61 lines
1.6 KiB
Rust
61 lines
1.6 KiB
Rust
// Copyright 2012 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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// xfail-pretty -- comments are unfaithfully preserved
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#[allow(unused_variable)];
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#[allow(dead_assignment)];
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fn cond() -> bool { fail!() }
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fn link<'a>(v: &'a uint, w: &mut &'a uint) -> bool { *w = v; true }
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fn separate_arms() {
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// Here both arms perform assignments, but only is illegal.
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let mut x = None;
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match x {
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None => {
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// It is ok to reassign x here, because there is in
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// fact no outstanding loan of x!
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x = Some(0);
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}
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Some(ref _i) => {
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x = Some(1); //~ ERROR cannot assign
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}
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}
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x.clone(); // just to prevent liveness warnings
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}
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fn guard() {
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// Here the guard performs a borrow. This borrow "infects" all
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// subsequent arms (but not the prior ones).
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let mut a = ~3;
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let mut b = ~4;
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let mut w = &*a;
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match 22 {
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_ if cond() => {
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b = ~5;
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}
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_ if link(&*b, &mut w) => {
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b = ~6; //~ ERROR cannot assign
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}
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_ => {
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b = ~7; //~ ERROR cannot assign
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}
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}
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b = ~8; //~ ERROR cannot assign
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}
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fn main() {}
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