T12973.hs:13:7: error: [GHC-55287]
    • The argument ‘3’ of ‘(+)’
      does not have a fixed runtime representation.
      Its type is:
        a0 :: TYPE c0
      Cannot unify ‘r’ with the type variable ‘c0’
      because it is not a concrete ‘RuntimeRep’.
    • In the expression: 3 + 4
      In an equation for ‘foo’: foo = 3 + 4
    • Relevant bindings include foo :: a (bound at T12973.hs:13:1)