Fix false positives for Y090 in relation to PEP-646 (#473)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

Author: Daverball

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Change Log
 
+Bugfixes:
+* Y090: Fix false positive for `tuple[Unpack[Ts]]`.
+
 ## 24.3.0
 
 New error codes:

pyi.py

@@ -349,6 +349,7 @@ def _is_object(node: ast.AST | None, name: str, *, from_: Container[str]) -> boo
     _is_object, name="AsyncGenerator", from_=_TYPING_OR_COLLECTIONS_ABC
 )
 _is_Generic = partial(_is_object, name="Generic", from_=_TYPING_MODULES)
+_is_Unpack = partial(_is_object, name="Unpack", from_=_TYPING_MODULES)
 
 
 def _is_object_or_Unused(node: ast.expr | None) -> bool:
@@ -1537,7 +1538,9 @@ def visit_Subscript(self, node: ast.Subscript) -> None:
             self._visit_slice_tuple(node.slice, subscripted_object_name)
         else:
             self.visit(node.slice)
-            if subscripted_object_name in {"tuple", "Tuple"}:
+            if subscripted_object_name in {"tuple", "Tuple"} and not (
+                isinstance(node.slice, ast.Subscript) and _is_Unpack(node.slice.value)
+            ):
                 self._Y090_error(node)
 
     def _visit_typing_Literal(self, node: ast.Subscript) -> None:

tests/pep646_py311.pyi

@@ -0,0 +1,7 @@
+# flags: --extend-select=Y090
+import typing
+
+_Ts = typing.TypeVarTuple("_Ts")
+
+e: tuple[*_Ts]
+f: typing.Tuple[*_Ts]  # Y022 Use "tuple[Foo, Bar]" instead of "typing.Tuple[Foo, Bar]" (PEP 585 syntax)

tests/single_element_tuples.pyi

@@ -2,7 +2,11 @@
 import builtins
 import typing
 
+_Ts = typing.TypeVarTuple("_Ts")
+
 a: tuple[int]  # Y090 "tuple[int]" means "a tuple of length 1, in which the sole element is of type 'int'". Perhaps you meant "tuple[int, ...]"?
 b: typing.Tuple[builtins.str]  # Y022 Use "tuple[Foo, Bar]" instead of "typing.Tuple[Foo, Bar]" (PEP 585 syntax)  # Y090 "typing.Tuple[builtins.str]" means "a tuple of length 1, in which the sole element is of type 'builtins.str'". Perhaps you meant "typing.Tuple[builtins.str, ...]"?
 c: tuple[int, ...]
 d: typing.Tuple[builtins.str, builtins.complex]  # Y022 Use "tuple[Foo, Bar]" instead of "typing.Tuple[Foo, Bar]" (PEP 585 syntax)
+e: tuple[typing.Unpack[_Ts]]
+f: typing.Tuple[typing.Unpack[_Ts]]  # Y022 Use "tuple[Foo, Bar]" instead of "typing.Tuple[Foo, Bar]" (PEP 585 syntax)