diff options
Diffstat (limited to 'Lib/typing.py')
| -rw-r--r-- | Lib/typing.py | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/Lib/typing.py b/Lib/typing.py index e31fc99e02..b5ba38e07c 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -702,8 +702,10 @@ class _GenericAlias(_BaseGenericAlias, _root=True): if isinstance(arg, TypeVar): arg = subst[arg] elif isinstance(arg, (_GenericAlias, GenericAlias)): - subargs = tuple(subst[x] for x in arg.__parameters__) - arg = arg[subargs] + subparams = arg.__parameters__ + if subparams: + subargs = tuple(subst[x] for x in subparams) + arg = arg[subargs] new_args.append(arg) return self.copy_with(tuple(new_args)) |