#2157: Equality Constraints with Type Families
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Reporter: hpacheco | Owner: chak
Type: feature request | Status: new
Priority: normal | Milestone:
Component: Compiler (Type checker) | Version: 6.9
Severity: normal | Resolution:
Keywords: | Testcase:
Architecture: Multiple | Os: Multiple
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Comment (by hpacheco):
Curiously if I have
{{{
fff a = fmapF a id
}}}
it compiles correctly.
But if I infer the type signature of fff I get
{{{
fff :: forall d x. (FunctorF d) => d -> F d x -> F d x
}}}
On the other side, a similar problem as before arises when
{{{
fff :: forall d x. (FunctorF d) => d -> F d x -> F d x
fff a = fmapF a id
}}}
fails to compile.
This must be a bug. Sorry for all this posts.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2157#comment:6>
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