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bpo-35224: Add What's new entry for evaluation order in dict comprehensions #14319

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pablogsal merged 2 commits into from
Jun 25, 2019
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bpo-35224: Add What's new entry for evaluation order in dict comprehensions #14319

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bpo-35224: Add What's new entry for evaluation order in dict comprehe…
pablogsal Jun 23, 2019
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fixup! bpo-35224: Add What's new entry for evaluation order in dict c…
pablogsal Jun 25, 2019
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8 changes: 8 additions & 0 deletions Doc/whatsnew/3.8.rst
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Expand Up @@ -349,6 +349,9 @@ Other Language Changes
is ``-1``, and a suitable power of that inverse for other negative exponents.
(Contributed by Mark Dickinson in :issue:`36027`.)

* When dictionary comprehensions are evaluated, the key is now evaluated before
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the value, as proposed by :pep:`572`.


New Modules
===========
Expand Down Expand Up @@ -1502,6 +1505,11 @@ CPython bytecode changes
when awaiting a next item in an :keyword:`async for` loop.
(Contributed by Serhiy Storchaka in :issue:`33041`.)

* The :opcode:`MAP_ADD` now expects the value as the first element in the
stack and the key as the second element. This change was made so the key
is always evaluated before the value in dictionary comprehensions, as
porposed by :pep:`572`. (Contributed by Jörn Heissler in :issue:`35224`.)

@gvanrossum gvanrossum Jun 25, 2019

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porposed -> proposed

@pablogsal pablogsal Jun 25, 2019

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Fixed in #14371



Demos and Tools
---------------
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