Closed
Description
Unsure of a better title for this, but I don't see why it's invalid to do. It makes adding some additional debug logging inside macros quite tedious. This example is a simple modification of one of the macros defined in the rust book (just above the introduction to recursive macros).
macro_rules! foo {
($v:ident) => (
let $v = 3;
println!("{}", $v); // If you comment this then it's fine.
);
}
fn main() {
foo!(x);
println!("{}", x);
}Expected:
print 3 (the value of x) twice
Actual:
<anon>:4:24: 4:26 error: unresolved name `x`
<anon>:4 println!("{}", $v); // If you comment this then it's fine.
^~
note: in expansion of format_args!
<std macros>:2:25: 2:56 note: expansion site
<std macros>:1:1: 2:62 note: in expansion of print!
<std macros>:3:1: 3:54 note: expansion site
<std macros>:1:1: 3:58 note: in expansion of println!
<anon>:4:9: 4:27 note: expansion site
<anon>:1:1: 6:2 note: in expansion of foo!
<anon>:9:5: 9:13 note: expansion site