rust/tests/ui/hygiene/hygienic-labels-in-let.rs

83 lines
1.6 KiB
Rust

//@ run-pass
#![allow(unreachable_code)]
#![allow(unused_labels)]
// Test that labels injected by macros do not break hygiene. This
// checks cases where the macros invocations are under the rhs of a
// let statement.
// 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 {
$e
}
};
}
macro_rules! while_true {
($e: expr) => {
// $e shouldn't be able to interact with this 'x
'x: while 1 + 1 == 2 {
$e
}
};
}
macro_rules! run_once {
($e: expr) => {
// ditto
'x: for _ in 0..1 {
$e
}
};
}
pub fn main() {
let mut i = 0;
let j: isize = {
'x: loop {
// this 'x should refer to the outer loop, lexically
loop_x!(break 'x);
i += 1;
}
i + 1
};
assert_eq!(j, 1);
let k: isize = {
'x: for _ in 0..1 {
// ditto
loop_x!(break 'x);
i += 1;
}
i + 1
};
assert_eq!(k, 1);
let l: isize = {
'x: for _ in 0..1 {
// ditto
while_true!(break 'x);
i += 1;
}
i + 1
};
assert_eq!(l, 1);
let n: isize = {
'x: for _ in 0..1 {
// ditto
run_once!(continue 'x);
i += 1;
}
i + 1
};
assert_eq!(n, 1);
}