defer with if

[Feoramund]

The potential for a distinction between the following two blocks of code came up recently in #3781 (comment):

defer if a { /*...*/ }

defer {
	if a { /*...*/ }
}

These two work the same at the moment, which is to say that the if is only checked when the deferred statement is run, but the first reads as if the block should only be deferred if a is true. Should defer if a ... raise a warning, or does this case need more documentation?

[programandala-net]

Feoramund escribió/skribis/wrote/scrit (2024-06-18T09:59:24-0700):

```odin defer if a { /*...*/ } defer { if a { /*...*/ } } ``` These two work the same at the moment, which is to say that the `if` is only checked when the deferred statement is run,

That's the expected behaviour in both cases, which is clear: "A `defer` statement defers the execution of a statement until the end of the scope it is in. (…) You can defer an entire block too". Therefore you can defer an `if` as well.

but the first reads as if the block should only be deferred if `a` is true.

You are right, but that impression may be caused by reading the code as plain English.

Should `defer if a ...` raise a warning, or does this case need more documentation?

I think nothing is needed. In fact, the current [documentation of `defer`](https://odin-lang.org/docs/overview/#defer-statement) already includes an example of `defer if` as a deferred block.