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// Copyright 2018 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. | ||
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// Test control flow to follow label_break_value semantics | ||
fn label_break(a: bool, b: bool) -> u32 { | ||
let mut v = 0; | ||
'b: { | ||
v = 1; | ||
if a { | ||
break 'b; | ||
} | ||
v = 2; | ||
if b { | ||
break 'b; | ||
} | ||
v = 3; | ||
} | ||
return v; | ||
} | ||
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// Test that values can be returned | ||
fn break_value(a: bool, b: bool) -> u32 { | ||
let result = 'block: { | ||
if a { break 'block 1; } | ||
if b { break 'block 2; } | ||
3 | ||
}; | ||
result | ||
} | ||
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// Test nesting of labeled blocks | ||
// here we only check that it compiles | ||
fn label_break_nested() { | ||
'b: { | ||
println!("hi"); | ||
if false { | ||
break 'b; | ||
} | ||
'c: { | ||
if false { | ||
break 'b; | ||
} | ||
break 'c; | ||
} | ||
println!("hello"); | ||
if true { | ||
break 'b; | ||
} | ||
} | ||
} | ||
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// Tests for mixing labeled blocks with loop constructs | ||
// This function should be the identity function | ||
fn label_break_mixed(v: u32) -> u32 { | ||
let mut r = 0; | ||
'b: { | ||
// Unlabeled break still works | ||
// (only crossing boundaries is an error) | ||
loop { | ||
break; | ||
} | ||
if v == 0 { | ||
break 'b; | ||
} | ||
// Labeled breaking an inner loop still works | ||
'c: loop { | ||
if r == 1 { | ||
break 'c; | ||
} | ||
r += 1; | ||
} | ||
assert_eq!(r, 1); | ||
if v == 1 { | ||
break 'b; | ||
} | ||
// Labeled breaking an outer loop still works | ||
'd: loop { | ||
'e: { | ||
if v == r { | ||
break 'b; | ||
} | ||
if r == 5 { | ||
break 'd; | ||
} | ||
r += 1; | ||
} | ||
} | ||
assert_eq!(r, 5); | ||
assert!(v > r); | ||
// Here we test return from inside a labeled block | ||
return v; | ||
} | ||
r | ||
} | ||
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pub fn main() { | ||
assert_eq!(label_break(true, false), 1); | ||
assert_eq!(label_break(false, true), 2); | ||
assert_eq!(label_break(false, false), 3); | ||
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assert_eq!(break_value(true, false), 1); | ||
assert_eq!(break_value(false, true), 2); | ||
assert_eq!(break_value(false, false), 3); | ||
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assert_eq!(label_break_mixed(0), 0); | ||
assert_eq!(label_break_mixed(1), 1); | ||
assert_eq!(label_break_mixed(2), 2); | ||
assert_eq!(label_break_mixed(3), 3); | ||
assert_eq!(label_break_mixed(4), 4); | ||
assert_eq!(label_break_mixed(5), 5); | ||
assert_eq!(label_break_mixed(6), 6); | ||
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// FIXME: ensure that labeled blocks work if produced by macros and in match arms | ||
} |