do not premote non-ZST mutable references ever
This commit is contained in:
parent
6c6003a7ad
commit
720293b640
2 changed files with 19 additions and 16 deletions
|
@ -364,15 +364,7 @@ impl<'tcx> Validator<'_, 'tcx> {
|
|||
// In theory, any zero-sized value could be borrowed
|
||||
// mutably without consequences. However, only &mut []
|
||||
// is allowed right now, and only in functions.
|
||||
if self.const_kind
|
||||
== Some(hir::ConstContext::Static(hir::Mutability::Mut))
|
||||
{
|
||||
// Inside a `static mut`, &mut [...] is also allowed.
|
||||
match ty.kind() {
|
||||
ty::Array(..) | ty::Slice(_) => {}
|
||||
_ => return Err(Unpromotable),
|
||||
}
|
||||
} else if let ty::Array(_, len) = ty.kind() {
|
||||
if let ty::Array(_, len) = ty.kind() {
|
||||
// FIXME(eddyb) the `self.is_non_const_fn` condition
|
||||
// seems unnecessary, given that this is merely a ZST.
|
||||
match len.try_eval_usize(self.tcx, self.param_env) {
|
||||
|
@ -673,13 +665,7 @@ impl<'tcx> Validator<'_, 'tcx> {
|
|||
// In theory, any zero-sized value could be borrowed
|
||||
// mutably without consequences. However, only &mut []
|
||||
// is allowed right now, and only in functions.
|
||||
if self.const_kind == Some(hir::ConstContext::Static(hir::Mutability::Mut)) {
|
||||
// Inside a `static mut`, &mut [...] is also allowed.
|
||||
match ty.kind() {
|
||||
ty::Array(..) | ty::Slice(_) => {}
|
||||
_ => return Err(Unpromotable),
|
||||
}
|
||||
} else if let ty::Array(_, len) = ty.kind() {
|
||||
if let ty::Array(_, len) = ty.kind() {
|
||||
// FIXME(eddyb): We only return `Unpromotable` for `&mut []` inside a
|
||||
// const context which seems unnecessary given that this is merely a ZST.
|
||||
match len.try_eval_usize(self.tcx, self.param_env) {
|
||||
|
|
17
src/test/ui/consts/promotion-mutable-ref.rs
Normal file
17
src/test/ui/consts/promotion-mutable-ref.rs
Normal file
|
@ -0,0 +1,17 @@
|
|||
// run-pass
|
||||
#![feature(const_mut_refs)]
|
||||
|
||||
static mut TEST: i32 = {
|
||||
// We cannot promote this, as CTFE needs to be able to mutate it later.
|
||||
let x = &mut [1,2,3];
|
||||
x[0] += 1;
|
||||
x[0]
|
||||
};
|
||||
|
||||
// This still works -- it's not done via promotion.
|
||||
#[allow(unused)]
|
||||
static mut TEST2: &'static mut [i32] = &mut [0,1,2];
|
||||
|
||||
fn main() {
|
||||
assert_eq!(unsafe { TEST }, 2);
|
||||
}
|
Loading…
Add table
Reference in a new issue