Fix parsing of empty tuple type Tuple[()]

Author: knutwannheden

rewrite/rewrite/python/_parser_visitor.py

@@ -1908,7 +1908,7 @@ def __convert_type_mapper(self, node) -> Optional[TypeTree]:
                     None
                 )
         elif isinstance(node, ast.Subscript):
-            slices = node.slice.elts if isinstance(node.slice, ast.Tuple) else [node.slice]
+            slices = [node.slice]
             return j.ParameterizedType(
                 random_id(),
                 self.__whitespace(),

rewrite/tests/python/all/type_hint_test.py

@@ -124,6 +124,15 @@ def test_union_type():
     rewrite_run(python("""foo: None | ... = None"""))
 
 
+def test_empty_tuple_type():
+    # language=python
+    rewrite_run(python('''
+        from typing import Tuple
+        foo: Tuple[()] = None
+    ''')
+    )
+
+
 def test_function_parameter_with_quoted_type_hint():
     # language=python
     rewrite_run(