:1:1: Ambiguous type variable `a' in the constraint: (Show a) arising from a use of `print' Cannot resolve unknown runtime types: a Use :print or :force to determine these types In a stmt of an interactive GHCi command: print it :1:1: Ambiguous type variable `a' in the constraint: (Show a) arising from a use of `print' Cannot resolve unknown runtime types: a Use :print or :force to determine these types In a stmt of an interactive GHCi command: print it