rust/tests/ui/hygiene/hygienic-labels.rs
2023-01-11 09:32:08 +00:00

61 lines
1.3 KiB
Rust

// run-pass
#![allow(unreachable_code)]
#![allow(unused_labels)]
// Test that labels injected by macros do not break hygiene.
// Issue #24278: The label/lifetime shadowing checker from #24162
// conservatively ignores hygiene, and thus issues warnings that are
// both true- and false-positives for this test.
macro_rules! loop_x {
($e: expr) => {
// $e shouldn't be able to interact with this 'x
'x: loop {
$e
}
};
}
macro_rules! run_once {
($e: expr) => {
// ditto
'x: for _ in 0..1 {
$e
}
};
}
macro_rules! while_x {
($e: expr) => {
// ditto
'x: while 1 + 1 == 2 {
$e
}
};
}
pub fn main() {
'x: for _ in 0..1 {
// this 'x should refer to the outer loop, lexically
loop_x!(break 'x);
panic!("break doesn't act hygienically inside for loop");
}
'x: loop {
// ditto
loop_x!(break 'x);
panic!("break doesn't act hygienically inside infinite loop");
}
'x: while 1 + 1 == 2 {
while_x!(break 'x);
panic!("break doesn't act hygienically inside infinite while loop");
}
'x: for _ in 0..1 {
// ditto
run_once!(continue 'x);
panic!("continue doesn't act hygienically inside for loop");
}
}