rust/tests/ui/lint/unused_labels.rs
2023-01-11 09:32:08 +00:00

86 lines
2.1 KiB
Rust

// The output should warn when a loop label is not used. However, it
// should also deal with the edge cases where a label is shadowed,
// within nested loops
// check-pass
#![warn(unused_labels)]
fn main() {
'unused_while_label: while 0 == 0 {
//~^ WARN unused label
}
let opt = Some(0);
'unused_while_let_label: while let Some(_) = opt {
//~^ WARN unused label
}
'unused_for_label: for _ in 0..10 {
//~^ WARN unused label
}
'used_loop_label: loop {
break 'used_loop_label;
}
'used_loop_label_outer_1: for _ in 0..10 {
'used_loop_label_inner_1: for _ in 0..10 {
break 'used_loop_label_inner_1;
}
break 'used_loop_label_outer_1;
}
'used_loop_label_outer_2: for _ in 0..10 {
'unused_loop_label_inner_2: for _ in 0..10 {
//~^ WARN unused label
break 'used_loop_label_outer_2;
}
}
'unused_loop_label_outer_3: for _ in 0..10 {
//~^ WARN unused label
'used_loop_label_inner_3: for _ in 0..10 {
break 'used_loop_label_inner_3;
}
}
// You should be able to break the same label many times
'many_used: loop {
if true {
break 'many_used;
} else {
break 'many_used;
}
}
// Test breaking many times with the same inner label doesn't break the
// warning on the outer label
'many_used_shadowed: for _ in 0..10 {
//~^ WARN unused label
'many_used_shadowed: for _ in 0..10 {
//~^ WARN label name `'many_used_shadowed` shadows a label name that is already in scope
if 1 % 2 == 0 {
break 'many_used_shadowed;
} else {
break 'many_used_shadowed;
}
}
}
'unused_loop_label: loop {
//~^ WARN unused label
break;
}
// Make sure unused block labels give warnings...
'unused_block_label: {
//~^ WARN unused label
}
// ...and that used ones don't:
'used_block_label: {
break 'used_block_label;
}
}