#7393: GHC cannot solve functional dependency
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Reporter: Khudyakov | Owner:
Type: bug | Status: closed
Priority: normal | Milestone:
Component: Compiler | Version: 7.6.1
Resolution: invalid | Keywords:
Os: Unknown/Multiple | Architecture: Unknown/Multiple
Failure: GHC rejects valid program | Difficulty: Unknown
Testcase: | Blockedby:
Blocking: | Related:
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Changes (by simonpj):
* status: new => closed
* difficulty: => Unknown
* resolution: => invalid
Comment:
I'm afraid functional dependencies don't work like that. Type families
do. (This is one of the reasons I prefer type families.)
You might try something like this
{{{
class TyPairs (xs :: [*]) where
type Ys xs :: [*]
}}}
Simon
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7393#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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