2 tcfail042.hs:16: tcfail042.hs:16: Context required by inferred type, but missing on a type signature:
3 in an instance declaration
4 `PrelBase.Num' `a{-aN7-}'
5 When checking superclass constraints of an instance declaration
7 tcfail042.hs:4: Module Main must include a definition for `Main.main'
10 Compilation had errors