[ty] Patch (implicit) Self on fallback types

Author: sharkdp

crates/ty_python_semantic/resources/mdtest/named_tuple.md

@@ -270,16 +270,14 @@ reveal_type(Person._field_defaults)  # revealed: dict[str, Any]
 reveal_type(Person._fields)  # revealed: tuple[str, ...]
 reveal_type(Person._make)  # revealed: bound method <class 'Person'>._make(iterable: Iterable[Any]) -> Person
 reveal_type(Person._asdict)  # revealed: def _asdict(self) -> dict[str, Any]
-reveal_type(Person._replace)  # revealed: def _replace(self, **kwargs: Any) -> Self@_replace
+reveal_type(Person._replace)  # revealed: def _replace(self, **kwargs: Any) -> Person
 
-# TODO: should be `Person` once we support `Self`
-reveal_type(Person._make(("Alice", 42)))  # revealed: Unknown
+reveal_type(Person._make(("Alice", 42)))  # revealed: Person
 
 person = Person("Alice", 42)
 
 reveal_type(person._asdict())  # revealed: dict[str, Any]
-# TODO: should be `Person` once we support `Self`
-reveal_type(person._replace(name="Bob"))  # revealed: Unknown
+reveal_type(person._replace(name="Bob"))  # revealed: Person
 ```
 
 ## `collections.namedtuple`
@@ -355,7 +353,7 @@ class Point(NamedTuple):
 
 reveal_type(Point._make)  # revealed: bound method <class 'Point'>._make(iterable: Iterable[Any]) -> Point
 reveal_type(Point._asdict)  # revealed: def _asdict(self) -> dict[str, Any]
-reveal_type(Point._replace)  # revealed: def _replace(self, **kwargs: Any) -> Self@_replace
+reveal_type(Point._replace)  # revealed: def _replace(self, **kwargs: Any) -> Point
 
 static_assert(is_assignable_to(Point, NamedTuple))
 

crates/ty_python_semantic/src/types/class.rs

@@ -25,12 +25,12 @@ use crate::types::signatures::{CallableSignature, Parameter, Parameters, Signatu
 use crate::types::tuple::{TupleSpec, TupleType};
 use crate::types::typed_dict::typed_dict_params_from_class_def;
 use crate::types::{
-    ApplyTypeMappingVisitor, Binding, BoundSuperError, BoundSuperType, CallableType,
-    DataclassParams, DeprecatedInstance, FindLegacyTypeVarsVisitor, HasRelationToVisitor,
-    IsEquivalentVisitor, KnownInstanceType, ManualPEP695TypeAliasType, MaterializationKind,
-    NormalizedVisitor, PropertyInstanceType, StringLiteralType, TypeAliasType, TypeMapping,
-    TypeRelation, TypeVarBoundOrConstraints, TypeVarInstance, TypeVarKind, TypedDictParams,
-    UnionBuilder, VarianceInferable, declaration_type, infer_definition_types,
+    ApplyTypeMappingVisitor, Binding, BindingContext, BoundSuperError, BoundSuperType,
+    CallableType, DataclassParams, DeprecatedInstance, FindLegacyTypeVarsVisitor,
+    HasRelationToVisitor, IsEquivalentVisitor, KnownInstanceType, ManualPEP695TypeAliasType,
+    MaterializationKind, NormalizedVisitor, PropertyInstanceType, StringLiteralType, TypeAliasType,
+    TypeMapping, TypeRelation, TypeVarBoundOrConstraints, TypeVarInstance, TypeVarKind,
+    TypedDictParams, UnionBuilder, VarianceInferable, declaration_type, infer_definition_types,
 };
 use crate::{
     Db, FxIndexMap, FxOrderSet, Program,
@@ -2257,6 +2257,15 @@ impl<'db> ClassLiteral<'db> {
                     .own_class_member(db, self.generic_context(db), None, name)
                     .place
                     .ignore_possibly_unbound()
+                    .map(|ty| {
+                        ty.apply_type_mapping(
+                            db,
+                            &TypeMapping::BindSelf(Type::instance(
+                                db,
+                                self.unknown_specialization(db),
+                            )),
+                        )
+                    })
             }
             (CodeGeneratorKind::DataclassLike, "__replace__")
                 if Program::get(db).python_version(db) >= PythonVersion::PY313 =>