dart2js后异步函数中两个keyCodes的比较不正确

Question

我不明白dart2js代码的这种行为.
我只在async函数中使用它,并且只在编译成JS之后.

e.keyCode is equal 13
KeyCode.ENTER is equal 13

但

(e.keyCode == KeyCode.ENTER) is false

这是调试我的问题的简单代码.
这是怎么回事？

import 'dart:html';

main() async
{
  await for(KeyboardEvent e in window.onKeyDown)
  {
    print('e.keyCode : ${e.keyCode}');
    print('e.keyCode.hashCode : ${e.keyCode.hashCode}');
    print('KeyCode.ENTER : ${KeyCode.ENTER}');
    print('KeyCode.ENTER.hashCode : ${KeyCode.ENTER.hashCode}');
    print('e.keyCode.runtimeType : ${e.keyCode.runtimeType}');
    print('KeyCode.ENTER.runtimeType : ${KeyCode.ENTER.runtimeType}');
    print('e.keyCode == KeyCode.ENTER ${e.keyCode == KeyCode.ENTER}');
    print('e.keyCode != KeyCode.ENTER ${e.keyCode != KeyCode.ENTER}');
    int a = e.keyCode;
    int b = KeyCode.ENTER;
    print('a = $a');
    print('b = $b');
    print('a.hashCode = ${a.hashCode}');
    print('b.hashCode = ${b.hashCode}');
    print('a == b ${(a == b).toString()}');
    print('a == 13 ${(a == 13).toString()}');
    print('b == 13 ${(b == 13).toString()}');
    if(a == b)
      print('DART: a == b');
    else
      print('DART: a != b');
  }
}

按Enter键后输出Chrome(dart2js - minified):

e.keyCode:13
e.keyCode.hashCode:13
KeyCode.ENTER:13
KeyCode.ENTER.hashCode:13
e.keyCode.runtimeType:int
KeyCode.ENTER.runtimeType:int
e.keyCode == KeyCode.ENTER false
e.keyCode != KeyCode.ENTER true
a = 13
b = 13
a.hashCode = 13
b.hashCode = 13
a == b true
a == 13 true
b == 13 true
DART:a!= b

在DartVM(Dartium)上一切都是正确的:

e.keyCode:13
e.keyCode.hashCode:13
KeyCode.ENTER:13
KeyCode.ENTER.hashCode:13
e.keyCode.runtimeType:int
KeyCode.ENTER.runtimeType:int
e.keyCode == KeyCode.ENTER true
e.keyCode != KeyCode.ENTER false
a = 13
b = 13
a.hashCode = 13
b.hashCode = 13
a == b true
a == 13 true
b == 13 true
DART:a == b

//编辑
我注意到我使用keyCode并不重要.
这是异步问题.
编译成JS后,下面的代码在Dartium上返回'OK',在Chrome上返回'NOPE'.

import 'dart:async';

main() async
{
  var ctrl = new StreamController();
  ctrl.add(true);

  await for(var e in ctrl.stream)
  {
    if(e == e)
      print('OK');
    else
      print('NOPE');
  }
}

Answer 1

这确实和这个bug是一样的。

为 async for 循环的迭代变量推断出错误的类型。

1.10 中已修复。