[red-knot] Fixup a few edge cases regarding type[] (#14918)

crates/red_knot_python_semantic/src/stdlib.rs

@@ -15,6 +15,8 @@ pub(crate) enum CoreStdlibModule {
     TypingExtensions,
     Typing,
     Sys,
+    #[allow(dead_code)]
+    Abc, // currently only used in tests
 }
 
 impl CoreStdlibModule {
@@ -26,6 +28,7 @@ impl CoreStdlibModule {
             Self::Typeshed => "_typeshed",
             Self::TypingExtensions => "typing_extensions",
             Self::Sys => "sys",
+            Self::Abc => "abc",
         }
     }
 

crates/red_knot_python_semantic/src/types.rs

@@ -654,14 +654,19 @@ impl<'db> Type<'db> {
                         },
                     )
             }
-            (Type::ClassLiteral(self_class), Type::SubclassOf(target_class)) => {
-                self_class.class.is_subclass_of_base(db, target_class.base)
-            }
             (
-                Type::Instance(InstanceType { class: self_class }),
+                Type::ClassLiteral(ClassLiteralType { class: self_class }),
-                Type::SubclassOf(target_class),
+                Type::SubclassOf(SubclassOfType {
-            ) if self_class.is_known(db, KnownClass::Type) => {
+                    base: ClassBase::Class(target_class),
-                self_class.is_subclass_of_base(db, target_class.base)
+                }),
+            ) => self_class.is_subclass_of(db, target_class),
+            (
+                Type::Instance(_),
+                Type::SubclassOf(SubclassOfType {
+                    base: ClassBase::Class(target_class),
+                }),
+            ) if target_class.is_known(db, KnownClass::Object) => {
+                self.is_subtype_of(db, KnownClass::Type.to_instance(db))
             }
             (
                 Type::SubclassOf(SubclassOfType {
@@ -928,10 +933,18 @@ impl<'db> Type<'db> {
                 | Type::ClassLiteral(..)),
             ) => left != right,
 
-            (Type::SubclassOf(type_class), Type::ClassLiteral(class_literal))
+            (
-            | (Type::ClassLiteral(class_literal), Type::SubclassOf(type_class)) => {
+                Type::SubclassOf(SubclassOfType {
-                !class_literal.class.is_subclass_of_base(db, type_class.base)
+                    base: ClassBase::Class(class_a),
-            }
+                }),
+                Type::ClassLiteral(ClassLiteralType { class: class_b }),
+            )
+            | (
+                Type::ClassLiteral(ClassLiteralType { class: class_b }),
+                Type::SubclassOf(SubclassOfType {
+                    base: ClassBase::Class(class_a),
+                }),
+            ) => !class_b.is_subclass_of(db, class_a),
             (Type::SubclassOf(_), Type::SubclassOf(_)) => false,
             (Type::SubclassOf(_), Type::Instance(_)) | (Type::Instance(_), Type::SubclassOf(_)) => {
                 false
@@ -2599,11 +2612,7 @@ impl<'db> Class<'db> {
     pub fn is_subclass_of(self, db: &'db dyn Db, other: Class) -> bool {
         // `is_subclass_of` is checking the subtype relation, in which gradual types do not
         // participate, so we should not return `True` if we find `Any/Unknown` in the MRO.
-        self.is_subclass_of_base(db, other)
+        self.iter_mro(db).contains(&ClassBase::Class(other))
-    }
-
-    fn is_subclass_of_base(self, db: &'db dyn Db, other: impl Into<ClassBase<'db>>) -> bool {
-        self.iter_mro(db).contains(&other.into())
     }
 
     /// Return the explicit `metaclass` of this class, if one is defined.
@@ -3038,12 +3047,18 @@ pub(crate) mod tests {
         // BuiltinInstance("str") corresponds to an instance of the builtin `str` class
         BuiltinInstance(&'static str),
         TypingInstance(&'static str),
+        /// Members of the `abc` stdlib module
+        AbcInstance(&'static str),
+        AbcClassLiteral(&'static str),
         TypingLiteral,
         // BuiltinClassLiteral("str") corresponds to the builtin `str` class object itself
         BuiltinClassLiteral(&'static str),
         KnownClassInstance(KnownClass),
         Union(Vec<Ty>),
-        Intersection { pos: Vec<Ty>, neg: Vec<Ty> },
+        Intersection {
+            pos: Vec<Ty>,
+            neg: Vec<Ty>,
+        },
         Tuple(Vec<Ty>),
         SubclassOfAny,
         SubclassOfBuiltinClass(&'static str),
@@ -3063,6 +3078,12 @@ pub(crate) mod tests {
                 Ty::LiteralString => Type::LiteralString,
                 Ty::BytesLiteral(s) => Type::bytes_literal(db, s.as_bytes()),
                 Ty::BuiltinInstance(s) => builtins_symbol(db, s).expect_type().to_instance(db),
+                Ty::AbcInstance(s) => core_module_symbol(db, CoreStdlibModule::Abc, s)
+                    .expect_type()
+                    .to_instance(db),
+                Ty::AbcClassLiteral(s) => {
+                    core_module_symbol(db, CoreStdlibModule::Abc, s).expect_type()
+                }
                 Ty::TypingInstance(s) => typing_symbol(db, s).expect_type().to_instance(db),
                 Ty::TypingLiteral => Type::KnownInstance(KnownInstanceType::Literal),
                 Ty::BuiltinClassLiteral(s) => builtins_symbol(db, s).expect_type(),
@@ -3148,6 +3169,7 @@ pub(crate) mod tests {
     #[test_case(Ty::BuiltinInstance("type"), Ty::SubclassOfAny)]
     #[test_case(Ty::BuiltinInstance("type"), Ty::SubclassOfBuiltinClass("object"))]
     #[test_case(Ty::BuiltinInstance("type"), Ty::BuiltinInstance("type"))]
+    #[test_case(Ty::BuiltinClassLiteral("str"), Ty::SubclassOfAny)]
     fn is_assignable_to(from: Ty, to: Ty) {
         let db = setup_db();
         assert!(from.into_type(&db).is_assignable_to(&db, to.into_type(&db)));
@@ -3214,6 +3236,8 @@ pub(crate) mod tests {
     #[test_case(Ty::BuiltinClassLiteral("int"), Ty::BuiltinInstance("object"))]
     #[test_case(Ty::TypingLiteral, Ty::TypingInstance("_SpecialForm"))]
     #[test_case(Ty::TypingLiteral, Ty::BuiltinInstance("object"))]
+    #[test_case(Ty::AbcClassLiteral("ABC"), Ty::AbcInstance("ABCMeta"))]
+    #[test_case(Ty::AbcInstance("ABCMeta"), Ty::SubclassOfBuiltinClass("object"))]
     fn is_subtype_of(from: Ty, to: Ty) {
         let db = setup_db();
         assert!(from.into_type(&db).is_subtype_of(&db, to.into_type(&db)));
@@ -3244,6 +3268,9 @@ pub(crate) mod tests {
     #[test_case(Ty::BuiltinClassLiteral("int"), Ty::BuiltinClassLiteral("object"))]
     #[test_case(Ty::BuiltinInstance("int"), Ty::BuiltinClassLiteral("int"))]
     #[test_case(Ty::TypingInstance("_SpecialForm"), Ty::TypingLiteral)]
+    #[test_case(Ty::BuiltinInstance("type"), Ty::SubclassOfBuiltinClass("str"))]
+    #[test_case(Ty::BuiltinClassLiteral("str"), Ty::SubclassOfAny)]
+    #[test_case(Ty::AbcInstance("ABCMeta"), Ty::SubclassOfBuiltinClass("type"))]
     fn is_not_subtype_of(from: Ty, to: Ty) {
         let db = setup_db();
         assert!(!from.into_type(&db).is_subtype_of(&db, to.into_type(&db)));
@@ -3403,6 +3430,7 @@ pub(crate) mod tests {
     #[test_case(Ty::Intersection{pos: vec![Ty::BuiltinInstance("int"), Ty::IntLiteral(2)], neg: vec![]}, Ty::IntLiteral(2))]
     #[test_case(Ty::Tuple(vec![Ty::IntLiteral(1), Ty::IntLiteral(2)]), Ty::Tuple(vec![Ty::IntLiteral(1), Ty::BuiltinInstance("int")]))]
     #[test_case(Ty::BuiltinClassLiteral("str"), Ty::BuiltinInstance("type"))]
+    #[test_case(Ty::BuiltinClassLiteral("str"), Ty::SubclassOfAny)]
     fn is_not_disjoint_from(a: Ty, b: Ty) {
         let db = setup_db();
         let a = a.into_type(&db);