Auto merge of #117087 - matthiaskrgr:rollup-08kkjkz, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - #116960 (Location-insensitive polonius: consider a loan escaping if an SCC has member constraints applied only)
 - #116978 (Rewrite gdb pretty-printer registration)
 - #117040 (coverage: Add UI tests for values accepted by `-Cinstrument-coverage`)
 - #117064 (Eliminate rustc_attrs::builtin::handle_errors in favor of emitting errors directly)
 - #117073 (Fix suggestion for renamed coroutines feature)

r? `@ghost`
`@rustbot` modify labels: rollup

5 files changed, 97 insertions, 154 deletions

diff --git a/compiler/rustc_attr/src/builtin.rs b/compiler/rustc_attr/src/builtin.rs
index 46683d2d258..60eacde1c72 100644
--- a/compiler/rustc_attr/src/builtin.rs
+++ b/compiler/rustc_attr/src/builtin.rs
@@ -31,16 +31,6 @@ pub fn is_builtin_attr(attr: &Attribute) -> bool {
     attr.is_doc_comment() || attr.ident().is_some_and(|ident| is_builtin_attr_name(ident.name))
 }
 
-enum AttrError {
-    MultipleItem(String),
-    UnknownMetaItem(String, &'static [&'static str]),
-    MissingSince,
-    NonIdentFeature,
-    MissingFeature,
-    MultipleStabilityLevels,
-    UnsupportedLiteral(UnsupportedLiteralReason, /* is_bytestr */ bool),
-}
-
 pub(crate) enum UnsupportedLiteralReason {
     Generic,
     CfgString,
@@ -48,37 +38,6 @@ pub(crate) enum UnsupportedLiteralReason {
     DeprecatedKvPair,
 }
 
-fn handle_errors(sess: &ParseSess, span: Span, error: AttrError) {
-    match error {
-        AttrError::MultipleItem(item) => {
-            sess.emit_err(session_diagnostics::MultipleItem { span, item });
-        }
-        AttrError::UnknownMetaItem(item, expected) => {
-            sess.emit_err(session_diagnostics::UnknownMetaItem { span, item, expected });
-        }
-        AttrError::MissingSince => {
-            sess.emit_err(session_diagnostics::MissingSince { span });
-        }
-        AttrError::NonIdentFeature => {
-            sess.emit_err(session_diagnostics::NonIdentFeature { span });
-        }
-        AttrError::MissingFeature => {
-            sess.emit_err(session_diagnostics::MissingFeature { span });
-        }
-        AttrError::MultipleStabilityLevels => {
-            sess.emit_err(session_diagnostics::MultipleStabilityLevels { span });
-        }
-        AttrError::UnsupportedLiteral(reason, is_bytestr) => {
-            sess.emit_err(session_diagnostics::UnsupportedLiteral {
-                span,
-                reason,
-                is_bytestr,
-                start_point_span: sess.source_map().start_point(span),
-            });
-        }
-    }
-}
-
 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub enum InlineAttr {
     None,
@@ -241,7 +200,7 @@ pub fn find_stability(
             sym::rustc_allowed_through_unstable_modules => allowed_through_unstable_modules = true,
             sym::unstable => {
                 if stab.is_some() {
-                    handle_errors(&sess.parse_sess, attr.span, AttrError::MultipleStabilityLevels);
+                    sess.emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span });
                     break;
                 }
 
@@ -251,7 +210,7 @@ pub fn find_stability(
             }
             sym::stable => {
                 if stab.is_some() {
-                    handle_errors(&sess.parse_sess, attr.span, AttrError::MultipleStabilityLevels);
+                    sess.emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span });
                     break;
                 }
                 if let Some((feature, level)) = parse_stability(sess, attr) {
@@ -295,7 +254,7 @@ pub fn find_const_stability(
             sym::rustc_promotable => promotable = true,
             sym::rustc_const_unstable => {
                 if const_stab.is_some() {
-                    handle_errors(&sess.parse_sess, attr.span, AttrError::MultipleStabilityLevels);
+                    sess.emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span });
                     break;
                 }
 
@@ -306,7 +265,7 @@ pub fn find_const_stability(
             }
             sym::rustc_const_stable => {
                 if const_stab.is_some() {
-                    handle_errors(&sess.parse_sess, attr.span, AttrError::MultipleStabilityLevels);
+                    sess.emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span });
                     break;
                 }
                 if let Some((feature, level)) = parse_stability(sess, attr) {
@@ -340,7 +299,7 @@ pub fn find_body_stability(
     for attr in attrs {
         if attr.has_name(sym::rustc_default_body_unstable) {
             if body_stab.is_some() {
-                handle_errors(&sess.parse_sess, attr.span, AttrError::MultipleStabilityLevels);
+                sess.emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span });
                 break;
             }
 
@@ -355,11 +314,10 @@ pub fn find_body_stability(
 
 fn insert_or_error(sess: &Session, meta: &MetaItem, item: &mut Option<Symbol>) -> Option<()> {
     if item.is_some() {
-        handle_errors(
-            &sess.parse_sess,
-            meta.span,
-            AttrError::MultipleItem(pprust::path_to_string(&meta.path)),
-        );
+        sess.emit_err(session_diagnostics::MultipleItem {
+            span: meta.span,
+            item: pprust::path_to_string(&meta.path),
+        });
         None
     } else if let Some(v) = meta.value_str() {
         *item = Some(v);
@@ -380,11 +338,12 @@ fn parse_stability(sess: &Session, attr: &Attribute) -> Option<(Symbol, Stabilit
     let mut since = None;
     for meta in metas {
         let Some(mi) = meta.meta_item() else {
-            handle_errors(
-                &sess.parse_sess,
-                meta.span(),
-                AttrError::UnsupportedLiteral(UnsupportedLiteralReason::Generic, false),
-            );
+            sess.emit_err(session_diagnostics::UnsupportedLiteral {
+                span: meta.span(),
+                reason: UnsupportedLiteralReason::Generic,
+                is_bytestr: false,
+                start_point_span: sess.source_map().start_point(meta.span()),
+            });
             return None;
         };
 
@@ -392,14 +351,11 @@ fn parse_stability(sess: &Session, attr: &Attribute) -> Option<(Symbol, Stabilit
             sym::feature => insert_or_error(sess, mi, &mut feature)?,
             sym::since => insert_or_error(sess, mi, &mut since)?,
             _ => {
-                handle_errors(
-                    &sess.parse_sess,
-                    meta.span(),
-                    AttrError::UnknownMetaItem(
-                        pprust::path_to_string(&mi.path),
-                        &["feature", "since"],
-                    ),
-                );
+                sess.emit_err(session_diagnostics::UnknownMetaItem {
+                    span: meta.span(),
+                    item: pprust::path_to_string(&mi.path),
+                    expected: &["feature", "since"],
+                });
                 return None;
             }
         }
@@ -417,11 +373,11 @@ fn parse_stability(sess: &Session, attr: &Attribute) -> Option<(Symbol, Stabilit
             Some((feature, level))
         }
         (None, _) => {
-            handle_errors(&sess.parse_sess, attr.span, AttrError::MissingFeature);
+            sess.emit_err(session_diagnostics::MissingFeature { span: attr.span });
             None
         }
         _ => {
-            handle_errors(&sess.parse_sess, attr.span, AttrError::MissingSince);
+            sess.emit_err(session_diagnostics::MissingSince { span: attr.span });
             None
         }
     }
@@ -441,11 +397,12 @@ fn parse_unstability(sess: &Session, attr: &Attribute) -> Option<(Symbol, Stabil
     let mut implied_by = None;
     for meta in metas {
         let Some(mi) = meta.meta_item() else {
-            handle_errors(
-                &sess.parse_sess,
-                meta.span(),
-                AttrError::UnsupportedLiteral(UnsupportedLiteralReason::Generic, false),
-            );
+            sess.emit_err(session_diagnostics::UnsupportedLiteral {
+                span: meta.span(),
+                reason: UnsupportedLiteralReason::Generic,
+                is_bytestr: false,
+                start_point_span: sess.source_map().start_point(meta.span()),
+            });
             return None;
         };
 
@@ -484,14 +441,11 @@ fn parse_unstability(sess: &Session, attr: &Attribute) -> Option<(Symbol, Stabil
             }
             sym::implied_by => insert_or_error(sess, mi, &mut implied_by)?,
             _ => {
-                handle_errors(
-                    &sess.parse_sess,
-                    meta.span(),
-                    AttrError::UnknownMetaItem(
-                        pprust::path_to_string(&mi.path),
-                        &["feature", "reason", "issue", "soft", "implied_by"],
-                    ),
-                );
+                sess.emit_err(session_diagnostics::UnknownMetaItem {
+                    span: meta.span(),
+                    item: pprust::path_to_string(&mi.path),
+                    expected: &["feature", "reason", "issue", "soft", "implied_by"],
+                });
                 return None;
             }
         }
@@ -500,7 +454,7 @@ fn parse_unstability(sess: &Session, attr: &Attribute) -> Option<(Symbol, Stabil
     match (feature, reason, issue) {
         (Some(feature), reason, Some(_)) => {
             if !rustc_lexer::is_ident(feature.as_str()) {
-                handle_errors(&sess.parse_sess, attr.span, AttrError::NonIdentFeature);
+                sess.emit_err(session_diagnostics::NonIdentFeature { span: attr.span });
                 return None;
             }
             let level = StabilityLevel::Unstable {
@@ -512,7 +466,7 @@ fn parse_unstability(sess: &Session, attr: &Attribute) -> Option<(Symbol, Stabil
             Some((feature, level))
         }
         (None, _, _) => {
-            handle_errors(&sess.parse_sess, attr.span, AttrError::MissingFeature);
+            sess.emit_err(session_diagnostics::MissingFeature { span: attr.span });
             return None;
         }
         _ => {
@@ -659,11 +613,12 @@ pub fn eval_condition(
         ast::MetaItemKind::List(mis) => {
             for mi in mis.iter() {
                 if !mi.is_meta_item() {
-                    handle_errors(
-                        sess,
-                        mi.span(),
-                        AttrError::UnsupportedLiteral(UnsupportedLiteralReason::Generic, false),
-                    );
+                    sess.emit_err(session_diagnostics::UnsupportedLiteral {
+                        span: mi.span(),
+                        reason: UnsupportedLiteralReason::Generic,
+                        is_bytestr: false,
+                        start_point_span: sess.source_map().start_point(mi.span()),
+                    });
                     return false;
                 }
             }
@@ -731,14 +686,12 @@ pub fn eval_condition(
             true
         }
         MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
-            handle_errors(
-                sess,
-                lit.span,
-                AttrError::UnsupportedLiteral(
-                    UnsupportedLiteralReason::CfgString,
-                    lit.kind.is_bytestr(),
-                ),
-            );
+            sess.emit_err(session_diagnostics::UnsupportedLiteral {
+                span: lit.span,
+                reason: UnsupportedLiteralReason::CfgString,
+                is_bytestr: lit.kind.is_bytestr(),
+                start_point_span: sess.source_map().start_point(lit.span),
+            });
             true
         }
         ast::MetaItemKind::Word | ast::MetaItemKind::NameValue(..) => {
@@ -795,11 +748,10 @@ pub fn find_deprecation(
             MetaItemKind::List(list) => {
                 let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
                     if item.is_some() {
-                        handle_errors(
-                            &sess.parse_sess,
-                            meta.span,
-                            AttrError::MultipleItem(pprust::path_to_string(&meta.path)),
-                        );
+                        sess.emit_err(session_diagnostics::MultipleItem {
+                            span: meta.span,
+                            item: pprust::path_to_string(&meta.path),
+                        });
                         return false;
                     }
                     if let Some(v) = meta.value_str() {
@@ -807,14 +759,12 @@ pub fn find_deprecation(
                         true
                     } else {
                         if let Some(lit) = meta.name_value_literal() {
-                            handle_errors(
-                                &sess.parse_sess,
-                                lit.span,
-                                AttrError::UnsupportedLiteral(
-                                    UnsupportedLiteralReason::DeprecatedString,
-                                    lit.kind.is_bytestr(),
-                                ),
-                            );
+                            sess.emit_err(session_diagnostics::UnsupportedLiteral {
+                                span: lit.span,
+                                reason: UnsupportedLiteralReason::DeprecatedString,
+                                is_bytestr: lit.kind.is_bytestr(),
+                                start_point_span: sess.source_map().start_point(lit.span),
+                            });
                         } else {
                             sess.emit_err(session_diagnostics::IncorrectMetaItem {
                                 span: meta.span,
@@ -852,30 +802,25 @@ pub fn find_deprecation(
                                 }
                             }
                             _ => {
-                                handle_errors(
-                                    &sess.parse_sess,
-                                    meta.span(),
-                                    AttrError::UnknownMetaItem(
-                                        pprust::path_to_string(&mi.path),
-                                        if features.deprecated_suggestion {
-                                            &["since", "note", "suggestion"]
-                                        } else {
-                                            &["since", "note"]
-                                        },
-                                    ),
-                                );
+                                sess.emit_err(session_diagnostics::UnknownMetaItem {
+                                    span: meta.span(),
+                                    item: pprust::path_to_string(&mi.path),
+                                    expected: if features.deprecated_suggestion {
+                                        &["since", "note", "suggestion"]
+                                    } else {
+                                        &["since", "note"]
+                                    },
+                                });
                                 continue 'outer;
                             }
                         },
                         NestedMetaItem::Lit(lit) => {
-                            handle_errors(
-                                &sess.parse_sess,
-                                lit.span,
-                                AttrError::UnsupportedLiteral(
-                                    UnsupportedLiteralReason::DeprecatedKvPair,
-                                    false,
-                                ),
-                            );
+                            sess.emit_err(session_diagnostics::UnsupportedLiteral {
+                                span: lit.span,
+                                reason: UnsupportedLiteralReason::DeprecatedKvPair,
+                                is_bytestr: false,
+                                start_point_span: sess.source_map().start_point(lit.span),
+                            });
                             continue 'outer;
                         }
                     }
@@ -885,7 +830,7 @@ pub fn find_deprecation(
 
         if is_rustc {
             if since.is_none() {
-                handle_errors(&sess.parse_sess, attr.span, AttrError::MissingSince);
+                sess.emit_err(session_diagnostics::MissingSince { span: attr.span });
                 continue;
             }
 
diff --git a/compiler/rustc_borrowck/src/dataflow.rs b/compiler/rustc_borrowck/src/dataflow.rs
index 6ea84620bbe..16814950b0d 100644
--- a/compiler/rustc_borrowck/src/dataflow.rs
+++ b/compiler/rustc_borrowck/src/dataflow.rs
@@ -272,21 +272,28 @@ impl<'tcx> PoloniusOutOfScopePrecomputer<'_, 'tcx> {
         loan_issued_at: Location,
     ) {
         let sccs = self.regioncx.constraint_sccs();
+        let universal_regions = self.regioncx.universal_regions();
         let issuing_region_scc = sccs.scc(issuing_region);
 
         // We first handle the cases where the loan doesn't go out of scope, depending on the issuing
         // region's successors.
         for scc in sccs.depth_first_search(issuing_region_scc) {
-            // 1. Via member constraints
+            // 1. Via applied member constraints
             //
             // The issuing region can flow into the choice regions, and they are either:
             // - placeholders or free regions themselves,
             // - or also transitively outlive a free region.
             //
-            // That is to say, if there are member constraints here, the loan escapes the function
-            // and cannot go out of scope. We can early return.
-            if self.regioncx.scc_has_member_constraints(scc) {
-                return;
+            // That is to say, if there are applied member constraints here, the loan escapes the
+            // function and cannot go out of scope. We could early return here.
+            //
+            // For additional insurance via fuzzing and crater, we verify that the constraint's min
+            // choice indeed escapes the function. In the future, we could e.g. turn this check into
+            // a debug assert and early return as an optimization.
+            for constraint in self.regioncx.applied_member_constraints(scc) {
+                if universal_regions.is_universal_region(constraint.min_choice) {
+                    return;
+                }
             }
 
             // 2. Via regions that are live at all points: placeholders and free regions.
@@ -413,12 +420,12 @@ impl<'a, 'tcx> Borrows<'a, 'tcx> {
             let mut polonius_prec = PoloniusOutOfScopePrecomputer::new(body, regioncx);
             for (loan_idx, loan_data) in borrow_set.iter_enumerated() {
                 let issuing_region = loan_data.region;
-                let issued_location = loan_data.reserve_location;
+                let loan_issued_at = loan_data.reserve_location;
 
                 polonius_prec.precompute_loans_out_of_scope(
                     loan_idx,
                     issuing_region,
-                    issued_location,
+                    loan_issued_at,
                 );
             }
 
diff --git a/compiler/rustc_borrowck/src/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs
index 96cbe98c216..05c2cbd4969 100644
--- a/compiler/rustc_borrowck/src/region_infer/mod.rs
+++ b/compiler/rustc_borrowck/src/region_infer/mod.rs
@@ -644,11 +644,12 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         self.scc_universes[scc]
     }
 
-    /// Once region solving has completed, this function will return
-    /// the member constraints that were applied to the value of a given
-    /// region `r`. See `AppliedMemberConstraint`.
-    pub(crate) fn applied_member_constraints(&self, r: RegionVid) -> &[AppliedMemberConstraint] {
-        let scc = self.constraint_sccs.scc(r);
+    /// Once region solving has completed, this function will return the member constraints that
+    /// were applied to the value of a given SCC `scc`. See `AppliedMemberConstraint`.
+    pub(crate) fn applied_member_constraints(
+        &self,
+        scc: ConstraintSccIndex,
+    ) -> &[AppliedMemberConstraint] {
         binary_search_util::binary_search_slice(
             &self.member_constraints_applied,
             |applied| applied.member_region_scc,
@@ -1945,7 +1946,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             // Member constraints can also give rise to `'r: 'x` edges that
             // were not part of the graph initially, so watch out for those.
             // (But they are extremely rare; this loop is very cold.)
-            for constraint in self.applied_member_constraints(r) {
+            for constraint in self.applied_member_constraints(self.constraint_sccs.scc(r)) {
                 let p_c = &self.member_constraints[constraint.member_constraint_index];
                 let constraint = OutlivesConstraint {
                     sup: r,
@@ -2292,11 +2293,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         self.constraint_sccs.as_ref()
     }
 
-    /// Returns whether the given SCC has any member constraints.
-    pub(crate) fn scc_has_member_constraints(&self, scc: ConstraintSccIndex) -> bool {
-        self.member_constraints.indices(scc).next().is_some()
-    }
-
     /// Returns whether the given SCC is live at all points: whether the representative is a
     /// placeholder or a free region.
     pub(crate) fn scc_is_live_at_all_points(&self, scc: ConstraintSccIndex) -> bool {
diff --git a/compiler/rustc_feature/src/removed.rs b/compiler/rustc_feature/src/removed.rs
index ac133f8b039..ed19274a7cc 100644
--- a/compiler/rustc_feature/src/removed.rs
+++ b/compiler/rustc_feature/src/removed.rs
@@ -99,7 +99,7 @@ declare_features! (
     /// Allows generators to be cloned.
     (removed, generator_clone, "1.65.0", Some(95360), None, Some("renamed to `coroutine_clone`")),
     /// Allows defining generators.
-    (removed, generators, "1.21.0", Some(43122), None, Some("renamed to `coroutine`")),
+    (removed, generators, "1.21.0", Some(43122), None, Some("renamed to `coroutines`")),
     /// Allows `impl Trait` in bindings (`let`, `const`, `static`).
     (removed, impl_trait_in_bindings, "1.55.0", Some(63065), None,
      Some("the implementation was not maintainable, the feature may get reintroduced once the current refactorings are done")),
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 2e991b4c0ad..462e7e85c65 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -3463,9 +3463,10 @@ impl DumpMonoStatsFormat {
 
 /// `-Zpolonius` values, enabling the borrow checker polonius analysis, and which version: legacy,
 /// or future prototype.
-#[derive(Clone, Copy, PartialEq, Hash, Debug)]
+#[derive(Clone, Copy, PartialEq, Hash, Debug, Default)]
 pub enum Polonius {
     /// The default value: disabled.
+    #[default]
     Off,
 
     /// Legacy version, using datalog and the `polonius-engine` crate. Historical value for `-Zpolonius`.
@@ -3475,12 +3476,6 @@ pub enum Polonius {
     Next,
 }
 
-impl Default for Polonius {
-    fn default() -> Self {
-        Polonius::Off
-    }
-}
-
 impl Polonius {
     /// Returns whether the legacy version of polonius is enabled
     pub fn is_legacy_enabled(&self) -> bool {