Rollup of 10 pull requests

compiler/rustc_ast/src/ast.rs

@@ -859,6 +859,8 @@ pub enum PatKind {
 pub enum PatFieldsRest {
     /// `module::StructName { field, ..}`
     Rest,
+    /// `module::StructName { field, syntax error }`
+    Recovered(ErrorGuaranteed),
     /// `module::StructName { field }`
     None,
 }

compiler/rustc_ast_lowering/src/pat.rs

@@ -92,7 +92,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                 span: self.lower_span(f.span),
                             }
                         }));
-                        break hir::PatKind::Struct(qpath, fs, *etc == ast::PatFieldsRest::Rest);
+                        break hir::PatKind::Struct(
+                            qpath,
+                            fs,
+                            matches!(
+                                etc,
+                                ast::PatFieldsRest::Rest | ast::PatFieldsRest::Recovered(_)
+                            ),
+                        );
                     }
                     PatKind::Tuple(pats) => {
                         let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple");

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -1654,11 +1654,14 @@ impl<'a> State<'a> {
                     },
                     |f| f.pat.span,
                 );
-                if *etc == ast::PatFieldsRest::Rest {
+                if let ast::PatFieldsRest::Rest | ast::PatFieldsRest::Recovered(_) = etc {
                     if !fields.is_empty() {
                         self.word_space(",");
                     }
                     self.word("..");
+                    if let ast::PatFieldsRest::Recovered(_) = etc {
+                        self.word("/* recovered parse error */");
+                    }
                 }
                 if !empty {
                     self.space();

compiler/rustc_borrowck/src/diagnostics/region_name.rs

@@ -459,11 +459,8 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
     ) -> RegionNameHighlight {
         let mut highlight = RegionHighlightMode::default();
         highlight.highlighting_region_vid(self.infcx.tcx, needle_fr, counter);
-        let type_name = self
-            .infcx
-            .err_ctxt()
-            .extract_inference_diagnostics_data(ty.into(), Some(highlight))
-            .name;
+        let type_name =
+            self.infcx.err_ctxt().extract_inference_diagnostics_data(ty.into(), highlight).name;
 
         debug!(
             "highlight_if_we_cannot_match_hir_ty: type_name={:?} needle_fr={:?}",
@@ -874,7 +871,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
         let type_name = self
             .infcx
             .err_ctxt()
-            .extract_inference_diagnostics_data(yield_ty.into(), Some(highlight))
+            .extract_inference_diagnostics_data(yield_ty.into(), highlight)
             .name;
 
         let yield_span = match tcx.hir_node(self.mir_hir_id()) {

compiler/rustc_feature/src/accepted.rs

@@ -175,6 +175,8 @@ declare_features! (
     (accepted, destructuring_assignment, "1.59.0", Some(71126)),
     /// Allows using the `#[diagnostic]` attribute tool namespace
     (accepted, diagnostic_namespace, "1.78.0", Some(111996)),
+    /// Controls errors in trait implementations.
+    (accepted, do_not_recommend, "CURRENT_RUSTC_VERSION", Some(51992)),
     /// Allows `#[doc(alias = "...")]`.
     (accepted, doc_alias, "1.48.0", Some(50146)),
     /// Allows `..` in tuple (struct) patterns.

compiler/rustc_feature/src/builtin_attrs.rs

@@ -1188,10 +1188,9 @@ pub static BUILTIN_ATTRIBUTE_MAP: LazyLock<FxHashMap<Symbol, &BuiltinAttribute>>
         map
     });
 
-pub fn is_stable_diagnostic_attribute(sym: Symbol, features: &Features) -> bool {
+pub fn is_stable_diagnostic_attribute(sym: Symbol, _features: &Features) -> bool {
     match sym {
-        sym::on_unimplemented => true,
-        sym::do_not_recommend => features.do_not_recommend(),
+        sym::on_unimplemented | sym::do_not_recommend => true,
         _ => false,
     }
 }

compiler/rustc_feature/src/unstable.rs

@@ -466,8 +466,6 @@ declare_features! (
     (unstable, deprecated_suggestion, "1.61.0", Some(94785)),
     /// Allows deref patterns.
     (incomplete, deref_patterns, "1.79.0", Some(87121)),
-    /// Controls errors in trait implementations.
-    (unstable, do_not_recommend, "1.67.0", Some(51992)),
     /// Tells rustdoc to automatically generate `#[doc(cfg(...))]`.
     (unstable, doc_auto_cfg, "1.58.0", Some(43781)),
     /// Allows `#[doc(cfg(...))]`.

compiler/rustc_mir_build/src/thir/cx/expr.rs

@@ -25,6 +25,14 @@ use crate::thir::cx::Cx;
 use crate::thir::util::UserAnnotatedTyHelpers;
 
 impl<'tcx> Cx<'tcx> {
+    /// Create a THIR expression for the given HIR expression. This expands all
+    /// adjustments and directly adds the type information from the
+    /// `typeck_results`. See the [dev-guide] for more details.
+    ///
+    /// (The term "mirror" in this case does not refer to "flipped" or
+    /// "reversed".)
+    ///
+    /// [dev-guide]: https://rustc-dev-guide.rust-lang.org/thir.html
     pub(crate) fn mirror_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) -> ExprId {
         // `mirror_expr` is recursing very deep. Make sure the stack doesn't overflow.
         ensure_sufficient_stack(|| self.mirror_expr_inner(expr))

compiler/rustc_parse/src/parser/pat.rs

@@ -1371,10 +1371,10 @@ impl<'a> Parser<'a> {
         self.bump();
         let (fields, etc) = self.parse_pat_fields().unwrap_or_else(|mut e| {
             e.span_label(path.span, "while parsing the fields for this pattern");
-            e.emit();
+            let guar = e.emit();
             self.recover_stmt();
             // When recovering, pretend we had `Foo { .. }`, to avoid cascading errors.
-            (ThinVec::new(), PatFieldsRest::Rest)
+            (ThinVec::new(), PatFieldsRest::Recovered(guar))
         });
         self.bump();
         Ok(PatKind::Struct(qself, path, fields, etc))

compiler/rustc_passes/messages.ftl

@@ -356,6 +356,9 @@ passes_ignored_derived_impls =
 passes_implied_feature_not_exist =
     feature `{$implied_by}` implying `{$feature}` does not exist
 
+passes_incorrect_do_not_recommend_args =
+    `#[diagnostic::do_not_recommend]` does not expect any arguments
+
 passes_incorrect_do_not_recommend_location =
     `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
 

compiler/rustc_passes/src/check_attr.rs

@@ -116,7 +116,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         for attr in attrs {
             match attr.path().as_slice() {
                 [sym::diagnostic, sym::do_not_recommend, ..] => {
-                    self.check_do_not_recommend(attr.span, hir_id, target)
+                    self.check_do_not_recommend(attr.span, hir_id, target, attr, item)
                 }
                 [sym::diagnostic, sym::on_unimplemented, ..] => {
                     self.check_diagnostic_on_unimplemented(attr.span, hir_id, target)
@@ -349,15 +349,36 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     }
 
     /// Checks if `#[diagnostic::do_not_recommend]` is applied on a trait impl.
-    fn check_do_not_recommend(&self, attr_span: Span, hir_id: HirId, target: Target) {
-        if !matches!(target, Target::Impl) {
+    fn check_do_not_recommend(
+        &self,
+        attr_span: Span,
+        hir_id: HirId,
+        target: Target,
+        attr: &Attribute,
+        item: Option<ItemLike<'_>>,
+    ) {
+        if !matches!(target, Target::Impl)
+            || matches!(
+                item,
+                Some(ItemLike::Item(hir::Item {  kind: hir::ItemKind::Impl(_impl),.. }))
+                    if _impl.of_trait.is_none()
+            )
+        {
             self.tcx.emit_node_span_lint(
                 UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
                 hir_id,
                 attr_span,
                 errors::IncorrectDoNotRecommendLocation,
             );
         }
+        if !matches!(attr.meta_kind(), Some(MetaItemKind::Word)) {
+            self.tcx.emit_node_span_lint(
+                UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
+                hir_id,
+                attr_span,
+                errors::DoNotRecommendDoesNotExpectArgs,
+            );
+        }
     }
 
     /// Checks if `#[diagnostic::on_unimplemented]` is applied to a trait definition

compiler/rustc_passes/src/errors.rs

@@ -20,6 +20,10 @@ use crate::lang_items::Duplicate;
 #[diag(passes_incorrect_do_not_recommend_location)]
 pub(crate) struct IncorrectDoNotRecommendLocation;
 
+#[derive(LintDiagnostic)]
+#[diag(passes_incorrect_do_not_recommend_args)]
+pub(crate) struct DoNotRecommendDoesNotExpectArgs;
+
 #[derive(Diagnostic)]
 #[diag(passes_autodiff_attr)]
 pub(crate) struct AutoDiffAttr {

compiler/rustc_resolve/src/late.rs

@@ -19,7 +19,9 @@ use rustc_ast::visit::{
 use rustc_ast::*;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
 use rustc_errors::codes::*;
-use rustc_errors::{Applicability, DiagArgValue, IntoDiagArg, StashKey, Suggestions};
+use rustc_errors::{
+    Applicability, DiagArgValue, ErrorGuaranteed, IntoDiagArg, StashKey, Suggestions,
+};
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, DefKind, LifetimeRes, NonMacroAttrKind, PartialRes, PerNS};
 use rustc_hir::def_id::{CRATE_DEF_ID, DefId, LOCAL_CRATE, LocalDefId};
@@ -264,12 +266,17 @@ impl RibKind<'_> {
 #[derive(Debug)]
 pub(crate) struct Rib<'ra, R = Res> {
     pub bindings: IdentMap<R>,
+    pub patterns_with_skipped_bindings: FxHashMap<DefId, Vec<(Span, Result<(), ErrorGuaranteed>)>>,
     pub kind: RibKind<'ra>,
 }
 
 impl<'ra, R> Rib<'ra, R> {
     fn new(kind: RibKind<'ra>) -> Rib<'ra, R> {
-        Rib { bindings: Default::default(), kind }
+        Rib {
+            bindings: Default::default(),
+            patterns_with_skipped_bindings: Default::default(),
+            kind,
+        }
     }
 }
 
@@ -3775,6 +3782,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
     /// When a whole or-pattern has been dealt with, the thing happens.
     ///
     /// See the implementation and `fresh_binding` for more details.
+    #[tracing::instrument(skip(self, bindings), level = "debug")]
     fn resolve_pattern_inner(
         &mut self,
         pat: &Pat,
@@ -3783,7 +3791,6 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
     ) {
         // Visit all direct subpatterns of this pattern.
         pat.walk(&mut |pat| {
-            debug!("resolve_pattern pat={:?} node={:?}", pat, pat.kind);
             match pat.kind {
                 PatKind::Ident(bmode, ident, ref sub) => {
                     // First try to resolve the identifier as some existing entity,
@@ -3809,8 +3816,9 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                 PatKind::Path(ref qself, ref path) => {
                     self.smart_resolve_path(pat.id, qself, path, PathSource::Pat);
                 }
-                PatKind::Struct(ref qself, ref path, ..) => {
+                PatKind::Struct(ref qself, ref path, ref _fields, ref rest) => {
                     self.smart_resolve_path(pat.id, qself, path, PathSource::Struct);
+                    self.record_patterns_with_skipped_bindings(pat, rest);
                 }
                 PatKind::Or(ref ps) => {
                     // Add a new set of bindings to the stack. `Or` here records that when a
@@ -3843,6 +3851,30 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
         });
     }
 
+    fn record_patterns_with_skipped_bindings(&mut self, pat: &Pat, rest: &ast::PatFieldsRest) {
+        match rest {
+            ast::PatFieldsRest::Rest | ast::PatFieldsRest::Recovered(_) => {
+                // Record that the pattern doesn't introduce all the bindings it could.
+                if let Some(partial_res) = self.r.partial_res_map.get(&pat.id)
+                    && let Some(res) = partial_res.full_res()
+                    && let Some(def_id) = res.opt_def_id()
+                {
+                    self.ribs[ValueNS]
+                        .last_mut()
+                        .unwrap()
+                        .patterns_with_skipped_bindings
+                        .entry(def_id)
+                        .or_default()
+                        .push((pat.span, match rest {
+                            ast::PatFieldsRest::Recovered(guar) => Err(*guar),
+                            _ => Ok(()),
+                        }));
+                }
+            }
+            ast::PatFieldsRest::None => {}
+        }
+    }
+
     fn fresh_binding(
         &mut self,
         ident: Ident,

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -430,6 +430,7 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         let mut err = self.r.dcx().struct_span_err(base_error.span, base_error.msg.clone());
         err.code(code);
 
+        self.detect_missing_binding_available_from_pattern(&mut err, path, following_seg);
         self.suggest_at_operator_in_slice_pat_with_range(&mut err, path);
         self.suggest_swapping_misplaced_self_ty_and_trait(&mut err, source, res, base_error.span);
 
@@ -1120,6 +1121,48 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         true
     }
 
+    fn detect_missing_binding_available_from_pattern(
+        &mut self,
+        err: &mut Diag<'_>,
+        path: &[Segment],
+        following_seg: Option<&Segment>,
+    ) {
+        let [segment] = path else { return };
+        let None = following_seg else { return };
+        for rib in self.ribs[ValueNS].iter().rev() {
+            for (def_id, spans) in &rib.patterns_with_skipped_bindings {
+                if let Some(fields) = self.r.field_idents(*def_id) {
+                    for field in fields {
+                        if field.name == segment.ident.name {
+                            if spans.iter().all(|(_, had_error)| had_error.is_err()) {
+                                // This resolution error will likely be fixed by fixing a
+                                // syntax error in a pattern, so it is irrelevant to the user.
+                                let multispan: MultiSpan =
+                                    spans.iter().map(|(s, _)| *s).collect::<Vec<_>>().into();
+                                err.span_note(
+                                    multispan,
+                                    "this pattern had a recovered parse error which likely lost \
+                                     the expected fields",
+                                );
+                                err.downgrade_to_delayed_bug();
+                            }
+                            let ty = self.r.tcx.item_name(*def_id);
+                            for (span, _) in spans {
+                                err.span_label(
+                                    *span,
+                                    format!(
+                                        "this pattern doesn't include `{field}`, which is \
+                                         available in `{ty}`",
+                                    ),
+                                );
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
     fn suggest_at_operator_in_slice_pat_with_range(
         &mut self,
         err: &mut Diag<'_>,

compiler/rustc_resolve/src/macros.rs

@@ -689,8 +689,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             && let [namespace, attribute, ..] = &*path.segments
             && namespace.ident.name == sym::diagnostic
             && !(attribute.ident.name == sym::on_unimplemented
-                || (attribute.ident.name == sym::do_not_recommend
-                    && self.tcx.features().do_not_recommend()))
+                || attribute.ident.name == sym::do_not_recommend)
         {
             let distance =
                 edit_distance(attribute.ident.name.as_str(), sym::on_unimplemented.as_str(), 5);