tcfail080.hs:11:
Ambiguous type variable(s) `c' in the constraint `Collection c a'
- arising from use of `isempty' at tcfail080.hs:11
+ arising from use of `singleton' at tcfail080.hs:11
+ In the first argument of `isempty', namely `(singleton x)'
In the right-hand side of an equation for `q':
isempty (singleton x)
-
-Compilation had errors
-