Auto merge of #132377 - matthiaskrgr:rollup-3p1c6hs, r=matthiaskrgr

Rollup of 3 pull requests

Successful merges:

 - #132368 (Remove `do_not_const_check` from `Iterator` methods)
 - #132373 (Make sure `type_param_predicates` resolves correctly for RPITIT)
 - #132374 (Remove dead code stemming from the old effects desugaring)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_hir_analysis/src/check/check.rs

@@ -821,8 +821,7 @@ pub(super) fn check_specialization_validity<'tcx>(
     let result = opt_result.unwrap_or(Ok(()));
 
     if let Err(parent_impl) = result {
-        // FIXME(effects) the associated type from effects could be specialized
-        if !tcx.is_impl_trait_in_trait(impl_item) && !tcx.is_effects_desugared_assoc_ty(impl_item) {
+        if !tcx.is_impl_trait_in_trait(impl_item) {
             report_forbidden_specialization(tcx, impl_item, parent_impl);
         } else {
             tcx.dcx().delayed_bug(format!("parent item: {parent_impl:?} not marked as default"));

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -2042,7 +2042,7 @@ pub(super) fn check_type_bounds<'tcx>(
     // A synthetic impl Trait for RPITIT desugaring or assoc type for effects desugaring has no HIR,
     // which we currently use to get the span for an impl's associated type. Instead, for these,
     // use the def_span for the synthesized  associated type.
-    let impl_ty_span = if impl_ty.is_impl_trait_in_trait() || impl_ty.is_effects_desugaring {
+    let impl_ty_span = if impl_ty.is_impl_trait_in_trait() {
         tcx.def_span(impl_ty_def_id)
     } else {
         match tcx.hir_node_by_def_id(impl_ty_def_id) {

compiler/rustc_hir_analysis/src/collect/item_bounds.rs

@@ -379,9 +379,6 @@ pub(super) fn explicit_item_bounds_with_filter(
     }
 
     let bounds = match tcx.hir_node_by_def_id(def_id) {
-        _ if tcx.is_effects_desugared_assoc_ty(def_id.to_def_id()) => {
-            associated_type_bounds(tcx, def_id, &[], tcx.def_span(def_id), filter)
-        }
         hir::Node::TraitItem(hir::TraitItem {
             kind: hir::TraitItemKind::Type(bounds, _),
             span,

compiler/rustc_hir_analysis/src/collect/predicates_of.rs

@@ -757,6 +757,16 @@ pub(super) fn type_param_predicates<'tcx>(
     tcx: TyCtxt<'tcx>,
     (item_def_id, def_id, assoc_name): (LocalDefId, LocalDefId, Ident),
 ) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]> {
+    match tcx.opt_rpitit_info(item_def_id.to_def_id()) {
+        Some(ty::ImplTraitInTraitData::Trait { opaque_def_id, .. }) => {
+            return tcx.type_param_predicates((opaque_def_id.expect_local(), def_id, assoc_name));
+        }
+        Some(ty::ImplTraitInTraitData::Impl { .. }) => {
+            unreachable!("should not be lowering bounds on RPITIT in impl")
+        }
+        None => {}
+    }
+
     use rustc_hir::*;
     use rustc_middle::ty::Ty;
 

compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs

@@ -140,9 +140,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                             tcx.associated_items(pred.def_id())
                                 .in_definition_order()
                                 .filter(|item| item.kind == ty::AssocKind::Type)
-                                .filter(|item| {
-                                    !item.is_impl_trait_in_trait() && !item.is_effects_desugaring
-                                })
+                                .filter(|item| !item.is_impl_trait_in_trait())
                                 .map(|item| item.def_id),
                         );
                     }

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -1365,7 +1365,6 @@ impl<'tcx> Pick<'tcx> {
                     trait_item_def_id: _,
                     fn_has_self_parameter: _,
                     opt_rpitit_info: _,
-                    is_effects_desugaring: _,
                 },
             kind: _,
             import_ids: _,

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -1317,9 +1317,7 @@ impl<'a> CrateMetadataRef<'a> {
     }
 
     fn get_associated_item(self, id: DefIndex, sess: &'a Session) -> ty::AssocItem {
-        let name = if self.root.tables.opt_rpitit_info.get(self, id).is_some()
-            || self.root.tables.is_effects_desugaring.get(self, id)
-        {
+        let name = if self.root.tables.opt_rpitit_info.get(self, id).is_some() {
             kw::Empty
         } else {
             self.item_name(id)
@@ -1342,7 +1340,6 @@ impl<'a> CrateMetadataRef<'a> {
             container,
             fn_has_self_parameter: has_self,
             opt_rpitit_info,
-            is_effects_desugaring: self.root.tables.is_effects_desugaring.get(self, id),
         }
     }
 

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1677,9 +1677,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 self.encode_precise_capturing_args(def_id);
             }
         }
-        if item.is_effects_desugaring {
-            self.tables.is_effects_desugaring.set(def_id.index, true);
-        }
     }
 
     fn encode_precise_capturing_args(&mut self, def_id: DefId) {

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -396,7 +396,6 @@ define_tables! {
     inherent_impls: Table<DefIndex, LazyArray<DefIndex>>,
     associated_types_for_impl_traits_in_associated_fn: Table<DefIndex, LazyArray<DefId>>,
     opt_rpitit_info: Table<DefIndex, Option<LazyValue<ty::ImplTraitInTraitData>>>,
-    is_effects_desugaring: Table<DefIndex, bool>,
     unused_generic_params: Table<DefIndex, UnusedGenericParams>,
     // Reexported names are not associated with individual `DefId`s,
     // e.g. a glob import can introduce a lot of names, all with the same `DefId`.

compiler/rustc_middle/src/ty/assoc.rs

@@ -34,8 +34,6 @@ pub struct AssocItem {
     /// return-position `impl Trait` in trait desugaring. The `ImplTraitInTraitData`
     /// provides additional information about its source.
     pub opt_rpitit_info: Option<ty::ImplTraitInTraitData>,
-
-    pub is_effects_desugaring: bool,
 }
 
 impl AssocItem {

compiler/rustc_middle/src/ty/mod.rs

@@ -1625,16 +1625,6 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 
-    /// Whether the `def_id` is an associated type that was desugared from a
-    /// `#[const_trait]` or `impl_const`.
-    pub fn is_effects_desugared_assoc_ty(self, def_id: DefId) -> bool {
-        if let DefKind::AssocTy = self.def_kind(def_id) {
-            self.associated_item(def_id).is_effects_desugaring
-        } else {
-            false
-        }
-    }
-
     pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<FieldIdx> {
         variant.fields.iter_enumerated().find_map(|(i, field)| {
             self.hygienic_eq(ident, field.ident(self), variant.def_id).then_some(i)

compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs

@@ -5222,12 +5222,6 @@ fn point_at_assoc_type_restriction<G: EmissionGuarantee>(
     let ty::ClauseKind::Projection(proj) = clause else {
         return;
     };
-    // avoid ICEing since effects desugared associated types don't have names.
-    // this path should only be hit for `~const` on invalid places, so they
-    // will have an informative error already.
-    if tcx.is_effects_desugared_assoc_ty(proj.projection_term.def_id) {
-        return;
-    }
     let name = tcx.item_name(proj.projection_term.def_id);
     let mut predicates = generics.predicates.iter().peekable();
     let mut prev: Option<&hir::WhereBoundPredicate<'_>> = None;

compiler/rustc_ty_utils/src/assoc.rs

@@ -143,7 +143,6 @@ fn associated_item_from_trait_item_ref(trait_item_ref: &hir::TraitItemRef) -> ty
         container: ty::TraitContainer,
         fn_has_self_parameter: has_self,
         opt_rpitit_info: None,
-        is_effects_desugaring: false,
     }
 }
 
@@ -163,7 +162,6 @@ fn associated_item_from_impl_item_ref(impl_item_ref: &hir::ImplItemRef) -> ty::A
         container: ty::ImplContainer,
         fn_has_self_parameter: has_self,
         opt_rpitit_info: None,
-        is_effects_desugaring: false,
     }
 }
 
@@ -275,7 +273,6 @@ fn associated_type_for_impl_trait_in_trait(
             fn_def_id: fn_def_id.to_def_id(),
             opaque_def_id: opaque_ty_def_id.to_def_id(),
         }),
-        is_effects_desugaring: false,
     });
 
     // Copy visility of the containing function.
@@ -327,7 +324,6 @@ fn associated_type_for_impl_trait_in_impl(
         container: ty::ImplContainer,
         fn_has_self_parameter: false,
         opt_rpitit_info: Some(ImplTraitInTraitData::Impl { fn_def_id: impl_fn_def_id.to_def_id() }),
-        is_effects_desugaring: false,
     });
 
     // Copy visility of the containing function.