class M {
  static f () : void {
    mutable x = 1;
    x = "foo"; // E: expected int.* got string
  }
  static g () : void {
    def x = 1;
    x = 3;    // E: .*read-only
  }
}

class C {
  f : int;
  static qux () : void
  {
    def q (x) { x.f = 3; } // E: needed writable
    q(C());
  }
}

// bug #809
class A { }
class B : A { }

mutable x = B ();
x = A (); // OK
mutable b : B = B();
b = A (); // E: expected B, got A in assigned value