Rollup of 8 pull requests

compiler/rustc_infer/src/infer/relate/combine.rs

@@ -165,9 +165,9 @@ impl<'tcx> InferCtxt<'tcx> {
         //
         // This probe is probably not strictly necessary but it seems better to be safe and not accidentally find
         // ourselves with a check to find bugs being required for code to compile because it made inference progress.
-        let compatible_types = self.probe(|_| {
+        self.probe(|_| {
             if a.ty() == b.ty() {
-                return Ok(());
+                return;
             }
 
             // We don't have access to trait solving machinery in `rustc_infer` so the logic for determining if the
@@ -177,32 +177,18 @@ impl<'tcx> InferCtxt<'tcx> {
                 relation.param_env().and((a.ty(), b.ty())),
                 &mut OriginalQueryValues::default(),
             );
-            self.tcx.check_tys_might_be_eq(canonical).map_err(|_| {
+            self.tcx.check_tys_might_be_eq(canonical).unwrap_or_else(|_| {
+                // The error will only be reported later. If we emit an ErrorGuaranteed
+                // here, then we will never get to the code that actually emits the error.
                 self.tcx.dcx().delayed_bug(format!(
                     "cannot relate consts of different types (a={a:?}, b={b:?})",
-                ))
-            })
+                ));
+                // We treat these constants as if they were of the same type, so that any
+                // such constants being used in impls make these impls match barring other mismatches.
+                // This helps with diagnostics down the road.
+            });
         });
 
-        // If the consts have differing types, just bail with a const error with
-        // the expected const's type. Specifically, we don't want const infer vars
-        // to do any type shapeshifting before and after resolution.
-        if let Err(guar) = compatible_types {
-            // HACK: equating both sides with `[const error]` eagerly prevents us
-            // from leaving unconstrained inference vars during things like impl
-            // matching in the solver.
-            let a_error = ty::Const::new_error(self.tcx, guar, a.ty());
-            if let ty::ConstKind::Infer(InferConst::Var(vid)) = a.kind() {
-                return self.unify_const_variable(vid, a_error, relation.param_env());
-            }
-            let b_error = ty::Const::new_error(self.tcx, guar, b.ty());
-            if let ty::ConstKind::Infer(InferConst::Var(vid)) = b.kind() {
-                return self.unify_const_variable(vid, b_error, relation.param_env());
-            }
-
-            return Ok(if relation.a_is_expected() { a_error } else { b_error });
-        }
-
         match (a.kind(), b.kind()) {
             (
                 ty::ConstKind::Infer(InferConst::Var(a_vid)),

compiler/rustc_mir_build/src/thir/pattern/check_match.rs

@@ -1130,7 +1130,7 @@ fn collect_non_exhaustive_tys<'tcx>(
         non_exhaustive_tys.insert(pat.ty().inner());
     }
     if let Constructor::IntRange(range) = pat.ctor() {
-        if cx.is_range_beyond_boundaries(range, pat.ty()) {
+        if cx.is_range_beyond_boundaries(range, *pat.ty()) {
             // The range denotes the values before `isize::MIN` or the values after `usize::MAX`/`isize::MAX`.
             non_exhaustive_tys.insert(pat.ty().inner());
         }

compiler/rustc_passes/src/dead.rs

@@ -4,6 +4,7 @@
 // is dead.
 
 use hir::def_id::{LocalDefIdMap, LocalDefIdSet};
+use hir::ItemKind;
 use rustc_data_structures::unord::UnordSet;
 use rustc_errors::MultiSpan;
 use rustc_hir as hir;
@@ -14,7 +15,7 @@ use rustc_hir::{Node, PatKind, TyKind};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::middle::privacy::Level;
 use rustc_middle::query::Providers;
-use rustc_middle::ty::{self, TyCtxt};
+use rustc_middle::ty::{self, TyCtxt, Visibility};
 use rustc_session::lint;
 use rustc_session::lint::builtin::DEAD_CODE;
 use rustc_span::symbol::{sym, Symbol};
@@ -381,9 +382,46 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
                     intravisit::walk_item(self, item)
                 }
                 hir::ItemKind::ForeignMod { .. } => {}
+                hir::ItemKind::Trait(..) => {
+                    for impl_def_id in self.tcx.all_impls(item.owner_id.to_def_id()) {
+                        if let Some(local_def_id) = impl_def_id.as_local()
+                            && let ItemKind::Impl(impl_ref) =
+                                self.tcx.hir().expect_item(local_def_id).kind
+                        {
+                            // skip items
+                            // mark dependent traits live
+                            intravisit::walk_generics(self, impl_ref.generics);
+                            // mark dependent parameters live
+                            intravisit::walk_path(self, impl_ref.of_trait.unwrap().path);
+                        }
+                    }
+
+                    intravisit::walk_item(self, item)
+                }
                 _ => intravisit::walk_item(self, item),
             },
             Node::TraitItem(trait_item) => {
+                // mark corresponing ImplTerm live
+                let trait_item_id = trait_item.owner_id.to_def_id();
+                if let Some(trait_id) = self.tcx.trait_of_item(trait_item_id) {
+                    // mark the trait live
+                    self.check_def_id(trait_id);
+
+                    for impl_id in self.tcx.all_impls(trait_id) {
+                        if let Some(local_impl_id) = impl_id.as_local()
+                            && let ItemKind::Impl(impl_ref) =
+                                self.tcx.hir().expect_item(local_impl_id).kind
+                        {
+                            // mark self_ty live
+                            intravisit::walk_ty(self, impl_ref.self_ty);
+                            if let Some(&impl_item_id) =
+                                self.tcx.impl_item_implementor_ids(impl_id).get(&trait_item_id)
+                            {
+                                self.check_def_id(impl_item_id);
+                            }
+                        }
+                    }
+                }
                 intravisit::walk_trait_item(self, trait_item);
             }
             Node::ImplItem(impl_item) => {
@@ -632,10 +670,6 @@ fn check_item<'tcx>(
             }
         }
         DefKind::Impl { of_trait } => {
-            if of_trait {
-                worklist.push((id.owner_id.def_id, ComesFromAllowExpect::No));
-            }
-
             // get DefIds from another query
             let local_def_ids = tcx
                 .associated_item_def_ids(id.owner_id)
@@ -644,7 +678,11 @@ fn check_item<'tcx>(
 
             // And we access the Map here to get HirId from LocalDefId
             for id in local_def_ids {
-                if of_trait {
+                // for impl trait blocks, mark associate functions live if the trait is public
+                if of_trait
+                    && (!matches!(tcx.def_kind(id), DefKind::AssocFn)
+                        || tcx.local_visibility(id) == Visibility::Public)
+                {
                     worklist.push((id, ComesFromAllowExpect::No));
                 } else if let Some(comes_from_allow) = has_allow_dead_code_or_lang_attr(tcx, id) {
                     worklist.push((id, comes_from_allow));
@@ -675,7 +713,7 @@ fn check_trait_item(
     use hir::TraitItemKind::{Const, Fn};
     if matches!(tcx.def_kind(id.owner_id), DefKind::AssocConst | DefKind::AssocFn) {
         let trait_item = tcx.hir().trait_item(id);
-        if matches!(trait_item.kind, Const(_, Some(_)) | Fn(_, hir::TraitFn::Provided(_)))
+        if matches!(trait_item.kind, Const(_, Some(_)) | Fn(..))
             && let Some(comes_from_allow) =
                 has_allow_dead_code_or_lang_attr(tcx, trait_item.owner_id.def_id)
         {
@@ -944,7 +982,8 @@ impl<'tcx> DeadVisitor<'tcx> {
             | DefKind::TyAlias
             | DefKind::Enum
             | DefKind::Union
-            | DefKind::ForeignTy => self.warn_dead_code(def_id, "used"),
+            | DefKind::ForeignTy
+            | DefKind::Trait => self.warn_dead_code(def_id, "used"),
             DefKind::Struct => self.warn_dead_code(def_id, "constructed"),
             DefKind::Variant | DefKind::Field => bug!("should be handled specially"),
             _ => {}
@@ -969,18 +1008,33 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
     let module_items = tcx.hir_module_items(module);
 
     for item in module_items.items() {
-        if let hir::ItemKind::Impl(impl_item) = tcx.hir().item(item).kind {
-            let mut dead_items = Vec::new();
-            for item in impl_item.items {
-                let def_id = item.id.owner_id.def_id;
-                if !visitor.is_live_code(def_id) {
-                    let name = tcx.item_name(def_id.to_def_id());
-                    let level = visitor.def_lint_level(def_id);
+        let def_kind = tcx.def_kind(item.owner_id);
 
-                    dead_items.push(DeadItem { def_id, name, level })
+        let mut dead_codes = Vec::new();
+        // if we have diagnosed the trait, do not diagnose unused methods
+        if matches!(def_kind, DefKind::Impl { .. })
+            || (def_kind == DefKind::Trait && live_symbols.contains(&item.owner_id.def_id))
+        {
+            for &def_id in tcx.associated_item_def_ids(item.owner_id.def_id) {
+                // We have diagnosed unused methods in traits
+                if matches!(def_kind, DefKind::Impl { of_trait: true })
+                    && tcx.def_kind(def_id) == DefKind::AssocFn
+                    || def_kind == DefKind::Trait && tcx.def_kind(def_id) != DefKind::AssocFn
+                {
+                    continue;
+                }
+
+                if let Some(local_def_id) = def_id.as_local()
+                    && !visitor.is_live_code(local_def_id)
+                {
+                    let name = tcx.item_name(def_id);
+                    let level = visitor.def_lint_level(local_def_id);
+                    dead_codes.push(DeadItem { def_id: local_def_id, name, level });
                 }
             }
-            visitor.warn_multiple(item.owner_id.def_id, "used", dead_items, ReportOn::NamedField);
+        }
+        if !dead_codes.is_empty() {
+            visitor.warn_multiple(item.owner_id.def_id, "used", dead_codes, ReportOn::NamedField);
         }
 
         if !live_symbols.contains(&item.owner_id.def_id) {
@@ -993,7 +1047,6 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
             continue;
         }
 
-        let def_kind = tcx.def_kind(item.owner_id);
         if let DefKind::Struct | DefKind::Union | DefKind::Enum = def_kind {
             let adt = tcx.adt_def(item.owner_id);
             let mut dead_variants = Vec::new();
@@ -1040,8 +1093,6 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
     for foreign_item in module_items.foreign_items() {
         visitor.check_definition(foreign_item.owner_id.def_id);
     }
-
-    // We do not warn trait items.
 }
 
 pub(crate) fn provide(providers: &mut Providers) {

compiler/rustc_pattern_analysis/src/lib.rs

@@ -82,7 +82,7 @@ impl<'a, T: ?Sized> Captures<'a> for T {}
 /// Most of the crate is parameterized on a type that implements this trait.
 pub trait TypeCx: Sized + fmt::Debug {
     /// The type of a pattern.
-    type Ty: Copy + Clone + fmt::Debug; // FIXME: remove Copy
+    type Ty: Clone + fmt::Debug;
     /// Errors that can abort analysis.
     type Error: fmt::Debug;
     /// The index of an enum variant.
@@ -97,16 +97,16 @@ pub trait TypeCx: Sized + fmt::Debug {
     fn is_exhaustive_patterns_feature_on(&self) -> bool;
 
     /// The number of fields for this constructor.
-    fn ctor_arity(&self, ctor: &Constructor<Self>, ty: Self::Ty) -> usize;
+    fn ctor_arity(&self, ctor: &Constructor<Self>, ty: &Self::Ty) -> usize;
 
     /// The types of the fields for this constructor. The result must have a length of
     /// `ctor_arity()`.
-    fn ctor_sub_tys(&self, ctor: &Constructor<Self>, ty: Self::Ty) -> &[Self::Ty];
+    fn ctor_sub_tys(&self, ctor: &Constructor<Self>, ty: &Self::Ty) -> &[Self::Ty];
 
     /// The set of all the constructors for `ty`.
     ///
     /// This must follow the invariants of `ConstructorSet`
-    fn ctors_for_ty(&self, ty: Self::Ty) -> Result<ConstructorSet<Self>, Self::Error>;
+    fn ctors_for_ty(&self, ty: &Self::Ty) -> Result<ConstructorSet<Self>, Self::Error>;
 
     /// Best-effort `Debug` implementation.
     fn debug_pat(f: &mut fmt::Formatter<'_>, pat: &DeconstructedPat<'_, Self>) -> fmt::Result;

compiler/rustc_pattern_analysis/src/lints.rs

@@ -46,7 +46,7 @@ impl<'p, 'tcx> PatternColumn<'p, 'tcx> {
     }
 
     fn head_ty(&self) -> Option<RevealedTy<'tcx>> {
-        self.patterns.first().map(|pat| pat.ty())
+        self.patterns.first().map(|pat| *pat.ty())
     }
 
     /// Do constructor splitting on the constructors of the column.
@@ -101,7 +101,7 @@ fn collect_nonexhaustive_missing_variants<'a, 'p, 'tcx>(
     let Some(ty) = column.head_ty() else {
         return Ok(Vec::new());
     };
-    let pcx = &PlaceCtxt::new_dummy(cx, ty);
+    let pcx = &PlaceCtxt::new_dummy(cx, &ty);
 
     let set = column.analyze_ctors(pcx)?;
     if set.present.is_empty() {

compiler/rustc_pattern_analysis/src/pat.rs

@@ -54,8 +54,8 @@ impl<'p, Cx: TypeCx> DeconstructedPat<'p, Cx> {
     pub fn ctor(&self) -> &Constructor<Cx> {
         &self.ctor
     }
-    pub fn ty(&self) -> Cx::Ty {
-        self.ty
+    pub fn ty(&self) -> &Cx::Ty {
+        &self.ty
     }
     /// Returns the extra data stored in a pattern. Returns `None` if the pattern is a wildcard that
     /// does not correspond to a user-supplied pattern.
@@ -242,15 +242,15 @@ impl<Cx: TypeCx> WitnessPat<Cx> {
     /// `Some(_)`.
     pub(crate) fn wild_from_ctor(pcx: &PlaceCtxt<'_, Cx>, ctor: Constructor<Cx>) -> Self {
         let field_tys = pcx.ctor_sub_tys(&ctor);
-        let fields = field_tys.iter().map(|ty| Self::wildcard(*ty)).collect();
-        Self::new(ctor, fields, pcx.ty)
+        let fields = field_tys.iter().cloned().map(|ty| Self::wildcard(ty)).collect();
+        Self::new(ctor, fields, pcx.ty.clone())
     }
 
     pub fn ctor(&self) -> &Constructor<Cx> {
         &self.ctor
     }
-    pub fn ty(&self) -> Cx::Ty {
-        self.ty
+    pub fn ty(&self) -> &Cx::Ty {
+        &self.ty
     }
 
     pub fn iter_fields(&self) -> impl Iterator<Item = &WitnessPat<Cx>> {

compiler/rustc_pattern_analysis/src/rustc.rs

@@ -766,7 +766,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> {
         let mut subpatterns = pat.iter_fields().map(|p| Box::new(cx.hoist_witness_pat(p)));
         let kind = match pat.ctor() {
             Bool(b) => PatKind::Constant { value: mir::Const::from_bool(cx.tcx, *b) },
-            IntRange(range) => return self.hoist_pat_range(range, pat.ty()),
+            IntRange(range) => return self.hoist_pat_range(range, *pat.ty()),
             Struct | Variant(_) | UnionField => match pat.ty().kind() {
                 ty::Tuple(..) => PatKind::Leaf {
                     subpatterns: subpatterns
@@ -785,7 +785,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> {
                         RustcMatchCheckCtxt::variant_index_for_adt(&pat.ctor(), *adt_def);
                     let variant = &adt_def.variant(variant_index);
                     let subpatterns = cx
-                        .list_variant_nonhidden_fields(pat.ty(), variant)
+                        .list_variant_nonhidden_fields(*pat.ty(), variant)
                         .zip(subpatterns)
                         .map(|((field, _ty), pattern)| FieldPat { field, pattern })
                         .collect();
@@ -796,7 +796,7 @@ impl<'p, 'tcx> RustcMatchCheckCtxt<'p, 'tcx> {
                         PatKind::Leaf { subpatterns }
                     }
                 }
-                _ => bug!("unexpected ctor for type {:?} {:?}", pat.ctor(), pat.ty()),
+                _ => bug!("unexpected ctor for type {:?} {:?}", pat.ctor(), *pat.ty()),
             },
             // Note: given the expansion of `&str` patterns done in `expand_pattern`, we should
             // be careful to reconstruct the correct constant pattern here. However a string
@@ -961,21 +961,21 @@ impl<'p, 'tcx> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> {
         self.tcx.features().exhaustive_patterns
     }
 
-    fn ctor_arity(&self, ctor: &crate::constructor::Constructor<Self>, ty: Self::Ty) -> usize {
-        self.ctor_arity(ctor, ty)
+    fn ctor_arity(&self, ctor: &crate::constructor::Constructor<Self>, ty: &Self::Ty) -> usize {
+        self.ctor_arity(ctor, *ty)
     }
     fn ctor_sub_tys(
         &self,
         ctor: &crate::constructor::Constructor<Self>,
-        ty: Self::Ty,
+        ty: &Self::Ty,
     ) -> &[Self::Ty] {
-        self.ctor_sub_tys(ctor, ty)
+        self.ctor_sub_tys(ctor, *ty)
     }
     fn ctors_for_ty(
         &self,
-        ty: Self::Ty,
+        ty: &Self::Ty,
     ) -> Result<crate::constructor::ConstructorSet<Self>, Self::Error> {
-        self.ctors_for_ty(ty)
+        self.ctors_for_ty(*ty)
     }
 
     fn debug_pat(
@@ -994,7 +994,7 @@ impl<'p, 'tcx> TypeCx for RustcMatchCheckCtxt<'p, 'tcx> {
         overlaps_on: IntRange,
         overlaps_with: &[&crate::pat::DeconstructedPat<'_, Self>],
     ) {
-        let overlap_as_pat = self.hoist_pat_range(&overlaps_on, pat.ty());
+        let overlap_as_pat = self.hoist_pat_range(&overlaps_on, *pat.ty());
         let overlaps: Vec<_> = overlaps_with
             .iter()
             .map(|pat| pat.data().unwrap().span)