Debugging info(?) leaks out: "Urk! Inventing strangely-kinded void TyCon"
With GHC 6.6, this module:
module G where
testL = foo undefined
class Foo t where
foo :: m a -> t m a
leaks some debugging info(?):
Urk! Inventing strangely-kinded void TyCon:
:t{tc ae2}
(* -> *) -> * -> *
tmp.hs:4:8:
Ambiguous type variable `t' in the constraint:
`Foo t' arising from use of `foo' at tmp.hs:4:8-20
Possible cause: the monomorphism restriction applied to the following:
testL :: forall (m :: * -> *) a. t m a (bound at tmp.hs:4:0)
Probable fix: give these definition(s) an explicit type signature
or use -fno-monomorphism-restriction
I haven't managed to get this message in an acceptable program.
(found by fasta on IRC)
Trac metadata
Trac field | Value |
---|---|
Version | 6.6 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler (Type checker) |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | Unknown |
Architecture | Unknown |