Infer parameter types on overrides

lib/runtime/dart/js.js

 dart_library.library('dart/js', null, /* Imports */[
   "dart_runtime/dart",
   'dart/core',
   'dart/collection',
   'dart/_js_helper'
 ], /* Lazy imports */[
 ], function(exports, dart, core, collection, _js_helper) {
   'use strict';
   let dartx = dart.dartx;
   dart.defineLazyProperties(exports, {
@@ skipping 183 matching lines @@
       }
       static _checkRange(start, end, length) {
         if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(length)) {
           dart.throw(new core.RangeError.range(start, 0, length));
         }
         if (dart.notNull(end) < dart.notNull(start) || dart.notNull(end) > dart.notNull(length)) {
           dart.throw(new core.RangeError.range(end, start, length));
         }
       }
       get(index) {
-        if (dart.is(index, core.num) && dart.equals(index, dart.dsend(index, 'toInt'))) {
-          this[_checkIndex](dart.as(index, core.int));
+        if (dart.is(index, core.num) && index == index[dartx.toInt]()) {
+          this[_checkIndex](index);
         }
         return dart.as(super.get(index), E);
       }
       set(index, value) {
         dart.as(value, E);
-        if (dart.is(index, core.num) && dart.equals(index, dart.dsend(index, 'toInt'))) {
-          this[_checkIndex](dart.as(index, core.int));
+        if (dart.is(index, core.num) && index == index[dartx.toInt]()) {
+          this[_checkIndex](index);
         }
         super.set(index, value);
       }
       get length() {
         let len = this[_jsObject].length;
         if (typeof len === "number" && len >>> 0 === len) {
           return len;
         }
         dart.throw(new core.StateError('Bad JsArray length'));
       }
@@ skipping 52 matching lines @@
     dart.defineNamedConstructor(JsArray, '_fromJs');
     dart.setSignature(JsArray, {
       constructors: () => ({
         JsArray: [JsArray$(E), []],
         from: [JsArray$(E), [core.Iterable$(E)]],
         _fromJs: [JsArray$(E), [dart.dynamic]]
       }),
       methods: () => ({
         [_checkIndex]: [dart.dynamic, [core.int]],
         [_checkInsertIndex]: [dart.dynamic, [core.int]],
-        get: [E, [dart.dynamic]],
-        set: [dart.void, [dart.dynamic, E]],
+        get: [E, [core.int]],
+        set: [dart.void, [core.int, E]],
         add: [dart.void, [E]],
         addAll: [dart.void, [core.Iterable$(E)]],
         insert: [dart.void, [core.int, E]],
         removeAt: [E, [core.int]],
         removeLast: [E, []],
         setRange: [dart.void, [core.int, core.int, core.Iterable$(E)], [core.int]],
         sort: [dart.void, [], [dart.functionType(core.int, [E, E])]]
       }),
       statics: () => ({_checkRange: [dart.dynamic, [core.int, core.int, core.int]]}),
       names: ['_checkRange']
@@ skipping 95 matching lines @@
     let __CastType0 = dart.typedef('__CastType0', () => dart.functionType(dart.dynamic, [E]));
     return __CastType0;
   });
   let __CastType0 = __CastType0$();
   // Exports:
   exports.JsObject = JsObject;
   exports.JsFunction = JsFunction;
   exports.JsArray$ = JsArray$;
   exports.JsArray = JsArray;
 });