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Allow two-phase borrows of &mut self in ops

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We need two-phase borrows of ops to be in the initial NLL release since without
them lots of existing code will break. Fixes #48129
This commit is contained in:
bobtwinkles 2018-02-13 20:28:10 -05:00
parent 4d2d3fc5da
commit 3118cbe41c
3 changed files with 55 additions and 61 deletions
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14
src/librustc_typeck/check/op.rs
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@ -201,10 +201,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let mutbl = match mt.mutbl {
hir::MutImmutable => AutoBorrowMutability::Immutable,
hir::MutMutable => AutoBorrowMutability::Mutable {
// For initial two-phase borrow
// deployment, conservatively omit
// overloaded binary ops.
allow_two_phase_borrow: false,
// Allow two-phase borrows for binops in initial deployment
// since they desugar to methods
allow_two_phase_borrow: true,
}
};
let autoref = Adjustment {
@ -219,10 +218,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let mutbl = match mt.mutbl {
hir::MutImmutable => AutoBorrowMutability::Immutable,
hir::MutMutable => AutoBorrowMutability::Mutable {
// For initial two-phase borrow
// deployment, conservatively omit
// overloaded binary ops.
allow_two_phase_borrow: false,
// Allow two-phase borrows for binops in initial deployment
// since they desugar to methods
allow_two_phase_borrow: true,
}
};
let autoref = Adjustment {

53
src/test/compile-fail/borrowck/two-phase-nonrecv-autoref.rs
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@ -30,8 +30,6 @@
// #![feature(rustc_attrs)]
use std::ops::{Index, IndexMut};
use std::ops::{AddAssign, SubAssign, MulAssign, DivAssign, RemAssign};
use std::ops::{BitAndAssign, BitOrAssign, BitXorAssign, ShlAssign, ShrAssign};
// This is case outlined by Niko that we want to ensure we reject
// (at least initially).
@ -186,56 +184,6 @@ fn coerce_index_op() {
//[nll]~^^ ERROR cannot borrow `i` as immutable because it is also borrowed as mutable [E0502]
}
struct A(i32);
macro_rules! trivial_binop {
($Trait:ident, $m:ident) => {
impl $Trait<i32> for A { fn $m(&mut self, rhs: i32) { self.0 = rhs; } }
}
}
trivial_binop!(AddAssign, add_assign);
trivial_binop!(SubAssign, sub_assign);
trivial_binop!(MulAssign, mul_assign);
trivial_binop!(DivAssign, div_assign);
trivial_binop!(RemAssign, rem_assign);
trivial_binop!(BitAndAssign, bitand_assign);
trivial_binop!(BitOrAssign, bitor_assign);
trivial_binop!(BitXorAssign, bitxor_assign);
trivial_binop!(ShlAssign, shl_assign);
trivial_binop!(ShrAssign, shr_assign);
fn overloaded_binops() {
let mut a = A(10);
a += a.0;
//[lxl]~^ ERROR cannot use `a.0` because it was mutably borrowed
//[nll]~^^ ERROR cannot use `a.0` because it was mutably borrowed
a -= a.0;
//[lxl]~^ ERROR cannot use `a.0` because it was mutably borrowed
//[nll]~^^ ERROR cannot use `a.0` because it was mutably borrowed
a *= a.0;
//[lxl]~^ ERROR cannot use `a.0` because it was mutably borrowed
//[nll]~^^ ERROR cannot use `a.0` because it was mutably borrowed
a /= a.0;
//[lxl]~^ ERROR cannot use `a.0` because it was mutably borrowed
//[nll]~^^ ERROR cannot use `a.0` because it was mutably borrowed
a &= a.0;
//[lxl]~^ ERROR cannot use `a.0` because it was mutably borrowed
//[nll]~^^ ERROR cannot use `a.0` because it was mutably borrowed
a |= a.0;
//[lxl]~^ ERROR cannot use `a.0` because it was mutably borrowed
//[nll]~^^ ERROR cannot use `a.0` because it was mutably borrowed
a ^= a.0;
//[lxl]~^ ERROR cannot use `a.0` because it was mutably borrowed
//[nll]~^^ ERROR cannot use `a.0` because it was mutably borrowed
a <<= a.0;
//[lxl]~^ ERROR cannot use `a.0` because it was mutably borrowed
//[nll]~^^ ERROR cannot use `a.0` because it was mutably borrowed
a >>= a.0;
//[lxl]~^ ERROR cannot use `a.0` because it was mutably borrowed
//[nll]~^^ ERROR cannot use `a.0` because it was mutably borrowed
}
fn main() {
// As a reminder, this is the basic case we want to ensure we handle.
@ -256,5 +204,4 @@ fn main() {
coerce_unsized();
coerce_index_op();
overloaded_binops();
}

49
src/test/run-pass/borrowck/two-phase-bin-ops.rs Normal file
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@ -0,0 +1,49 @@
// Copyright 2018 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.
// revisions: lxl nll
//[lxl]compile-flags: -Z borrowck=mir -Z two-phase-borrows
#![cfg_attr(nll, feature(nll))]
use std::ops::{AddAssign, SubAssign, MulAssign, DivAssign, RemAssign};
use std::ops::{BitAndAssign, BitOrAssign, BitXorAssign, ShlAssign, ShrAssign};
struct A(i32);
macro_rules! trivial_binop {
($Trait:ident, $m:ident) => {
impl $Trait<i32> for A { fn $m(&mut self, rhs: i32) { self.0 = rhs; } }
}
}
trivial_binop!(AddAssign, add_assign);
trivial_binop!(SubAssign, sub_assign);
trivial_binop!(MulAssign, mul_assign);
trivial_binop!(DivAssign, div_assign);
trivial_binop!(RemAssign, rem_assign);
trivial_binop!(BitAndAssign, bitand_assign);
trivial_binop!(BitOrAssign, bitor_assign);
trivial_binop!(BitXorAssign, bitxor_assign);
trivial_binop!(ShlAssign, shl_assign);
trivial_binop!(ShrAssign, shr_assign);
fn main() {
let mut a = A(10);
a += a.0;
a -= a.0;
a *= a.0;
a /= a.0;
a &= a.0;
a |= a.0;
a ^= a.0;
a <<= a.0;
a >>= a.0;
}