#4896: Deriving Data does not work for attached code
---------------------------------+------------------------------------------
Reporter: mitar | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.1 | Keywords:
Testcase: | Blockedby:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: None/Unknown
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I get the following error when I try to derive `Data` for the attached
code:
{{{
Main.hs:17:66:
Couldn't match expected type `Bar (D a b)'
with actual type `t' a1 b1'
Expected type: Maybe (c (Bar (D a b)))
Actual type: Maybe (c (t' a1 b1))
In the expression: gcast2 f
In an equation for `dataCast2': dataCast2 f = gcast2 f
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4896>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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