Rollup of 8 pull requests

compiler/rustc_error_messages/locales/en-US/infer.ftl

@@ -253,8 +253,8 @@ infer_trait_placeholder_mismatch = implementation of `{$trait_def_id}` is not ge
 infer_trait_impl_diff = `impl` item signature doesn't match `trait` item signature
     .found = found `{$found}`
     .expected = expected `{$expected}`
-    .expected_found = expected `{$expected}`
-               {"   "}found `{$found}`
+    .expected_found = expected signature `{$expected}`
+               {"   "}found signature `{$found}`
 
 infer_tid_rel_help = verify the lifetime relationships in the `trait` and `impl` between the `self` argument, the other inputs and its output
 infer_tid_consider_borrowing = consider borrowing this type parameter in the trait

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -270,8 +270,8 @@ fn compare_method_predicate_entailment<'tcx>(
     let unnormalized_impl_fty = tcx.mk_fn_ptr(ty::Binder::dummy(unnormalized_impl_sig));
 
     let norm_cause = ObligationCause::misc(impl_m_span, impl_m_hir_id);
-    let impl_fty = ocx.normalize(&norm_cause, param_env, unnormalized_impl_fty);
-    debug!("compare_impl_method: impl_fty={:?}", impl_fty);
+    let impl_sig = ocx.normalize(&norm_cause, param_env, unnormalized_impl_sig);
+    debug!("compare_impl_method: impl_fty={:?}", impl_sig);
 
     let trait_sig = tcx.bound_fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs);
     let trait_sig = tcx.liberate_late_bound_regions(impl_m.def_id, trait_sig);
@@ -294,18 +294,17 @@ fn compare_method_predicate_entailment<'tcx>(
     // type would be more appropriate. In other places we have a `Vec<Span>`
     // corresponding to their `Vec<Predicate>`, but we don't have that here.
     // Fixing this would improve the output of test `issue-83765.rs`.
-    let result = ocx.sup(&cause, param_env, trait_fty, impl_fty);
+    let result = ocx.sup(&cause, param_env, trait_sig, impl_sig);
 
     if let Err(terr) = result {
-        debug!(?terr, "sub_types failed: impl ty {:?}, trait ty {:?}", impl_fty, trait_fty);
+        debug!(?impl_sig, ?trait_sig, ?terr, "sub_types failed");
 
         let emitted = report_trait_method_mismatch(
             &infcx,
             cause,
             terr,
-            (trait_m, trait_fty),
-            (impl_m, impl_fty),
-            trait_sig,
+            (trait_m, trait_sig),
+            (impl_m, impl_sig),
             impl_trait_ref,
         );
         return Err(emitted);
@@ -484,7 +483,8 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
     let impl_trait_ref = tcx.impl_trait_ref(impl_m.impl_container(tcx).unwrap()).unwrap();
     let param_env = tcx.param_env(def_id);
 
-    // First, check a few of the same thing as `compare_impl_method`, just so we don't ICE during substitutions later.
+    // First, check a few of the same things as `compare_impl_method`,
+    // just so we don't ICE during substitution later.
     compare_number_of_generics(tcx, impl_m, trait_m, tcx.hir().span_if_local(impl_m.def_id), true)?;
     compare_generic_param_kinds(tcx, impl_m, trait_m, true)?;
     check_region_bounds_on_impl_item(tcx, impl_m, trait_m, true)?;
@@ -577,14 +577,11 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
 
     debug!(?trait_sig, ?impl_sig, "equating function signatures");
 
-    let trait_fty = tcx.mk_fn_ptr(ty::Binder::dummy(trait_sig));
-    let impl_fty = tcx.mk_fn_ptr(ty::Binder::dummy(impl_sig));
-
     // Unify the whole function signature. We need to do this to fully infer
     // the lifetimes of the return type, but do this after unifying just the
     // return types, since we want to avoid duplicating errors from
     // `compare_method_predicate_entailment`.
-    match ocx.eq(&cause, param_env, trait_fty, impl_fty) {
+    match ocx.eq(&cause, param_env, trait_sig, impl_sig) {
         Ok(()) => {}
         Err(terr) => {
             // This function gets called during `compare_method_predicate_entailment` when normalizing a
@@ -595,9 +592,8 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
                 infcx,
                 cause,
                 terr,
-                (trait_m, trait_fty),
-                (impl_m, impl_fty),
-                trait_sig,
+                (trait_m, trait_sig),
+                (impl_m, impl_sig),
                 impl_trait_ref,
             );
             return Err(emitted);
@@ -771,9 +767,8 @@ fn report_trait_method_mismatch<'tcx>(
     infcx: &InferCtxt<'tcx>,
     mut cause: ObligationCause<'tcx>,
     terr: TypeError<'tcx>,
-    (trait_m, trait_fty): (&ty::AssocItem, Ty<'tcx>),
-    (impl_m, impl_fty): (&ty::AssocItem, Ty<'tcx>),
-    trait_sig: ty::FnSig<'tcx>,
+    (trait_m, trait_sig): (&ty::AssocItem, ty::FnSig<'tcx>),
+    (impl_m, impl_sig): (&ty::AssocItem, ty::FnSig<'tcx>),
     impl_trait_ref: ty::TraitRef<'tcx>,
 ) -> ErrorGuaranteed {
     let tcx = infcx.tcx;
@@ -858,10 +853,7 @@ fn report_trait_method_mismatch<'tcx>(
         &mut diag,
         &cause,
         trait_err_span.map(|sp| (sp, "type in trait".to_owned())),
-        Some(infer::ValuePairs::Terms(ExpectedFound {
-            expected: trait_fty.into(),
-            found: impl_fty.into(),
-        })),
+        Some(infer::ValuePairs::Sigs(ExpectedFound { expected: trait_sig, found: impl_sig })),
         terr,
         false,
         false,

compiler/rustc_hir_typeck/src/demand.rs

@@ -57,6 +57,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             || self.suggest_boxing_when_appropriate(err, expr, expected, expr_ty)
             || self.suggest_block_to_brackets_peeling_refs(err, expr, expr_ty, expected)
             || self.suggest_copied_or_cloned(err, expr, expr_ty, expected)
+            || self.suggest_clone_for_ref(err, expr, expr_ty, expected)
             || self.suggest_into(err, expr, expr_ty, expected)
             || self.suggest_floating_point_literal(err, expr, expected);
         if !suggested {

compiler/rustc_hir_typeck/src/expr.rs

@@ -2217,7 +2217,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span, None);
                             return field_ty;
                         }
-                        private_candidate = Some((adjustments, base_def.did(), field_ty));
+                        private_candidate = Some((adjustments, base_def.did()));
                     }
                 }
                 ty::Tuple(tys) => {
@@ -2240,12 +2240,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
         self.structurally_resolved_type(autoderef.span(), autoderef.final_ty(false));
 
-        if let Some((adjustments, did, field_ty)) = private_candidate {
+        if let Some((adjustments, did)) = private_candidate {
             // (#90483) apply adjustments to avoid ExprUseVisitor from
             // creating erroneous projection.
             self.apply_adjustments(base, adjustments);
             self.ban_private_field_access(expr, base_ty, field, did);
-            return field_ty;
+            return self.tcx().ty_error();
         }
 
         if field.name == kw::Empty {

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1014,6 +1014,36 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    pub(crate) fn suggest_clone_for_ref(
+        &self,
+        diag: &mut Diagnostic,
+        expr: &hir::Expr<'_>,
+        expr_ty: Ty<'tcx>,
+        expected_ty: Ty<'tcx>,
+    ) -> bool {
+        if let ty::Ref(_, inner_ty, hir::Mutability::Not) = expr_ty.kind()
+            && let Some(clone_trait_def) = self.tcx.lang_items().clone_trait()
+            && expected_ty == *inner_ty
+            && self
+                .infcx
+                .type_implements_trait(
+                    clone_trait_def,
+                    [self.tcx.erase_regions(expected_ty)],
+                    self.param_env
+                )
+                .must_apply_modulo_regions()
+          {
+              diag.span_suggestion_verbose(
+                  expr.span.shrink_to_hi(),
+                  "consider using clone here",
+                  ".clone()",
+                  Applicability::MachineApplicable,
+              );
+              return true;
+          }
+        false
+    }
+
     pub(crate) fn suggest_copied_or_cloned(
         &self,
         diag: &mut Diagnostic,

compiler/rustc_hir_typeck/src/method/mod.rs

@@ -57,7 +57,12 @@ pub enum MethodError<'tcx> {
     PrivateMatch(DefKind, DefId, Vec<DefId>),
 
     // Found a `Self: Sized` bound where `Self` is a trait object.
-    IllegalSizedBound(Vec<DefId>, bool, Span),
+    IllegalSizedBound {
+        candidates: Vec<DefId>,
+        needs_mut: bool,
+        bound_span: Span,
+        self_expr: &'tcx hir::Expr<'tcx>,
+    },
 
     // Found a match, but the return type is wrong
     BadReturnType,
@@ -112,7 +117,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             Err(NoMatch(..)) => false,
             Err(Ambiguity(..)) => true,
             Err(PrivateMatch(..)) => allow_private,
-            Err(IllegalSizedBound(..)) => true,
+            Err(IllegalSizedBound { .. }) => true,
             Err(BadReturnType) => bug!("no return type expectations but got BadReturnType"),
         }
     }
@@ -236,7 +241,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     _ => Vec::new(),
                 };
 
-            return Err(IllegalSizedBound(candidates, needs_mut, span));
+            return Err(IllegalSizedBound { candidates, needs_mut, bound_span: span, self_expr });
         }
 
         Ok(result.callee)

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -176,10 +176,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 err.emit();
             }
 
-            MethodError::IllegalSizedBound(candidates, needs_mut, bound_span) => {
-                let msg = format!("the `{}` method cannot be invoked on a trait object", item_name);
+            MethodError::IllegalSizedBound { candidates, needs_mut, bound_span, self_expr } => {
+                let msg = if needs_mut {
+                    with_forced_trimmed_paths!(format!(
+                        "the `{item_name}` method cannot be invoked on `{rcvr_ty}`"
+                    ))
+                } else {
+                    format!("the `{item_name}` method cannot be invoked on a trait object")
+                };
                 let mut err = self.sess().struct_span_err(span, &msg);
-                err.span_label(bound_span, "this has a `Sized` requirement");
+                if !needs_mut {
+                    err.span_label(bound_span, "this has a `Sized` requirement");
+                }
                 if !candidates.is_empty() {
                     let help = format!(
                         "{an}other candidate{s} {were} found in the following trait{s}, perhaps \
@@ -197,7 +205,32 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             *region,
                             ty::TypeAndMut { ty: *t_type, mutbl: mutability.invert() },
                         );
-                        err.note(&format!("you need `{}` instead of `{}`", trait_type, rcvr_ty));
+                        let msg = format!("you need `{}` instead of `{}`", trait_type, rcvr_ty);
+                        let mut kind = &self_expr.kind;
+                        while let hir::ExprKind::AddrOf(_, _, expr)
+                        | hir::ExprKind::Unary(hir::UnOp::Deref, expr) = kind
+                        {
+                            kind = &expr.kind;
+                        }
+                        if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = kind
+                            && let hir::def::Res::Local(hir_id) = path.res
+                            && let Some(hir::Node::Pat(b)) = self.tcx.hir().find(hir_id)
+                            && let Some(hir::Node::Param(p)) = self.tcx.hir().find_parent(b.hir_id)
+                            && let Some(node) = self.tcx.hir().find_parent(p.hir_id)
+                            && let Some(decl) = node.fn_decl()
+                            && let Some(ty) = decl.inputs.iter().find(|ty| ty.span == p.ty_span)
+                            && let hir::TyKind::Ref(_, mut_ty) = &ty.kind
+                            && let hir::Mutability::Not = mut_ty.mutbl
+                        {
+                            err.span_suggestion_verbose(
+                                mut_ty.ty.span.shrink_to_lo(),
+                                &msg,
+                                "mut ",
+                                Applicability::MachineApplicable,
+                            );
+                        } else {
+                            err.help(&msg);
+                        }
                     }
                 }
                 err.emit();

compiler/rustc_infer/src/infer/at.rs

@@ -427,3 +427,15 @@ impl<'tcx> ToTrace<'tcx> for ty::AliasTy<'tcx> {
         }
     }
 }
+
+impl<'tcx> ToTrace<'tcx> for ty::FnSig<'tcx> {
+    fn to_trace(
+        _: TyCtxt<'tcx>,
+        cause: &ObligationCause<'tcx>,
+        a_is_expected: bool,
+        a: Self,
+        b: Self,
+    ) -> TypeTrace<'tcx> {
+        TypeTrace { cause: cause.clone(), values: Sigs(ExpectedFound::new(a_is_expected, a, b)) }
+    }
+}

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -1428,8 +1428,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         impl<'tcx> OpaqueTypesVisitor<'tcx> {
             fn visit_expected_found(
                 tcx: TyCtxt<'tcx>,
-                expected: Ty<'tcx>,
-                found: Ty<'tcx>,
+                expected: impl TypeVisitable<'tcx>,
+                found: impl TypeVisitable<'tcx>,
                 ignore_span: Span,
             ) -> Self {
                 let mut types_visitor = OpaqueTypesVisitor {
@@ -1569,6 +1569,11 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                             _ => (false, Mismatch::Fixed("type")),
                         }
                     }
+                    ValuePairs::Sigs(infer::ExpectedFound { expected, found }) => {
+                        OpaqueTypesVisitor::visit_expected_found(self.tcx, expected, found, span)
+                            .report(diag);
+                        (false, Mismatch::Fixed("signature"))
+                    }
                     ValuePairs::TraitRefs(_) | ValuePairs::PolyTraitRefs(_) => {
                         (false, Mismatch::Fixed("trait"))
                     }
@@ -2040,6 +2045,17 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     ret => ret,
                 }
             }
+            infer::Sigs(exp_found) => {
+                let exp_found = self.resolve_vars_if_possible(exp_found);
+                if exp_found.references_error() {
+                    return None;
+                }
+                let (exp, fnd) = self.cmp_fn_sig(
+                    &ty::Binder::dummy(exp_found.expected),
+                    &ty::Binder::dummy(exp_found.found),
+                );
+                Some((exp, fnd, None, None))
+            }
         }
     }
 

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs

@@ -3,14 +3,15 @@
 use crate::errors::{ConsiderBorrowingParamHelp, RelationshipHelp, TraitImplDiff};
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
 use crate::infer::lexical_region_resolve::RegionResolutionError;
-use crate::infer::Subtype;
+use crate::infer::{Subtype, ValuePairs};
 use crate::traits::ObligationCauseCode::CompareImplItemObligation;
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::Visitor;
 use rustc_middle::hir::nested_filter;
+use rustc_middle::ty::error::ExpectedFound;
 use rustc_middle::ty::print::RegionHighlightMode;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor};
 use rustc_span::Span;
@@ -23,22 +24,27 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         let error = self.error.as_ref()?;
         debug!("try_report_impl_not_conforming_to_trait {:?}", error);
         if let RegionResolutionError::SubSupConflict(
-                _,
-                var_origin,
-                sub_origin,
-                _sub,
-                sup_origin,
-                _sup,
-                _,
-            ) = error.clone()
+            _,
+            var_origin,
+            sub_origin,
+            _sub,
+            sup_origin,
+            _sup,
+            _,
+        ) = error.clone()
             && let (Subtype(sup_trace), Subtype(sub_trace)) = (&sup_origin, &sub_origin)
-            && let sub_expected_found @ Some((sub_expected, sub_found)) = sub_trace.values.ty()
-            && let sup_expected_found @ Some(_) = sup_trace.values.ty()
             && let CompareImplItemObligation { trait_item_def_id, .. } = sub_trace.cause.code()
-            && sup_expected_found == sub_expected_found
+            && sub_trace.values == sup_trace.values
+            && let ValuePairs::Sigs(ExpectedFound { expected, found }) = sub_trace.values
         {
-            let guar =
-                self.emit_err(var_origin.span(), sub_expected, sub_found, *trait_item_def_id);
+            // FIXME(compiler-errors): Don't like that this needs `Ty`s, but
+            // all of the region highlighting machinery only deals with those.
+            let guar = self.emit_err(
+                var_origin.span(),
+                self.cx.tcx.mk_fn_ptr(ty::Binder::dummy(expected)),
+                self.cx.tcx.mk_fn_ptr(ty::Binder::dummy(found)),
+                *trait_item_def_id,
+            );
             return Some(guar);
         }
         None

compiler/rustc_infer/src/infer/mod.rs

@@ -361,6 +361,7 @@ pub enum ValuePairs<'tcx> {
     Terms(ExpectedFound<ty::Term<'tcx>>),
     TraitRefs(ExpectedFound<ty::TraitRef<'tcx>>),
     PolyTraitRefs(ExpectedFound<ty::PolyTraitRef<'tcx>>),
+    Sigs(ExpectedFound<ty::FnSig<'tcx>>),
 }
 
 impl<'tcx> ValuePairs<'tcx> {