Warnings for macro-in-macro.

[back2dos]

Until macro-in-macro is properly supported, we should warn when it's used (personally I wouldn't mind an error). It would go a long way to make things easier for newcomers. I've lost count of how many times I saw some variant of this problem: https://community.haxe.org/t/injecting-a-local-variable-with-macro/953

[jdonaldson]

Are all of the problems here due to macros containing macros in the same file? I'm wondering if we could just detect that somehow and give a more specific error for that.

[Simn]

We have an option to show macro-in-macro by using -D macro-debug. Of course that doesn't actually help you unless you know that macro-in-macro is your problem in the first place.

[Simn]

If we add a warning for this we also need a way to avoid the warning in case you genuinely want to have a macro-in-macro call.

[back2dos]

Ok, more drastic then: How about forbidding it to see if anybody complains? Since macro-in-macro busts the cache, I doubt anybody would "genuinely want to have a macro-in-macro call" other than for some funky experiments. It creates way more problems than it solves.

[Simn]

I'm experimenting with this, but our mutual friend haxelib gets in the way because of this:

class Main {
	static var VERSION:SemVer = SemVer.ofString(getHaxelibVersion());
	static var VERSION_LONG:String = getHaxelibVersionLong();

	macro static function getHaxelibVersion() {
		var haxelibJson:Infos = Json.parse(File.getContent("haxelib.json"));
		return macro $v{haxelibJson.version};
	}

	macro static function getHaxelibVersionLong() {
		var version:String = VERSION;

[back2dos]

How about #if-fencing it in haxelib then?

[Simn]

That won't be enough because there's some legit macro-in-macro handling going because macro getHaxelibVersionLong works with VERSION which is initialized using a macro call.

[back2dos]

Without further ado I present to you: #if !macro macro #end

[Simn]

That still won't do because.... you know what, how about you just fix it? :P

[back2dos]

I'll do my best, but I have no way of knowing if it's fixed, do I? :P

[Simn]

-D check-macro should not give warnings.

Although the way it's implemented right now is not ideal. It warns when typing a macro-in-macro, which is not necessary. We only care about it if we actually call such a macro.

[Simn]

I meant -D macro-debug