Automatically derived Read of operator is not inverse of automatically derived Show
This program fails as shown below using ghc 6.13 snapshot 20100519
data T = (:=:) | (:!=:) deriving (Show,Read)
main =
putStrLn ("show (:=:) = " ++ show (:=:)) >>
putStrLn ("read (show (:=:)) :: T = " ++
show (read (show (:=:)) :: T))
Result:
> main
show (:=:) = :=:
read (show (:=:)) :: T = *** Exception: Prelude.read: no parse
Trac metadata
Trac field | Value |
---|---|
Version | 6.13 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |