[GHC] #12907: ExtendedDefaultRules-related regression in GHC 8.0.2
GHC
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Thu Dec 1 13:40:11 UTC 2016
#12907: ExtendedDefaultRules-related regression in GHC 8.0.2
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Reporter: RyanGlScott | Owner:
Type: bug | Status: new
Priority: high | Milestone: 8.0.2
Component: Compiler (Type | Version: 8.0.2-rc1
checker) |
Resolution: | Keywords:
Operating System: Unknown/Multiple | Architecture:
| Unknown/Multiple
Type of failure: None/Unknown | Test Case:
Blocked By: | Blocking:
Related Tickets: | Differential Rev(s):
Wiki Page: |
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Comment (by goldfire):
I agree with comment:2. The change to reject the program reported was
intentional, following the Report. When `-XExtendedDefaultRules` is in
effect, the program given is accepted, as `Bool` is a member of several of
the classes defaultable under the extended rules.
I'd be willing to consider other designs here, but I believe what's
implemented is the most faithful to the Report.
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12907#comment:3>
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