Crate tsz_solver

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Query-Based Structural Solver

This module implements a declarative, query-based type solver architecture. It uses:

Ena: For unification (Union-Find) in generic type inference
Custom TypeData: Structural type representation with interning
Cycle Detection: Coinductive semantics for recursive types

Key benefits:

O(1) type equality via interning (TypeId comparison)
Automatic cycle handling via coinductive semantics
Lazy evaluation - only compute types that are queried

Re-exports§

pub use operations::infer_generic_function;
pub use operations::widening;
pub use operations::compound_assignment;
pub use operations::expression_ops;
pub use operations::AssignabilityChecker;
pub use operations::BinaryOpEvaluator;
pub use operations::BinaryOpResult;
pub use operations::CallEvaluator;
pub use operations::CallResult;
pub use operations::MAX_CONSTRAINT_RECURSION_DEPTH;
pub use operations::PrimitiveClass;
pub use operations::get_contextual_signature_with_compat_checker;
pub use relations::subtype::TypeEnvironment;
pub use relations::subtype::TypeResolver;
pub use types::CallSignature;
pub use types::CallableShapeId;
pub use types::IntrinsicKind;
pub use types::LiteralValue;
pub use types::MappedModifier;
pub use types::ObjectShapeId;
pub use types::PropertyInfo;
pub use types::PropertyLookup;
pub use types::SymbolRef;
pub use types::TypeApplication;
pub use types::TypeApplicationId;
pub use types::TypeData;
pub use types::TypeId;
pub use types::TypeListId;
pub use types::Visibility;
pub use types::is_compiler_managed_type;
pub use types::CallableShape;
pub use types::ConditionalType;
pub use types::FunctionShape;
pub use types::FunctionShapeId;
pub use types::IndexSignature;
pub use types::MappedType;
pub use types::MappedTypeId;
pub use types::ObjectFlags;
pub use types::ObjectShape;
pub use types::OrderedFloat;
pub use types::ParamInfo;
pub use types::RelationCacheKey;
pub use types::TemplateSpan;
pub use types::TupleElement;
pub use types::TupleListId;
pub use types::TypeParamInfo;
pub use types::TypePredicate;
pub use types::TypePredicateTarget;
pub use canonicalize::*;
pub use classes::class_hierarchy::*;
pub use classes::inheritance::*;
pub use def::*;
pub use objects::*;
pub use operations::compound_assignment::*;
pub use operations::expression_ops::*;
pub use unsoundness_audit::*;
pub use widening::*;

Modules§

canonicalize: Canonicalization for structural type identity (Task #32: Graph Isomorphism)
classes: Class hierarchy and inheritance graph.
def: Definition identifiers and storage for the solver.
evaluation
judge
objects: Object property query ecosystem.
operations: Type operations and expression evaluation.
recursion: Unified recursion guard for cycle detection, depth limiting, and iteration bounding in recursive type computations.
relations
type_queries: Type Query Functions
type_resolver: Type resolution trait and environment.
types: Type representation for the structural solver.
unsoundness_audit: TypeScript Unsoundness Catalog Implementation Audit
utils: Shared utility functions for the solver module.
visitor

Structs§

AnyPropagationRules: Rules for any propagation in type checking.
ApplicationEvaluator: Evaluator for generic type applications.
AssignabilityFailureAnalysis: Structured failure details for assignability diagnostics.
CompatChecker: Compatibility checker that applies TypeScript’s unsound rules before delegating to the structural subtype engine.
ConstAssertionVisitor: Visitor that applies as const transformation to a type.
ConstraintSet: Constraint set for an inference variable. Tracks both lower bounds (L <: α) and upper bounds (α <: U).
ContextualTypeContext: Context for contextual typing. Holds the expected type and provides methods to extract type information.
DefaultJudge: Default implementation of the Judge trait.
DiagnosticBuilder: Builder for creating type error diagnostics.
DiagnosticCollector: A diagnostic collector that accumulates diagnostics with source tracking.
DiscriminantInfo: Result of finding discriminant properties in a union.
InferenceCandidate: A candidate type for an inference variable.
InferenceContext: Type inference context for a single function call or expression.
InferenceInfo: Value stored for each inference variable root.
InferenceVar: An inference variable representing an unknown type. These are created when instantiating generic functions.
JudgeConfig: Configuration options for the Judge.
NarrowingCache: Narrowing context for type guards and control flow analysis. Shared across multiple narrowing contexts to persist resolution results.
NarrowingContext: Narrowing context for type guards and control flow analysis.
NarrowingResult: Result of a narrowing operation.
NoopOverrideProvider: A no-op implementation of AssignabilityOverrideProvider for when no checker context is available.
PendingDiagnostic: A pending diagnostic that hasn’t been rendered yet.
PendingDiagnosticBuilder: Builder for creating lazy pending diagnostics.
PrimitiveFlags: Flags indicating primitive-like behavior.
QueryCache: Query database wrapper with basic caching.
RecursiveTypeCollector: A visitor that recursively collects all types referenced by a root type. Unlike TypeCollectorVisitor, this properly traverses into nested structures.
RelationCacheStats
RelationContext: Optional shared context needed by relation engines.
RelationPolicy: Policy knobs for relation checks.
RelationQueryInputs: Bundled inputs for relation queries.
RelationResult: Result of a relation check.
SourceLocation: Tracks source locations for AST nodes during type checking.
SourceSpan: A source location span.
SpannedDiagnosticBuilder: A diagnostic builder that automatically attaches source spans.
SubtypeChecker: Subtype checking context. Maintains the “seen” set for cycle detection.
TypeCollectorVisitor: Visitor that collects all TypeIds referenced by a type.
TypeEvaluator: Type evaluator for meta-types.
TypeFactory
TypeFormatter: Context for generating type strings.
TypeInstantiator: Instantiator for applying type substitutions.
TypeInterner: Type interning table with lock-free concurrent access.
TypeKindVisitor: Visitor that checks if a type is a specific TypeKind.
TypePredicateVisitor: Visitor that checks if a type matches a specific predicate.
TypeSubstitution: A substitution map from type parameter names to concrete types.

Enums§

AnyPropagationMode: Controls how any is treated during subtype checks.
ApplicationResult: Result of application type evaluation.
CallableKind: Classification of how a type can be called.
ConditionalResult: Result of conditional type evaluation
ConstraintConflict: Conflict detected between constraints on an inference variable.
DiagnosticArg: Argument for a diagnostic message template.
DiagnosticSeverity: Diagnostic severity level.
InferenceError: Inference error
IterableKind: Classification of how a type can be iterated.
ObjectTypeKind: Classification of object types for freshness tracking.
PropertyResult: Property access result from the Judge.
RelationCacheProbe
RelationKind: Relation categories supported by the unified query API.
SubtypeFailureReason: Detailed reason for a subtype check failure.
SubtypeResult: Result of a subtype check
TruthinessKind: Classification of a type’s truthiness behavior.
TypeGuard: AST-agnostic representation of a type narrowing condition.
TypeKind: Classification of types into broad categories.
TypeofKind: The result of a typeof expression, restricted to the 8 standard JavaScript types.

Constants§

ARRAY_METHODS_RETURN_ANY: Array methods that return any (used for apparent type computation).
ARRAY_METHODS_RETURN_BOOLEAN: Array methods that return boolean.
ARRAY_METHODS_RETURN_NUMBER: Array methods that return number.
ARRAY_METHODS_RETURN_STRING: Array methods that return string.
ARRAY_METHODS_RETURN_VOID: Array methods that return void.
MAX_CONSTRAINT_ITERATIONS: Maximum iterations for constraint strengthening loops to prevent infinite loops.
MAX_INSTANTIATION_DEPTH: Maximum depth for recursive type instantiation.
MAX_TYPE_RECURSION_DEPTH: Maximum recursion depth for type containment checks.
MAX_VISITING_SET_SIZE: Maximum number of unique types to track in the visiting set. Prevents unbounded memory growth in pathological cases.

Traits§

AssignabilityOverrideProvider: Trait for providing checker-specific assignability overrides.
Judge: The Judge trait: pure type algebra queries.
QueryDatabase: Query layer for higher-level solver operations.
TypeDatabase: Query interface for the solver.
TypeVisitor: Visitor pattern for TypeData traversal and transformation.

Functions§

analyze_assignability_failure_with_resolver: Analyze assignability failure details using a configured compat checker.
application_id: Extract the application id if this is a generic application type.
apply_contextual_type: Apply contextual type to infer a more specific type.
are_types_structurally_identical: Check if two types are structurally identical using De Bruijn indices for cycles.
array_element_type: Extract the array element type if this is an array type.
bound_parameter_index: Extract the De Bruijn index if this is a bound type parameter.
callable_shape_id: Extract the callable shape id if this is a callable type.
classify_object_type: Classify a type as an object type kind.
collect_all_types: Collect all types recursively reachable from a root type.
collect_enum_def_ids: Collect all unique enum DefIds reachable from root.
collect_infer_bindings: Recursively walk the type graph and collect all Infer type bindings.
collect_lazy_def_ids: Collect all unique lazy DefIds reachable from root.
collect_referenced_types: Collect all types referenced by a type.
collect_type_queries: Collect all unique type-query symbol references reachable from root.
conditional_type_id: Extract the conditional type id if this is a conditional type.
contains_error_type: Check if a type contains the error type.
contains_infer_types: Check if a type contains any infer types.
contains_this_type: Check if a type contains the this type anywhere.
contains_type_matching: Check if a type contains any type matching a predicate.
contains_type_parameters: Check if a type contains any type parameters.
enum_components: Extract the enum components (DefId and member type) if this is an Enum type.
evaluate_conditional: Convenience function for evaluating conditional types
evaluate_index_access: Convenience function for evaluating index access types
evaluate_index_access_with_options: Convenience function for evaluating index access types with options.
evaluate_keyof: Convenience function for evaluating keyof types
evaluate_mapped: Convenience function for evaluating mapped types
evaluate_type: Convenience function for full type evaluation
find_discriminants: Convenience function for finding discriminants.
for_each_child: Invoke a function on each immediate child TypeId of a TypeData.
for_each_child_by_id: Walk all transitively referenced type IDs from root.
function_shape_id: Extract the function shape id if this is a function type.
index_access_parts: Extract index access components if this is an index access type.
instantiate_type: Convenience function for instantiating a type with a substitution.
intersection_list_id: Extract the intersection list id if this is an intersection type.
intrinsic_kind: Extract the intrinsic kind if this is an intrinsic type.
is_array_type: Check if a type is an array type.
is_conditional_type: Check if a type is a conditional type.
is_definitely_nullish: Check if a type is definitely nullish (only null/undefined/void).
is_empty_object_type: Check if a type is an empty object type (no properties, no index signatures).
is_empty_object_type_db: Check if a type is an empty object type (TypeDatabase version).
is_enum_type: Check if this is an Enum type.
is_error_type: Check whether this is an explicit error type.
is_function_type: Check if a type is a function type (Function or Callable).
is_function_type_db: Check if a type is a function type (TypeDatabase version).
is_generic_application: Check if a type is a generic type application.
is_identity_comparable_type: Check if a type can be compared by TypeId identity alone (O(1) equality).
is_index_access_type: Check if a type is an index access type.
is_intersection_type: Check if a type is an intersection type.
is_literal_type: Check if a type is a literal type.
is_literal_type_db: Check if a type is a literal type (TypeDatabase version).
is_mapped_type: Check if a type is a mapped type.
is_module_namespace_type: Check if a type is a module namespace type (import * as ns).
is_nullish_type: Check if a type is nullish (null/undefined/void or union containing them).
is_object_like_type: Check if a type is an object-like type (suitable for typeof “object”).
is_object_like_type_db: Check if a type is object-like (TypeDatabase version).
is_primitive_type: Check if a type is a primitive type (intrinsic or literal).
is_subtype_of: Convenience function for one-off subtype checks (without resolver)
is_template_literal_type: Check if a type is a template literal type.
is_this_type: Check if a type is the special this type.
is_tuple_type: Check if a type is a tuple type.
is_type_kind: Check if a type is a specific kind using the TypeKindVisitor.
is_type_parameter: Check if a type is a type parameter.
is_type_reference: Check if a type is a type reference (Lazy/DefId).
is_union_type: Check if a type is a union type.
keyof_inner_type: Extract the inner type if this is a keyof type.
lazy_def_id: Extract the lazy DefId if this is a Lazy type.
literal_number: Extract the numeric literal if this is a number literal type.
literal_string: Extract the string literal atom if this is a string literal type.
literal_value: Extract the literal value if this is a literal type.
mapped_type_id: Extract the mapped type id if this is a mapped type.
module_namespace_symbol_ref: Extract the module namespace symbol ref if this is a module namespace type.
narrow_by_discriminant: Convenience function for narrowing by discriminant.
narrow_by_typeof: Convenience function for typeof narrowing.
no_infer_inner_type: Extract the inner type if this is a NoInfer type.
object_shape_id: Extract the object shape id if this is an object type.
object_with_index_shape_id: Extract the object-with-index shape id if this is an indexed object type.
query_relation: Query a relation using a no-op resolver and no overrides.
query_relation_with_overrides: Query a relation using a custom resolver and checker-provided overrides.
query_relation_with_resolver: Query a relation using a custom resolver and no checker overrides.
readonly_inner_type: Extract the inner type if this is a readonly type.
recursive_index: Extract the De Bruijn index if this is a recursive type reference.
ref_symbol: Extract the type reference symbol if this is a Ref type.
remove_definitely_falsy_types: Remove types that are definitely falsy from a union, without narrowing non-falsy types. This matches TypeScript’s removeDefinitelyFalsyTypes: removes null, undefined, void, false, 0, "", 0n but keeps boolean, string, number, bigint, and object types unchanged.
remove_nullish: Remove nullish parts of a type (non-null assertion).
split_nullish_type: Split a type into its non-nullish part and its nullish cause.
string_intrinsic_components: Extract string intrinsic components if this is a string intrinsic type.
substitute_this_type: Substitute ThisType with a concrete type throughout a type.
template_literal_id: Extract the template literal list id if this is a template literal type.
test_type: Test a type against a predicate function.
tuple_list_id: Extract the tuple list id if this is a tuple type.
type_contains_undefined: Check if a type contains undefined (or void).
type_param_info: Extract the type parameter info if this is a type parameter or infer type.
type_query_symbol: Extract the type query symbol if this is a TypeQuery.
union_list_id: Extract the union list id if this is a union type.
unique_symbol_ref: Extract the unique symbol ref if this is a unique symbol type.
walk_referenced_types: The callback is invoked once per unique reachable type (including root).

Crate tsz_solver

Crate tsz_solver Copy item path

Re-exports§

Modules§

Structs§

Enums§

Constants§

Traits§

Functions§

Crate tsz_solver