Fix cases of type object handling for overloads (#16168)

Fixes most of #12320. I didn't add tests for every code path because
it's niche. I also didn't fix everything, in particular the cases where
we proceed to use `ret_type`

Author: hauntsaninja

mypy/checker.py

@@ -2986,7 +2986,7 @@ def check_assignment(
                 p_rvalue_type = get_proper_type(rvalue_type)
                 p_lvalue_type = get_proper_type(lvalue_type)
                 if (
-                    isinstance(p_rvalue_type, CallableType)
+                    isinstance(p_rvalue_type, FunctionLike)
                     and p_rvalue_type.is_type_obj()
                     and (
                         p_rvalue_type.type_object().is_abstract
@@ -3771,7 +3771,7 @@ def split_around_star(
 
     def type_is_iterable(self, type: Type) -> bool:
         type = get_proper_type(type)
-        if isinstance(type, CallableType) and type.is_type_obj():
+        if isinstance(type, FunctionLike) and type.is_type_obj():
             type = type.fallback
         return is_subtype(
             type, self.named_generic_type("typing.Iterable", [AnyType(TypeOfAny.special_form)])

mypy/checkexpr.py

@@ -694,7 +694,7 @@ def check_runtime_protocol_test(self, e: CallExpr) -> None:
         for expr in mypy.checker.flatten(e.args[1]):
             tp = get_proper_type(self.chk.lookup_type(expr))
             if (
-                isinstance(tp, CallableType)
+                isinstance(tp, FunctionLike)
                 and tp.is_type_obj()
                 and tp.type_object().is_protocol
                 and not tp.type_object().runtime_protocol
@@ -704,7 +704,7 @@ def check_runtime_protocol_test(self, e: CallExpr) -> None:
     def check_protocol_issubclass(self, e: CallExpr) -> None:
         for expr in mypy.checker.flatten(e.args[1]):
             tp = get_proper_type(self.chk.lookup_type(expr))
-            if isinstance(tp, CallableType) and tp.is_type_obj() and tp.type_object().is_protocol:
+            if isinstance(tp, FunctionLike) and tp.is_type_obj() and tp.type_object().is_protocol:
                 attr_members = non_method_protocol_members(tp.type_object())
                 if attr_members:
                     self.chk.msg.report_non_method_protocol(tp.type_object(), attr_members, e)
@@ -4190,7 +4190,7 @@ def visit_index_with_type(
         elif isinstance(left_type, TypedDictType):
             return self.visit_typeddict_index_expr(left_type, e.index)
         elif (
-            isinstance(left_type, CallableType)
+            isinstance(left_type, FunctionLike)
             and left_type.is_type_obj()
             and left_type.type_object().is_enum
         ):
@@ -5832,7 +5832,7 @@ def has_abstract_type_part(self, caller_type: ProperType, callee_type: ProperTyp
 
     def has_abstract_type(self, caller_type: ProperType, callee_type: ProperType) -> bool:
         return (
-            isinstance(caller_type, CallableType)
+            isinstance(caller_type, FunctionLike)
             and isinstance(callee_type, TypeType)
             and caller_type.is_type_obj()
             and (caller_type.type_object().is_abstract or caller_type.type_object().is_protocol)

mypy/messages.py

@@ -416,7 +416,7 @@ def has_no_attr(
         elif member == "__getitem__":
             # Indexed get.
             # TODO: Fix this consistently in format_type
-            if isinstance(original_type, CallableType) and original_type.is_type_obj():
+            if isinstance(original_type, FunctionLike) and original_type.is_type_obj():
                 self.fail(
                     "The type {} is not generic and not indexable".format(
                         format_type(original_type, self.options)

mypy/plugins/proper_plugin.py

@@ -17,7 +17,6 @@
 from mypy.subtypes import is_proper_subtype
 from mypy.types import (
     AnyType,
-    CallableType,
     FunctionLike,
     Instance,
     NoneTyp,
@@ -131,7 +130,7 @@ def is_dangerous_target(typ: ProperType) -> bool:
     """Is this a dangerous target (right argument) for an isinstance() check?"""
     if isinstance(typ, TupleType):
         return any(is_dangerous_target(get_proper_type(t)) for t in typ.items)
-    if isinstance(typ, CallableType) and typ.is_type_obj():
+    if isinstance(typ, FunctionLike) and typ.is_type_obj():
         return typ.type_object().has_base("mypy.types.Type")
     return False
 

mypy/typeops.py

@@ -989,7 +989,7 @@ def custom_special_method(typ: Type, name: str, check_all: bool = False) -> bool
         return any(custom_special_method(t, name) for t in typ.items)
     if isinstance(typ, TupleType):
         return custom_special_method(tuple_fallback(typ), name, check_all)
-    if isinstance(typ, CallableType) and typ.is_type_obj():
+    if isinstance(typ, FunctionLike) and typ.is_type_obj():
         # Look up __method__ on the metaclass for class objects.
         return custom_special_method(typ.fallback, name, check_all)
     if isinstance(typ, AnyType):

test-data/unit/check-abstract.test

@@ -241,7 +241,7 @@ f(GoodAlias)
 
 [case testInstantiationAbstractsInTypeForVariables]
 # flags: --no-strict-optional
-from typing import Type
+from typing import Type, overload
 from abc import abstractmethod
 
 class A:
@@ -269,6 +269,15 @@ if int():
     var_old = B # E: Can only assign concrete classes to a variable of type "Type[A]"
 if int():
     var_old = C # OK
+
+class D(A):
+    @overload
+    def __new__(cls, a) -> "D": ...
+    @overload
+    def __new__(cls) -> "D": ...
+    def __new__(cls, a=None) -> "D": ...
+if int():
+    var = D # E: Can only assign concrete classes to a variable of type "Type[A]"
 [out]
 
 [case testInstantiationAbstractsInTypeForClassMethods]

test-data/unit/pythoneval.test

@@ -1801,9 +1801,9 @@ C = str | int
 D: TypeAlias = str | int
 [out]
 _testTypeAliasNotSupportedWithNewStyleUnion.py:3: error: Invalid type alias: expression is not a valid type
-_testTypeAliasNotSupportedWithNewStyleUnion.py:3: error: Value of type "Type[type]" is not indexable
+_testTypeAliasNotSupportedWithNewStyleUnion.py:3: error: The type "Type[type]" is not generic and not indexable
 _testTypeAliasNotSupportedWithNewStyleUnion.py:4: error: Invalid type alias: expression is not a valid type
-_testTypeAliasNotSupportedWithNewStyleUnion.py:4: error: Value of type "Type[type]" is not indexable
+_testTypeAliasNotSupportedWithNewStyleUnion.py:4: error: The type "Type[type]" is not generic and not indexable
 _testTypeAliasNotSupportedWithNewStyleUnion.py:5: error: Invalid type alias: expression is not a valid type
 _testTypeAliasNotSupportedWithNewStyleUnion.py:5: error: Unsupported left operand type for | ("Type[str]")
 _testTypeAliasNotSupportedWithNewStyleUnion.py:6: error: Invalid type alias: expression is not a valid type