Ambiguous type variable(s) `t'
in the constraint `PrelGHC.CCallable t'
arising from an argument in the _ccall_ to `foo', namely `(undefined ())' at cc001.hs:5
Ambiguous type variable(s) `t'
in the constraint `PrelGHC.CCallable t'
arising from an argument in the _ccall_ to `foo', namely `(undefined ())' at cc001.hs:5