tcfail023.hs:2: Duplicate or overlapping instance declarations
    for `A B' at tcfail023.hs:8 and tcfail023.hs:11
 
tcfail023.hs:11: Couldn't match the type
		     `B' against `PrelBase.Bool'
    Expected: `B'
    Inferred: `PrelBase.Bool'
    In an equation for function `op': `op C = PrelBase.True'
 
tcfail023.hs:8: Couldn't match the type `B' against `PrelBase.Bool'
    Expected: `B'
    Inferred: `PrelBase.Bool'
    In an equation for function `op': `op C = PrelBase.True'
 
tcfail023.hs:2: Module Main must include a definition for `Main.main'


Compilation had errors