T21650_b.hs:34:7: error: [GHC-55287]
    • Unsaturated use of a representation-polymorphic newtype constructor.
      The first argument of ‘MkN’
      does not have a fixed runtime representation.
      Its type is:
        a :: TYPE (RR T1 t2)
    • In the expression: MkN
      In an equation for ‘foo’: foo = MkN

T21650_b.hs:37:7: error: [GHC-55287]
    • Unsaturated use of a representation-polymorphic newtype constructor.
      The first argument of ‘MkN’
      does not have a fixed runtime representation.
      Its type is:
        a :: TYPE (RR T1 t2)
    • In the expression: MkN
      In an equation for ‘bar’: bar = MkN