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Add tests for various diverging & converging loops
Mostly testing borrowck and typeck behaviour in presence of `loop` expression
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src/test/compile-fail/loop-does-not-diverge.rs

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@@ -18,5 +18,4 @@ fn forever() -> ! {
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}
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fn main() {
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if 1 == 2 { forever(); }
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}
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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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fn test1() {
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// In this test the outer 'a loop may terminate without `x` getting initialised. Although the
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// `x = loop { ... }` statement is reached, the value itself ends up never being computed and
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// thus leaving `x` uninit.
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let x: i32;
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'a: loop {
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x = loop { break 'a };
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}
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println!("{:?}", x); //~ ERROR use of possibly uninitialized variable
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}
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// test2 and test3 should not fail.
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fn test2() {
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// In this test the `'a` loop will never terminate thus making the use of `x` unreachable.
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let x: i32;
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'a: loop {
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x = loop { continue 'a };
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}
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println!("{:?}", x);
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}
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fn test3() {
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let x: i32;
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// Similarly, the use of variable `x` is unreachable.
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'a: loop {
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x = loop { return };
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}
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println!("{:?}", x);
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}
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fn main() {
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}
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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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fn forever2() -> i32 {
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let x: i32 = loop { break }; //~ ERROR mismatched types
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x
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}
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fn main() {}
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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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fn forever2() -> ! { //~ ERROR computation may converge in a function marked as diverging
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loop { break }
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}
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fn main() {}

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