Auto merge of #139018 - oli-obk:incremental-trait-impls, r=compiler-errors

Various local trait item iteration cleanups

Adding a trait impl for `Foo` unconditionally affected all queries that are interested in a completely independent trait `Bar`. Perf has no effect on this. We probably don't have a good perf test for this tho.

r? `@compiler-errors`

I am unsure about 9d05efb as it doesn't improve anything wrt incremental, because we still do all the checks for valid `Drop` impls, which subsequently will still invoke many queries and basically keep the depgraph the same.

I want to do

https://github.com/rust-lang/rust/blob/9549077a47099dc826039c051b528d1013740e6f/compiler/rustc_middle/src/ty/trait_def.rs#L141

but would leave that to a follow-up PR, this one changes enough things as it is

Author: bors

compiler/rustc_hir_analysis/src/check/always_applicable.rs

@@ -36,10 +36,8 @@ use crate::hir::def_id::{DefId, LocalDefId};
 ///    cannot do `struct S<T>; impl<T:Clone> Drop for S<T> { ... }`).
 pub(crate) fn check_drop_impl(
     tcx: TyCtxt<'_>,
-    drop_impl_did: DefId,
+    drop_impl_did: LocalDefId,
 ) -> Result<(), ErrorGuaranteed> {
-    let drop_impl_did = drop_impl_did.expect_local();
-
     match tcx.impl_polarity(drop_impl_did) {
         ty::ImplPolarity::Positive => {}
         ty::ImplPolarity::Negative => {
@@ -56,9 +54,9 @@ pub(crate) fn check_drop_impl(
 
     tcx.ensure_ok().orphan_check_impl(drop_impl_did)?;
 
-    let dtor_impl_trait_ref = tcx.impl_trait_ref(drop_impl_did).unwrap().instantiate_identity();
+    let self_ty = tcx.type_of(drop_impl_did).instantiate_identity();
 
-    match dtor_impl_trait_ref.self_ty().kind() {
+    match self_ty.kind() {
         ty::Adt(adt_def, adt_to_impl_args) => {
             ensure_impl_params_and_item_params_correspond(
                 tcx,

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -114,11 +114,11 @@ pub fn provide(providers: &mut Providers) {
 }
 
 fn adt_destructor(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<ty::Destructor> {
-    tcx.calculate_dtor(def_id.to_def_id(), always_applicable::check_drop_impl)
+    tcx.calculate_dtor(def_id, always_applicable::check_drop_impl)
 }
 
 fn adt_async_destructor(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<ty::AsyncDestructor> {
-    tcx.calculate_async_dtor(def_id.to_def_id(), always_applicable::check_drop_impl)
+    tcx.calculate_async_dtor(def_id, always_applicable::check_drop_impl)
 }
 
 /// Given a `DefId` for an opaque type in return position, find its parent item's return

compiler/rustc_hir_analysis/src/coherence/mod.rs

@@ -153,9 +153,12 @@ pub(crate) fn provide(providers: &mut Providers) {
 }
 
 fn coherent_trait(tcx: TyCtxt<'_>, def_id: DefId) -> Result<(), ErrorGuaranteed> {
+    let impls = tcx.local_trait_impls(def_id);
     // If there are no impls for the trait, then "all impls" are trivially coherent and we won't check anything
     // anyway. Thus we bail out even before the specialization graph, avoiding the dep_graph edge.
-    let Some(impls) = tcx.all_local_trait_impls(()).get(&def_id) else { return Ok(()) };
+    if impls.is_empty() {
+        return Ok(());
+    }
     // Trigger building the specialization graph for the trait. This will detect and report any
     // overlap errors.
     let mut res = tcx.ensure_ok().specialization_graph_of(def_id);

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -1730,25 +1730,23 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                         .is_accessible_from(self.item_def_id(), tcx)
                     && tcx.all_impls(*trait_def_id)
                         .any(|impl_def_id| {
-                            let impl_header = tcx.impl_trait_header(impl_def_id);
-                            impl_header.is_some_and(|header| {
-                                let trait_ref = header.trait_ref.instantiate(
-                                    tcx,
-                                    infcx.fresh_args_for_item(DUMMY_SP, impl_def_id),
-                                );
-
-                                let value = fold_regions(tcx, qself_ty, |_, _| tcx.lifetimes.re_erased);
-                                // FIXME: Don't bother dealing with non-lifetime binders here...
-                                if value.has_escaping_bound_vars() {
-                                    return false;
-                                }
-                                infcx
-                                    .can_eq(
-                                        ty::ParamEnv::empty(),
-                                        trait_ref.self_ty(),
-                                        value,
-                                    ) && header.polarity != ty::ImplPolarity::Negative
-                            })
+                            let header = tcx.impl_trait_header(impl_def_id).unwrap();
+                            let trait_ref = header.trait_ref.instantiate(
+                                tcx,
+                                infcx.fresh_args_for_item(DUMMY_SP, impl_def_id),
+                            );
+
+                            let value = fold_regions(tcx, qself_ty, |_, _| tcx.lifetimes.re_erased);
+                            // FIXME: Don't bother dealing with non-lifetime binders here...
+                            if value.has_escaping_bound_vars() {
+                                return false;
+                            }
+                            infcx
+                                .can_eq(
+                                    ty::ParamEnv::empty(),
+                                    trait_ref.self_ty(),
+                                    value,
+                                ) && header.polarity != ty::ImplPolarity::Negative
                         })
             })
             .map(|trait_def_id| tcx.def_path_str(trait_def_id))

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -330,14 +330,8 @@ provide! { tcx, def_id, other, cdata,
 
     visibility => { cdata.get_visibility(def_id.index) }
     adt_def => { cdata.get_adt_def(def_id.index, tcx) }
-    adt_destructor => {
-        let _ = cdata;
-        tcx.calculate_dtor(def_id, |_,_| Ok(()))
-    }
-    adt_async_destructor => {
-        let _ = cdata;
-        tcx.calculate_async_dtor(def_id, |_,_| Ok(()))
-    }
+    adt_destructor => { table }
+    adt_async_destructor => { table }
     associated_item_def_ids => {
         tcx.arena.alloc_from_iter(cdata.get_associated_item_or_field_def_ids(def_id.index))
     }

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1634,6 +1634,14 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 record!(self.tables.fn_sig[variant.def_id] <- fn_sig);
             }
         }
+
+        if let Some(destructor) = tcx.adt_destructor(local_def_id) {
+            record!(self.tables.adt_destructor[def_id] <- destructor);
+        }
+
+        if let Some(destructor) = tcx.adt_async_destructor(local_def_id) {
+            record!(self.tables.adt_async_destructor[def_id] <- destructor);
+        }
     }
 
     #[instrument(level = "debug", skip(self))]

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -452,6 +452,8 @@ define_tables! {
     fn_arg_names: Table<DefIndex, LazyArray<Option<Ident>>>,
     coroutine_kind: Table<DefIndex, hir::CoroutineKind>,
     coroutine_for_closure: Table<DefIndex, RawDefId>,
+    adt_destructor: Table<DefIndex, LazyValue<ty::Destructor>>,
+    adt_async_destructor: Table<DefIndex, LazyValue<ty::AsyncDestructor>>,
     coroutine_by_move_body_def_id: Table<DefIndex, RawDefId>,
     eval_static_initializer: Table<DefIndex, LazyValue<mir::interpret::ConstAllocation<'static>>>,
     trait_def: Table<DefIndex, LazyValue<ty::TraitDef>>,

compiler/rustc_middle/src/hir/map.rs

@@ -367,10 +367,6 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 
-    pub fn hir_trait_impls(self, trait_did: DefId) -> &'tcx [LocalDefId] {
-        self.all_local_trait_impls(()).get(&trait_did).map_or(&[], |xs| &xs[..])
-    }
-
     /// Gets the attributes on the crate. This is preferable to
     /// invoking `krate.attrs` because it registers a tighter
     /// dep-graph access.

compiler/rustc_middle/src/hir/mod.rs

@@ -238,6 +238,8 @@ pub fn provide(providers: &mut Providers) {
         }
     };
     providers.all_local_trait_impls = |tcx, ()| &tcx.resolutions(()).trait_impls;
+    providers.local_trait_impls =
+        |tcx, trait_id| tcx.resolutions(()).trait_impls.get(&trait_id).map_or(&[], |xs| &xs[..]);
     providers.expn_that_defined =
         |tcx, id| tcx.resolutions(()).expn_that_defined.get(&id).copied().unwrap_or(ExpnId::root());
     providers.in_scope_traits_map = |tcx, id| {

compiler/rustc_middle/src/query/mod.rs

@@ -1502,6 +1502,11 @@ rustc_queries! {
         desc { "finding local trait impls" }
     }
 
+    /// Return all `impl` blocks of the given trait in the current crate.
+    query local_trait_impls(trait_id: DefId) -> &'tcx [LocalDefId] {
+        desc { "finding local trait impls of `{}`", tcx.def_path_str(trait_id) }
+    }
+
     /// Given a trait `trait_id`, return all known `impl` blocks.
     query trait_impls_of(trait_id: DefId) -> &'tcx ty::trait_def::TraitImpls {
         arena_cache

compiler/rustc_middle/src/ty/adt.rs

@@ -236,7 +236,7 @@ impl<'tcx> rustc_type_ir::inherent::AdtDef<TyCtxt<'tcx>> for AdtDef<'tcx> {
     }
 
     fn destructor(self, tcx: TyCtxt<'tcx>) -> Option<AdtDestructorKind> {
-        Some(match self.destructor(tcx)?.constness {
+        Some(match tcx.constness(self.destructor(tcx)?.did) {
             hir::Constness::Const => AdtDestructorKind::Const,
             hir::Constness::NotConst => AdtDestructorKind::NotConst,
         })

compiler/rustc_middle/src/ty/mod.rs

@@ -1119,8 +1119,6 @@ pub struct PseudoCanonicalInput<'tcx, T> {
 pub struct Destructor {
     /// The `DefId` of the destructor method
     pub did: DefId,
-    /// The constness of the destructor method
-    pub constness: hir::Constness,
 }
 
 // FIXME: consider combining this definition with regular `Destructor`

compiler/rustc_middle/src/ty/parameterized.rs

@@ -65,9 +65,11 @@ trivially_parameterized_over_tcx! {
     crate::middle::lib_features::FeatureStability,
     crate::middle::resolve_bound_vars::ObjectLifetimeDefault,
     crate::mir::ConstQualifs,
+    ty::AsyncDestructor,
     ty::AssocItemContainer,
     ty::Asyncness,
     ty::DeducedParamAttrs,
+    ty::Destructor,
     ty::Generics,
     ty::ImplPolarity,
     ty::ImplTraitInTraitData,

compiler/rustc_middle/src/ty/trait_def.rs

@@ -129,21 +129,6 @@ impl<'tcx> TraitDef {
 }
 
 impl<'tcx> TyCtxt<'tcx> {
-    /// `trait_def_id` MUST BE the `DefId` of a trait.
-    pub fn for_each_impl<F: FnMut(DefId)>(self, trait_def_id: DefId, mut f: F) {
-        let impls = self.trait_impls_of(trait_def_id);
-
-        for &impl_def_id in impls.blanket_impls.iter() {
-            f(impl_def_id);
-        }
-
-        for v in impls.non_blanket_impls.values() {
-            for &impl_def_id in v {
-                f(impl_def_id);
-            }
-        }
-    }
-
     /// Iterate over every impl that could possibly match the self type `self_ty`.
     ///
     /// `trait_def_id` MUST BE the `DefId` of a trait.
@@ -235,7 +220,7 @@ pub(super) fn trait_impls_of_provider(tcx: TyCtxt<'_>, trait_id: DefId) -> Trait
         }
     }
 
-    for &impl_def_id in tcx.hir_trait_impls(trait_id) {
+    for &impl_def_id in tcx.local_trait_impls(trait_id) {
         let impl_def_id = impl_def_id.to_def_id();
 
         let impl_self_ty = tcx.type_of(impl_def_id).instantiate_identity();

compiler/rustc_middle/src/ty/util.rs

@@ -389,63 +389,73 @@ impl<'tcx> TyCtxt<'tcx> {
     /// Calculate the destructor of a given type.
     pub fn calculate_dtor(
         self,
-        adt_did: DefId,
-        validate: impl Fn(Self, DefId) -> Result<(), ErrorGuaranteed>,
+        adt_did: LocalDefId,
+        validate: impl Fn(Self, LocalDefId) -> Result<(), ErrorGuaranteed>,
     ) -> Option<ty::Destructor> {
         let drop_trait = self.lang_items().drop_trait()?;
         self.ensure_ok().coherent_trait(drop_trait).ok()?;
 
-        let ty = self.type_of(adt_did).instantiate_identity();
         let mut dtor_candidate = None;
-        self.for_each_relevant_impl(drop_trait, ty, |impl_did| {
+        // `Drop` impls can only be written in the same crate as the adt, and cannot be blanket impls
+        for &impl_did in self.local_trait_impls(drop_trait) {
+            let Some(adt_def) = self.type_of(impl_did).skip_binder().ty_adt_def() else { continue };
+            if adt_def.did() != adt_did.to_def_id() {
+                continue;
+            }
+
             if validate(self, impl_did).is_err() {
                 // Already `ErrorGuaranteed`, no need to delay a span bug here.
-                return;
+                continue;
             }
 
             let Some(item_id) = self.associated_item_def_ids(impl_did).first() else {
                 self.dcx()
                     .span_delayed_bug(self.def_span(impl_did), "Drop impl without drop function");
-                return;
+                continue;
             };
 
-            if let Some((old_item_id, _)) = dtor_candidate {
+            if let Some(old_item_id) = dtor_candidate {
                 self.dcx()
                     .struct_span_err(self.def_span(item_id), "multiple drop impls found")
                     .with_span_note(self.def_span(old_item_id), "other impl here")
                     .delay_as_bug();
             }
 
-            dtor_candidate = Some((*item_id, self.impl_trait_header(impl_did).unwrap().constness));
-        });
+            dtor_candidate = Some(*item_id);
+        }
 
-        let (did, constness) = dtor_candidate?;
-        Some(ty::Destructor { did, constness })
+        let did = dtor_candidate?;
+        Some(ty::Destructor { did })
     }
 
     /// Calculate the async destructor of a given type.
     pub fn calculate_async_dtor(
         self,
-        adt_did: DefId,
-        validate: impl Fn(Self, DefId) -> Result<(), ErrorGuaranteed>,
+        adt_did: LocalDefId,
+        validate: impl Fn(Self, LocalDefId) -> Result<(), ErrorGuaranteed>,
     ) -> Option<ty::AsyncDestructor> {
         let async_drop_trait = self.lang_items().async_drop_trait()?;
         self.ensure_ok().coherent_trait(async_drop_trait).ok()?;
 
-        let ty = self.type_of(adt_did).instantiate_identity();
         let mut dtor_candidate = None;
-        self.for_each_relevant_impl(async_drop_trait, ty, |impl_did| {
+        // `AsyncDrop` impls can only be written in the same crate as the adt, and cannot be blanket impls
+        for &impl_did in self.local_trait_impls(async_drop_trait) {
+            let Some(adt_def) = self.type_of(impl_did).skip_binder().ty_adt_def() else { continue };
+            if adt_def.did() != adt_did.to_def_id() {
+                continue;
+            }
+
             if validate(self, impl_did).is_err() {
                 // Already `ErrorGuaranteed`, no need to delay a span bug here.
-                return;
+                continue;
             }
 
             let [future, ctor] = self.associated_item_def_ids(impl_did) else {
                 self.dcx().span_delayed_bug(
                     self.def_span(impl_did),
                     "AsyncDrop impl without async_drop function or Dropper type",
                 );
-                return;
+                continue;
             };
 
             if let Some((_, _, old_impl_did)) = dtor_candidate {
@@ -456,7 +466,7 @@ impl<'tcx> TyCtxt<'tcx> {
             }
 
             dtor_candidate = Some((*future, *ctor, impl_did));
-        });
+        }
 
         let (future, ctor, _) = dtor_candidate?;
         Some(ty::AsyncDestructor { future, ctor })

compiler/rustc_mir_transform/src/check_const_item_mutation.rs

@@ -53,9 +53,13 @@ impl<'tcx> ConstMutationChecker<'_, 'tcx> {
         //
         //     #[const_mutation_allowed]
         //     pub const LOG: Log = Log { msg: "" };
-        match self.tcx.calculate_dtor(def_id, |_, _| Ok(())) {
-            Some(_) => None,
-            None => Some(def_id),
+        // FIXME: this should not be checking for `Drop` impls,
+        // but whether it or any field has a Drop impl (`needs_drop`)
+        // as fields' Drop impls may make this observable, too.
+        match self.tcx.type_of(def_id).skip_binder().ty_adt_def().map(|adt| adt.has_dtor(self.tcx))
+        {
+            Some(true) => None,
+            Some(false) | None => Some(def_id),
         }
     }
 

compiler/rustc_monomorphize/messages.ftl

@@ -48,7 +48,7 @@ monomorphize_large_assignments =
     .note = The current maximum size is {$limit}, but it can be customized with the move_size_limit attribute: `#![move_size_limit = "..."]`
 
 monomorphize_no_optimized_mir =
-    missing optimized MIR for an item in the crate `{$crate_name}`
+    missing optimized MIR for `{$instance}` in the crate `{$crate_name}`
     .note = missing optimized MIR for this item (was the crate `{$crate_name}` compiled with `--emit=metadata`?)
 
 monomorphize_recursion_limit =

compiler/rustc_monomorphize/src/collector.rs

@@ -989,6 +989,7 @@ fn should_codegen_locally<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) ->
         tcx.dcx().emit_fatal(NoOptimizedMir {
             span: tcx.def_span(def_id),
             crate_name: tcx.crate_name(def_id.krate),
+            instance: instance.to_string(),
         });
     }
 

compiler/rustc_monomorphize/src/errors.rs

@@ -24,6 +24,7 @@ pub(crate) struct NoOptimizedMir {
     #[note]
     pub span: Span,
     pub crate_name: Symbol,
+    pub instance: String,
 }
 
 #[derive(LintDiagnostic)]

compiler/rustc_passes/src/dead.rs

@@ -421,10 +421,8 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
                 }
                 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
+                    for &impl_def_id in self.tcx.local_trait_impls(item.owner_id.def_id) {
+                        if let ItemKind::Impl(impl_ref) = self.tcx.hir_expect_item(impl_def_id).kind
                         {
                             // skip items
                             // mark dependent traits live

compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs

@@ -365,7 +365,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
                 // obligation comes from the `impl`. Find that `impl` so that we can point
                 // at it in the suggestion.
                 let trait_did = trait_id.to_def_id();
-                tcx.hir_trait_impls(trait_did).iter().find_map(|&impl_did| {
+                tcx.local_trait_impls(trait_did).iter().find_map(|&impl_did| {
                     if let Node::Item(Item {
                         kind: ItemKind::Impl(hir::Impl { self_ty, .. }), ..
                     }) = tcx.hir_node_by_def_id(impl_did)