pythonPackages.mypy_extensions: use typing from stdlib on >=3.5

It's not necessary to depend on the "typing" backport since it's in
the standard library; I also observed serious breakage in anything
using the typing module (including) when the backport was in the
closure on >=3.5.

1 files changed, 2 insertions, 2 deletions

diff --git a/pkgs/development/python-modules/mypy/extensions.nix b/pkgs/development/python-modules/mypy/extensions.nix
index f57ac12c0da8..36407fd684ae 100644
--- a/pkgs/development/python-modules/mypy/extensions.nix
+++ b/pkgs/development/python-modules/mypy/extensions.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchPypi, buildPythonPackage, typing, isPy3k }:
+{ stdenv, fetchPypi, buildPythonPackage, typing, pythonOlder }:
 
 buildPythonPackage rec {
   pname = "mypy_extensions";
@@ -12,7 +12,7 @@ buildPythonPackage rec {
     sha256 = "04h8brrbbx151dfa2cvvlnxgmb5wa00mhd2z7nd20s8kyibfkq1p";
   };
 
-  propagatedBuildInputs = [ typing ];
+  propagatedBuildInputs = if pythonOlder "3.5" then [ typing ] else [ ];
 
   meta = with stdenv.lib; {
     description = "Experimental type system extensions for programs checked with the mypy typechecker";