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  • Glasgow Haskell CompilerGlasgow Haskell Compiler
  • GHCGHC
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  • #2112
Closed
Open
Issue created Feb 19, 2008 by chevalier@alum.wellesley.edu@trac-chevalier

Bad error message for malformed GADTs

Compiling the following code:

data Foo a where
   Bar :: a -> a

results in the following error message:

$ ghc-6.8.1 gadt.hs -XGADTs

gadt.hs:5:3:
    Malformed constructor result type: a
    In the result type of a data constructor: a
    In the data type declaration for `Foo'
$ 

It would be nice if the error message mentioned the name of the offending data constructor (Bar in this case) -- since there might be more than one.

Trac metadata
Trac field Value
Version 6.8.1
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler (Type checker)
Test case
Differential revisions
BlockedBy
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Blocking
CC
Operating system Unknown
Architecture Unknown
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