut Ctx, id: LiteralExpressionId) -> Result<(), ParseError> {
 
        let upcast_id = id.upcast();
 
        let expr = &ctx.heap[id];
 
        let expr_idx = expr.unique_id_in_definition;
 
        let extra_idx = self.expr_types[expr_idx as usize].extra_data_idx;
 

	
 
        debug_log!("Literal expr: {}", upcast_id.index);
 
        debug_log!(" * Before:");
 
        debug_log!("   - Expr type: {}", self.debug_get_display_name(ctx, upcast_id));
 

	
 
        let progress_expr = match &expr.value {
 
            Literal::Null => {
 
                self.apply_template_constraint(ctx, upcast_id, &MESSAGE_TEMPLATE)?
 
            },
 
            Literal::Integer(_) => {
 
                self.apply_template_constraint(ctx, upcast_id, &INTEGERLIKE_TEMPLATE)?
 
            },
 
            Literal::True | Literal::False => {
 
                self.apply_forced_constraint(ctx, upcast_id, &BOOL_TEMPLATE)?
 
            },
 
            Literal::Character(_) => {
 
                self.apply_forced_constraint(ctx, upcast_id, &CHARACTER_TEMPLATE)?
 
            },
 
            Literal::String(_) => {
 
                self.apply_forced_constraint(ctx, upcast_id, &STRING_TEMPLATE)?
 
            },
 
            Literal::Struct(data) => {
 
                let extra = &mut self.extra_data[extra_idx as usize];
 
                for _poly in &extra.poly_vars {
 
                    debug_log!(" * Poly: {}", _poly.display_name(&ctx.heap));
 
                }
 
                let mut poly_progress = HashSet::new();
 
                debug_assert_eq!(extra.embedded.len(), data.fields.len());
 

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

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

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

	
 
                    if progress_arg {
 
                        self.expr_queued.push_back(field_expr_idx);
 
                    }
 
                }
 

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

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

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

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

	
 
                // Check which expressions use the polymorphic arguments. If the
 
                // polymorphic variables have been progressed then we try to 
 
@@ -3724,196 +3804,200 @@ impl PassTyping {
 
        let expr_type = &self.expr_types[expr_idx as usize].expr_type;
 

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

	
 
    /// Constructs a human interpretable error in the case that type inference
 
    /// on a polymorphic variable to a function call or literal construction 
 
    /// failed. This may only be caused by a pair of inference types (which may 
 
    /// come from arguments or the return type) having two different inferred 
 
    /// values for that polymorphic variable.
 
    ///
 
    /// So we find this pair and construct the error using it.
 
    ///
 
    /// We assume that the expression is a function call or a struct literal,
 
    /// and that an actual error has occurred.
 
    fn construct_poly_arg_error(
 
        ctx: &Ctx, poly_data: &ExtraData, expr_id: ExpressionId
 
    ) -> ParseError {
 
        // Helper function to check for polymorph mismatch between two inference
 
        // types.
 
        fn has_poly_mismatch<'a>(type_a: &'a InferenceType, type_b: &'a InferenceType) -> Option<(u32, &'a [InferenceTypePart], &'a [InferenceTypePart])> {
 
            if !type_a.has_marker || !type_b.has_marker {
 
                return None
 
            }
 

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

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

	
 
            None
 
        }
 

	
 
        // Helper function to check for polymorph mismatch between an inference
 
        // type and the polymorphic variables in the poly_data struct.
 
        fn has_explicit_poly_mismatch<'a>(
 
            poly_vars: &'a [InferenceType], arg: &'a InferenceType
 
        ) -> Option<(u32, &'a [InferenceTypePart], &'a [InferenceTypePart])> {
 
            for (marker, section) in arg.marker_iter() {
 
                debug_assert!((marker as usize) < poly_vars.len());
 
                let poly_section = &poly_vars[marker as usize].parts;
 
                if !InferenceType::check_subtrees(poly_section, 0, section, 0) {
 
                    return Some((marker, poly_section, section))
 
                }
 
            }
 

	
 
            None
 
        }
 

	
 
        // Helpers function to retrieve polyvar name and definition name
 
        fn get_poly_var_and_definition_name<'a>(ctx: &'a Ctx, poly_var_idx: u32, definition_id: DefinitionId) -> (&'a str, &'a str) {
 
            let definition = &ctx.heap[definition_id];
 
            let poly_var = definition.poly_vars()[poly_var_idx as usize].value.as_str();
 
            let func_name = definition.identifier().value.as_str();
 

	
 
            (poly_var, func_name)
 
        }
 

	
 
        // Helper function to construct initial error
 
        fn construct_main_error(ctx: &Ctx, poly_data: &ExtraData, poly_var_idx: u32, expr: &Expression) -> ParseError {
 
            match expr {
 
                Expression::Call(expr) => {
 
                    let (poly_var, func_name) = get_poly_var_and_definition_name(ctx, poly_var_idx, poly_data.definition_id);
 
                    return ParseError::new_error_at_span(
 
                        &ctx.module().source, expr.func_span, format!(
 
                            "Conflicting type for polymorphic variable '{}' of '{}'",
 
                            poly_var, func_name
 
                        )
 
                    )
 
                },
 
                Expression::Literal(expr) => {
 
                    let (poly_var, type_name) = get_poly_var_and_definition_name(ctx, poly_var_idx, poly_data.definition_id);
 
                    return ParseError::new_error_at_span(
 
                        &ctx.module().source, expr.span, format!(
 
                            "Conflicting type for polymorphic variable '{}' of instantiation of '{}'",
 
                            poly_var, type_name
 
                        )
 
                    );
 
                },
 
                Expression::Select(expr) => {
 
                    let (poly_var, struct_name) = get_poly_var_and_definition_name(ctx, poly_var_idx, poly_data.definition_id);
 
                    let field_name = match &expr.kind {
 
                        SelectKind::StructField(v) => v,
 
                        SelectKind::TupleMember(_) => unreachable!(), // because we're constructing a polymorph error, and tuple access does not deal with polymorphs
 
                    };
 
                    return ParseError::new_error_at_span(
 
                        &ctx.module().source, expr.full_span, format!(
 
                            "Conflicting type for polymorphic variable '{}' while accessing field '{}' of '{}'",
 
                            poly_var, expr.field_name.value.as_str(), struct_name
 
                            poly_var, field_name.value.as_str(), struct_name
 
                        )
 
                    )
 
                }
 
                _ => unreachable!("called construct_poly_arg_error without an expected expression, got: {:?}", expr)
 
            }
 
        }
 

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

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

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

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

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

	
 
            // Check with return type
 
            if let Some((poly_idx, section_arg, section_ret)) = has_poly_mismatch(arg_a, &poly_data.returned) {
 
                let arg = &ctx.heap[expr_args[arg_a_idx]];
 
                return construct_main_error(ctx, poly_data, poly_idx, expr)
 
                    .with_info_at_span(
 
                        &ctx.module().source, arg.full_span(), format!(
 
                            "This argument inferred it to '{}'",
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