black/parser: optimize deepcopying nodes (#2611)

[etc/vim.git] / src / blib2to3 / pytree.py

diff --git a/src/blib2to3/pytree.py b/src/blib2to3/pytree.py
index 4b841b768e7fefcb64f04045edba9ce9ab162221..001652df09fb85d623ede558f75a2ea102549e4e 100644 (file)
--- a/src/blib2to3/pytree.py
+++ b/src/blib2to3/pytree.py
@@ -25,7 +25,6 @@ from typing import (
     Union,
     Set,
     Iterable,
-    Sequence,
 )
 from blib2to3.pgen2.grammar import Grammar
 
@@ -53,7 +52,7 @@ def type_repr(type_num: int) -> Union[Text, int]:
     return _type_reprs.setdefault(type_num, type_num)
 
 
-_P = TypeVar("_P")
+_P = TypeVar("_P", bound="Base")
 
 NL = Union["Node", "Leaf"]
 Context = Tuple[Text, Tuple[int, int]]
@@ -110,6 +109,9 @@ class Base(object):
         """
         raise NotImplementedError
 
+    def __deepcopy__(self: _P, memo: Any) -> _P:
+        return self.clone()
+
     def clone(self: _P) -> _P:
         """
         Return a cloned (deep) copy of self.