tcfail204.hs:10:7: Warning:
    Defaulting the following constraint(s) to type ‘Double’
      (RealFrac a0)
        arising from a use of ‘ceiling’ at tcfail204.hs:10:7-13
      (Fractional a0)
        arising from the literal ‘6.3’ at tcfail204.hs:10:15-17
    In the expression: ceiling 6.3
    In an equation for ‘foo’: foo = ceiling 6.3

<no location info>: 
Failing due to -Werror.