Rollup of 9 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_mir_build/src/build/expr/as_place.rs

@@ -647,13 +647,31 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
         match place_ty.kind() {
             ty::Array(_elem_ty, len_const) => {
-                // We know how long an array is, so just use that as a constant
-                // directly -- no locals needed. We do need one statement so
-                // that borrow- and initialization-checking consider it used,
-                // though. FIXME: Do we really *need* to count this as a use?
-                // Could partial array tracking work off something else instead?
-                self.cfg.push_fake_read(block, source_info, FakeReadCause::ForIndex, place);
-                let const_ = Const::from_ty_const(*len_const, usize_ty, self.tcx);
+                let ty_const = if let Some((_, len_ty)) = len_const.try_to_valtree()
+                    && len_ty != self.tcx.types.usize
+                {
+                    // Bad const generics can give us a constant from the type that's
+                    // not actually a `usize`, so in that case give an error instead.
+                    // FIXME: It'd be nice if the type checker made sure this wasn't
+                    // possible, instead.
+                    let err = self.tcx.dcx().span_delayed_bug(
+                        span,
+                        format!(
+                            "Array length should have already been a type error, as it's {len_ty:?}"
+                        ),
+                    );
+                    ty::Const::new_error(self.tcx, err)
+                } else {
+                    // We know how long an array is, so just use that as a constant
+                    // directly -- no locals needed. We do need one statement so
+                    // that borrow- and initialization-checking consider it used,
+                    // though. FIXME: Do we really *need* to count this as a use?
+                    // Could partial array tracking work off something else instead?
+                    self.cfg.push_fake_read(block, source_info, FakeReadCause::ForIndex, place);
+                    *len_const
+                };
+
+                let const_ = Const::from_ty_const(ty_const, usize_ty, self.tcx);
                 Operand::Constant(Box::new(ConstOperand { span, user_ty: None, const_ }))
             }
             ty::Slice(_elem_ty) => {

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_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_target/src/spec/mod.rs

@@ -3166,7 +3166,7 @@ impl Target {
                 // Note that the `lp64e` is still unstable as it's not (yet) part of the ELF psABI.
                 check_matches!(
                     &*self.llvm_abiname,
-                    "lp64" | "lp64f" | "lp64d" | "lp64q" | "lp64e",
+                    "lp64" | "lp64f" | "lp64d" | "lp64e",
                     "invalid RISC-V ABI name"
                 );
             }

compiler/rustc_target/src/target_features.rs

@@ -39,7 +39,7 @@ pub enum Stability<Toggleability> {
         allow_toggle: Toggleability,
     },
     /// This feature can not be set via `-Ctarget-feature` or `#[target_feature]`, it can only be
-    /// set in the basic target definition. It is never set in `cfg(target_feature)`. Used in
+    /// set in the target spec. It is never set in `cfg(target_feature)`. Used in
     /// particular for features that change the floating-point ABI.
     Forbidden { reason: &'static str },
 }
@@ -590,9 +590,76 @@ const RISCV_FEATURES: &[(&str, StabilityUncomputed, ImpliedFeatures)] = &[
     // tidy-alphabetical-start
     ("a", STABLE, &["zaamo", "zalrsc"]),
     ("c", STABLE, &[]),
-    ("d", unstable(sym::riscv_target_feature), &["f"]),
-    ("e", unstable(sym::riscv_target_feature), &[]),
-    ("f", unstable(sym::riscv_target_feature), &[]),
+    (
+        "d",
+        Stability::Unstable {
+            nightly_feature: sym::riscv_target_feature,
+            allow_toggle: |target, enable| match &*target.llvm_abiname {
+                "ilp32d" | "lp64d" if !enable => {
+                    // The ABI requires the `d` feature, so it cannot be disabled.
+                    Err("feature is required by ABI")
+                }
+                "ilp32e" if enable => {
+                    // ilp32e is incompatible with features that need aligned load/stores > 32 bits,
+                    // like `d`.
+                    Err("feature is incompatible with ABI")
+                }
+                _ => Ok(()),
+            },
+        },
+        &["f"],
+    ),
+    (
+        "e",
+        Stability::Unstable {
+            // Given that this is a negative feature, consider this before stabilizing:
+            // does it really make sense to enable this feature in an individual
+            // function with `#[target_feature]`?
+            nightly_feature: sym::riscv_target_feature,
+            allow_toggle: |target, enable| {
+                match &*target.llvm_abiname {
+                    _ if !enable => {
+                        // Disabling this feature means we can use more registers (x16-x31).
+                        // The "e" ABIs treat them as caller-save, so it is safe to use them only
+                        // in some parts of a program while the rest doesn't know they even exist.
+                        // On other ABIs, the feature is already disabled anyway.
+                        Ok(())
+                    }
+                    "ilp32e" | "lp64e" => {
+                        // Embedded ABIs should already have the feature anyway, it's fine to enable
+                        // it again from an ABI perspective.
+                        Ok(())
+                    }
+                    _ => {
+                        // *Not* an embedded ABI. Enabling `e` is invalid.
+                        Err("feature is incompatible with ABI")
+                    }
+                }
+            },
+        },
+        &[],
+    ),
+    (
+        "f",
+        Stability::Unstable {
+            nightly_feature: sym::riscv_target_feature,
+            allow_toggle: |target, enable| {
+                match &*target.llvm_abiname {
+                    "ilp32f" | "ilp32d" | "lp64f" | "lp64d" if !enable => {
+                        // The ABI requires the `f` feature, so it cannot be disabled.
+                        Err("feature is required by ABI")
+                    }
+                    _ => Ok(()),
+                }
+            },
+        },
+        &[],
+    ),
+    (
+        "forced-atomics",
+        Stability::Forbidden { reason: "unsound because it changes the ABI of atomic operations" },
+        &[],
+    ),
     ("m", STABLE, &[]),
     ("relax", unstable(sym::riscv_target_feature), &[]),
     ("unaligned-scalar-mem", unstable(sym::riscv_target_feature), &[]),