Allow better tuple type aliases, fix "Type application" error

mypy/checkexpr.py

@@ -3242,7 +3242,11 @@ def apply_type_arguments_to_callable(
         tp = get_proper_type(tp)
 
         if isinstance(tp, CallableType):
-            if len(tp.variables) != len(args):
+            if tp.is_type_obj() and tp.type_object().fullname == 'builtins.tuple':
+                # We special case `tuple` callable, because it can accept
+                # a different amount of args: `tuple[int]`, `tuple[int, str, str]`
+                return tp
+            elif len(tp.variables) != len(args):
                 self.msg.incompatible_type_application(len(tp.variables),
                                                        len(args), ctx)
                 return AnyType(TypeOfAny.from_error)

mypy/semanal.py

@@ -2883,11 +2883,18 @@ def analyze_name_lvalue(self,
                     lvalue.fullname = var._fullname
                 else:
                     lvalue.fullname = lvalue.name
-                if self.is_func_scope():
-                    if unmangle(name) == '_':
-                        # Special case for assignment to local named '_': always infer 'Any'.
-                        typ = AnyType(TypeOfAny.special_form)
-                        self.store_declared_types(lvalue, typ)
+
+                # Special case for assignment to local named '_': always infer 'Any'.
+                is_special_unused = self.is_func_scope() and unmangle(name) == '_'
+
+                # Special case, `Any` is defined as `= object()` in typeshed,
+                # so we need to make it a real type variable.
+                is_typing_any = var.fullname == 'typing.Any'
+
+                if is_special_unused or is_typing_any:
+                    typ = AnyType(TypeOfAny.special_form)
+                    self.store_declared_types(lvalue, typ)
+
             if is_final and self.is_final_redefinition(kind, name):
                 self.fail("Cannot redefine an existing name as final", lvalue)
         else:

test-data/unit/check-type-aliases.test

@@ -753,6 +753,29 @@ A: TypeAlias = str
 [builtins fixtures/bool.pyi]
 [out]
 
+[case testTupleWithDifferentArgsPy38]
+# flags: --python-version 3.8
+NotYet1 = tuple[float]  # E: "tuple" is not subscriptable
+NotYet2 = tuple[float, float]  # E: "tuple" is not subscriptable
+[builtins fixtures/tuple.pyi]
+
+[case testTupleWithDifferentArgsStub]
+# https://github.com/python/mypy/issues/11098
+import tup
+[file tup.pyi]
+Correct1 = str | tuple[float, float, str]
+Correct2 = tuple[float] | str
+Correct3 = tuple[float, ...] | str
+
+RHSAlias1: type = tuple[int, int]
+RHSAlias2: type = tuple[int]
+RHSAlias3: type = tuple[int, ...]
+
+# Wrong:
+
+WrongTypeElement = str | tuple[float, 1]  # E: Invalid type: try using Literal[1] instead?
+WrongEllipsis = str | tuple[float, float, ...]  # E: Unexpected "..."
+[builtins fixtures/tuple.pyi]
 
 [case testLiteralStringPep675]
 # flags: --python-version 3.11

test-data/unit/pythoneval.test

@@ -1603,3 +1603,21 @@ class Foo(Enum):
 _testEnumValueWithPlaceholderNodeType.py:5: error: Incompatible types in assignment (expression has type "object", variable has type "Foo")
 _testEnumValueWithPlaceholderNodeType.py:6: error: Incompatible types in assignment (expression has type "object", variable has type "Foo")
 _testEnumValueWithPlaceholderNodeType.py:6: error: Name "Missing" is not defined
+
+[case testTupleWithDifferentArgsPy310]
+# https://github.com/python/mypy/issues/11098
+# flags: --python-version 3.10
+Correct1 = str | tuple[float, float, str]
+Correct2 = tuple[float] | str
+Correct3 = tuple[float, ...] | str
+
+RHSAlias1: type = tuple[int, int]
+RHSAlias2: type = tuple[int]
+RHSAlias3: type = tuple[int, ...]
+
+# Wrong:
+WrongTypeElement = str | tuple[float, 1]
+WrongEllipsis = tuple[float, float, ...] | str
+[out]
+_testTupleWithDifferentArgsPy310.py:12: error: Invalid type: try using Literal[1] instead? 
+_testTupleWithDifferentArgsPy310.py:13: error: Unexpected "..."