No dynamic at runtime

test/codegen/expect/sunflower/sunflower.js

 var sunflower = dart.defineLibrary(sunflower, {});
 var math = dart.import(math);
 var dom = dart.import(dom);
 var core = dart.import(core);
 (function(exports, math, dom, core) {
   'use strict';
   let ORANGE = "orange";
   let SEED_RADIUS = 2;
   let SCALE_FACTOR = 4;
   let TAU = dart.notNull(math.PI) * 2;
@@ skipping 13 matching lines @@
       return querySelector("#notes");
     },
     get PHI() {
       return (dart.notNull(math.sqrt(5)) + 1) / 2;
     },
     get context() {
       return dart.as(dart.as(querySelector("#canvas"), dom.CanvasElement).getContext('2d'), dom.CanvasRenderingContext2D);
     }
   });
   function main() {
-    exports.slider.addEventListener('change', dart.fn(e => draw(), dart.void, [dart.dynamic]));
+    exports.slider.addEventListener('change', dart.fn(e => draw(), dart.void, [core.Object]));
     draw();
   }
   dart.fn(main, dart.void, []);
   function draw() {
     exports.seeds = core.int.parse(exports.slider.value);
     exports.context.clearRect(0, 0, MAX_D, MAX_D);
     for (let i = 0; dart.notNull(i) < dart.notNull(exports.seeds); i = dart.notNull(i) + 1) {
       let theta = dart.notNull(i) * dart.notNull(TAU) / dart.notNull(exports.PHI);
       let r = dart.notNull(math.sqrt(i)) * dart.notNull(SCALE_FACTOR);
       let x = dart.notNull(centerX) + dart.notNull(r) * dart.notNull(math.cos(theta));
@@ skipping 46 matching lines @@
   exports.MAX_D = MAX_D;
   exports.centerX = centerX;
   exports.centerY = centerY;
   exports.querySelector = querySelector;
   exports.main = main;
   exports.draw = draw;
   exports.Circle = Circle;
   exports.CirclePainter = CirclePainter;
   exports.SunflowerSeed = SunflowerSeed;
 })(sunflower, math, dom, core);