This probably won't make a huge difference, but it is an example of where we can remove unused parameters without much analysis. I think there are 20-30 useless expressions that can be eliminated in swarm.

An initializing formal is not a parameter of a generative constructor body.

-------- example
class A {
  var a,b,c,d;

 A(this.a, b, c, d) : b = b {
    // There are only three parameters: b, c, d. 'a' resolves to this.a
    if (false) throw 123; // inhibit inlining
    this.c = c;
    a++;b++;c++;
    this.d = [a, b, c, d];
  }

  toString() => 'A($a, $b, $c, $d)';
}

make() => new A(10, 20, 30, 40);

main() {
  print((make)());
}

-------- output
A(11, 20, 30, [11, 21, 31, 40])

-------- generated code
  make: [function() {
    var t1 = new E.A(10, 20, null, null);
    t1.A$4(10, 20, 30, 40);
    return t1;
  }, "call$0", "make$closure", 0, 0, 0],
  main: ...,
  A: {
    ...,
    A$4: function(a, b, c, d) {
      var t1;
      this.c = c;
      t1 = this.a + 1;
      this.a = t1;
      this.d = [t1, b + 1, c + 1, d];
    }
  }

Notice that A$4 has a useless 'a' parameter, and the call is passed a useless argument.