1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
|
pub enum En {
A(Vec<u8>)
}
fn get_usize() -> usize {
0
}
macro_rules! force_expr {
($e:expr) => { $e }
}
macro_rules! force_pat {
($a:expr, $b:expr) => { $a..=$b }
}
macro_rules! make_vec {
() => { force_expr!(Vec::new()) } //~ ERROR arbitrary expressions aren't allowed
}
macro_rules! make_pat {
() => { force_pat!(get_usize(), get_usize()) }
//~^ ERROR arbitrary expressions aren't allowed
//~| ERROR arbitrary expressions aren't allowed
}
#[allow(unreachable_code)]
fn f() -> Result<(), impl core::fmt::Debug> {
let x: En = loop {};
assert!(matches!(x, En::A(make_vec!())));
assert!(matches!(5, make_pat!()));
Ok::<(), &'static str>(())
}
fn main() {}
|
