diff --git a/Cargo.lock b/Cargo.lock
index ed3e30342f2f6..bb7598bbf3e6f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4616,6 +4616,7 @@ dependencies = [
"rustc_attr",
"rustc_data_structures",
"rustc_errors",
+ "rustc_feature",
"rustc_graphviz",
"rustc_hir",
"rustc_hir_pretty",
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index ad9ed798e558b..3b58996e501d6 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -417,6 +417,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
|| attr.has_name(sym::stable)
|| attr.has_name(sym::rustc_const_unstable)
|| attr.has_name(sym::rustc_const_stable)
+ || attr.has_name(sym::rustc_default_body_unstable)
{
struct_span_err!(
self.sess,
diff --git a/compiler/rustc_attr/src/builtin.rs b/compiler/rustc_attr/src/builtin.rs
index 10a9cfb626e63..62ccd734fe720 100644
--- a/compiler/rustc_attr/src/builtin.rs
+++ b/compiler/rustc_attr/src/builtin.rs
@@ -131,6 +131,14 @@ impl ConstStability {
}
}
+/// Represents the `#[rustc_default_body_unstable]` attribute.
+#[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(HashStable_Generic)]
+pub struct DefaultBodyStability {
+ pub level: StabilityLevel,
+ pub feature: Symbol,
+}
+
/// The available stability levels.
#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)]
#[derive(HashStable_Generic)]
@@ -214,7 +222,8 @@ pub fn find_stability(
sess: &Session,
attrs: &[Attribute],
item_sp: Span,
-) -> (Option<(Stability, Span)>, Option<(ConstStability, Span)>) {
+) -> (Option<(Stability, Span)>, Option<(ConstStability, Span)>, Option<(DefaultBodyStability, Span)>)
+{
find_stability_generic(sess, attrs.iter(), item_sp)
}
@@ -222,7 +231,7 @@ fn find_stability_generic<'a, I>(
sess: &Session,
attrs_iter: I,
item_sp: Span,
-) -> (Option<(Stability, Span)>, Option<(ConstStability, Span)>)
+) -> (Option<(Stability, Span)>, Option<(ConstStability, Span)>, Option<(DefaultBodyStability, Span)>)
where
I: Iterator<Item = &'a Attribute>,
{
@@ -230,6 +239,7 @@ where
let mut stab: Option<(Stability, Span)> = None;
let mut const_stab: Option<(ConstStability, Span)> = None;
+ let mut body_stab: Option<(DefaultBodyStability, Span)> = None;
let mut promotable = false;
let mut allowed_through_unstable_modules = false;
@@ -243,6 +253,7 @@ where
sym::stable,
sym::rustc_promotable,
sym::rustc_allowed_through_unstable_modules,
+ sym::rustc_default_body_unstable,
]
.iter()
.any(|&s| attr.has_name(s))
@@ -280,7 +291,7 @@ where
let meta_name = meta.name_or_empty();
match meta_name {
- sym::rustc_const_unstable | sym::unstable => {
+ sym::rustc_const_unstable | sym::rustc_default_body_unstable | sym::unstable => {
if meta_name == sym::unstable && stab.is_some() {
handle_errors(
&sess.parse_sess,
@@ -295,6 +306,13 @@ where
AttrError::MultipleStabilityLevels,
);
break;
+ } else if meta_name == sym::rustc_default_body_unstable && body_stab.is_some() {
+ handle_errors(
+ &sess.parse_sess,
+ attr.span,
+ AttrError::MultipleStabilityLevels,
+ );
+ break;
}
let mut feature = None;
@@ -405,11 +423,16 @@ where
};
if sym::unstable == meta_name {
stab = Some((Stability { level, feature }, attr.span));
- } else {
+ } else if sym::rustc_const_unstable == meta_name {
const_stab = Some((
ConstStability { level, feature, promotable: false },
attr.span,
));
+ } else if sym::rustc_default_body_unstable == meta_name {
+ body_stab =
+ Some((DefaultBodyStability { level, feature }, attr.span));
+ } else {
+ unreachable!("Unknown stability attribute {meta_name}");
}
}
(None, _, _) => {
@@ -542,7 +565,7 @@ where
}
}
- (stab, const_stab)
+ (stab, const_stab, body_stab)
}
pub fn find_crate_name(sess: &Session, attrs: &[Attribute]) -> Option<Symbol> {
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index 6e093811fcf6e..852ea806b20ff 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -772,7 +772,7 @@ impl SyntaxExtension {
)
})
.unwrap_or_else(|| (None, helper_attrs));
- let (stability, const_stability) = attr::find_stability(&sess, attrs, span);
+ let (stability, const_stability, body_stability) = attr::find_stability(&sess, attrs, span);
if let Some((_, sp)) = const_stability {
sess.parse_sess
.span_diagnostic
@@ -784,6 +784,17 @@ impl SyntaxExtension {
)
.emit();
}
+ if let Some((_, sp)) = body_stability {
+ sess.parse_sess
+ .span_diagnostic
+ .struct_span_err(sp, "macros cannot have body stability attributes")
+ .span_label(sp, "invalid body stability attribute")
+ .span_label(
+ sess.source_map().guess_head_span(span),
+ "body stability attribute affects this macro",
+ )
+ .emit();
+ }
SyntaxExtension {
kind,
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index c806df8214586..d8fd627c100d3 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -499,6 +499,10 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
),
ungated!(rustc_const_unstable, Normal, template!(List: r#"feature = "name""#), DuplicatesOk),
ungated!(rustc_const_stable, Normal, template!(List: r#"feature = "name""#), DuplicatesOk),
+ ungated!(
+ rustc_default_body_unstable, Normal,
+ template!(List: r#"feature = "name", reason = "...", issue = "N""#), DuplicatesOk
+ ),
gated!(
allow_internal_unstable, Normal, template!(Word, List: "feat1, feat2, ..."), DuplicatesOk,
"allow_internal_unstable side-steps feature gating and stability checks",
diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index 65cae29c58dcb..35a6719a2fba6 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -207,6 +207,7 @@ provide! { <'tcx> tcx, def_id, other, cdata,
def_ident_span => { table }
lookup_stability => { table }
lookup_const_stability => { table }
+ lookup_default_body_stability => { table }
lookup_deprecation_entry => { table }
visibility => { table }
unused_generic_params => { table }
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 50d983754e89c..f30f139584aa0 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1029,6 +1029,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
if should_encode_stability(def_kind) {
self.encode_stability(def_id);
self.encode_const_stability(def_id);
+ self.encode_default_body_stability(def_id);
self.encode_deprecation(def_id);
}
if should_encode_variances(def_kind) {
@@ -1397,6 +1398,18 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
}
}
+ fn encode_default_body_stability(&mut self, def_id: DefId) {
+ debug!("EncodeContext::encode_default_body_stability({:?})", def_id);
+
+ // The query lookup can take a measurable amount of time in crates with many items. Check if
+ // the stability attributes are even enabled before using their queries.
+ if self.feat.staged_api || self.tcx.sess.opts.unstable_opts.force_unstable_if_unmarked {
+ if let Some(stab) = self.tcx.lookup_default_body_stability(def_id) {
+ record!(self.tables.lookup_default_body_stability[def_id] <- stab)
+ }
+ }
+ }
+
fn encode_deprecation(&mut self, def_id: DefId) {
debug!("EncodeContext::encode_deprecation({:?})", def_id);
if let Some(depr) = self.tcx.lookup_deprecation(def_id) {
diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
index 0f291f9264777..a1d3c918ebdfc 100644
--- a/compiler/rustc_metadata/src/rmeta/mod.rs
+++ b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -343,6 +343,7 @@ define_tables! {
def_ident_span: Table<DefIndex, LazyValue<Span>>,
lookup_stability: Table<DefIndex, LazyValue<attr::Stability>>,
lookup_const_stability: Table<DefIndex, LazyValue<attr::ConstStability>>,
+ lookup_default_body_stability: Table<DefIndex, LazyValue<attr::DefaultBodyStability>>,
lookup_deprecation_entry: Table<DefIndex, LazyValue<attr::Deprecation>>,
// As an optimization, a missing entry indicates an empty `&[]`.
explicit_item_bounds: Table<DefIndex, LazyArray<(ty::Predicate<'static>, Span)>>,
diff --git a/compiler/rustc_middle/src/middle/stability.rs b/compiler/rustc_middle/src/middle/stability.rs
index 414912dd0f7d8..7a9ad44d1d9ae 100644
--- a/compiler/rustc_middle/src/middle/stability.rs
+++ b/compiler/rustc_middle/src/middle/stability.rs
@@ -5,7 +5,7 @@ pub use self::StabilityLevel::*;
use crate::ty::{self, DefIdTree, TyCtxt};
use rustc_ast::NodeId;
-use rustc_attr::{self as attr, ConstStability, Deprecation, Stability};
+use rustc_attr::{self as attr, ConstStability, DefaultBodyStability, Deprecation, Stability};
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::{Applicability, Diagnostic};
use rustc_feature::GateIssue;
@@ -61,6 +61,7 @@ pub struct Index {
/// are filled by the annotator.
pub stab_map: FxHashMap<LocalDefId, Stability>,
pub const_stab_map: FxHashMap<LocalDefId, ConstStability>,
+ pub default_body_stab_map: FxHashMap<LocalDefId, DefaultBodyStability>,
pub depr_map: FxHashMap<LocalDefId, DeprecationEntry>,
/// Mapping from feature name to feature name based on the `implied_by` field of `#[unstable]`
/// attributes. If a `#[unstable(feature = "implier", implied_by = "impliee")]` attribute
@@ -86,6 +87,10 @@ impl Index {
self.const_stab_map.get(&def_id).copied()
}
+ pub fn local_default_body_stability(&self, def_id: LocalDefId) -> Option<DefaultBodyStability> {
+ self.default_body_stab_map.get(&def_id).copied()
+ }
+
pub fn local_deprecation_entry(&self, def_id: LocalDefId) -> Option<DeprecationEntry> {
self.depr_map.get(&def_id).cloned()
}
@@ -416,6 +421,12 @@ impl<'tcx> TyCtxt<'tcx> {
return EvalResult::Allow;
}
+ // Only the cross-crate scenario matters when checking unstable APIs
+ let cross_crate = !def_id.is_local();
+ if !cross_crate {
+ return EvalResult::Allow;
+ }
+
let stability = self.lookup_stability(def_id);
debug!(
"stability: \
@@ -423,12 +434,6 @@ impl<'tcx> TyCtxt<'tcx> {
def_id, span, stability
);
- // Only the cross-crate scenario matters when checking unstable APIs
- let cross_crate = !def_id.is_local();
- if !cross_crate {
- return EvalResult::Allow;
- }
-
// Issue #38412: private items lack stability markers.
if skip_stability_check_due_to_privacy(self, def_id) {
return EvalResult::Allow;
@@ -492,6 +497,62 @@ impl<'tcx> TyCtxt<'tcx> {
}
}
+ /// Evaluates the default-impl stability of an item.
+ ///
+ /// Returns `EvalResult::Allow` if the item's default implementation is stable, or unstable but the corresponding
+ /// `#![feature]` has been provided. Returns `EvalResult::Deny` which describes the offending
+ /// unstable feature otherwise.
+ pub fn eval_default_body_stability(self, def_id: DefId, span: Span) -> EvalResult {
+ let is_staged_api = self.lookup_stability(def_id.krate.as_def_id()).is_some();
+ if !is_staged_api {
+ return EvalResult::Allow;
+ }
+
+ // Only the cross-crate scenario matters when checking unstable APIs
+ let cross_crate = !def_id.is_local();
+ if !cross_crate {
+ return EvalResult::Allow;
+ }
+
+ let stability = self.lookup_default_body_stability(def_id);
+ debug!(
+ "body stability: inspecting def_id={def_id:?} span={span:?} of stability={stability:?}"
+ );
+
+ // Issue #38412: private items lack stability markers.
+ if skip_stability_check_due_to_privacy(self, def_id) {
+ return EvalResult::Allow;
+ }
+
+ match stability {
+ Some(DefaultBodyStability {
+ level: attr::Unstable { reason, issue, is_soft, .. },
+ feature,
+ }) => {
+ if span.allows_unstable(feature) {
+ debug!("body stability: skipping span={:?} since it is internal", span);
+ return EvalResult::Allow;
+ }
+ if self.features().active(feature) {
+ return EvalResult::Allow;
+ }
+
+ EvalResult::Deny {
+ feature,
+ reason: reason.to_opt_reason(),
+ issue,
+ suggestion: None,
+ is_soft,
+ }
+ }
+ Some(_) => {
+ // Stable APIs are always ok to call
+ EvalResult::Allow
+ }
+ None => EvalResult::Unmarked,
+ }
+ }
+
/// Checks if an item is stable or error out.
///
/// If the item defined by `def_id` is unstable and the corresponding `#![feature]` does not
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 466a0fc25f7d1..0d03f506aac2b 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -1094,6 +1094,11 @@ rustc_queries! {
separate_provide_extern
}
+ query lookup_default_body_stability(def_id: DefId) -> Option<attr::DefaultBodyStability> {
+ desc { |tcx| "looking up default body stability of `{}`", tcx.def_path_str(def_id) }
+ separate_provide_extern
+ }
+
query should_inherit_track_caller(def_id: DefId) -> bool {
desc { |tcx| "computing should_inherit_track_caller of `{}`", tcx.def_path_str(def_id) }
}
diff --git a/compiler/rustc_middle/src/ty/parameterized.rs b/compiler/rustc_middle/src/ty/parameterized.rs
index e189ee2fc4db1..ae6e2eecbffb5 100644
--- a/compiler/rustc_middle/src/ty/parameterized.rs
+++ b/compiler/rustc_middle/src/ty/parameterized.rs
@@ -64,6 +64,7 @@ trivially_parameterized_over_tcx! {
rustc_ast::Attribute,
rustc_ast::MacArgs,
rustc_attr::ConstStability,
+ rustc_attr::DefaultBodyStability,
rustc_attr::Deprecation,
rustc_attr::Stability,
rustc_hir::Constness,
diff --git a/compiler/rustc_passes/src/lib_features.rs b/compiler/rustc_passes/src/lib_features.rs
index e05994f13e4d9..868887c66cdec 100644
--- a/compiler/rustc_passes/src/lib_features.rs
+++ b/compiler/rustc_passes/src/lib_features.rs
@@ -29,11 +29,16 @@ impl<'tcx> LibFeatureCollector<'tcx> {
}
fn extract(&self, attr: &Attribute) -> Option<(Symbol, Option<Symbol>, Span)> {
- let stab_attrs =
- [sym::stable, sym::unstable, sym::rustc_const_stable, sym::rustc_const_unstable];
+ let stab_attrs = [
+ sym::stable,
+ sym::unstable,
+ sym::rustc_const_stable,
+ sym::rustc_const_unstable,
+ sym::rustc_default_body_unstable,
+ ];
// Find a stability attribute: one of #[stable(…)], #[unstable(…)],
- // #[rustc_const_stable(…)], or #[rustc_const_unstable(…)].
+ // #[rustc_const_stable(…)], #[rustc_const_unstable(…)] or #[rustc_default_body_unstable].
if let Some(stab_attr) = stab_attrs.iter().find(|stab_attr| attr.has_name(**stab_attr)) {
let meta_kind = attr.meta_kind();
if let Some(MetaItemKind::List(ref metas)) = meta_kind {
@@ -53,8 +58,12 @@ impl<'tcx> LibFeatureCollector<'tcx> {
// This additional check for stability is to make sure we
// don't emit additional, irrelevant errors for malformed
// attributes.
- let is_unstable =
- matches!(*stab_attr, sym::unstable | sym::rustc_const_unstable);
+ let is_unstable = matches!(
+ *stab_attr,
+ sym::unstable
+ | sym::rustc_const_unstable
+ | sym::rustc_default_body_unstable
+ );
if since.is_some() || is_unstable {
return Some((feature, since, attr.span));
}
diff --git a/compiler/rustc_passes/src/stability.rs b/compiler/rustc_passes/src/stability.rs
index ca6a2ac3db34c..be920601ee43f 100644
--- a/compiler/rustc_passes/src/stability.rs
+++ b/compiler/rustc_passes/src/stability.rs
@@ -1,8 +1,9 @@
//! A pass that annotates every item and method with its stability level,
//! propagating default levels lexically from parent to children ast nodes.
-use attr::StabilityLevel;
-use rustc_attr::{self as attr, ConstStability, Stability, Unstable, UnstableReason};
+use rustc_attr::{
+ self as attr, ConstStability, Stability, StabilityLevel, Unstable, UnstableReason,
+};
use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
use rustc_errors::{struct_span_err, Applicability};
use rustc_hir as hir;
@@ -161,7 +162,7 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
return;
}
- let (stab, const_stab) = attr::find_stability(&self.tcx.sess, attrs, item_sp);
+ let (stab, const_stab, body_stab) = attr::find_stability(&self.tcx.sess, attrs, item_sp);
let mut const_span = None;
let const_stab = const_stab.map(|(const_stab, const_span_node)| {
@@ -209,6 +210,13 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
}
}
+ if let Some((body_stab, _span)) = body_stab {
+ // FIXME: check that this item can have body stability
+
+ self.index.default_body_stab_map.insert(def_id, body_stab);
+ debug!(?self.index.default_body_stab_map);
+ }
+
let stab = stab.map(|(stab, span)| {
// Error if prohibited, or can't inherit anything from a container.
if kind == AnnotationKind::Prohibited
@@ -613,6 +621,7 @@ fn stability_index(tcx: TyCtxt<'_>, (): ()) -> Index {
let mut index = Index {
stab_map: Default::default(),
const_stab_map: Default::default(),
+ default_body_stab_map: Default::default(),
depr_map: Default::default(),
implications: Default::default(),
};
@@ -673,6 +682,9 @@ pub(crate) fn provide(providers: &mut Providers) {
stability_implications: |tcx, _| tcx.stability().implications.clone(),
lookup_stability: |tcx, id| tcx.stability().local_stability(id.expect_local()),
lookup_const_stability: |tcx, id| tcx.stability().local_const_stability(id.expect_local()),
+ lookup_default_body_stability: |tcx, id| {
+ tcx.stability().local_default_body_stability(id.expect_local())
+ },
lookup_deprecation_entry: |tcx, id| {
tcx.stability().local_deprecation_entry(id.expect_local())
},
@@ -723,7 +735,8 @@ impl<'tcx> Visitor<'tcx> for Checker<'tcx> {
let features = self.tcx.features();
if features.staged_api {
let attrs = self.tcx.hir().attrs(item.hir_id());
- let (stab, const_stab) = attr::find_stability(&self.tcx.sess, attrs, item.span);
+ let (stab, const_stab, _) =
+ attr::find_stability(&self.tcx.sess, attrs, item.span);
// If this impl block has an #[unstable] attribute, give an
// error if all involved types and traits are stable, because
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 54d67c5254188..036f087e2d23b 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1215,6 +1215,7 @@ symbols! {
rustc_const_unstable,
rustc_conversion_suggestion,
rustc_def_path,
+ rustc_default_body_unstable,
rustc_diagnostic_item,
rustc_diagnostic_macros,
rustc_dirty,
diff --git a/compiler/rustc_typeck/Cargo.toml b/compiler/rustc_typeck/Cargo.toml
index faf52e2695a33..cae29c1d3c5f9 100644
--- a/compiler/rustc_typeck/Cargo.toml
+++ b/compiler/rustc_typeck/Cargo.toml
@@ -30,3 +30,4 @@ rustc_ty_utils = { path = "../rustc_ty_utils" }
rustc_lint = { path = "../rustc_lint" }
rustc_serialize = { path = "../rustc_serialize" }
rustc_type_ir = { path = "../rustc_type_ir" }
+rustc_feature = { path = "../rustc_feature" }
diff --git a/compiler/rustc_typeck/src/check/check.rs b/compiler/rustc_typeck/src/check/check.rs
index 9497d5c4528cc..0293bf7803a66 100644
--- a/compiler/rustc_typeck/src/check/check.rs
+++ b/compiler/rustc_typeck/src/check/check.rs
@@ -18,6 +18,7 @@ use rustc_infer::infer::{DefiningAnchor, RegionVariableOrigin, TyCtxtInferExt};
use rustc_infer::traits::Obligation;
use rustc_lint::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS;
use rustc_middle::hir::nested_filter;
+use rustc_middle::middle::stability::EvalResult;
use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES};
use rustc_middle::ty::subst::GenericArgKind;
use rustc_middle::ty::util::{Discr, IntTypeExt};
@@ -1104,12 +1105,28 @@ fn check_impl_items_against_trait<'tcx>(
missing_items.push(tcx.associated_item(trait_item_id));
}
- if let Some(required_items) = &must_implement_one_of {
- // true if this item is specifically implemented in this impl
- let is_implemented_here = ancestors
- .leaf_def(tcx, trait_item_id)
- .map_or(false, |node_item| !node_item.defining_node.is_from_trait());
+ // true if this item is specifically implemented in this impl
+ let is_implemented_here = ancestors
+ .leaf_def(tcx, trait_item_id)
+ .map_or(false, |node_item| !node_item.defining_node.is_from_trait());
+
+ if !is_implemented_here {
+ match tcx.eval_default_body_stability(trait_item_id, full_impl_span) {
+ EvalResult::Deny { feature, reason, issue, .. } => default_body_is_unstable(
+ tcx,
+ full_impl_span,
+ trait_item_id,
+ feature,
+ reason,
+ issue,
+ ),
+ // Unmarked default bodies are considered stable (at least for now).
+ EvalResult::Allow | EvalResult::Unmarked => {}
+ }
+ }
+
+ if let Some(required_items) = &must_implement_one_of {
if is_implemented_here {
let trait_item = tcx.associated_item(trait_item_id);
if required_items.contains(&trait_item.ident(tcx)) {
diff --git a/compiler/rustc_typeck/src/check/mod.rs b/compiler/rustc_typeck/src/check/mod.rs
index 17c2e4868aac7..b5201c737dfe3 100644
--- a/compiler/rustc_typeck/src/check/mod.rs
+++ b/compiler/rustc_typeck/src/check/mod.rs
@@ -122,13 +122,14 @@ use rustc_session::parse::feature_err;
use rustc_session::Session;
use rustc_span::source_map::DUMMY_SP;
use rustc_span::symbol::{kw, Ident};
-use rustc_span::{self, BytePos, Span};
+use rustc_span::{self, BytePos, Span, Symbol};
use rustc_target::abi::VariantIdx;
use rustc_target::spec::abi::Abi;
use rustc_trait_selection::traits;
use rustc_trait_selection::traits::error_reporting::recursive_type_with_infinite_size_error;
use rustc_trait_selection::traits::error_reporting::suggestions::ReturnsVisitor;
use std::cell::RefCell;
+use std::num::NonZeroU32;
use crate::require_c_abi_if_c_variadic;
use crate::util::common::indenter;
@@ -662,6 +663,37 @@ fn missing_items_must_implement_one_of_err(
err.emit();
}
+fn default_body_is_unstable(
+ tcx: TyCtxt<'_>,
+ impl_span: Span,
+ item_did: DefId,
+ feature: Symbol,
+ reason: Option<Symbol>,
+ issue: Option<NonZeroU32>,
+) {
+ let missing_item_name = &tcx.associated_item(item_did).name;
+ let use_of_unstable_library_feature_note = match reason {
+ Some(r) => format!("use of unstable library feature '{feature}': {r}"),
+ None => format!("use of unstable library feature '{feature}'"),
+ };
+
+ let mut err = struct_span_err!(
+ tcx.sess,
+ impl_span,
+ E0046,
+ "not all trait items implemented, missing: `{missing_item_name}`",
+ );
+ err.note(format!("default implementation of `{missing_item_name}` is unstable"));
+ err.note(use_of_unstable_library_feature_note);
+ rustc_session::parse::add_feature_diagnostics_for_issue(
+ &mut err,
+ &tcx.sess.parse_sess,
+ feature,
+ rustc_feature::GateIssue::Library(issue),
+ );
+ err.emit();
+}
+
/// Re-sugar `ty::GenericPredicates` in a way suitable to be used in structured suggestions.
fn bounds_from_generic_predicates<'tcx>(
tcx: TyCtxt<'tcx>,
diff --git a/src/test/ui/stability-attribute/auxiliary/default_body.rs b/src/test/ui/stability-attribute/auxiliary/default_body.rs
new file mode 100644
index 0000000000000..3a177419d666d
--- /dev/null
+++ b/src/test/ui/stability-attribute/auxiliary/default_body.rs
@@ -0,0 +1,29 @@
+#![crate_type = "lib"]
+#![feature(staged_api, rustc_attrs)]
+#![stable(feature = "stable_feature", since = "1.0.0")]
+
+#[stable(feature = "stable_feature", since = "1.0.0")]
+pub trait JustTrait {
+ #[stable(feature = "stable_feature", since = "1.0.0")]
+ #[rustc_default_body_unstable(feature = "constant_default_body", issue = "none")]
+ const CONSTANT: usize = 0;
+
+ #[rustc_default_body_unstable(feature = "fun_default_body", issue = "none")]
+ #[stable(feature = "stable_feature", since = "1.0.0")]
+ fn fun() {}
+}
+
+#[rustc_must_implement_one_of(eq, neq)]
+#[stable(feature = "stable_feature", since = "1.0.0")]
+pub trait Equal {
+ #[rustc_default_body_unstable(feature = "eq_default_body", issue = "none")]
+ #[stable(feature = "stable_feature", since = "1.0.0")]
+ fn eq(&self, other: &Self) -> bool {
+ !self.neq(other)
+ }
+
+ #[stable(feature = "stable_feature", since = "1.0.0")]
+ fn neq(&self, other: &Self) -> bool {
+ !self.eq(other)
+ }
+}
diff --git a/src/test/ui/stability-attribute/default-body-stability-err.rs b/src/test/ui/stability-attribute/default-body-stability-err.rs
new file mode 100644
index 0000000000000..ecb281bccf604
--- /dev/null
+++ b/src/test/ui/stability-attribute/default-body-stability-err.rs
@@ -0,0 +1,19 @@
+// aux-build:default_body.rs
+#![crate_type = "lib"]
+
+extern crate default_body;
+
+use default_body::{Equal, JustTrait};
+
+struct Type;
+
+impl JustTrait for Type {}
+//~^ ERROR not all trait items implemented, missing: `CONSTANT` [E0046]
+//~| ERROR not all trait items implemented, missing: `fun` [E0046]
+
+impl Equal for Type {
+ //~^ ERROR not all trait items implemented, missing: `eq` [E0046]
+ fn neq(&self, other: &Self) -> bool {
+ false
+ }
+}
diff --git a/src/test/ui/stability-attribute/default-body-stability-err.stderr b/src/test/ui/stability-attribute/default-body-stability-err.stderr
new file mode 100644
index 0000000000000..ef666f30fc2a2
--- /dev/null
+++ b/src/test/ui/stability-attribute/default-body-stability-err.stderr
@@ -0,0 +1,38 @@
+error[E0046]: not all trait items implemented, missing: `CONSTANT`
+ --> $DIR/default-body-stability-err.rs:10:1
+ |
+LL | impl JustTrait for Type {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: default implementation of `CONSTANT` is unstable
+ = note: use of unstable library feature 'constant_default_body'
+ = help: add `#![feature(constant_default_body)]` to the crate attributes to enable
+
+error[E0046]: not all trait items implemented, missing: `fun`
+ --> $DIR/default-body-stability-err.rs:10:1
+ |
+LL | impl JustTrait for Type {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: default implementation of `fun` is unstable
+ = note: use of unstable library feature 'fun_default_body'
+ = help: add `#![feature(fun_default_body)]` to the crate attributes to enable
+
+error[E0046]: not all trait items implemented, missing: `eq`
+ --> $DIR/default-body-stability-err.rs:14:1
+ |
+LL | / impl Equal for Type {
+LL | |
+LL | | fn neq(&self, other: &Self) -> bool {
+LL | | false
+LL | | }
+LL | | }
+ | |_^
+ |
+ = note: default implementation of `eq` is unstable
+ = note: use of unstable library feature 'eq_default_body'
+ = help: add `#![feature(eq_default_body)]` to the crate attributes to enable
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0046`.
diff --git a/src/test/ui/stability-attribute/default-body-stability-ok-enables.rs b/src/test/ui/stability-attribute/default-body-stability-ok-enables.rs
new file mode 100644
index 0000000000000..bdc7522f48dde
--- /dev/null
+++ b/src/test/ui/stability-attribute/default-body-stability-ok-enables.rs
@@ -0,0 +1,18 @@
+// check-pass
+// aux-build:default_body.rs
+#![crate_type = "lib"]
+#![feature(fun_default_body, eq_default_body, constant_default_body)]
+
+extern crate default_body;
+
+use default_body::{Equal, JustTrait};
+
+struct Type;
+
+impl JustTrait for Type {}
+
+impl Equal for Type {
+ fn neq(&self, other: &Self) -> bool {
+ false
+ }
+}
diff --git a/src/test/ui/stability-attribute/default-body-stability-ok-impls.rs b/src/test/ui/stability-attribute/default-body-stability-ok-impls.rs
new file mode 100644
index 0000000000000..e1f5c017096ab
--- /dev/null
+++ b/src/test/ui/stability-attribute/default-body-stability-ok-impls.rs
@@ -0,0 +1,21 @@
+// check-pass
+// aux-build:default_body.rs
+#![crate_type = "lib"]
+
+extern crate default_body;
+
+use default_body::{Equal, JustTrait};
+
+struct Type;
+
+impl JustTrait for Type {
+ const CONSTANT: usize = 1;
+
+ fn fun() {}
+}
+
+impl Equal for Type {
+ fn eq(&self, other: &Self) -> bool {
+ false
+ }
+}