Enable inference in the core libs

test/codegen/expect/dart/async.js

 var async;
 (function(exports) {
   'use strict';
   // Function _invokeErrorHandler: (Function, Object, StackTrace) → dynamic
   function _invokeErrorHandler(errorHandler, error, stackTrace) {
     if (dart.is(errorHandler, ZoneBinaryCallback)) {
       return dart.dinvokef(errorHandler, error, stackTrace);
     } else {
       return dart.dinvokef(errorHandler, error);
     }
@@ skipping 1368 matching lines @@
       exports._lastPriorityCallback.next = entry;
       exports._lastPriorityCallback = entry;
       if (entry.next === null) {
         exports._lastCallback = entry;
       }
     }
   }
   // Function scheduleMicrotask: (() → void) → void
   function scheduleMicrotask(callback) {
     if (core.identical(_ROOT_ZONE, Zone.current)) {
-      _rootScheduleMicrotask(null, null, dart.as(_ROOT_ZONE, Zone), callback);
+      _rootScheduleMicrotask(null, null, _ROOT_ZONE, callback);
       return;
     }
     Zone.current.scheduleMicrotask(Zone.current.bindCallback(callback, {runGuarded: true}));
   }
   let _scheduleImmediate = Symbol('_scheduleImmediate');
   let _initializeScheduleImmediate = Symbol('_initializeScheduleImmediate');
   let _scheduleImmediateJsOverride = Symbol('_scheduleImmediateJsOverride');
   let _scheduleImmediateWithSetImmediate = Symbol('_scheduleImmediateWithSetImmediate');
   let _scheduleImmediateWithTimer = Symbol('_scheduleImmediateWithTimer');
   class _AsyncRun extends core.Object {
@@ skipping 2850 matching lines @@
       let previous = _current;
       _current = zone;
       return previous;
     }
     static [_leave](previous) {
       dart.assert(previous !== null);
       Zone[_current] = previous;
     }
   }
   dart.defineNamedConstructor(Zone, '_');
-  Zone.ROOT = dart.as(_ROOT_ZONE, Zone);
-  Zone._current = dart.as(_ROOT_ZONE, Zone);
+  Zone.ROOT = _ROOT_ZONE;
+  Zone._current = _ROOT_ZONE;
   let _delegate = Symbol('_delegate');
   // Function _parentDelegate: (_Zone) → ZoneDelegate
   function _parentDelegate(zone) {
     if (zone.parent === null)
       return null;
     return zone.parent[_delegate];
   }
   let _delegationTarget = Symbol('_delegationTarget');
   let _handleUncaughtError = Symbol('_handleUncaughtError');
   let _run = Symbol('_run');
@@ skipping 332 matching lines @@
   function _rootRegisterBinaryCallback(self, parent, zone, f) {
     return f;
   }
   // Function _rootErrorCallback: (Zone, ZoneDelegate, Zone, Object, StackTrace) → AsyncError
   function _rootErrorCallback(self, parent, zone, error, stackTrace) {
     return null;
   }
   // Function _rootScheduleMicrotask: (Zone, ZoneDelegate, Zone, () → dynamic) → void
   function _rootScheduleMicrotask(self, parent, zone, f) {
     if (!dart.notNull(core.identical(_ROOT_ZONE, zone))) {
-      let hasErrorHandler = dart.dunary('!', dart.dinvoke(_ROOT_ZONE, 'inSameErrorZone', zone));
+      let hasErrorHandler = !dart.notNull(_ROOT_ZONE.inSameErrorZone(zone));
       f = zone.bindCallback(f, {runGuarded: hasErrorHandler});
     }
     _scheduleAsyncCallback(f);
   }
   // Function _rootCreateTimer: (Zone, ZoneDelegate, Zone, Duration, () → void) → Timer
   function _rootCreateTimer(self, parent, zone, duration, callback) {
     if (!dart.notNull(core.identical(_ROOT_ZONE, zone))) {
       callback = zone.bindCallback(callback);
     }
     return Timer._createTimer(duration, callback);
@@ skipping 72 matching lines @@
     }
     get fork() {
       return _rootFork;
     }
   }
   class _RootZone extends _Zone {
     _RootZone() {
       super._Zone();
     }
     get [_run]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootRun);
+      return new _ZoneFunction(_ROOT_ZONE, _rootRun);
     }
     get [_runUnary]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootRunUnary);
+      return new _ZoneFunction(_ROOT_ZONE, _rootRunUnary);
     }
     get [_runBinary]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootRunBinary);
+      return new _ZoneFunction(_ROOT_ZONE, _rootRunBinary);
     }
     get [_registerCallback]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootRegisterCallback);
+      return new _ZoneFunction(_ROOT_ZONE, _rootRegisterCallback);
     }
     get [_registerUnaryCallback]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootRegisterUnaryCallback);
+      return new _ZoneFunction(_ROOT_ZONE, _rootRegisterUnaryCallback);
     }
     get [_registerBinaryCallback]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootRegisterBinaryCallback);
+      return new _ZoneFunction(_ROOT_ZONE, _rootRegisterBinaryCallback);
     }
     get [_errorCallback]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootErrorCallback);
+      return new _ZoneFunction(_ROOT_ZONE, _rootErrorCallback);
     }
     get [_scheduleMicrotask]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootScheduleMicrotask);
+      return new _ZoneFunction(_ROOT_ZONE, _rootScheduleMicrotask);
     }
     get [_createTimer]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootCreateTimer);
+      return new _ZoneFunction(_ROOT_ZONE, _rootCreateTimer);
     }
     get [_createPeriodicTimer]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootCreatePeriodicTimer);
+      return new _ZoneFunction(_ROOT_ZONE, _rootCreatePeriodicTimer);
     }
     get [_print]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootPrint);
+      return new _ZoneFunction(_ROOT_ZONE, _rootPrint);
     }
     get [_fork]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootFork);
+      return new _ZoneFunction(_ROOT_ZONE, _rootFork);
     }
     get [_handleUncaughtError]() {
-      return new _ZoneFunction(dart.as(_ROOT_ZONE, _Zone), _rootHandleUncaughtError);
+      return new _ZoneFunction(_ROOT_ZONE, _rootHandleUncaughtError);
     }
     get parent() {
       return null;
     }
     get [_map]() {
       return _rootMap;
     }
     get [_delegate]() {
       if (_rootDelegate !== null)
         return _rootDelegate;
@@ skipping 189 matching lines @@
   exports.StreamIterator$ = StreamIterator$;
   exports.StreamController = StreamController;
   exports.StreamController$ = StreamController$;
   exports.Timer = Timer;
   exports.AsyncError = AsyncError;
   exports.ZoneSpecification = ZoneSpecification;
   exports.ZoneDelegate = ZoneDelegate;
   exports.Zone = Zone;
   exports.runZoned = runZoned;
 })(async || (async = {}));