t2712-1.scala:7: error: no type parameters for method foo: (m: M[A])Unit exist so that it can be applied to arguments (test.Two[Int,String])
 --- because ---
argument expression's type is not compatible with formal parameter type;
 found   : test.Two[Int,String]
 required: ?M[?A]
  def test(ma: Two[Int, String]) = foo(ma) // should fail with -Ypartial-unification *disabled*
                                   ^
t2712-1.scala:7: error: type mismatch;
 found   : test.Two[Int,String]
 required: M[A]
  def test(ma: Two[Int, String]) = foo(ma) // should fail with -Ypartial-unification *disabled*
                                       ^
two errors found