2b67d88809
needed. Regarding soundness: there was a subtle bug in how it was done before; see the compile-fail test for an example. Regarding reborrowing: reborrowing allows mut and const slices/borrowed-pointers to be used with pure fns that expect immutable data. r=brson
56 lines
2.2 KiB
Rust
56 lines
2.2 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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fn with<T>(t: T, f: fn(T)) { f(t) }
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fn nested(x: &x/int) { // (1)
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do with(
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fn&(x: &x/int, // Refers to the region `x` at (1)
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y: &y/int, // A fresh region `y` (2)
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z: fn(x: &x/int, // Refers to `x` at (1)
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y: &y/int, // Refers to `y` at (2)
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z: &z/int) -> &z/int) // A fresh region `z` (3)
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-> &x/int {
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if false { return z(x, y, x); }
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if false { return z(x, y, y); }
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//~^ ERROR cannot infer an appropriate lifetime
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return z(y, x, x);
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//~^ ERROR cannot infer an appropriate lifetime
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}
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) |foo| {
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let a: &x/int = foo(x, x, |_x, _y, z| z );
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let b: &x/int = foo(x, a, |_x, _y, z| z );
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let c: &x/int = foo(a, a, |_x, _y, z| z );
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let z = 3i;
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let d: &x/int = foo(x, x, |_x, _y, z| z );
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let e: &x/int = foo(x, &z, |_x, _y, z| z );
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// This would result in an error, but it is not reported by typeck
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// anymore but rather borrowck. Therefore, it doesn't end up
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// getting printed out since compilation fails after typeck.
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//
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// let f: &x/int = foo(&z, &z, |_x, _y, z| z ); // ERROR mismatched types: expected `&x/int` but found
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foo(x, &z, |x, _y, _z| x); //~ ERROR mismatched types: expected `&z/int` but found `&x/int`
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// Note: originally I had foo(x, &z, ...) here, but in that
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// case the region inferencer deduced that this was valid if
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// &y==&static, and so inference would succeed but borrow
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// check would fail because the lifetime of &z is not &static.
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foo(x, x, |_x, y, _z| y); //~ ERROR cannot infer an appropriate lifetime
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}
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}
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fn main() {} |