Fixity declaration reported as ambiguous
Christopher Dove reports: So I have some module, in a work project that I'm portnig from GHC
- 12.3 to GHC 7.4.2,
module Data.Monoid.Operator where
import Data.Monoid
(++) :: Monoid a => a -> a -> a
(++) = mappend
infixr 5 ++
This compiles happily on GHC 6.12.3, but on 7.4.2 says:
src/Data/Monoid/Operator.hs:9:10:
Ambiguous occurrence `++'
It could refer to either `Data.Monoid.Operator.++',
defined at src/Data/Monoid/Operator.hs:8:1
or `Prelude.++',
imported from `Prelude' at src/Data/Monoid/Operator.hs:3:8-27
(and originally defined in `GHC.Base')
Trac metadata
Trac field | Value |
---|---|
Version | 7.4.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |