#2206: GADT pattern match with non-rigid return type
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Reporter: simonpj | Owner: simonpj
Type: bug | Status: closed
Priority: normal | Milestone: 6.10 branch
Component: Compiler | Version: 6.8.2
Severity: normal | Resolution: fixed
Keywords: | Difficulty: Unknown
Testcase: gadt-escape1 | Os: Unknown/Multiple
Architecture: Unknown/Multiple |
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Changes (by simonpj):
* status: new => closed
* resolution: => fixed
Comment:
Indeed GHC 6.10 now (correctly) reports
{{{
$ ghc -c T2206.hs
T2206.hs:12:51:
GADT pattern match with non-rigid result type `t'
Solution: add a type signature
In a case alternative: Hidden (ExpInt _) a -> a
In the expression:
case (hval :: Hidden) of { Hidden (ExpInt _) a -> a }
In the definition of `weird':
weird = case (hval :: Hidden) of { Hidden (ExpInt _) a -> a }
}}}
which seems like a decent error message. So I'll close this one.
Simon
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2206#comment:6>
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