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Turn unstable trait impl error into a lint, so it can be disabled.

This commit is contained in:
Mara Bos 2020-09-10 20:43:13 +02:00
parent cf8e5d1bc9
commit 89fb34fea7
2 changed files with 36 additions and 22 deletions
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49
compiler/rustc_passes/src/stability.rs
View File

@ -16,6 +16,7 @@ use rustc_middle::middle::stability::{DeprecationEntry, Index};
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::TyCtxt;
use rustc_session::lint;
use rustc_session::lint::builtin::INEFFECTIVE_UNSTABLE_TRAIT_IMPL;
use rustc_session::parse::feature_err;
use rustc_session::Session;
use rustc_span::symbol::{sym, Symbol};
@ -539,27 +540,33 @@ impl Visitor<'tcx> for Checker<'tcx> {
// individually as it's possible to have a stable trait with unstable
// items.
hir::ItemKind::Impl { of_trait: Some(ref t), self_ty, items, .. } => {
// If this impl block has an #[unstable] attribute, give an
// error if all involved types and traits are stable, because
// it will have no effect.
// See: https://github.com/rust-lang/rust/issues/55436
if let (Some(Stability { level: attr::Unstable { .. }, .. }), _) =
attr::find_stability(&self.tcx.sess, &item.attrs, item.span)
{
let mut c = CheckTraitImplStable { tcx: self.tcx, fully_stable: true };
c.visit_ty(self_ty);
c.visit_trait_ref(t);
if c.fully_stable {
let span = item
.attrs
.iter()
.find(|a| a.has_name(sym::unstable))
.map_or(item.span, |a| a.span);
self.tcx.sess.span_err(
span,
"An `#[unstable]` annotation here has no effect. \
See issue #55436 <https://github.com/rust-lang/rust/issues/55436> for more information.",
);
if self.tcx.features().staged_api {
// If this impl block has an #[unstable] attribute, give an
// error if all involved types and traits are stable, because
// it will have no effect.
// See: https://github.com/rust-lang/rust/issues/55436
if let (Some(Stability { level: attr::Unstable { .. }, .. }), _) =
attr::find_stability(&self.tcx.sess, &item.attrs, item.span)
{
let mut c = CheckTraitImplStable { tcx: self.tcx, fully_stable: true };
c.visit_ty(self_ty);
c.visit_trait_ref(t);
if c.fully_stable {
let span = item
.attrs
.iter()
.find(|a| a.has_name(sym::unstable))
.map_or(item.span, |a| a.span);
self.tcx.struct_span_lint_hir(
INEFFECTIVE_UNSTABLE_TRAIT_IMPL,
item.hir_id,
span,
|lint| lint.build(
"An `#[unstable]` annotation here has no effect. \
See issue #55436 <https://github.com/rust-lang/rust/issues/55436> for more information.",
).emit()
);
}
}
}

9
compiler/rustc_session/src/lint/builtin.rs
View File

@ -5,7 +5,7 @@
//! lints are all available in `rustc_lint::builtin`.
use crate::lint::FutureIncompatibleInfo;
use crate::{declare_lint, declare_lint_pass};
use crate::{declare_lint, declare_lint_pass, declare_tool_lint};
use rustc_span::edition::Edition;
use rustc_span::symbol::sym;
@ -555,6 +555,12 @@ declare_lint! {
};
}
declare_tool_lint! {
pub rustc::INEFFECTIVE_UNSTABLE_TRAIT_IMPL,
Deny,
"detects `#[unstable]` on stable trait implementations for stable types"
}
declare_lint_pass! {
/// Does nothing as a lint pass, but registers some `Lint`s
/// that are used by other parts of the compiler.
@ -630,6 +636,7 @@ declare_lint_pass! {
INCOMPLETE_INCLUDE,
CENUM_IMPL_DROP_CAST,
CONST_EVALUATABLE_UNCHECKED,
INEFFECTIVE_UNSTABLE_TRAIT_IMPL,
]
}