tcfail017.hs:10:
- Could not deduce `C [a]'
- (arising from an instance declaration at tcfail017.hs:10)
- from the context: (B a)
- Probable cause: missing `C [a]' in instance declaration context
- or missing instance declaration for `C [a]'
- When checking the superclasses of an instance declaration
-
-Compilation had errors
-
+ Could not deduce `C [a]' from the context (B a)
+ Probable fix:
+ Add `C [a]' to the instance declaration context
+ Or add an instance declaration for `C [a]'
+ arising from an instance declaration at tcfail017.hs:10