Implement Final[...] in a way so it doesn't completely fail

jedi/inference/gradual/typing.py

@@ -33,7 +33,8 @@ _TYPE_ALIAS_TYPES = {
     'DefaultDict': 'collections.defaultdict',
     'Deque': 'collections.deque',
 }
-_PROXY_TYPES = 'Optional Union ClassVar Annotated'.split()
+_PROXY_TYPES = ['Optional', 'Union', 'ClassVar', 'Annotated', 'Final']
+_IGNORE_ANNOTATION_PARTS = ['ClassVar', 'Annotated', 'Final']
 
 
 class TypingModuleName(NameWrapper):
@@ -114,7 +115,7 @@ class ProxyWithGenerics(BaseTypingClassWithGenerics):
         elif string_name == 'Type':
             # The type is actually already given in the index_value
             return self._generics_manager[0]
-        elif string_name in ['ClassVar', 'Annotated']:
+        elif string_name in _IGNORE_ANNOTATION_PARTS:
             # For now don't do anything here, ClassVars are always used.
             return self._generics_manager[0].execute_annotation()
 

test/completion/pep0484_typing.py

@@ -3,7 +3,7 @@ Test the typing library, with docstrings and annotations
 """
 import typing
 from typing import Sequence, MutableSequence, List, Iterable, Iterator, \
-    AbstractSet, Tuple, Mapping, Dict, Union, Optional
+    AbstractSet, Tuple, Mapping, Dict, Union, Optional, Final
 
 class B:
     pass
@@ -555,3 +555,15 @@ def typed_dict_test_foo(arg: Bar):
     arg['an_int']
     #? int()
     arg['another_variable']
+
+# -------------------------
+# Final
+# -------------------------
+
+x: Final[str] = 1
+y: Final = 1
+#? str()
+x
+# TODO
+#?
+y