#[macro_export(hello, world)]

[SoniEx2]

I tried this code:

#[macro_export(hello, world)]
macro_rules! foo {
    () => {}
}

https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=9c40221c498bdc99beb7022d53fdb086

I expected to see this happen: it shouldn't compile

Instead, this happened: it compiles

Meta

rustc --version --verbose:

N/A

Backtrace

<backtrace>

[fmease]

For anyone who would like to work on this, the following code needs to be adjusted to check if the meta-item list is empty or if it only contains the identifier local_inner_macros (i.e. only allowing the attribute to be #[macro_export] or #[macro_export(local_inner_macros)]:

rust/compiler/rustc_passes/src/check_attr.rs

Line 2010 in c8e6a9e

fn check_macro_export(&self, hir_id: HirId, attr: &Attribute, target: Target) {

Due to backward compatibility concerns, probably only a future-incompat warning should be issued if the verification fails.

@rustbot label T-compiler A-attributes

[blyxyas]

@rustbot claim

[blyxyas]

First rust-lang/rust contribution I hope this goes well