[ty] Reduce false positives for TypedDict types (#19354)

crates/ty_python_semantic/resources/mdtest/narrow/assignment.md

@@ -245,7 +245,7 @@ class D(TypedDict):
 td = D(x=1, label="a")
 td["x"] = 0
 # TODO: should be Literal[0]
-reveal_type(td["x"])  # revealed: @Todo(TypedDict)
+reveal_type(td["x"])  # revealed: @Todo(Support for `TypedDict`)
 
 # error: [unresolved-reference]
 does["not"]["exist"] = 0

crates/ty_python_semantic/resources/mdtest/typed_dict.md

@@ -10,8 +10,6 @@ class Person(TypedDict):
     name: str
     age: int | None
 
-# TODO: This should not be an error:
-# error: [invalid-assignment]
 alice: Person = {"name": "Alice", "age": 30}
 
 # Alternative syntax
@@ -22,6 +20,6 @@ msg = Message(id=1, content="Hello")
 # No errors for yet-unsupported features (`closed`):
 OtherMessage = TypedDict("OtherMessage", {"id": int, "content": str}, closed=True)
 
-reveal_type(Person.__required_keys__)  # revealed: @Todo(TypedDict)
+reveal_type(Person.__required_keys__)  # revealed: @Todo(Support for `TypedDict`)
-reveal_type(Message.__required_keys__)  # revealed: @Todo(TypedDict)
+reveal_type(Message.__required_keys__)  # revealed: @Todo(Support for `TypedDict`)
 ```

crates/ty_python_semantic/src/types.rs

@@ -5880,6 +5880,9 @@ pub enum DynamicType {
     /// A special Todo-variant for type aliases declared using `typing.TypeAlias`.
     /// A temporary variant to detect and special-case the handling of these aliases in autocomplete suggestions.
     TodoTypeAlias,
+    /// A special Todo-variant for classes inheriting from `TypedDict`.
+    /// A temporary variant to avoid false positives while we wait for full support.
+    TodoTypedDict,
 }
 
 impl DynamicType {
@@ -5911,6 +5914,13 @@ impl std::fmt::Display for DynamicType {
                     f.write_str("@Todo")
                 }
             }
+            DynamicType::TodoTypedDict => {
+                if cfg!(debug_assertions) {
+                    f.write_str("@Todo(Support for `TypedDict`)")
+                } else {
+                    f.write_str("@Todo")
+                }
+            }
         }
     }
 }

crates/ty_python_semantic/src/types/call/bind.rs

@@ -985,7 +985,7 @@ impl<'db> Bindings<'db> {
                     },
 
                     Type::SpecialForm(SpecialFormType::TypedDict) => {
-                        overload.set_return_type(todo_type!("TypedDict"));
+                        overload.set_return_type(todo_type!("Support for `TypedDict`"));
                     }
 
                     // Not a special case

crates/ty_python_semantic/src/types/class.rs

@@ -21,7 +21,7 @@ use crate::types::signatures::{CallableSignature, Parameter, Parameters, Signatu
 use crate::types::tuple::TupleType;
 use crate::types::{
     BareTypeAliasType, Binding, BoundSuperError, BoundSuperType, CallableType, DataclassParams,
-    KnownInstanceType, TypeAliasType, TypeMapping, TypeRelation, TypeTransformer,
+    DynamicType, KnownInstanceType, TypeAliasType, TypeMapping, TypeRelation, TypeTransformer,
     TypeVarBoundOrConstraints, TypeVarInstance, TypeVarKind, infer_definition_types,
 };
 use crate::{
@@ -415,6 +415,15 @@ impl<'db> ClassType<'db> {
         other: Self,
         relation: TypeRelation,
     ) -> bool {
+        // TODO: remove this branch once we have proper support for TypedDicts.
+        if self.is_known(db, KnownClass::Dict)
+            && other
+                .iter_mro(db)
+                .any(|b| matches!(b, ClassBase::Dynamic(DynamicType::TodoTypedDict)))
+        {
+            return true;
+        }
+
         self.iter_mro(db).any(|base| {
             match base {
                 ClassBase::Dynamic(_) => match relation {

crates/ty_python_semantic/src/types/class_base.rs

@@ -51,7 +51,8 @@ impl<'db> ClassBase<'db> {
             ClassBase::Dynamic(
                 DynamicType::Todo(_)
                 | DynamicType::TodoPEP695ParamSpec
-                | DynamicType::TodoTypeAlias,
+                | DynamicType::TodoTypeAlias
+                | DynamicType::TodoTypedDict,
             ) => "@Todo",
             ClassBase::Protocol => "Protocol",
             ClassBase::Generic => "Generic",
@@ -229,7 +230,7 @@ impl<'db> ClassBase<'db> {
                 SpecialFormType::OrderedDict => {
                     Self::try_from_type(db, KnownClass::OrderedDict.to_class_literal(db))
                 }
-                SpecialFormType::TypedDict => Self::try_from_type(db, todo_type!("TypedDict")),
+                SpecialFormType::TypedDict => Some(Self::Dynamic(DynamicType::TodoTypedDict)),
                 SpecialFormType::Callable => {
                     Self::try_from_type(db, todo_type!("Support for Callable as a base class"))
                 }

crates/ty_python_semantic/src/types/infer.rs

@@ -6508,7 +6508,8 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                 todo @ Type::Dynamic(
                     DynamicType::Todo(_)
                     | DynamicType::TodoPEP695ParamSpec
-                    | DynamicType::TodoTypeAlias,
+                    | DynamicType::TodoTypeAlias
+                    | DynamicType::TodoTypedDict,
                 ),
                 _,
                 _,
@@ -6518,7 +6519,8 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                 todo @ Type::Dynamic(
                     DynamicType::Todo(_)
                     | DynamicType::TodoPEP695ParamSpec
-                    | DynamicType::TodoTypeAlias,
+                    | DynamicType::TodoTypeAlias
+                    | DynamicType::TodoTypedDict,
                 ),
                 _,
             ) => Some(todo),

crates/ty_python_semantic/src/types/type_ordering.rs

@@ -253,6 +253,9 @@ fn dynamic_elements_ordering(left: DynamicType, right: DynamicType) -> Ordering
 
         (DynamicType::TodoTypeAlias, _) => Ordering::Less,
         (_, DynamicType::TodoTypeAlias) => Ordering::Greater,
+
+        (DynamicType::TodoTypedDict, _) => Ordering::Less,
+        (_, DynamicType::TodoTypedDict) => Ordering::Greater,
     }
 }