3 Context constrains type variable(s) `a'
4 that do not appear in `Int -> Int'
5 in the type signature for `f'
8 Context constrains in-scope type variable(s) `a'
9 in the type signature for `op'
12 Context constrains type variable(s) `a'
13 that do not appear in `Eq Bool'
14 in the type signature for an instance decl
16 Compilation had errors