Don't ignore default values of arguments of inlined functions

[RealyUniqueName]

Fixes #7032

[Simn]

This doesn't seem quite right because we now handle default values in two places. This PR would introduce unwanted branching in cases where we have all the static information, e.g. if we're calling your def2 directly.

Please make sure to check the output without -D analyzer-optimize to make sure this doesn't happen. The branching should only occur if we're calling the function with a statically unknown value.

[RealyUniqueName]

Actually, we don't handle default values like that anywhere in the compiler. Generators have to do that manually. And this branching is only inserted on the call site. Original function body is not changed.

Please make sure to check the output without -D analyzer-optimize to make sure this doesn't happen. The branching should only occur if we're calling the function with a statically unknown value.

Here is the generated js:

// Generated by Haxe 4.0.0-rc.3
(function ($global) { "use strict";
var Main = function() { };
Main.main = function() {
	console.log("src/Main.hx:3:",10);  // This is for `trace(def2(null))` or `trace(def2())`
	console.log("src/Main.hx:4:",Main.def(null));
};
Main.def = function(p) {
	var p1 = p;
	if(p == null) {
		p1 = 10;
	}
	return p1;
};
Main.main();
})({});

[Simn]

class Main {
	static function main() {
		trace(f());
	}

	static inline function f(p = 10) {
		return p;
	}
}

Compiled to JS without -D analyzer-optimize:

Main.main = function() {
	var p = 10;
	if(p == null) {
		p = 10;
	}
	console.log("source/Main.hx:3:",p);
};

[RealyUniqueName]

Sorry, I run it with analyzer-optimize

[RealyUniqueName]

What would be the correct fix then?
Because if I have a code like this:

var p = null;
trace(f(p));

does it count for p being statucally known? Or do we need an analyzer pass prior to inlining to be able to fix the issue?

[Simn]

In that case we have to accept the branching, nothing we can do about it. The analyzer will clean this up where possible and it's fair to require its usage in these situations.