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Rollup merge of #77420 - ecstatic-morse:const-checking-raw-mut-ref, r=davidtwco

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Unify const-checking structured errors for `&mut` and `&raw mut`

Resolves #77414 as well as a FIXME.
This commit is contained in:
Yuki Okushi
2020-10-22 09:45:25 +09:00
committed by GitHub
parent 1eaadebb3d c1494d60db
commit 6245b951d5
6 changed files with 32 additions and 54 deletions
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38
compiler/rustc_mir/src/transform/check_consts/ops.rs
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@@ -224,7 +224,8 @@ impl NonConstOp for CellBorrow {
}
#[derive(Debug)]
pub struct MutBorrow;
pub struct MutBorrow(pub hir::BorrowKind);
impl NonConstOp for MutBorrow {
fn status_in_item(&self, ccx: &ConstCx<'_, '_>) -> Status {
// Forbid everywhere except in const fn with a feature gate
@@ -236,22 +237,28 @@ impl NonConstOp for MutBorrow {
}
fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
let raw = match self.0 {
hir::BorrowKind::Raw => "raw ",
hir::BorrowKind::Ref => "",
};
let mut err = if ccx.const_kind() == hir::ConstContext::ConstFn {
feature_err(
&ccx.tcx.sess.parse_sess,
sym::const_mut_refs,
span,
&format!("mutable references are not allowed in {}s", ccx.const_kind()),
&format!("{}mutable references are not allowed in {}s", raw, ccx.const_kind()),
)
} else {
let mut err = struct_span_err!(
ccx.tcx.sess,
span,
E0764,
"mutable references are not allowed in {}s",
"{}mutable references are not allowed in {}s",
raw,
ccx.const_kind(),
);
err.span_label(span, format!("`&mut` is only allowed in `const fn`"));
err.span_label(span, format!("`&{}mut` is only allowed in `const fn`", raw));
err
};
if ccx.tcx.sess.teach(&err.get_code().unwrap()) {
@@ -270,29 +277,6 @@ impl NonConstOp for MutBorrow {
}
}
// FIXME(ecstaticmorse): Unify this with `MutBorrow`. It has basically the same issues.
#[derive(Debug)]
pub struct MutAddressOf;
impl NonConstOp for MutAddressOf {
fn status_in_item(&self, ccx: &ConstCx<'_, '_>) -> Status {
// Forbid everywhere except in const fn with a feature gate
if ccx.const_kind() == hir::ConstContext::ConstFn {
Status::Unstable(sym::const_mut_refs)
} else {
Status::Forbidden
}
}
fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
feature_err(
&ccx.tcx.sess.parse_sess,
sym::const_mut_refs,
span,
&format!("`&raw mut` is not allowed in {}s", ccx.const_kind()),
)
}
}
#[derive(Debug)]
pub struct MutDeref;
impl NonConstOp for MutDeref {