Incorrect comparison of two keyCodes in async function after dart2js

Question

I don't understand this behavior of dart2js code.
I have this only in async function and only after compiling to JS.

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

but

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

This is simple code to debugging my issue.
Whats going on?

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');
  }
}

Output on Chrome after pressing Enter (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

On DartVM (Dartium) everything is correct:

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

// EDIT
I noticed that it does not matter that I'm using keyCode.
This is async issue.
Code below returns 'OK' on Dartium and 'NOPE' on Chrome after compiling to JS.

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');
  }
}

Folkmoot

You should file a bug at www.dartbug.com. Which version of dart-sdk are you using? – Tennietenniel

the final .js code does not even contain the string "DART: a == b". – Tennietenniel

Dart Editor version 1.9.3.release (STABLE) Dart SDK version 1.9.3 – Folkmoot

Answer 1

This is indeed the same as this bug.

The wrong type was inferred for the iteration variable of async for loops.

It is fixed in 1.10.

Lisabethlisan

This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post - you can always comment on your own posts, and once you have sufficient reputation you will be able to comment on any post. – Reavis

@Reavis I do think this answer the question, as there's no real solution but to update. I edited the answer to add the link to the bugtracker for future readers reference. – Lode

I also don't see any additional info to @0pako0 s answer. – Inventive

@GünterZöchbauer Well, there's the confirmation this is a known bug, gives the link to it, does a brief in case the link break and ensure the version where is it fixed. It's a better answer IMHO as there's facts and not only observations. – Lode

I would have prefered to comment @0pako0's answer - but did not have enough points. – Lisabethlisan

Answer 2

This must be 1.9.3 dart2js bug.

I use now Dart SDK version 1.10.0-dev.1.5 and everything works fine. This is only solution what I found, if I want use 'await for'.

Folkmoot