270f0eef73
This is the kind of change that one is expected to need to make to accommodate overloaded-`box`. ---- Note that this is not *all* of the changes necessary to accommodate Issue 22181. It is merely the subset of those cases where there was already a let-binding in place that made it easy to add the necesasry type ascription. (For unnamed intermediate `Box` values, one must go down a different route; `Box::new` is the option that maximizes portability, but has potential inefficiency depending on whether the call is inlined.) ---- There is one place worth note, `run-pass/coerce-match.rs`, where I used an ugly form of `Box<_>` type ascription where I would have preferred to use `Box::new` to accommodate overloaded-`box`. I deliberately did not use `Box::new` here, because that is already done in coerce-match-calls.rs. ---- Precursor for overloaded-`box` and placement-`in`; see Issue 22181.
55 lines
1.5 KiB
Rust
55 lines
1.5 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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// Note: the borrowck analysis is currently flow-insensitive.
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// Therefore, some of these errors are marked as spurious and could be
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// corrected by a simple change to the analysis. The others are
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// either genuine or would require more advanced changes. The latter
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// cases are noted.
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#![feature(box_syntax)]
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fn borrow(_v: &isize) {}
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fn borrow_mut(_v: &mut isize) {}
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fn cond() -> bool { panic!() }
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fn for_func<F>(_f: F) where F: FnOnce() -> bool { panic!() }
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fn produce<T>() -> T { panic!(); }
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fn inc(v: &mut Box<isize>) {
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*v = box() (**v + 1);
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}
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fn pre_freeze_cond() {
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// In this instance, the freeze is conditional and starts before
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// the mut borrow.
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let mut v: Box<_> = box 3;
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let _w;
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if cond() {
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_w = &v;
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}
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borrow_mut(&mut *v); //~ ERROR cannot borrow
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}
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fn pre_freeze_else() {
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// In this instance, the freeze and mut borrow are on separate sides
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// of the if.
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let mut v: Box<_> = box 3;
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let _w;
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if cond() {
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_w = &v;
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} else {
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borrow_mut(&mut *v);
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}
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}
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fn main() {}
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