| // Copyright 2017 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // 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 |
| |
| // compile-pass |
| |
| #![feature(label_break_value)] |
| #![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; |
| } |
| } |