Setting the value of an abstract property does not work with enum type inference

[jgranick]

When setting an enum value in Haxe, ordinarily, type inference allows you to use enum values through type inference without an import:

classInstance.classProperty = NO;

Using @:forward on an abstract allows this same functionality in the Haxe 4 preview 5 release, however it is not possible if you define an abstract property:

enumInstance.enumProperty = NO; // Unknown identifier: NO

Here's code to reproduce the problem, thank you 😄

class Test {
    static function main() {
        // Base Class
        var classInstance = new MyBaseClass ();
        classInstance.classProperty = haxe.zip.FlushMode.NO; // Works
        classInstance.classProperty = NO; // Works
        
        // Abstract
        var enumInstance = new MyAbstract ();
        enumInstance.abstractProperty = haxe.zip.FlushMode.NO; // Works
        enumInstance.abstractProperty = NO; // Broken
    }
}

abstract MyAbstract(MyBaseClass) {
    public var abstractProperty (get, set):haxe.zip.FlushMode;
    public function new () { this = new MyBaseClass (); }
    private inline function get_abstractProperty () { return haxe.zip.FlushMode.NO; }
    private inline function set_abstractProperty (value) { return haxe.zip.FlushMode.NO; }
}

class MyBaseClass {
    public var classProperty:haxe.zip.FlushMode;
    public function new () {}
}

https://try.haxe.org/#53B4c

[Simn]

Looks like this doesn't employ top-down inference at all:

class Main {
    static function main() {
        var enumInstance = new MyAbstract ();
        enumInstance.abstractProperty = [1];
    }
}

abstract MyAbstract({}) {
    public var abstractProperty (get, set):Array<Float>;
    public function new () { this = {}; }
    private inline function get_abstractProperty () { return []; }
    private inline function set_abstractProperty (value:Array<Float>) { return []; }
}

source/Main.hx:5: characters 9-44 : error: Int should be Float
source/Main.hx:5: characters 9-44 :  have: Array<Int>
source/Main.hx:5: characters 9-44 :  want: Array<Float>

I'm gonna take a look at this for Haxe 4.

[Simn]

Note that I'm cheating a bit in my example because I type-hint value:Array<Float>. In the original example, this was untyped and as it turns out, we delay the property checks so far that we don't have the proper type when making the access:

AKUsing([Field:(this : { }, value : Unknown<0>) -> Array<Unknown<1>>]
        [TypeExpr _Main.MyAbstract_Impl_:Class<_Main.MyAbstract_Impl_>]
        [FStatic:(this : { }, value : Unknown<0>) -> Array<Unknown<1>>]
                _Main.MyAbstract_Impl_
                set_abstractProperty:(this : { }, value : Unknown<0>) -> Array<Unknown<1>>, _Main.MyAbstract_Impl_, set_abstractProperty, [Local enumInstance(18):MyAbstract:MyAbstract])

All the Array instances there have an unknown type parameter. This is a different but very much related problem because we cannot top-down infer with uninferred types.

[Simn]

Argh, this changes when we put MyAbstract above Main.