3 Duplicate or overlapping instance declarations
4 for `Eq (a, b)' at PrelTup.hi:11 and tcfail073.hs:8
7 Could not deduce `Eq a'
8 (arising from use of `==' at tcfail073.hs:8)
9 from the context (Eq (a, b), /= at (a, b), == at (a, b))
10 Probable cause: missing `Eq a' in instance declaration context
11 When checking the methods of an instance declaration
14 Compilation had errors