10 Feb
2015
10 Feb
'15
10:52 a.m.
On Tue, Feb 10, 2015 at 7:58 PM, Joel Neely
sumDigits (n:ns) | n < 10 = n + sumDigits ns | n >= 10 = r + sumDigits (q : ns) where (q, r) = n `quotRem` 10
To reiterate what Mike and Brandon just said, it's not that both the [] and (n:ns) cases have not been covered. They have. It's that the (n:ns) case hasn't been covered completely because of the guards. This will work: sumDigits (n:ns) | n < 10 = n + sumDigits ns | otherwise = r + sumDigits (q : ns) As will this: sumDigits (n:ns) | n < 10 = n + sumDigits ns | n >= 10 = r + sumDigits (q : ns) | otherwise = error "will never fire, only to suppress spurious warning" There's also -fno-warn-incomplete-patterns. -- Kim-Ee