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// Copyright 2012 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.
// A dummy trait/impl that work close over any type. The trait will
// be parameterized by a region due to the &self/int constraint.
trait foo {
fn foo(&self, i: &'self int) -> int;
}
impl<T:Copy> foo<'self> for T {
fn foo(&self, i: &'self int) -> int {*i}
}
fn to_foo<T:Copy>(t: T) {
// This version is ok because, although T may contain borrowed
// pointers, it never escapes the fn body. We know this because
// the type of foo includes a region which will be resolved to
// the fn body itself.
let v = &3;
struct F<T> { f: T }
let x = @F {f:t} as @foo;
fail_unless!(x.foo(v) == 3);
}
fn to_foo_2<T:Copy>(t: T) -> @foo {
// Not OK---T may contain borrowed ptrs and it is going to escape
// as part of the returned foo value
struct F<T> { f: T }
@F {f:t} as @foo //~ ERROR value may contain borrowed pointers; use `&static` bound
}
fn to_foo_3<T:Copy + &static>(t: T) -> @foo {
// OK---T may escape as part of the returned foo value, but it is
// owned and hence does not contain borrowed ptrs
struct F<T> { f: T }
@F {f:t} as @foo
}
fn main() {
}
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