rust/src/test/compile-fail/loops-reject-duplicate-labels.rs

61 lines
2.5 KiB
Rust

// Copyright 2015 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.
#![feature(rustc_attrs)]
// ignore-tidy-linelength
// Issue #21633: reject duplicate loop labels in function bodies.
// This is testing the exact cases that are in the issue description.
fn foo() {
'fl: for _ in 0..10 { break; } //~ NOTE shadowed label `'fl` declared here
'fl: loop { break; } //~ WARN label name `'fl` shadows a label name that is already in scope
'lf: loop { break; } //~ NOTE shadowed label `'lf` declared here
'lf: for _ in 0..10 { break; } //~ WARN label name `'lf` shadows a label name that is already in scope
'wl: while 2 > 1 { break; } //~ NOTE shadowed label `'wl` declared here
'wl: loop { break; } //~ WARN label name `'wl` shadows a label name that is already in scope
'lw: loop { break; } //~ NOTE shadowed label `'lw` declared here
'lw: while 2 > 1 { break; } //~ WARN label name `'lw` shadows a label name that is already in scope
'fw: for _ in 0..10 { break; } //~ NOTE shadowed label `'fw` declared here
'fw: while 2 > 1 { break; } //~ WARN label name `'fw` shadows a label name that is already in scope
'wf: while 2 > 1 { break; } //~ NOTE shadowed label `'wf` declared here
'wf: for _ in 0..10 { break; } //~ WARN label name `'wf` shadows a label name that is already in scope
'tl: while let Some(_) = None::<i32> { break; } //~ NOTE shadowed label `'tl` declared here
'tl: loop { break; } //~ WARN label name `'tl` shadows a label name that is already in scope
'lt: loop { break; } //~ NOTE shadowed label `'lt` declared here
'lt: while let Some(_) = None::<i32> { break; }
//~^ WARN label name `'lt` shadows a label name that is already in scope
}
// Note however that it is okay for the same label to be reused in
// different methods of one impl, as illustrated here.
struct S;
impl S {
fn m1(&self) { 'okay: loop { break 'okay; } }
fn m2(&self) { 'okay: loop { break 'okay; } }
}
#[rustc_error]
pub fn main() { //~ ERROR compilation successful
let s = S;
s.m1();
s.m2();
foo();
}