Add test case for unpacked tuple in TypeAlias

Author: hyperkai

test-data/unit/check-python310.test

@@ -2389,6 +2389,18 @@ X = None | C
 Y = None | D
 [builtins fixtures/type.pyi]
 
+[case testGenericTypeAliasArgOfTypeAliasIsUnpackedTuple]
+from typing_extensions import TypeAlias
+from typing import TypeVarTuple, Unpack
+
+Ts = TypeVarTuple('Ts')
+TA: TypeAlias = tuple[Unpack[Ts]]
+
+# v1: TA[*list[int]]  # E: Invalid syntax
+
+v2: TA[Unpack[list[int]]]  # E: "list[int]" cannot be unpacked (must be tuple or TypeVarTuple)
+[builtins fixtures/tuple.pyi]
+
 [case testMatchStatementWalrus]
 class A:
     a = 1