merge

diff --cc Misc/NEWS
index 5cf3bc86e8c109cd2b18f5f5ba1a35e7b3e06e76,cc421b03e2af167007bf3b436620e2f58ed24f75..4eb0408a89407b89b9a78d4f8779c72d522d834c
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -10,11 -10,12 +10,15 @@@ What's New in Python 3.7.0 alpha 
  Core and Builtins
  -----------------
  
 +- Issue #28731: Optimize _PyDict_NewPresized() to create correct size dict.
 +  Improve speed of dict literal with constant keys up to 30%.
 +
  - Issue #28532: Show sys.version when -V option is supplied twice.
  
+ - Issue #27100: The with-statement now checks for __enter__ before it
+   checks for __exit__.  This gives less confusing error messages when
+   both methods are missing. Patch by Jonathan Ellington.
+ 
  - Issue #28746: Fix the set_inheritable() file descriptor method on platforms
    that do not have the ioctl FIOCLEX and FIONCLEX commands.
  

diff --cc Python/ceval.c
Simple merge