Macros do not accept empty vis at the end of the token tree #131950
Description
I tried this code:
macro_rules! m { ( ($v:vis) ) => {}; } fn main() { m!( () ); }I expected to see this happen: the code compile successfully. The reference says vis is "a possibly empty Visibility qualifier", so it should match empty.
Instead, this happened: the code is rejected with:
error: no rules expected the token `)` --> src/main.rs:6:10 | 1 | macro_rules! m { | -------------- when calling this macro ... 6 | m!( () ); | ^ no rules expected this token in macro call | note: while trying to match meta-variable `$v:vis` --> src/main.rs:2:8 | 2 | ( ($v:vis) ) => {}; | ^^^^^^ @rustbot label +A-macros