Changeset - f79a98e9e2d9
Parent rev.
Child rev.
[Not reviewed]
0 1 0
mh - 3 years ago 2022-02-22 16:32:29
contact@maxhenger.nl
WIP: Replaced old expr-based with new rule-based inferencing code
1 file changed with 481 insertions and 68 deletions:
src/protocol/parser/pass_typing.rs
481
68
0 comments (0 inline, 0 general)
src/protocol/parser/pass_typing.rs
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@@ -807,12 +807,13 @@ enum SingleInferenceResult {
 
// -----------------------------------------------------------------------------
 
// PassTyping - Public Interface
 
// -----------------------------------------------------------------------------
 

			




	
	
	
		
 
type InferNodeIndex = usize;

			




	
	
	
		
 
type PolyDataIndex = usize;

			




	
	
	
		
 
type VarDataIndex = usize;

			




	
	
	
		
 

			




	
	
	
		
 
enum DefinitionType{

			




	
	
	
		
 
    Component(ComponentDefinitionId),

			




	
	
	
		
 
    Function(FunctionDefinitionId),

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
		
 
@@ -882,12 +883,15 @@ impl InferenceRule {

			




	
	
	
		
 
    union_cast_method_impl!(as_select_struct_field, InferenceRuleSelectStructField, InferenceRule::SelectStructField);

			




	
	
	
		
 
    union_cast_method_impl!(as_select_tuple_member, InferenceRuleSelectTupleMember, InferenceRule::SelectTupleMember);

			




	
	
	
		
 
    union_cast_method_impl!(as_literal_struct, InferenceRuleLiteralStruct, InferenceRule::LiteralStruct);

			




	
	
	
		
 
    union_cast_method_impl!(as_literal_union, InferenceRuleLiteralUnion, InferenceRule::LiteralUnion);

			




	
	
	
		
 
    union_cast_method_impl!(as_literal_array, InferenceRuleLiteralArray, InferenceRule::LiteralArray);

			




	
	
	
		
 
    union_cast_method_impl!(as_literal_tuple, InferenceRuleLiteralTuple, InferenceRule::LiteralTuple);

			




	
	
	
		
 
    union_cast_method_impl!(as_cast_expr, InferenceRuleCastExpr, InferenceRule::CastExpr);

			




	
	
	
		
 
    union_cast_method_impl!(as_call_expr, InferenceRuleCallExpr, InferenceRule::CallExpr);

			




	
	
	
		
 
    union_cast_method_impl!(as_variable_expr, InferenceRuleVariableExpr, InferenceRule::VariableExpr);

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
struct InferenceRuleTemplate {

			




	
	
	
		
 
    template: &'static [InferenceTypePart],

			




	
	
	
		
 
    application: InferenceRuleTemplateApplication,

			




	
	
	
		
 
}

			




	
	
		
 
@@ -999,19 +1003,13 @@ struct InferenceRuleCallExpr {

			




	
	
	
		
 
    argument_indices: Vec<InferNodeIndex>

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
/// Data associated with a variable expression: an expression that reads the

			




	
	
	
		
 
/// value from a variable.

			




	
	
	
		
 
struct InferenceRuleVariableExpr {

			




	
	
	
		
 
    variable_index: InferNodeIndex,

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
/// Data associated with a variable: keeping track of all the variable

			




	
	
	
		
 
/// expressions in which it is used.

			




	
	
	
		
 
struct InferenceRuleVariable {

			




	
	
	
		
 
    used_at_indices: Vec<InferNodeIndex>,

			




	
	
	
		
 
    var_data_index: VarDataIndex, // shared variable information

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
/// This particular visitor will recurse depth-first into the AST and ensures

			




	
	
	
		
 
/// that all expressions have the appropriate types.

			




	
	
	
		
 
pub(crate) struct PassTyping {

			




	
	
	
		
 
    // Current definition we're typechecking.

			




	
	
		
 
@@ -1024,25 +1022,28 @@ pub(crate) struct PassTyping {

			




	
	
	
		
 
    var_buffer: ScopedBuffer<VariableId>,

			




	
	
	
		
 
    expr_buffer: ScopedBuffer<ExpressionId>,

			




	
	
	
		
 
    stmt_buffer: ScopedBuffer<StatementId>,

			




	
	
	
		
 
    bool_buffer: ScopedBuffer<bool>,

			




	
	
	
		
 
    index_buffer: ScopedBuffer<usize>,

			




	
	
	
		
 
    poly_progress_buffer: ScopedBuffer<u32>,

			




	
	
	
		
 
    temp_type_parts: Vec<InferenceTypePart>,

			




	
	
	
		
 
    // Mapping from parser type to inferred type. We attempt to continue to

			




	
	
	
		
 
    // specify these types until we're stuck or we've fully determined the type.

			




	
	
	
		
 
    var_types: HashMap<VariableId, VarData>,            // types of variables

			




	
	
	
		
 
    var_types: HashMap<VariableId, VarDataDeprecated>,            // types of variables

			




	
	
	
		
 
    infer_nodes: Vec<InferenceNode>,                     // will be transferred to type table at end

			




	
	
	
		
 
    poly_data: Vec<PolyData>,       // data for polymorph inference

			




	
	
	
		
 
    var_data: Vec<VarData>,

			




	
	
	
		
 
    // Keeping track of which expressions need to be reinferred because the

			




	
	
	
		
 
    // expressions they're linked to made progression on an associated type

			




	
	
	
		
 
    expr_queued: DequeSet<i32>,

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
/// Generic struct that is used to store inferred types associated with

			




	
	
	
		
 
/// polymorphic types.

			




	
	
	
		
 
struct PolyData {

			




	
	
	
		
 
    first_rule_application: bool,

			




	
	
	
		
 
    definition_id: DefinitionId, // the definition, only used for user feedback

			




	
	
	
		
 
    /// Inferred types of the polymorphic variables as they are written down

			




	
	
	
		
 
    /// at the type's definition.

			




	
	
	
		
 
    poly_vars: Vec<InferenceType>,

			




	
	
	
		
 
    /// Inferred types of associated types (e.g. struct fields, tuple members,

			




	
	
	
		
 
    /// function arguments). These types may depend on the polymorphic variables

			




	
	
		
 
@@ -1084,31 +1085,38 @@ impl PolyData {

			




	
	
	
		
 
            PolyDataTypeIndex::Associated(index) => return &mut self.associated[index],

			




	
	
	
		
 
            PolyDataTypeIndex::Returned => return &mut self.returned,

			




	
	
	
		
 
        }

			




	
	
	
		
 
    }

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
struct VarData {

			




	
	
	
		
 
struct VarDataDeprecated {

			




	
	
	
		
 
    /// Type of the variable

			




	
	
	
		
 
    var_type: InferenceType,

			




	
	
	
		
 
    /// VariableExpressions that use the variable

			




	
	
	
		
 
    used_at: Vec<ExpressionId>,

			




	
	
	
		
 
    /// For channel statements we link to the other variable such that when one

			




	
	
	
		
 
    /// channel's interior type is resolved, we can also resolve the other one.

			




	
	
	
		
 
    linked_var: Option<VariableId>,

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
impl VarData {

			




	
	
	
		
 
impl VarDataDeprecated {

			




	
	
	
		
 
    fn new_channel(var_type: InferenceType, other_port: VariableId) -> Self {

			




	
	
	
		
 
        Self{ var_type, used_at: Vec::new(), linked_var: Some(other_port) }

			




	
	
	
		
 
    }

			




	
	
	
		
 
    fn new_local(var_type: InferenceType) -> Self {

			




	
	
	
		
 
        Self{ var_type, used_at: Vec::new(), linked_var: None }

			




	
	
	
		
 
    }

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
struct VarData {

			




	
	
	
		
 
    var_id: VariableId,

			




	
	
	
		
 
    var_type: InferenceType,

			




	
	
	
		
 
    used_at: Vec<InferNodeIndex>, // of variable expressions

			




	
	
	
		
 
    linked_var: Option<VarDataIndex>,

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
impl PassTyping {

			




	
	
	
		
 
    pub(crate) fn new() -> Self {

			




	
	
	
		
 
        PassTyping {

			




	
	
	
		
 
            reserved_type_id: TypeId::new_invalid(),

			




	
	
	
		
 
            definition_type: DefinitionType::Function(FunctionDefinitionId::new_invalid()),

			




	
	
	
		
 
            poly_vars: Vec::new(),

			




	
	
		
 
@@ -1233,13 +1241,13 @@ impl PassTyping {

			




	
	
	
		
 
        // Visit parameters

			




	
	
	
		
 
        let section = self.var_buffer.start_section_initialized(comp_def.parameters.as_slice());

			




	
	
	
		
 
        for param_id in section.iter_copied() {

			




	
	
	
		
 
            let param = &ctx.heap[param_id];

			




	
	
	
		
 
            let var_type = self.determine_inference_type_from_parser_type_elements(&param.parser_type.elements, true);

			




	
	
	
		
 
            debug_assert!(var_type.is_done, "expected component arguments to be concrete types");

			




	
	
	
		
 
            self.var_types.insert(param_id, VarData::new_local(var_type));

			




	
	
	
		
 
            self.var_types.insert(param_id, VarDataDeprecated::new_local(var_type));

			




	
	
	
		
 
        }

			




	
	
	
		
 
        section.forget();

			




	
	
	
		
 

			




	
	
	
		
 
        // Visit the body and all of its expressions

			




	
	
	
		
 
        let body_stmt_id = ctx.heap[id].body;

			




	
	
	
		
 
        self.parent_index = None;

			




	
	
		
 
@@ -1274,13 +1282,13 @@ impl PassTyping {

			




	
	
	
		
 
        // Visit parameters

			




	
	
	
		
 
        let section = self.var_buffer.start_section_initialized(func_def.parameters.as_slice());

			




	
	
	
		
 
        for param_id in section.iter_copied() {

			




	
	
	
		
 
            let param = &ctx.heap[param_id];

			




	
	
	
		
 
            let var_type = self.determine_inference_type_from_parser_type_elements(&param.parser_type.elements, true);

			




	
	
	
		
 
            debug_assert!(var_type.is_done, "expected function arguments to be concrete types");

			




	
	
	
		
 
            self.var_types.insert(param_id, VarData::new_local(var_type));

			




	
	
	
		
 
            self.var_types.insert(param_id, VarDataDeprecated::new_local(var_type));

			




	
	
	
		
 
        }

			




	
	
	
		
 
        section.forget();

			




	
	
	
		
 

			




	
	
	
		
 
        // Visit all of the expressions within the body

			




	
	
	
		
 
        let body_stmt_id = ctx.heap[id].body;

			




	
	
	
		
 
        self.parent_index = None;

			




	
	
		
 
@@ -1311,33 +1319,50 @@ impl PassTyping {

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_local_memory_stmt(&mut self, ctx: &mut Ctx, id: MemoryStatementId) -> VisitorResult {

			




	
	
	
		
 
        let memory_stmt = &ctx.heap[id];

			




	
	
	
		
 
        let initial_expr_id = memory_stmt.initial_expr;

			




	
	
	
		
 

			




	
	
	
		
 
        // Setup memory statement inference

			




	
	
	
		
 
        let local = &ctx.heap[memory_stmt.variable];

			




	
	
	
		
 
        let var_type = self.determine_inference_type_from_parser_type_elements(&local.parser_type.elements, true);

			




	
	
	
		
 
        self.var_types.insert(memory_stmt.variable, VarData::new_local(var_type));

			




	
	
	
		
 
        self.var_data.push(VarData{

			




	
	
	
		
 
            var_id: memory_stmt.variable,

			




	
	
	
		
 
            var_type,

			




	
	
	
		
 
            used_at: Vec::new(),

			




	
	
	
		
 
            linked_var: None,

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        // Process the initial value

			




	
	
	
		
 
        self.visit_assignment_expr(ctx, initial_expr_id)?;

			




	
	
	
		
 

			




	
	
	
		
 
        Ok(())

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_local_channel_stmt(&mut self, ctx: &mut Ctx, id: ChannelStatementId) -> VisitorResult {

			




	
	
	
		
 
        let channel_stmt = &ctx.heap[id];

			




	
	
	
		
 

			




	
	
	
		
 
        let from_var_index = self.var_data.len() as VarDataIndex;

			




	
	
	
		
 
        let to_var_index = from_var_index + 1;

			




	
	
	
		
 

			




	
	
	
		
 
        let from_local = &ctx.heap[channel_stmt.from];

			




	
	
	
		
 
        let from_var_type = self.determine_inference_type_from_parser_type_elements(&from_local.parser_type.elements, true);

			




	
	
	
		
 
        self.var_types.insert(from_local.this, VarData::new_channel(from_var_type, channel_stmt.to));

			




	
	
	
		
 
        self.var_data.push(VarData{

			




	
	
	
		
 
            var_id: channel_stmt.from,

			




	
	
	
		
 
            var_type: from_var_type,

			




	
	
	
		
 
            used_at: Vec::new(),

			




	
	
	
		
 
            linked_var: Some(to_var_index),

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        let to_local = &ctx.heap[channel_stmt.to];

			




	
	
	
		
 
        let to_var_type = self.determine_inference_type_from_parser_type_elements(&to_local.parser_type.elements, true);

			




	
	
	
		
 
        self.var_types.insert(to_local.this, VarData::new_channel(to_var_type, channel_stmt.from));

			




	
	
	
		
 
        self.var_data.push(VarData{

			




	
	
	
		
 
            var_id: channel_stmt.to,

			




	
	
	
		
 
            var_type: to_var_type,

			




	
	
	
		
 
            used_at: Vec::new(),

			




	
	
	
		
 
            linked_var: Some(from_var_index),

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        Ok(())

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_labeled_stmt(&mut self, ctx: &mut Ctx, id: LabeledStatementId) -> VisitorResult {

			




	
	
	
		
 
        let labeled_stmt = &ctx.heap[id];

			




	
	
		
 
@@ -1486,13 +1511,14 @@ impl PassTyping {

			




	
	
	
		
 
            result_template: InferenceRuleTemplate::new_forced(&VOID_TEMPLATE),

			




	
	
	
		
 
            argument1_index: left_index,

			




	
	
	
		
 
            argument2_index: right_index,

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_assignment_expr(ctx, id)

			




	
	
	
		
 
        self.progress_inference_rule_tri_equal_args(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_binding_expr(&mut self, ctx: &mut Ctx, id: BindingExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
	
		
 
        let self_index = self.insert_initial_inference_node(ctx, upcast_id)?;

			




	
	
	
		
 

			




	
	
		
 
@@ -1510,13 +1536,14 @@ impl PassTyping {

			




	
	
	
		
 
            result_template: InferenceRuleTemplate::new_forced(&BOOL_TEMPLATE),

			




	
	
	
		
 
            argument1_index: arg_to_index,

			




	
	
	
		
 
            argument2_index: arg_from_index,

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_binding_expr(ctx, id)

			




	
	
	
		
 
        self.progress_inference_rule_tri_equal_args(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_conditional_expr(&mut self, ctx: &mut Ctx, id: ConditionalExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
	
		
 
        let self_index = self.insert_initial_inference_node(ctx, upcast_id)?;

			




	
	
	
		
 

			




	
	
		
 
@@ -1539,13 +1566,14 @@ impl PassTyping {

			




	
	
	
		
 
            template: InferenceRuleTemplate::new_none(),

			




	
	
	
		
 
            argument1_index: true_index,

			




	
	
	
		
 
            argument2_index: false_index,

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_conditional_expr(ctx, id)

			




	
	
	
		
 
        self.progress_inference_rule_tri_equal_all(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_binary_expr(&mut self, ctx: &mut Ctx, id: BinaryExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        use BinaryOperator as BO;

			




	
	
	
		
 

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
		
 
@@ -1553,13 +1581,13 @@ impl PassTyping {

			




	
	
	
		
 

			




	
	
	
		
 
        let binary_expr = &ctx.heap[id];

			




	
	
	
		
 
        let binary_op = binary_expr.operation;

			




	
	
	
		
 
        let lhs_expr_id = binary_expr.left;

			




	
	
	
		
 
        let rhs_expr_id = binary_expr.right;

			




	
	
	
		
 

			




	
	
	
		
 
        let parent_index = self.parent_index.replace(self_index);

			




	
	
	
		
 
        let old_parent = self.parent_index.replace(self_index);

			




	
	
	
		
 
        let left_index = self.visit_expr(ctx, lhs_expr_id)?;

			




	
	
	
		
 
        let right_index = self.visit_expr(ctx, rhs_expr_id)?;

			




	
	
	
		
 

			




	
	
	
		
 
        let inference_rule = match binary_op {

			




	
	
	
		
 
            BO::Concatenate =>

			




	
	
	
		
 
                InferenceRule::Concatenate(InferenceRuleTwoArgs{

			




	
	
		
 
@@ -1601,13 +1629,14 @@ impl PassTyping {

			




	
	
	
		
 
        };

			




	
	
	
		
 

			




	
	
	
		
 
        let node = &mut self.infer_nodes[self_index];

			




	
	
	
		
 
        node.inference_rule = inference_rule;

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_binary_expr(ctx, id)

			




	
	
	
		
 
        self.progress_inference_rule(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_unary_expr(&mut self, ctx: &mut Ctx, id: UnaryExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        use UnaryOperator as UO;

			




	
	
	
		
 

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
		
 
@@ -1632,13 +1661,14 @@ impl PassTyping {

			




	
	
	
		
 
        let node = &mut self.infer_nodes[self_index];

			




	
	
	
		
 
        node.inference_rule = InferenceRule::BiEqual(InferenceRuleBiEqual{

			




	
	
	
		
 
            template, argument_index,

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_unary_expr(ctx, id)

			




	
	
	
		
 
        self.progress_inference_rule_bi_equal(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_indexing_expr(&mut self, ctx: &mut Ctx, id: IndexingExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
	
		
 
        let self_index = self.insert_initial_inference_node(ctx, upcast_id)?;

			




	
	
	
		
 

			




	
	
		
 
@@ -1653,13 +1683,14 @@ impl PassTyping {

			




	
	
	
		
 
        let node = &mut self.infer_nodes[self_index];

			




	
	
	
		
 
        node.inference_rule = InferenceRule::IndexingExpr(InferenceRuleIndexingExpr{

			




	
	
	
		
 
            subject_index, index_index,

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_indexing_expr(ctx, id)

			




	
	
	
		
 
        self.progress_inference_rule_indexing_expr(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_slicing_expr(&mut self, ctx: &mut Ctx, id: SlicingExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
	
		
 
        let self_index = self.insert_initial_inference_node(ctx, upcast_id)?;

			




	
	
	
		
 

			




	
	
		
 
@@ -1676,13 +1707,14 @@ impl PassTyping {

			




	
	
	
		
 
        let node = &mut self.infer_nodes[self_index];

			




	
	
	
		
 
        node.inference_rule = InferenceRule::SlicingExpr(InferenceRuleSlicingExpr{

			




	
	
	
		
 
            subject_index, from_index, to_index,

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_slicing_expr(ctx, id)

			




	
	
	
		
 
        self.progress_inference_rule_slicing_expr(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_select_expr(&mut self, ctx: &mut Ctx, id: SelectExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
	
		
 
        let self_index = self.insert_initial_inference_node(ctx, upcast_id)?;

			




	
	
	
		
 

			




	
	
		
 
@@ -1690,18 +1722,29 @@ impl PassTyping {

			




	
	
	
		
 
        let subject_expr_id = select_expr.subject;

			




	
	
	
		
 

			




	
	
	
		
 
        let old_parent = self.parent_index.replace(self_index);

			




	
	
	
		
 
        let subject_index = self.visit_expr(ctx, subject_expr_id)?;

			




	
	
	
		
 

			




	
	
	
		
 
        let node = &mut self.infer_nodes[self_index];

			




	
	
	
		
 
        node.inference_rule = InferenceRule::SelectExpr(InferenceRuleSelectExpr{

			




	
	
	
		
 
        let inference_rule = match &ctx.heap[id].kind {

			




	
	
	
		
 
            SelectKind::StructField(field_identifier) =>

			




	
	
	
		
 
                InferenceRule::SelectStructField(InferenceRuleSelectStructField{

			




	
	
	
		
 
                    subject_index,

			




	
	
	
		
 
        });

			




	
	
	
		
 
                    selected_field: field_identifier.clone(),

			




	
	
	
		
 
                }),

			




	
	
	
		
 
            SelectKind::TupleMember(member_index) =>

			




	
	
	
		
 
                InferenceRule::SelectTupleMember(InferenceRuleSelectTupleMember{

			




	
	
	
		
 
                    subject_index,

			




	
	
	
		
 
                    selected_index: *member_index,

			




	
	
	
		
 
                }),

			




	
	
	
		
 
        };

			




	
	
	
		
 
        node.inference_rule = inference_rule;

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_select_expr(ctx, id)

			




	
	
	
		
 
        self.progress_inference_rule(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_literal_expr(&mut self, ctx: &mut Ctx, id: LiteralExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
	
		
 
        let self_index = self.insert_initial_inference_node(ctx, upcast_id)?;

			




	
	
	
		
 

			




	
	
		
 
@@ -1757,15 +1800,13 @@ impl PassTyping {

			




	
	
	
		
 
                // have a user-defined polymorphic marker variable. For this 

			




	
	
	
		
 
                // reason we may still have to apply inference to this 

			




	
	
	
		
 
                // polymorphic variable

			




	
	
	
		
 
                let extra_index = self.insert_initial_enum_polymorph_data(ctx, id);

			




	
	
	
		
 
                let node = &mut self.infer_nodes[self_index];

			




	
	
	
		
 
                node.poly_data_index = extra_index;

			




	
	
	
		
 
                node.inference_rule = InferenceRule::LiteralEnum(InferenceRuleLiteralEnum{

			




	
	
	
		
 

			




	
	
	
		
 
                });

			




	
	
	
		
 
                node.inference_rule = InferenceRule::LiteralEnum;

			




	
	
	
		
 
            },

			




	
	
	
		
 
            Literal::Union(literal) => {

			




	
	
	
		
 
                // May carry subexpressions and polymorphic arguments

			




	
	
	
		
 
                let expr_ids = self.expr_buffer.start_section_initialized(literal.values.as_slice());

			




	
	
	
		
 
                let extra_index = self.insert_initial_union_polymorph_data(ctx, id);

			




	
	
	
		
 

			




	
	
		
 
@@ -1800,13 +1841,14 @@ impl PassTyping {

			




	
	
	
		
 
                    element_indices,

			




	
	
	
		
 
                })

			




	
	
	
		
 
            }

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_literal_expr(ctx, id)

			




	
	
	
		
 
        self.progress_inference_rule(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_cast_expr(&mut self, ctx: &mut Ctx, id: CastExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
	
		
 
        let self_index = self.insert_initial_inference_node(ctx, upcast_id)?;

			




	
	
	
		
 

			




	
	
		
 
@@ -1819,13 +1861,24 @@ impl PassTyping {

			




	
	
	
		
 
        let node = &mut self.infer_nodes[self_index];

			




	
	
	
		
 
        node.inference_rule = InferenceRule::CastExpr(InferenceRuleCastExpr{

			




	
	
	
		
 
            subject_index,

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_cast_expr(ctx, id)

			




	
	
	
		
 

			




	
	
	
		
 
        // The cast expression is a bit special at this point: the progression

			




	
	
	
		
 
        // function simply makes sure input/output types are compatible. But if

			




	
	
	
		
 
        // the programmer explicitly specified the output type, then we can

			




	
	
	
		
 
        // already perform that inference rule here.

			




	
	
	
		
 
        {

			




	
	
	
		
 
            let specified_type = self.determine_inference_type_from_parser_type_elements(&cast_expr.to_type.elements, true);

			




	
	
	
		
 
            let _progress = self.apply_template_constraint(ctx, self_index, &specified_type.parts)?;

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        self.progress_inference_rule_cast_expr(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_call_expr(&mut self, ctx: &mut Ctx, id: CallExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
	
		
 
        let self_index = self.insert_initial_inference_node(ctx, upcast_id)?;

			




	
	
	
		
 
        let extra_index = self.insert_initial_call_polymorph_data(ctx, id);

			




	
	
		
 
@@ -1853,41 +1906,64 @@ impl PassTyping {

			




	
	
	
		
 
        node.poly_data_index = extra_index;

			




	
	
	
		
 
        node.inference_rule = InferenceRule::CallExpr(InferenceRuleCallExpr{

			




	
	
	
		
 
            argument_indices,

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_call_expr(ctx, id)

			




	
	
	
		
 
        self.progress_inference_rule_call_expr(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn visit_variable_expr(&mut self, ctx: &mut Ctx, id: VariableExpressionId) -> VisitExprResult {

			




	
	
	
		
 
        let upcast_id = id.upcast();

			




	
	
	
		
 
        self.insert_initial_inference_node(ctx, upcast_id)?;

			




	
	
	
		
 
        let self_index = self.insert_initial_inference_node(ctx, upcast_id)?;

			




	
	
	
		
 

			




	
	
	
		
 
        let var_expr = &ctx.heap[id];

			




	
	
	
		
 
        debug_assert!(var_expr.declaration.is_some());

			




	
	
	
		
 
        let old_parent = self.parent_index.replace(self_index);

			




	
	
	
		
 

			




	
	
	
		
 
        // Not pretty: if a binding expression, then this is the first time we

			




	
	
	
		
 
        // encounter the variable, so we still need to insert the variable data.

			




	
	
	
		
 
        let declaration = &ctx.heap[var_expr.declaration.unwrap()];

			




	
	
	
		
 
        if !self.var_types.contains_key(&declaration.this)  {

			




	
	
	
		
 
            debug_assert!(declaration.kind == VariableKind::Binding);

			




	
	
	
		
 
        let mut var_data_index = None;

			




	
	
	
		
 
        for (index, var_data) in self.var_data.iter().enumerate() {

			




	
	
	
		
 
            if var_data.var_id == declaration.this {

			




	
	
	
		
 
                var_data_index = Some(index);

			




	
	
	
		
 
                break;

			




	
	
	
		
 
            }

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        let var_data_index = if let Some(var_data_index) = var_data_index {

			




	
	
	
		
 
            let var_data = &mut self.var_data[var_data_index];

			




	
	
	
		
 
            var_data.used_at.push(self_index);

			




	
	
	
		
 

			




	
	
	
		
 
            var_data_index

			




	
	
	
		
 
        } else {

			




	
	
	
		
 
            // If we're in a binding expression then it might the first time we

			




	
	
	
		
 
            // encounter the variable, so add a `VarData` entry.

			




	
	
	
		
 
            debug_assert_eq!(declaration.kind, VariableKind::Binding);

			




	
	
	
		
 
            let var_type = self.determine_inference_type_from_parser_type_elements(

			




	
	
	
		
 
                &declaration.parser_type.elements, true

			




	
	
	
		
 
            );

			




	
	
	
		
 
            self.var_types.insert(declaration.this, VarData{

			




	
	
	
		
 
            let var_data_index = self.var_data.len();

			




	
	
	
		
 
            self.var_data.push(VarData{

			




	
	
	
		
 
                var_id: declaration.this,

			




	
	
	
		
 
                var_type,

			




	
	
	
		
 
                used_at: vec![upcast_id],

			




	
	
	
		
 
                linked_var: None

			




	
	
	
		
 
                used_at: vec![self_index],

			




	
	
	
		
 
                linked_var: None,

			




	
	
	
		
 
            });

			




	
	
	
		
 
        } else {

			




	
	
	
		
 
            let var_data = self.var_types.get_mut(&declaration.this).unwrap();

			




	
	
	
		
 
            var_data.used_at.push(upcast_id);

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        self.progress_variable_expr(ctx, id)

			




	
	
	
		
 
            var_data_index

			




	
	
	
		
 
        };

			




	
	
	
		
 

			




	
	
	
		
 
        let node = &mut self.infer_nodes[self_index];

			




	
	
	
		
 
        node.inference_rule = InferenceRule::VariableExpr(InferenceRuleVariableExpr{

			




	
	
	
		
 
            var_data_index,

			




	
	
	
		
 
        });

			




	
	
	
		
 

			




	
	
	
		
 
        self.parent_index = old_parent;

			




	
	
	
		
 
        self.progress_inference_rule_variable_expr(ctx, self_index)?;

			




	
	
	
		
 
        return Ok(self_index);

			




	
	
	
		
 
    }

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
// -----------------------------------------------------------------------------

			




	
	
	
		
 
// PassTyping - Type-inference progression

			




	
	
	
		
 
// -----------------------------------------------------------------------------

			




	
	
		
 
@@ -2097,12 +2173,66 @@ impl PassTyping {

			




	
	
	
		
 
            });

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        Ok(())

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        use InferenceRule as IR;

			




	
	
	
		
 

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        match &node.inference_rule {

			




	
	
	
		
 
            IR::Noop =>

			




	
	
	
		
 
                return Ok(()),

			




	
	
	
		
 
            IR::MonoTemplate(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_mono_template(ctx, node_index),

			




	
	
	
		
 
            IR::BiEqual(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_bi_equal(ctx, node_index),

			




	
	
	
		
 
            IR::TriEqualArgs(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_tri_equal_args(ctx, node_index),

			




	
	
	
		
 
            IR::TriEqualAll(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_tri_equal_all(ctx, node_index),

			




	
	
	
		
 
            IR::Concatenate(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_concatenate(ctx, node_index),

			




	
	
	
		
 
            IR::IndexingExpr(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_indexing_expr(ctx, node_index),

			




	
	
	
		
 
            IR::SlicingExpr(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_slicing_expr(ctx, node_index),

			




	
	
	
		
 
            IR::SelectStructField(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_select_struct_field(ctx, node_index),

			




	
	
	
		
 
            IR::SelectTupleMember(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_select_tuple_member(ctx, node_index),

			




	
	
	
		
 
            IR::LiteralStruct(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_literal_struct(ctx, node_index),

			




	
	
	
		
 
            IR::LiteralEnum =>

			




	
	
	
		
 
                self.progress_inference_rule_literal_enum(ctx, node_index),

			




	
	
	
		
 
            IR::LiteralUnion(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_literal_union(ctx, node_index),

			




	
	
	
		
 
            IR::LiteralArray(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_literal_array(ctx, node_index),

			




	
	
	
		
 
            IR::LiteralTuple(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_literal_tuple(ctx, node_index),

			




	
	
	
		
 
            IR::CastExpr(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_cast_expr(ctx, node_index),

			




	
	
	
		
 
            IR::CallExpr(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_call_expr(ctx, node_index),

			




	
	
	
		
 
            IR::VariableExpr(_) =>

			




	
	
	
		
 
                self.progress_inference_rule_variable_expr(ctx, node_index),

			




	
	
	
		
 
        }

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_mono_template(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_mono_template();

			




	
	
	
		
 

			




	
	
	
		
 
        let progress = self.progress_template(ctx, node_index, rule.application, rule.template)?;

			




	
	
	
		
 
        if progress { self.queue_node_parent(node_index); }

			




	
	
	
		
 

			




	
	
	
		
 
        return Ok(());

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_bi_equal(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_bi_equal();

			




	
	
	
		
 
        let arg_index = rule.argument_index;

			




	
	
	
		
 

			




	
	
	
		
 
        let base_progress = self.progress_template(ctx, node_index, rule.template.application, rule.template.template)?;

			




	
	
		
 
@@ -2145,13 +2275,13 @@ impl PassTyping {

			




	
	
	
		
 
        if arg1_progress { self.queue_node(arg1_index); }

			




	
	
	
		
 
        if arg2_progress { self.queue_node(arg2_index); }

			




	
	
	
		
 

			




	
	
	
		
 
        return Ok(());

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_concatenate(&mut self, ctx: &mut Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
    fn progress_inference_rule_concatenate(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_concatenate();

			




	
	
	
		
 
        let arg1_index = rule.argument1_index;

			




	
	
	
		
 
        let arg2_index = rule.argument2_index;

			




	
	
	
		
 

			




	
	
	
		
 
        // Two cases: one of the arguments is a string (then all must be), or

			




	
	
		
 
@@ -2267,13 +2397,13 @@ impl PassTyping {

			




	
	
	
		
 
        if from_template_progress || from_index_progress { self.queue_node(from_index_index); }

			




	
	
	
		
 
        if to_template_progress || to_index_progress { self.queue_node(to_index_index); }

			




	
	
	
		
 

			




	
	
	
		
 
        return Ok(());

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_select_struct_field(&mut self, ctx: &mut Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
    fn progress_inference_rule_select_struct_field(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_select_struct_field();

			




	
	
	
		
 

			




	
	
	
		
 
        let subject_index = rule.subject_index;

			




	
	
	
		
 

			




	
	
	
		
 
        fn get_definition_id_from_inference_type(inference_type: &InferenceType) -> Result<Option<DefinitionId>, ()> {

			




	
	
		
 
@@ -2380,37 +2510,22 @@ impl PassTyping {

			




	
	
	
		
 
        );

			




	
	
	
		
 

			




	
	
	
		
 
        if progress_subject_1 || progress_subject_2 { self.queue_node(subject_index); }

			




	
	
	
		
 
        if progress_field_1 || progress_field_2 { self.queue_node_parent(node_index); }

			




	
	
	
		
 

			




	
	
	
		
 
        poly_progress_section.forget();

			




	
	
	
		
 

			




	
	
	
		
 
        self.finish_polydata_constraint(node_index);

			




	
	
	
		
 
        return Ok(())

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_select_tuple_member(&mut self, ctx: &mut Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
    fn progress_inference_rule_select_tuple_member(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_select_tuple_member();

			




	
	
	
		
 
        let subject_index = rule.subject_index;

			




	
	
	
		
 
        let tuple_member_index = rule.selected_index;

			




	
	
	
		
 

			




	
	
	
		
 
        fn get_tuple_size_from_inference_type(inference_type: &InferenceType) -> Result<Option<u32>, ()> {

			




	
	
	
		
 
            for part in &inference_type.parts {

			




	
	
	
		
 
                if part.is_marker() { continue; }

			




	
	
	
		
 
                if !part.is_concrete() { break; }

			




	
	
	
		
 

			




	
	
	
		
 
                if let InferenceTypePart::Tuple(size) = part {

			




	
	
	
		
 
                    return Ok(Some(*size));

			




	
	
	
		
 
                } else {

			




	
	
	
		
 
                    return Err(()); // not a tuple!

			




	
	
	
		
 
                }

			




	
	
	
		
 
            }

			




	
	
	
		
 

			




	
	
	
		
 
            return Ok(None);

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        if node.field_or_monomorph_index < 0 {

			




	
	
	
		
 
            let subject_type = &self.infer_nodes[subject_index].expr_type;

			




	
	
	
		
 
            let tuple_size = get_tuple_size_from_inference_type(subject_type);

			




	
	
	
		
 
            let tuple_size = match tuple_size {

			




	
	
	
		
 
                Ok(Some(tuple_size)) => {

			




	
	
	
		
 
                    tuple_size

			




	
	
		
 
@@ -2509,13 +2624,13 @@ impl PassTyping {

			




	
	
	
		
 
            node_index, &poly_progress_section

			




	
	
	
		
 
        );

			




	
	
	
		
 

			




	
	
	
		
 
        if progress_literal_1 || progress_literal_2 { self.queue_node_parent(node_index); }

			




	
	
	
		
 

			




	
	
	
		
 
        poly_progress_section.forget();

			




	
	
	
		
 

			




	
	
	
		
 
        self.finish_polydata_constraint(node_index);

			




	
	
	
		
 
        return Ok(())

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_literal_enum(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_literal_enum();

			




	
	
		
 
@@ -2533,12 +2648,13 @@ impl PassTyping {

			




	
	
	
		
 
            ctx, node_index, PolyDataTypeIndex::Returned, node_index, &poly_progress_section

			




	
	
	
		
 
        );

			




	
	
	
		
 

			




	
	
	
		
 
        if progress_literal_1 || progress_literal_2 { self.queue_node_parent(node_index); }

			




	
	
	
		
 

			




	
	
	
		
 
        poly_progress_section.forget();

			




	
	
	
		
 
        self.finish_polydata_constraint(node_index);

			




	
	
	
		
 
        return Ok(());

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_literal_union(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_literal_union();

			




	
	
		
 
@@ -2578,12 +2694,13 @@ impl PassTyping {

			




	
	
	
		
 
            ctx, node_index, PolyDataTypeIndex::Returned, node_index, &poly_progress_section

			




	
	
	
		
 
        );

			




	
	
	
		
 

			




	
	
	
		
 
        if progress_literal_1 || progress_literal_2 { self.queue_node_parent(node_index); }

			




	
	
	
		
 

			




	
	
	
		
 
        poly_progress_section.forget();

			




	
	
	
		
 
        self.finish_polydata_constraint(node_index);

			




	
	
	
		
 
        return Ok(());

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_literal_array(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_literal_array();

			




	
	
		
 
@@ -2625,12 +2742,255 @@ impl PassTyping {

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_literal_tuple(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_literal_tuple();

			




	
	
	
		
 

			




	
	
	
		
 
        let element_indices = self.index_buffer.start_section_initialized(&rule.element_indices);

			




	
	
	
		
 

			




	
	
	
		
 
        // Check if we need to apply the initial tuple template type. Note that

			




	
	
	
		
 
        // this is a hacky check.

			




	
	
	
		
 
        let num_tuple_elements = rule.element_indices.len();

			




	
	
	
		
 
        let mut template_type = Vec::with_capacity(num_tuple_elements + 1); // TODO: @performance

			




	
	
	
		
 
        template_type.push(InferenceTypePart::Tuple(num_tuple_elements as u32));

			




	
	
	
		
 
        for _ in 0..num_tuple_elements {

			




	
	
	
		
 
            template_type.push(InferenceTypePart::Unknown);

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        let mut progress_literal = self.apply_template_constraint(ctx, node_index, &template_type)?;

			




	
	
	
		
 

			




	
	
	
		
 
        // Because of the (early returning error) check above, we're certain

			




	
	
	
		
 
        // that the tuple has the correct number of elements. Now match each

			




	
	
	
		
 
        // element expression type to the tuple subtype.

			




	
	
	
		
 
        let mut element_subtree_start_index = 1; // first element is InferenceTypePart::Tuple

			




	
	
	
		
 
        for element_node_index in element_indices.iter_copied() {

			




	
	
	
		
 
            let (progress_literal_element, progress_element) = self.apply_equal2_constraint(

			




	
	
	
		
 
                ctx, node_index, node_index, element_subtree_start_index, element_node_index, 0

			




	
	
	
		
 
            )?;

			




	
	
	
		
 

			




	
	
	
		
 
            progress_literal = progress_literal || progress_literal_element;

			




	
	
	
		
 
            if progress_element {

			




	
	
	
		
 
                self.queue_node(element_node_index);

			




	
	
	
		
 
            }

			




	
	
	
		
 

			




	
	
	
		
 
            // Prepare for next element

			




	
	
	
		
 
            let subtree_end_index = InferenceType::find_subtree_end_idx(&node.expr_type.parts, element_subtree_start_index);

			




	
	
	
		
 
            element_subtree_start_index = subtree_end_index;

			




	
	
	
		
 
        }

			




	
	
	
		
 
        debug_assert_eq!(element_subtree_end_index, node.expr_type.parts.len());

			




	
	
	
		
 

			




	
	
	
		
 
        if progress_literal { self.queue_node_parent(node_index); }

			




	
	
	
		
 

			




	
	
	
		
 
        element_indices.forget();

			




	
	
	
		
 
        return Ok(());

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_cast_expr(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_cast_expr();

			




	
	
	
		
 
        let subject_index = rule.subject_index;

			




	
	
	
		
 
        let subject = &self.infer_nodes[subject_index];

			




	
	
	
		
 

			




	
	
	
		
 
        // Make sure that both types are completely done. Note: a cast

			




	
	
	
		
 
        // expression cannot really infer anything between the subject and the

			




	
	
	
		
 
        // output type, we can only make sure that, at the end, the cast is

			




	
	
	
		
 
        // correct.

			




	
	
	
		
 
        if !node.expr_type.is_done || !subject.expr_type.is_done {

			




	
	
	
		
 
            return Ok(());

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        // Both types are known, currently the only valid casts are bool,

			




	
	
	
		
 
        // integer and character casts.

			




	
	
	
		
 
        fn is_bool_int_or_char(parts: &[InferenceTypePart]) -> bool {

			




	
	
	
		
 
            let mut index = 0;

			




	
	
	
		
 
            while index < parts.len() {

			




	
	
	
		
 
                let part = &parts[index];

			




	
	
	
		
 
                if !part.is_marker() { break; }

			




	
	
	
		
 
                index += 1;

			




	
	
	
		
 
            }

			




	
	
	
		
 

			




	
	
	
		
 
            debug_assert!(index != parts.len());

			




	
	
	
		
 
            let part = &parts[index];

			




	
	
	
		
 
            if (

			




	
	
	
		
 
                *part == InferenceTypePart::Bool ||

			




	
	
	
		
 
                *part == InferenceTypePart::Character ||

			




	
	
	
		
 
                part.is_concrete_integer()

			




	
	
	
		
 
            ) {

			




	
	
	
		
 
                debug_assert!(index + 1 == parts.len()); // type is done, first part does not have children -> must be at end

			




	
	
	
		
 
                return true;

			




	
	
	
		
 
            } else {

			




	
	
	
		
 
                return false;

			




	
	
	
		
 
            }

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        let is_valid = if is_bool_int_or_char(&node.expr_type.parts) && is_bool_int_or_char(&subject.expr_type.parts) {

			




	
	
	
		
 
            true

			




	
	
	
		
 
        } else if InferenceType::check_subtrees(&node.expr_type.parts, 0, &subject.expr_type.parts, 0) {

			




	
	
	
		
 
            // again: check_subtrees is sufficient since both types are done

			




	
	
	
		
 
            true

			




	
	
	
		
 
        } else {

			




	
	
	
		
 
            false

			




	
	
	
		
 
        };

			




	
	
	
		
 

			




	
	
	
		
 
        if !is_valid {

			




	
	
	
		
 
            let cast_expr = &ctx.heap[node.expr_id];

			




	
	
	
		
 
            let subject_expr = &ctx.heap[subject.expr_id];

			




	
	
	
		
 
            return Err(ParseError::new_error_str_at_span(

			




	
	
	
		
 
                &ctx.module().source, cast_expr.full_span(), "invalid casting operation"

			




	
	
	
		
 
            ).with_info_at_span(

			




	
	
	
		
 
                &ctx.module.source, subject_expr.full_span(), format!(

			




	
	
	
		
 
                    "cannot cast the argument type '{}' to the type '{}'",

			




	
	
	
		
 
                    subject.expr_type.display_name(&ctx.heap),

			




	
	
	
		
 
                    node.expr_type.display_name(&ctx.heap)

			




	
	
	
		
 
                )

			




	
	
	
		
 
            ));

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        return Ok(())

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_call_expr(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_call_expr();

			




	
	
	
		
 

			




	
	
	
		
 
        let mut poly_progress_section = self.poly_progress_buffer.start_section();

			




	
	
	
		
 
        let argument_node_indices = self.index_buffer.start_section_initialized(&rule.argument_indices);

			




	
	
	
		
 

			




	
	
	
		
 
        // Perform inference on arguments to function, while trying to figure

			




	
	
	
		
 
        // out the polymorphic variables

			




	
	
	
		
 
        for (argument_index, argument_node_index) in argument_node_indices.iter_copied().enumerate() {

			




	
	
	
		
 
            let argument_expr_id = self.infer_nodes[argument_node_index].expr_id;

			




	
	
	
		
 
            let (_, progress_argument) = self.apply_polydata_equal2_constraint(

			




	
	
	
		
 
                ctx, node_index, argument_expr_id, "argument's",

			




	
	
	
		
 
                PolyDataTypeIndex::Associated(argument_index), 0,

			




	
	
	
		
 
                argument_node_index, 0, &mut poly_progress_section

			




	
	
	
		
 
            )?;

			




	
	
	
		
 

			




	
	
	
		
 
            if progress_argument { self.queue_node(argument_node_index); }

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        // Same for the return type.

			




	
	
	
		
 
        let call_expr_id = node.expr_id;

			




	
	
	
		
 
        let (_, progress_call_1) = self.apply_polydata_equal2_constraint(

			




	
	
	
		
 
            ctx, node_index, call_expr_id, "return",

			




	
	
	
		
 
            PolyDataTypeIndex::Returned, 0,

			




	
	
	
		
 
            node_index, 0, &mut poly_progress_section

			




	
	
	
		
 
        )?;

			




	
	
	
		
 

			




	
	
	
		
 
        // We will now apply any progression in the polymorphic variable type

			




	
	
	
		
 
        // back to the arguments.

			




	
	
	
		
 
        for (argument_index, argument_node_index) in argument_node_indices.iter_copied().enumerate() {

			




	
	
	
		
 
            let progress_argument = self.apply_polydata_polyvar_constraint(

			




	
	
	
		
 
                ctx, node_index, PolyDataTypeIndex::Associated(argument_index),

			




	
	
	
		
 
                argument_node_index, &poly_progress_section

			




	
	
	
		
 
            );

			




	
	
	
		
 

			




	
	
	
		
 
            if progress_argument { self.queue_node(argument_node_index); }

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        // And back to the return type.

			




	
	
	
		
 
        let progress_call_2 = self.apply_polydata_polyvar_constraint(

			




	
	
	
		
 
            ctx, node_index, PolyDataTypeIndex::Returned,

			




	
	
	
		
 
            node_index, &poly_progress_section

			




	
	
	
		
 
        );

			




	
	
	
		
 

			




	
	
	
		
 
        if progress_call_1 || progress_call_2 { self.queue_node_parent(node_index); }

			




	
	
	
		
 

			




	
	
	
		
 
        poly_progress_section.forget();

			




	
	
	
		
 
        argument_node_indices.forget();

			




	
	
	
		
 

			




	
	
	
		
 
        self.finish_polydata_constraint(node_index);

			




	
	
	
		
 
        return Ok(())

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_inference_rule_variable_expr(&mut self, ctx: &Ctx, node_index: InferNodeIndex) -> Result<(), ParseError> {

			




	
	
	
		
 
        let node = &mut self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_variable_expr();

			




	
	
	
		
 
        let var_data_index = rule.var_data_index;

			




	
	
	
		
 
        let var_data = &mut self.var_data[var_data_index];

			




	
	
	
		
 

			




	
	
	
		
 
        // Apply inference to the shared variable type and the expression type

			




	
	
	
		
 
        let shared_type: *mut _ = &mut var_data.var_type;

			




	
	
	
		
 
        let expr_type: *mut _ = &mut node.expr_type;

			




	
	
	
		
 

			




	
	
	
		
 
        let inference_result = unsafe {

			




	
	
	
		
 
            // safety: vectors exist in different storage vectors, so cannot alias

			




	
	
	
		
 
            InferenceType::infer_subtrees_for_both_types(shared_type, 0, expr_type, 0)

			




	
	
	
		
 
        };

			




	
	
	
		
 

			




	
	
	
		
 
        if inference_result == DualInferenceResult::Incompatible {

			




	
	
	
		
 
            return Err(self.construct_variable_type_error(ctx, node_index));

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        let progress_var_data = inference_result.modified_lhs();

			




	
	
	
		
 
        let progress_expr = inference_result.modified_rhs();

			




	
	
	
		
 

			




	
	
	
		
 
        if progress_var_data {

			




	
	
	
		
 
            // We progressed the type of the shared variable, so propagate this

			




	
	
	
		
 
            // to all associated variable expressions (and relatived variables).

			




	
	
	
		
 
            for other_node_index in var_data.used_at.iter().copied() {

			




	
	
	
		
 
                if other_node_index != node_index {

			




	
	
	
		
 
                    self.queue_node(other_node_index);

			




	
	
	
		
 
                }

			




	
	
	
		
 
            }

			




	
	
	
		
 

			




	
	
	
		
 
            if let Some(linked_var_data_index) = var_data.linked_var {

			




	
	
	
		
 
                // Only perform one-way inference, progressing the linked

			




	
	
	
		
 
                // variable.

			




	
	
	
		
 
                // note: because this "linking" is used only for channels, we

			




	
	
	
		
 
                // will start inference one level below the top-level in the

			




	
	
	
		
 
                // type tree (i.e. ensure `T` in `in<T>` and `out<T>` is equal).

			




	
	
	
		
 
                debug_assert!(

			




	
	
	
		
 
                    var_data.var_type.parts[0] == InferenceTypePart::Input ||

			




	
	
	
		
 
                    var_data.var_type.parts[0] == InferenceTypePart::Output

			




	
	
	
		
 
                );

			




	
	
	
		
 
                let this_var_type: *const _ = &var_data.var_type;

			




	
	
	
		
 
                let linked_var_data = &mut self.var_data[linked_var_data_index];

			




	
	
	
		
 
                debug_assert!(

			




	
	
	
		
 
                    linked_var_data.var_type.parts[0] == InferenceTypePart::Input ||

			




	
	
	
		
 
                    linked_var_data.var_type.parts[0] == InferenceTypePart::Output

			




	
	
	
		
 
                );

			




	
	
	
		
 

			




	
	
	
		
 
                // safety: by construction var_data_index and linked_var_data_index cannot be the

			




	
	
	
		
 
                // same, hence we're not aliasing here.

			




	
	
	
		
 
                let inference_result = InferenceType::infer_subtree_for_single_type(

			




	
	
	
		
 
                    &mut linked_var_data.var_type, 1,

			




	
	
	
		
 
                    unsafe{ &(*this_var_type).parts }, 1, false

			




	
	
	
		
 
                );

			




	
	
	
		
 
                match inference_result {

			




	
	
	
		
 
                    SingleInferenceResult::Modified => {

			




	
	
	
		
 
                        for used_at in linked_var_data.used_at.iter().copied() {

			




	
	
	
		
 
                            self.queue_node(used_at);

			




	
	
	
		
 
                        }

			




	
	
	
		
 
                    },

			




	
	
	
		
 
                    SingleInferenceResult::Unmodified => {},

			




	
	
	
		
 
                    SingleInferenceResult::Incompatible => {

			




	
	
	
		
 
                        let var_data_this = &self.var_data[var_data_index];

			




	
	
	
		
 
                        let var_decl_this = &ctx.heap[var_data_this.var_id];

			




	
	
	
		
 
                        let var_data_linked = &self.var_data[linked_var_data_index];

			




	
	
	
		
 
                        let var_decl_linked = &ctx.heap[var_data_linked.var_id];

			




	
	
	
		
 

			




	
	
	
		
 
                        return Err(ParseError::new_error_at_span(

			




	
	
	
		
 
                            &ctx.module().source, var_decl_this.identifier.span, format!(

			




	
	
	
		
 
                                "conflicting types for this channel, this port has type '{}'",

			




	
	
	
		
 
                                var_data_this.var_type.display_name(&ctx.heap)

			




	
	
	
		
 
                            )

			




	
	
	
		
 
                        ).with_info_at_span(

			




	
	
	
		
 
                            &ctx.module().source, var_decl_linked.identifier.span, format!(

			




	
	
	
		
 
                                "while this port has type '{}'",

			




	
	
	
		
 
                                var_data_linked.var_type.display_name(&ctx.heap)

			




	
	
	
		
 
                            )

			




	
	
	
		
 
                        ));

			




	
	
	
		
 
                    }

			




	
	
	
		
 
                }

			




	
	
	
		
 
            }

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        if progress_expr { self.queue_node_parent(node_index); }

			




	
	
	
		
 

			




	
	
	
		
 
        return Ok(());

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn progress_template(&mut self, ctx: &Ctx, node_index: InferNodeIndex, application: InferenceRuleTemplateApplication, template: &[InferenceTypePart]) -> Result<bool, ParseError> {

			




	
	
	
		
 
        use InferenceRuleTemplateApplication as TA;

			




	
	
	
		
 

			




	
	
	
		
 
        match application {

			




	
	
		
 
@@ -4008,13 +4368,13 @@ impl PassTyping {

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    /// Applies an equal2 constraint between a member of the `PolyData` struct,

			




	
	
	
		
 
    /// and another inferred type. If any progress is made in the `PolyData`

			




	
	
	
		
 
    /// struct then the affected polymorphic variables are updated as well.

			




	
	
	
		
 
    ///

			




	
	
	
		
 
    /// Because a lot of types/expressions are involved in polymorphic type

			




	
	
	
		
 
    /// Because a lot of types/expressions are involved in polymorphic typFe

			




	
	
	
		
 
    /// inference, some explanation: "outer_node" refers to the main expression

			




	
	
	
		
 
    /// that is the root cause of type inference (e.g. a struct literal

			




	
	
	
		
 
    /// expression, or a tuple member select expression). Associated with that

			




	
	
	
		
 
    /// outer node is `PolyData`, so that is what the "poly_data" variables

			




	
	
	
		
 
    /// are referring to. We are applying equality between a "poly_data" type

			




	
	
	
		
 
    /// and an associated expression (not necessarily the "outer_node", e.g.

			




	
	
		
 
@@ -4121,20 +4481,27 @@ impl PassTyping {

			




	
	
	
		
 
        outer_node_index: InferNodeIndex, poly_data_type_index: PolyDataTypeIndex,

			




	
	
	
		
 
        associated_node_index: InferNodeIndex, poly_progress_section: &ScopedSection<u32>

			




	
	
	
		
 
    ) -> bool {

			




	
	
	
		
 
        let poly_data_index = self.infer_nodes[outer_node_index].poly_data_index;

			




	
	
	
		
 
        let poly_data = &mut self.poly_data[poly_data_index];

			




	
	
	
		
 

			




	
	
	
		
 
        // Early exit, most common case (literals or functions calls which are

			




	
	
	
		
 
        // actually not polymorphic)

			




	
	
	
		
 
        if !poly_data.first_rule_application && poly_progress_section.len() == 0 {

			




	
	
	
		
 
            return false;

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        // safety: we're borrowing from two distinct fields, so should be fine

			




	
	
	
		
 
        let poly_data_type = poly_data.get_type_mut(poly_data_type_index);

			




	
	
	
		
 
        let mut last_start_index = 0;

			




	
	
	
		
 
        let mut modified_poly_type = false;

			




	
	
	
		
 

			




	
	
	
		
 
        while let Some((poly_var_index, poly_var_start_index)) = poly_data_type.find_marker(last_start_index) {

			




	
	
	
		
 
            let poly_var_end_index = InferenceType::find_subtree_end_idx(&poly_data_type.parts, poly_var_start_index);

			




	
	
	
		
 
            if poly_progress_section.contains(&poly_var_index) {

			




	
	
	
		
 

			




	
	
	
		
 
            if poly_data.first_rule_application || poly_progress_section.contains(&poly_var_index) {

			




	
	
	
		
 
                // We have updated this polymorphic variable, so try updating it

			




	
	
	
		
 
                // in the PolyData type

			




	
	
	
		
 
                let modified_in_poly_data = match InferenceType::infer_subtree_for_single_type(

			




	
	
	
		
 
                    poly_data_type, poly_var_start_index, &poly_data.poly_vars[poly_var_index as usize].parts, 0, false

			




	
	
	
		
 
                ) {

			




	
	
	
		
 
                    SingleInferenceResult::Modified => true,

			




	
	
		
 
@@ -4166,12 +4533,20 @@ impl PassTyping {

			




	
	
	
		
 
        } else {

			




	
	
	
		
 
            // Did not update associated type

			




	
	
	
		
 
            return false;

			




	
	
	
		
 
        }

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    /// Should be called after completing one full round of applying polydata

			




	
	
	
		
 
    /// constraints.

			




	
	
	
		
 
    fn finish_polydata_constraint(&mut self, outer_node_index: InferNodeIndex) {

			




	
	
	
		
 
        let poly_data_index = self.infer_nodes[outer_node_index].poly_data_index;

			




	
	
	
		
 
        let poly_data = &mut self.poly_data[poly_data_index];

			




	
	
	
		
 
        poly_data.first_rule_application = false;

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    /// Applies an equal2 constraint between a signature type (e.g. a function

			




	
	
	
		
 
    /// argument or struct field) and an expression whose type should match that

			




	
	
	
		
 
    /// expression. If we make progress on the signature, then we try to see if

			




	
	
	
		
 
    /// any of the embedded polymorphic types can be progressed.

			




	
	
	
		
 
    ///

			




	
	
	
		
 
    /// `outer_expr_id` is the main expression we're progressing (e.g. a 

			




	
	
		
 
@@ -4957,12 +5332,35 @@ impl PassTyping {

			




	
	
	
		
 
                expr_type.display_name(&ctx.heap), 

			




	
	
	
		
 
                InferenceType::partial_display_name(&ctx.heap, template)

			




	
	
	
		
 
            )

			




	
	
	
		
 
        )

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    fn construct_variable_type_error(

			




	
	
	
		
 
        &self, ctx: &Ctx, node_index: InferNodeIndex,

			




	
	
	
		
 
    ) -> ParseError {

			




	
	
	
		
 
        let node = &self.infer_nodes[node_index];

			




	
	
	
		
 
        let rule = node.inference_rule.as_variable_expr();

			




	
	
	
		
 

			




	
	
	
		
 
        let var_data = &self.var_data[rule.var_data_index];

			




	
	
	
		
 
        let var_decl = &ctx.heap[var_data.var_id];

			




	
	
	
		
 
        let var_expr = &ctx.heap[node.expr_id];

			




	
	
	
		
 

			




	
	
	
		
 
        return ParseError::new_error_at_span(

			




	
	
	
		
 
            &ctx.module().source, var_decl.identifier.span, format!(

			




	
	
	
		
 
                "conflicting types for this variable, previously assigned the type '{}'",

			




	
	
	
		
 
                var_data.var_type.display_name(&ctx.heap)

			




	
	
	
		
 
            )

			




	
	
	
		
 
        ).with_info_at_span(

			




	
	
	
		
 
            &ctx.module().source, var_expr.full_span(), format!(

			




	
	
	
		
 
                "but inferred to have incompatible type '{}' here",

			




	
	
	
		
 
                node.expr_type.display_name(&ctx.heap)

			




	
	
	
		
 
            )

			




	
	
	
		
 
        );

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    /// 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.

			




	
	
	
		
 
    ///

			




	
	
		
 
@@ -5191,12 +5589,27 @@ impl PassTyping {

			




	
	
	
		
 
        }

			




	
	
	
		
 

			




	
	
	
		
 
        unreachable!("construct_poly_arg_error without actual error found?")

			




	
	
	
		
 
    }

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
fn get_tuple_size_from_inference_type(inference_type: &InferenceType) -> Result<Option<u32>, ()> {

			




	
	
	
		
 
    for part in &inference_type.parts {

			




	
	
	
		
 
        if part.is_marker() { continue; }

			




	
	
	
		
 
        if !part.is_concrete() { break; }

			




	
	
	
		
 

			




	
	
	
		
 
        if let InferenceTypePart::Tuple(size) = part {

			




	
	
	
		
 
            return Ok(Some(*size));

			




	
	
	
		
 
        } else {

			




	
	
	
		
 
            return Err(()); // not a tuple!

			




	
	
	
		
 
        }

			




	
	
	
		
 
    }

			




	
	
	
		
 

			




	
	
	
		
 
    return Ok(None);

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
#[cfg(test)]

			




	
	
	
		
 
mod tests {

			




	
	
	
		
 
    use super::*;

			




	
	
	
		
 
    use crate::protocol::arena::Id;

			




	
	
	
		
 
    use InferenceTypePart as ITP;

			




	
	
	
		
 
    use InferenceType as IT;

			




        

    



    


    



    



      

      





    
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