- Nothing -> Nothing -- c1 succeeds
- Just {} -> c2 tc -- c1 fails, try c2
--- orCond produced just one error message, namely from c2
--- Getting two can be confusing. For a zero-constructor
--- type with a standalone isntance decl, we previously got:
--- Can't make a derived instance of `Bounded (Test a)':
--- `Test' has no data constructors
--- and
--- `Test' does not have precisely one constructor
+ Nothing -> Nothing -- c1 succeeds
+ Just x -> case c2 tc of -- c1 fails
+ Nothing -> Nothing
+ Just y -> Just (x $$ ptext (sLit " and") $$ y)
+ -- Both fail