#5736: Possible regression with functional dependencies
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Reporter: magnus | Owner:
Type: bug | Status: closed
Priority: normal | Milestone:
Component: Compiler (Type checker) | Version: 7.2.1
Resolution: invalid | Keywords:
Os: Unknown/Multiple | Architecture: Unknown/Multiple
Failure: None/Unknown | Difficulty: Unknown
Testcase: | Blockedby:
Blocking: | Related:
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Changes (by simonpj):
* status: new => closed
* difficulty: => Unknown
* resolution: => invalid
Comment:
I think 7.0.4 had a bug. Consider
* 'a' determines 'b'. So if two instances have matching a's they must
have matching b's.
* The first intstance says that the second parameter must always match
the first.
* But it doesn't in the second instance declaration.
This is one of the rules in Mark Jones's original paper.
Simon
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5736#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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