Rollup merge of #136281 - nnethercote:rustc_hir_analysis, r=lcnr

`rustc_hir_analysis` cleanups

Just some improvements I found while looking through this code.

r? `@lcnr`

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -424,12 +424,12 @@ fn compare_method_predicate_entailment<'tcx>(
     Ok(())
 }
 
-struct RemapLateParam<'a, 'tcx> {
+struct RemapLateParam<'tcx> {
     tcx: TyCtxt<'tcx>,
-    mapping: &'a FxIndexMap<ty::LateParamRegionKind, ty::LateParamRegionKind>,
+    mapping: FxIndexMap<ty::LateParamRegionKind, ty::LateParamRegionKind>,
 }
 
-impl<'tcx> TypeFolder<TyCtxt<'tcx>> for RemapLateParam<'_, 'tcx> {
+impl<'tcx> TypeFolder<TyCtxt<'tcx>> for RemapLateParam<'tcx> {
     fn cx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }

compiler/rustc_hir_analysis/src/check/compare_impl_item/refine.rs

@@ -299,8 +299,7 @@ fn report_mismatched_rpitit_signature<'tcx>(
     })
     .collect();
 
-    let mut return_ty =
-        trait_m_sig.output().fold_with(&mut super::RemapLateParam { tcx, mapping: &mapping });
+    let mut return_ty = trait_m_sig.output().fold_with(&mut super::RemapLateParam { tcx, mapping });
 
     if tcx.asyncness(impl_m_def_id).is_async() && tcx.asyncness(trait_m_def_id).is_async() {
         let ty::Alias(ty::Projection, future_ty) = return_ty.kind() else {

compiler/rustc_hir_analysis/src/check/dropck.rs

@@ -1,7 +1,3 @@
-// FIXME(@lcnr): Move this module out of `rustc_hir_analysis`.
-//
-// We don't do any drop checking during hir typeck.
-
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::codes::*;
 use rustc_errors::{ErrorGuaranteed, struct_span_code_err};
@@ -32,7 +28,10 @@ use crate::hir::def_id::{DefId, LocalDefId};
 ///    struct/enum definition for the nominal type itself (i.e.
 ///    cannot do `struct S<T>; impl<T:Clone> Drop for S<T> { ... }`).
 ///
-pub fn check_drop_impl(tcx: TyCtxt<'_>, drop_impl_did: DefId) -> Result<(), ErrorGuaranteed> {
+pub(crate) fn check_drop_impl(
+    tcx: TyCtxt<'_>,
+    drop_impl_did: DefId,
+) -> Result<(), ErrorGuaranteed> {
     match tcx.impl_polarity(drop_impl_did) {
         ty::ImplPolarity::Positive => {}
         ty::ImplPolarity::Negative => {

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -199,7 +199,8 @@ pub fn check_intrinsic_type(
         let split: Vec<&str> = name_str.split('_').collect();
         assert!(split.len() >= 2, "Atomic intrinsic in an incorrect format");
 
-        //We only care about the operation here
+        // Each atomic op has variants with different suffixes (`_seq_cst`, `_acquire`, etc.). Use
+        // string ops to strip the suffixes, because the variants all get the same treatment here.
         let (n_tps, inputs, output) = match split[1] {
             "cxchg" | "cxchgweak" => (
                 1,

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -455,18 +455,14 @@ fn fn_sig_suggestion<'tcx>(
     let mut output = sig.output();
 
     let asyncness = if tcx.asyncness(assoc.def_id).is_async() {
-        output = if let ty::Alias(_, alias_ty) = *output.kind() {
-            tcx.explicit_item_self_bounds(alias_ty.def_id)
+        output = if let ty::Alias(_, alias_ty) = *output.kind()
+            && let Some(output) = tcx
+                .explicit_item_self_bounds(alias_ty.def_id)
                 .iter_instantiated_copied(tcx, alias_ty.args)
                 .find_map(|(bound, _)| {
                     bound.as_projection_clause()?.no_bound_vars()?.term.as_type()
-                })
-                .unwrap_or_else(|| {
-                    span_bug!(
-                        ident.span,
-                        "expected async fn to have `impl Future` output, but it returns {output}"
-                    )
-                })
+                }) {
+            output
         } else {
             span_bug!(
                 ident.span,

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -2267,14 +2267,12 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
 
 fn check_mod_type_wf(tcx: TyCtxt<'_>, module: LocalModDefId) -> Result<(), ErrorGuaranteed> {
     let items = tcx.hir_module_items(module);
-    let mut res = items.par_items(|item| tcx.ensure().check_well_formed(item.owner_id.def_id));
-    res =
-        res.and(items.par_impl_items(|item| tcx.ensure().check_well_formed(item.owner_id.def_id)));
-    res =
-        res.and(items.par_trait_items(|item| tcx.ensure().check_well_formed(item.owner_id.def_id)));
-    res = res
-        .and(items.par_foreign_items(|item| tcx.ensure().check_well_formed(item.owner_id.def_id)));
-    res = res.and(items.par_opaques(|item| tcx.ensure().check_well_formed(item)));
+    let res = items
+        .par_items(|item| tcx.ensure().check_well_formed(item.owner_id.def_id))
+        .and(items.par_impl_items(|item| tcx.ensure().check_well_formed(item.owner_id.def_id)))
+        .and(items.par_trait_items(|item| tcx.ensure().check_well_formed(item.owner_id.def_id)))
+        .and(items.par_foreign_items(|item| tcx.ensure().check_well_formed(item.owner_id.def_id)))
+        .and(items.par_opaques(|item| tcx.ensure().check_well_formed(item)));
     if module == LocalModDefId::CRATE_DEF_ID {
         super::entry::check_for_entry_fn(tcx);
     }

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -404,17 +404,12 @@ pub(crate) fn coerce_unsized_info<'tcx>(
             check_mutbl(mt_a, mt_b, &|ty| Ty::new_imm_ref(tcx, r_b, ty))
         }
 
-        (&ty::Ref(_, ty_a, mutbl_a), &ty::RawPtr(ty_b, mutbl_b)) => check_mutbl(
-            ty::TypeAndMut { ty: ty_a, mutbl: mutbl_a },
-            ty::TypeAndMut { ty: ty_b, mutbl: mutbl_b },
-            &|ty| Ty::new_imm_ptr(tcx, ty),
-        ),
-
-        (&ty::RawPtr(ty_a, mutbl_a), &ty::RawPtr(ty_b, mutbl_b)) => check_mutbl(
-            ty::TypeAndMut { ty: ty_a, mutbl: mutbl_a },
-            ty::TypeAndMut { ty: ty_b, mutbl: mutbl_b },
-            &|ty| Ty::new_imm_ptr(tcx, ty),
-        ),
+        (&ty::Ref(_, ty_a, mutbl_a), &ty::RawPtr(ty_b, mutbl_b))
+        | (&ty::RawPtr(ty_a, mutbl_a), &ty::RawPtr(ty_b, mutbl_b)) => {
+            let mt_a = ty::TypeAndMut { ty: ty_a, mutbl: mutbl_a };
+            let mt_b = ty::TypeAndMut { ty: ty_b, mutbl: mutbl_b };
+            check_mutbl(mt_a, mt_b, &|ty| Ty::new_imm_ptr(tcx, ty))
+        }
 
         (&ty::Adt(def_a, args_a), &ty::Adt(def_b, args_b))
             if def_a.is_struct() && def_b.is_struct() =>

compiler/rustc_hir_analysis/src/coherence/mod.rs

@@ -158,12 +158,12 @@ fn coherent_trait(tcx: TyCtxt<'_>, def_id: DefId) -> Result<(), ErrorGuaranteed>
         let trait_ref = trait_header.trait_ref.instantiate_identity();
         let trait_def = tcx.trait_def(trait_ref.def_id);
 
-        res = res.and(check_impl(tcx, impl_def_id, trait_ref, trait_def));
-        res = res.and(check_object_overlap(tcx, impl_def_id, trait_ref));
-
-        res = res.and(unsafety::check_item(tcx, impl_def_id, trait_header, trait_def));
-        res = res.and(tcx.ensure().orphan_check_impl(impl_def_id));
-        res = res.and(builtin::check_trait(tcx, def_id, impl_def_id, trait_header));
+        res = res
+            .and(check_impl(tcx, impl_def_id, trait_ref, trait_def))
+            .and(check_object_overlap(tcx, impl_def_id, trait_ref))
+            .and(unsafety::check_item(tcx, impl_def_id, trait_header, trait_def))
+            .and(tcx.ensure().orphan_check_impl(impl_def_id))
+            .and(builtin::check_trait(tcx, def_id, impl_def_id, trait_header));
     }
 
     res

compiler/rustc_hir_analysis/src/collect.rs

@@ -57,7 +57,7 @@ mod type_of;
 
 ///////////////////////////////////////////////////////////////////////////
 
-pub fn provide(providers: &mut Providers) {
+pub(crate) fn provide(providers: &mut Providers) {
     resolve_bound_vars::provide(providers);
     *providers = Providers {
         type_of: type_of::type_of,
@@ -122,7 +122,7 @@ pub fn provide(providers: &mut Providers) {
 /// `ItemCtxt` is parameterized by a `DefId` that it uses to satisfy
 /// `probe_ty_param_bounds` requests, drawing the information from
 /// the HIR (`hir::Generics`), recursively.
-pub struct ItemCtxt<'tcx> {
+pub(crate) struct ItemCtxt<'tcx> {
     tcx: TyCtxt<'tcx>,
     item_def_id: LocalDefId,
     tainted_by_errors: Cell<Option<ErrorGuaranteed>>,
@@ -148,7 +148,7 @@ impl<'v> Visitor<'v> for HirPlaceholderCollector {
     }
 }
 
-pub struct CollectItemTypesVisitor<'tcx> {
+pub(crate) struct CollectItemTypesVisitor<'tcx> {
     pub tcx: TyCtxt<'tcx>,
 }
 
@@ -364,19 +364,19 @@ fn bad_placeholder<'cx, 'tcx>(
 }
 
 impl<'tcx> ItemCtxt<'tcx> {
-    pub fn new(tcx: TyCtxt<'tcx>, item_def_id: LocalDefId) -> ItemCtxt<'tcx> {
+    pub(crate) fn new(tcx: TyCtxt<'tcx>, item_def_id: LocalDefId) -> ItemCtxt<'tcx> {
         ItemCtxt { tcx, item_def_id, tainted_by_errors: Cell::new(None) }
     }
 
-    pub fn lower_ty(&self, hir_ty: &hir::Ty<'tcx>) -> Ty<'tcx> {
+    pub(crate) fn lower_ty(&self, hir_ty: &hir::Ty<'tcx>) -> Ty<'tcx> {
         self.lowerer().lower_ty(hir_ty)
     }
 
-    pub fn hir_id(&self) -> hir::HirId {
+    pub(crate) fn hir_id(&self) -> hir::HirId {
         self.tcx.local_def_id_to_hir_id(self.item_def_id)
     }
 
-    pub fn node(&self) -> hir::Node<'tcx> {
+    pub(crate) fn node(&self) -> hir::Node<'tcx> {
         self.tcx.hir_node(self.hir_id())
     }