ZDoom

Fixed in [url=https://github.com/coelckers/gzdoom/commit/7d1af25b46eb28e9d154a68f92ab3143a4091e08]7d1af25[/url].

Code of such for loop is not generated at all. Made [url=https://github.com/coelckers/gzdoom/pull/572]PR[/url] with the fix to be sure that it's OK to fix the problem this way.

[quote="Graf Zahl"]The return type mismatch is because the compiler is not smart enough to detect that the end of the loop is never reached. So it sees both a boolean return and a void return and complains about it.[/quote]
Yeah, I'm aware of that, which is why I suspect something is going horribly wrong when it tries to compile the "for (;;)" loop.
... Which the disassembly seems to agree with. There's no disassembly for TestActor's "a" function in it at all.
[url=https://www.dropbox.com/s/8yxty57c4n1dyax/ZScriptForLoopCrash-disasm.zip?dl=0]Here's the disassembly[/url] if you want to take a look.

The return type mismatch is because the compiler is not smart enough to detect that the end of the loop is never reached. So it sees both a boolean return and a void return and complains about it.
I cannot run this myself until late this evening, so if you could run this thing with "-dumpdisasm" and post the output I may give some feedback earlier.

Exactly what it says on the thread title.

Steps to reproduce:
[list]
[*]Start a new game with the attached PK3 loaded
[*]Summon "TestActor"[/list]

Based on a few observations, I'm guessing either the compiler backend or the compiler frontend is compiling it completely wrong. It doesn't even start if you replace the "for (;;)" loop with a "while (true)" loop, as it errors out with the "Return type mismatch" error, which doesn't happen at all with the "for (;;)" loop.