tcfail008.hs:3:5: error: [GHC-39999]
    • Ambiguous type variable ‘a0’ arising from the literal ‘1’
      prevents the constraint ‘(Num a0)’ from being solved.
      Relevant bindings include o :: [a0] (bound at tcfail008.hs:3:1)
      Probable fix: use a type annotation to specify what ‘a0’ should be.
      Potentially matching instances:
        instance Num Integer -- Defined in ‘GHC.Num’
        instance Num Double -- Defined in ‘GHC.Float’
        ...plus three others
        ...plus one instance involving out-of-scope types
        (use -fprint-potential-instances to see them all)
    • In the first argument of ‘(:)’, namely ‘1’
      In the expression: 1 : 2
      In an equation for ‘o’: o = 1 : 2

tcfail008.hs:3:7: error: [GHC-39999]
    • No instance for ‘Num [a0]’ arising from the literal ‘2’
    • In the second argument of ‘(:)’, namely ‘2’
      In the expression: 1 : 2
      In an equation for ‘o’: o = 1 : 2