Fix disjointness relation for class literals and generic aliases #1842
Description
There are some inconsistencies in our disjointness relation modeling for class literals and generic aliases. They are documented in the failing tests here:
We should fix those tests and probably also increase the test coverage.
If it's helpful, I started to work on this, and this is how far I got:
Diff
diff --git a/crates/ty_python_semantic/src/types.rs b/crates/ty_python_semantic/src/types.rs
index 12a38a8e34..49021d4b08 100644
--- a/crates/ty_python_semantic/src/types.rs
+++ b/crates/ty_python_semantic/src/types.rs
@@ -3347,7 +3347,6 @@ impl<'db> Type<'db> {
| Type::WrapperDescriptor(..)
| Type::ModuleLiteral(..)
| Type::ClassLiteral(..)
- | Type::GenericAlias(..)
| Type::SpecialForm(..)
| Type::KnownInstance(..)),
right @ (Type::BooleanLiteral(..)
@@ -3361,11 +3360,90 @@ impl<'db> Type<'db> {
| Type::WrapperDescriptor(..)
| Type::ModuleLiteral(..)
| Type::ClassLiteral(..)
- | Type::GenericAlias(..)
| Type::SpecialForm(..)
| Type::KnownInstance(..)),
) => ConstraintSet::from(left != right),
+ (
+ Type::GenericAlias(..),
+ Type::BooleanLiteral(..)
+ | Type::IntLiteral(..)
+ | Type::StringLiteral(..)
+ | Type::BytesLiteral(..)
+ | Type::EnumLiteral(..)
+ | Type::FunctionLiteral(..)
+ | Type::BoundMethod(..)
+ | Type::KnownBoundMethod(..)
+ | Type::WrapperDescriptor(..)
+ | Type::ModuleLiteral(..)
+ | Type::SpecialForm(..)
+ | Type::KnownInstance(..),
+ )
+ | (
+ Type::BooleanLiteral(..)
+ | Type::IntLiteral(..)
+ | Type::StringLiteral(..)
+ | Type::BytesLiteral(..)
+ | Type::EnumLiteral(..)
+ | Type::FunctionLiteral(..)
+ | Type::BoundMethod(..)
+ | Type::KnownBoundMethod(..)
+ | Type::WrapperDescriptor(..)
+ | Type::ModuleLiteral(..)
+ | Type::SpecialForm(..)
+ | Type::KnownInstance(..),
+ Type::GenericAlias(..),
+ ) => ConstraintSet::from(false),
+
+ (Type::GenericAlias(left_alias), Type::GenericAlias(right_alias)) => {
+ disjointness_visitor.visit((self, other), || {
+ ConstraintSet::from(left_alias != right_alias).or(db, || {
+ (left_alias
+ .specialization(db)
+ .has_relation_to_impl(
+ db,
+ right_alias.specialization(db),
+ InferableTypeVars::None,
+ TypeRelation::Assignability,
+ relation_visitor,
+ disjointness_visitor,
+ )
+ .negate(db))
+ .and(db, || {
+ right_alias
+ .specialization(db)
+ .has_relation_to_impl(
+ db,
+ left_alias.specialization(db),
+ InferableTypeVars::None,
+ TypeRelation::Assignability,
+ relation_visitor,
+ disjointness_visitor,
+ )
+ .negate(db)
+ })
+ })
+ })
+ }
+
+ (Type::ClassLiteral(class_literal), Type::GenericAlias(alias))
+ | (Type::GenericAlias(alias), Type::ClassLiteral(class_literal)) => {
+ disjointness_visitor.visit((self, other), || {
+ class_literal
+ .default_specialization(db)
+ .into_generic_alias()
+ .when_none_or(|other_alias| {
+ Type::GenericAlias(other_alias).is_disjoint_from_impl(
+ db,
+ Type::GenericAlias(alias),
+ inferable,
+ disjointness_visitor,
+ relation_visitor,
+ )
+ })
+ })
+ }
+
(
Type::SubclassOf(_),
Type::BooleanLiteral(..)