avm1 super doesn't correctly resolve this properties

[Dinnerbone]

Well that's a difficult bug to summarize.

In a method on a superclass, this should look at the current object top-down when resolving properties, and not just from the current point in the prototype chain.

Test case:

class Base {
	function Base() {
		trace("// Base");
		trace(this["test"]);
	}
}
class Extended extends Base {
	var test = "Extended";
	function Extended() {
		super();
		trace("// Extended");
		trace(this["test"]);
	}
}
class ExtendedFurther extends Extended {
	var test = "ExtendedFurther";
	function ExtendedFurther() {
		super();
		trace("// ExtendedFurther");
		trace(this["test"]);
	}
}
new ExtendedFurther();

Expected output:

// Base
ExtendedFurther
// Extended
ExtendedFurther
// ExtendedFurther
ExtendedFurther

In ruffle:

// Base
undefined
// Extended
Extended
// ExtendedFurther
ExtendedFurther

[kmeisthax]

I know how this happened. The underlying problem is how we handle super calls: super needs to remember how many levels deep we are in a call chain. The current AVM1 super implementation achieves this by maintaining a reference to the current super-prototype and super-constructor to call. However, preserving this across call boundaries is difficult. To get around having to extend call, I instead just passed super as this to the called function. This worked up until I started testing what super actually responded to in Flash Player. It actually does very little. For accuracy's sake, I reduced what super could do, which ultimately introduced this bug.

In my AVM2 proposal (PR #404), because super is NOT an AVM2 object, I couldn't store information in it. Instead, each call calculates a base_proto which is stored in the activation object, and the various super-related opcodes reference the activation's base_proto. I will attempt to backport this approach to AVM1 (where it actually makes more sense). This will also mean call and everything surrounding it will need to take a base_proto so that super and CallMethod can properly cooperate rather than the hacky AVM1 method of proxying stuff from super to this.