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