Fix Unpack imported from typing (#14378)

Add missing check for `typing.Unpack` to fix running with `--python
3.11`.

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

Author: cdce8p

mypy/semanal.py

@@ -1881,7 +1881,7 @@ def analyze_unbound_tvar(self, t: Type) -> tuple[str, TypeVarLikeExpr] | None:
                 # It's bound by our type variable scope
                 return None
             return unbound.name, sym.node
-        if sym and sym.fullname == "typing_extensions.Unpack":
+        if sym and sym.fullname in ("typing.Unpack", "typing_extensions.Unpack"):
             inner_t = unbound.args[0]
             if not isinstance(inner_t, UnboundType):
                 return None

test-data/unit/check-python311.test

@@ -51,3 +51,15 @@ try:
 except* (RuntimeError, ExceptionGroup) as e:  # E: Exception type in except* cannot derive from BaseExceptionGroup
     reveal_type(e)  # N: Revealed type is "builtins.ExceptionGroup[Union[builtins.RuntimeError, Any]]"
 [builtins fixtures/exception.pyi]
+
+[case testBasicTypeVarTupleGeneric]
+from typing import Generic, TypeVarTuple, Unpack
+
+Ts = TypeVarTuple("Ts")
+
+class Variadic(Generic[Unpack[Ts]]):
+    ...
+
+variadic: Variadic[int, str]
+reveal_type(variadic)  # N: Revealed type is "__main__.Variadic[builtins.int, builtins.str]"
+[builtins fixtures/tuple.pyi]

test-data/unit/lib-stub/typing.pyi

@@ -27,6 +27,8 @@ NoReturn = 0
 Never = 0
 NewType = 0
 ParamSpec = 0
+TypeVarTuple = 0
+Unpack = 0
 Self = 0
 TYPE_CHECKING = 0