67 lines
1.7 KiB
Rust
67 lines
1.7 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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struct point { x: int, y: int }
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trait methods {
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fn impurem(&self);
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fn blockm(&self, f: &fn());
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pure fn purem(&self);
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}
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impl methods for point {
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fn impurem(&self) {
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}
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fn blockm(&self, f: &fn()) { f() }
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pure fn purem(&self) {
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}
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}
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fn a() {
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let mut p = point {x: 3, y: 4};
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// Here: it's ok to call even though receiver is mutable, because we
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// can loan it out.
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p.purem();
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p.impurem();
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// But in this case we do not honor the loan:
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do p.blockm { //~ NOTE loan of mutable local variable granted here
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p.x = 10; //~ ERROR assigning to mutable field prohibited due to outstanding loan
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}
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}
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fn b() {
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let mut p = point {x: 3, y: 4};
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// Here I create an outstanding loan and check that we get conflicts:
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let l = &mut p; //~ NOTE prior loan as mutable granted here
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//~^ NOTE prior loan as mutable granted here
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p.purem(); //~ ERROR loan of mutable local variable as immutable conflicts with prior loan
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p.impurem(); //~ ERROR loan of mutable local variable as immutable conflicts with prior loan
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l.x += 1;
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}
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fn c() {
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// Loaning @mut as & is considered legal due to dynamic checks:
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let q = @mut point {x: 3, y: 4};
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q.purem();
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q.impurem();
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}
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fn main() {
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}
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