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hygiene: cannot find macro foo! in this scope #63685
Description
This code (playpen) compiles on stable but not on nightly and beta:
macro_rules! foo {
() => {
"foo"
};
}
macro_rules! bar {
() => {
foo!()
};
}
fn main() {
println!(bar!());
}Standard Error
Compiling playground v0.0.1 (/playground)
error: cannot find macro `foo!` in this scope
--> src/main.rs:9:9
|
9 | foo!()
| ^^^
warning: unused macro definition
--> src/main.rs:1:1
|
1 | / macro_rules! foo {
2 | | () => {
3 | | "foo"
4 | | };
5 | | }
| |_^
|
= note: `#[warn(unused_macros)]` on by default
error: aborting due to previous error
error: Could not compile `playground`.
To learn more, run the command again with --verbose.Edit: Removed concat! macro
Originally posted by @lzutao in #63460 (comment)
Activity
tesuji commentedon Aug 18, 2019
tesuji commentedon Aug 18, 2019
petrochenkov commentedon Aug 18, 2019
This is a regression from #63114 (cc @matthewjasper).
Slightly more minimized reproduction will look like this:
format_argsperforms eager expansion on its arguments and hygienic context offooproduced by such expansion looks like it was produced by the opaqueformat_argsfor some reason, so it's resolved atformat_args' definition site.It maybe either some issue with hygiene infra interacting with eager expansion, but it also may be caused by incorrect spans produced by
format_args.petrochenkov commentedon Aug 18, 2019
(I'm currently looking into the details.)
UPD: I have a fix locally, will submit tomorrow.
petrochenkov commentedon Aug 19, 2019
Fixed in #63717.
Rollup merge of rust-lang#63717 - petrochenkov:eager, r=matthewjasper