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// Copyright 2017 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.
// ignore-tidy-linelength
// revisions: nll_target
// The following revisions are disabled due to missing support from two-phase beyond autorefs
//[nll_beyond]compile-flags: -Z borrowck=mir -Z two-phase-borrows -Z two-phase-beyond-autoref
//[nll_beyond] should-fail
//[nll_target]compile-flags: -Z borrowck=mir -Z two-phase-borrows
// This is a corner case that the current implementation is (probably)
// treating more conservatively than is necessary. But it also does
// not seem like a terribly important use case to cover.
//
// So this test is just making a note of the current behavior, with
// the caveat that in the future, the rules may be loosened, at which
// point this test might be thrown out.
//
// The convention for the listed revisions: "lxl" means lexical
// lifetimes (which can be easier to reason about). "nll" means
// non-lexical lifetimes. "nll_target" means the initial conservative
// two-phase borrows that only applies to autoref-introduced borrows.
// "nll_beyond" means the generalization of two-phase borrows to all
// `&mut`-borrows (doing so makes it easier to write code for specific
// corner cases).
fn main() {
let mut vec = vec![0, 1];
let delay: &mut Vec<_>;
{
let shared = &vec;
// we reserve here, which could (on its own) be compatible
// with the shared borrow. But in the current implementation,
// its an error.
delay = &mut vec;
//[nll_beyond]~^ ERROR cannot borrow `vec` as mutable because it is also borrowed as immutable
//[nll_target]~^^ ERROR cannot borrow `vec` as mutable because it is also borrowed as immutable
shared[0];
}
// the &mut-borrow only becomes active way down here.
//
// (At least in theory; part of the reason this test fails is that
// the constructed MIR throws in extra &mut reborrows which
// flummoxes our attmpt to delay the activation point here.)
delay.push(2);
}
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