tcrun032 regressed
The tcrun032 test:
{-# OPTIONS -fglasgow-exts -fallow-undecidable-instances #-}
-- This tests the recursive-dictionary stuff.
--
-- The derived instance needs
module Main where
data Fix f = In (f (Fix f)) deriving( Show, Eq )
data L x = Nil | Cons Int x deriving (Show, Eq)
main = do { print (In Nil);
print (In Nil == In Nil) }
now fails with:
tcrun032.hs:9:5:
No instance for (Show (f (Fix f)))
arising from the 'deriving' clause of a data type declaration
at tcrun032.hs:9:5
Possible fix: add an instance declaration for (Show (f (Fix f)))
When deriving the instance for `Show (Fix f)'
tcrun032.hs:9:5:
No instance for (Eq (f (Fix f)))
arising from the 'deriving' clause of a data type declaration
at tcrun032.hs:9:5
Possible fix: add an instance declaration for (Eq (f (Fix f)))
When deriving the instance for `Eq (Fix f)'
in the 6.6 branch. Both 6.6 and the HEAD work.
Trac metadata
Trac field | Value |
---|---|
Version | 6.6 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | Unknown |
Architecture | Unknown |