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Better span for attribute suggestions

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`def_span` has the same issues as `body.span`, so do it this way instead.
This commit is contained in:
Dylan MacKenzie 2020-09-30 09:48:18 -07:00
parent 7c6d685551
commit 0c26144b1a
2 changed files with 19 additions and 11 deletions
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10
compiler/rustc_mir/src/transform/check_consts/mod.rs
View File

@ -57,6 +57,16 @@ impl ConstCx<'mir, 'tcx> {
&& self.tcx.features().staged_api
&& is_const_stable_const_fn(self.tcx, self.def_id.to_def_id())
}
/// Returns the function signature of the item being const-checked if it is a `fn` or `const fn`.
pub fn fn_sig(&self) -> Option<&'tcx hir::FnSig<'tcx>> {
// Get this from the HIR map instead of a query to avoid cycle errors.
//
// FIXME: Is this still an issue?
let hir_map = self.tcx.hir();
let hir_id = hir_map.local_def_id_to_hir_id(self.def_id);
hir_map.fn_sig_by_hir_id(hir_id)
}
}
/// Returns `true` if this `DefId` points to one of the official `panic` lang items.

20
compiler/rustc_mir/src/transform/check_consts/validation.rs
View File

@ -1,7 +1,7 @@
//! The `Visitor` responsible for actually checking a `mir::Body` for invalid operations.
use rustc_errors::{struct_span_err, Applicability, Diagnostic};
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::def_id::DefId;
use rustc_hir::{self as hir, HirId, LangItem};
use rustc_infer::infer::TyCtxtInferExt;
use rustc_middle::mir::visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor};
@ -209,7 +209,7 @@ impl Validator<'mir, 'tcx> {
// `async` functions cannot be `const fn`. This is checked during AST lowering, so there's
// no need to emit duplicate errors here.
if is_async_fn(tcx, def_id) || body.generator_kind.is_some() {
if is_async_fn(self.ccx) || body.generator_kind.is_some() {
tcx.sess.delay_span_bug(body.span, "`async` functions cannot be `const fn`");
return;
}
@ -929,15 +929,13 @@ fn is_int_bool_or_char(ty: Ty<'_>) -> bool {
ty.is_bool() || ty.is_integral() || ty.is_char()
}
fn is_async_fn(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
let hir_map = tcx.hir();
let hir_id = hir_map.local_def_id_to_hir_id(def_id);
hir_map
.fn_sig_by_hir_id(hir_id)
.map_or(false, |sig| sig.header.asyncness == hir::IsAsync::Async)
fn is_async_fn(ccx: &ConstCx<'_, '_>) -> bool {
ccx.fn_sig().map_or(false, |sig| sig.header.asyncness == hir::IsAsync::Async)
}
fn emit_unstable_in_stable_error(ccx: &ConstCx<'_, '_>, span: Span, gate: Symbol) {
let attr_span = ccx.fn_sig().map_or(ccx.body.span, |sig| sig.span.shrink_to_lo());
ccx.tcx
.sess
.struct_span_err(
@ -945,15 +943,15 @@ fn emit_unstable_in_stable_error(ccx: &ConstCx<'_, '_>, span: Span, gate: Symbol
&format!("const-stable function cannot use `#[feature({})]`", gate.as_str()),
)
.span_suggestion(
ccx.body.span,
attr_span,
"if it is not part of the public API, make this function unstably const",
concat!(r#"#[rustc_const_unstable(feature = "...", issue = "...")]"#, '\n').to_owned(),
Applicability::HasPlaceholders,
)
.span_suggestion(
ccx.body.span,
attr_span,
"otherwise `#[allow_internal_unstable]` can be used to bypass stability checks",
format!("#[allow_internal_unstable({})]", gate),
format!("#[allow_internal_unstable({})]\n", gate),
Applicability::MaybeIncorrect,
)
.emit();