Failure to find class instance specified with extra parentheses
The following two-line program fails to compile under GHC 7.6.3 and compiles fine with GHC 7.4.1:
instance Eq (((->) a) b)
instance (Ord b) => Ord (((->) a) b)
Error message:
Could not deduce (Eq (a -> b))
arising from the superclasses of an instance declaration
from the context (Ord b)
Compilation goes through if I tweak the Eq
instance to use "((->) a b)
" or "(a -> b)
" in place of "(((->) a) b)
".
Trac metadata
Trac field | Value |
---|---|
Version | 7.6.3 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |