Commit a452c6e5 authored by Ryan Scott's avatar Ryan Scott Committed by Ben Gamari

Make note of #12907 in 8.0.2 release notes

Test Plan: Read it, commit it, merge it, ship it

Reviewers: goldfire, bgamari, austin, hvr, simonpj

Reviewed By: simonpj

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2774

GHC Trac Issues: #12907
parent 514c01ee
...@@ -86,6 +86,19 @@ Language ...@@ -86,6 +86,19 @@ Language
instance {-# OVERLAPPING #-} Foo Int instance {-# OVERLAPPING #-} Foo Int
- GHC now adheres more closely to the Haskell 2010 Report with respect to
defaulting rules. As a result, GHC will now reject some defaulting rules
which GHC 8.0.1 and earlier would accept. For example, this is now
rejected ::
module Foo where
default (Bool)
because when the :ghc-flag:`-XExtendedDefaultRules` extension is not
enabled, defaulting rules only work for the ``Num`` class, of which ``Bool``
is not an instance. To make GHC accept the above program, simply enable the
:ghc-flag:`-XExtendedDefaultRules` extension.
Compiler Compiler
~~~~~~~~ ~~~~~~~~
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