Why, neko?

build.hxml

-cp .
-main Main
-x Main.n

Main.hx

class Main
{
    private static function main()
    {
        function newEmptyHandler():Void->Void
        {
            return function():Void {};
        }

        var a:Void->Void = newEmptyHandler();
        var b:Void->Void = newEmptyHandler();
        trace(a);
        trace(b);
        trace(a == b);
        trace(Reflect.compareMethods(a, b));
    }
}

output

Main.hx:12: #function:0
Main.hx:13: #function:0
Main.hx:14: true
Main.hx:15: true

What's even more confusing, this works as expected:

class Main
{
private static function main()
{
var a:Void->Void = function():Void {};
var b:Void->Void = function():Void {};
trace(a);
trace(b);
trace(a == b);
trace(Reflect.compareMethods(a, b));
}
}

Output:

Main.hx:7: #function:0
Main.hx:8: #function:0
Main.hx:9: false
Main.hx:10: false

After some research, I found out that it depends on whether function holds any context from outer scope:

class Main
{
private static function newHandlerWithContext()
{
var ctx = "something";
return function() { ctx; };
}

private static function newHandlerWithoutContext()
{
    return function() { };
}

private static function main()
{
    var a = newHandlerWithContext();
    var b = newHandlerWithContext();
    trace(a == b);
    trace(Reflect.compareMethods(a, b));

    var a = newHandlerWithoutContext();
    var b = newHandlerWithoutContext();
    trace(a == b);
    trace(Reflect.compareMethods(a, b));
}

}

Output:

Main.hx:18: false
Main.hx:19: false
Main.hx:23: true
Main.hx:24: true