macro expanding to nothing in match arm causes uninformative parse error

[durka]

Failing code:

macro_rules! empty { () => () }

fn main() {
    match 42 {
        _ => empty!()
    };
}

The error is "unexpected token: <eof>" with a span of 1:1: 1:1.

Workaround:

macro_rules! empty { () => () }

fn main() {
    match 42 {
        _ => { empty!(); }
    };
}

Expected: the failing code either compiles or at least gives an error pointing at the problem.

Found by mohawk on IRC.

[makoConstruct]

A further reduced case, probably the same problem:

macro_rules! mac { () => () }

fn main(){ let a = mac!(); }

Likely connected to #10951 as well.

[estebank]

Possibly related to #26288.

[estebank]

CC #27569

[estebank]

CC #33953