Auto merge of #122338 - workingjubilee:rollup-xzpt4v4, r=workingjubilee

Rollup of 15 pull requests

Successful merges:

 - #116791 (Allow codegen backends to opt-out of parallel codegen)
 - #116793 (Allow targets to override default codegen backend)
 - #117458 (LLVM Bitcode Linker: A self contained linker for nvptx and other targets)
 - #119385 (Fix type resolution of associated const equality bounds (take 2))
 - #121438 (std support for wasm32 panic=unwind)
 - #121893 (Add tests (and a bit of cleanup) for interior mut handling in promotion and const-checking)
 - #122080 (Clarity improvements to `DropTree`)
 - #122152 (Improve diagnostics for parenthesized type arguments)
 - #122166 (Remove the unused `field_remapping` field from `TypeLowering`)
 - #122249 (interpret: do not call machine read hooks during validation)
 - #122299 (Store backtrace for `must_produce_diag`)
 - #122318 (Revision-related tweaks for next-solver tests)
 - #122320 (Use ptradd for vtable indexing)
 - #122328 (unix_sigpipe: Replace `inherit` with `sig_dfl` in syntax tests)
 - #122330 (bootstrap readme: fix, improve, update)

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

2 files changed, 20 insertions, 33 deletions

diff --git a/compiler/rustc_hir_analysis/src/astconv/bounds.rs b/compiler/rustc_hir_analysis/src/astconv/bounds.rs
index 6d8a5bc0e90..17e0aeb044c 100644
--- a/compiler/rustc_hir_analysis/src/astconv/bounds.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/bounds.rs
@@ -408,7 +408,7 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
             // Create the generic arguments for the associated type or constant by joining the
             // parent arguments (the arguments of the trait) and the own arguments (the ones of
             // the associated item itself) and construct an alias type using them.
-            candidate.map_bound(|trait_ref| {
+            let alias_ty = candidate.map_bound(|trait_ref| {
                 let ident = Ident::new(assoc_item.name, binding.ident.span);
                 let item_segment = hir::PathSegment {
                     ident,
@@ -430,7 +430,25 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
                 // *constants* to represent *const projections*. Alias *term* would be a more
                 // appropriate name but alas.
                 ty::AliasTy::new(tcx, assoc_item.def_id, alias_args)
-            })
+            });
+
+            // Provide the resolved type of the associated constant to `type_of(AnonConst)`.
+            if !speculative
+                && let hir::TypeBindingKind::Equality { term: hir::Term::Const(anon_const) } =
+                    binding.kind
+            {
+                let ty = alias_ty.map_bound(|ty| tcx.type_of(ty.def_id).instantiate(tcx, ty.args));
+                // Since the arguments passed to the alias type above may contain early-bound
+                // generic parameters, the instantiated type may contain some as well.
+                // Therefore wrap it in `EarlyBinder`.
+                // FIXME(fmease): Reject escaping late-bound vars.
+                tcx.feed_anon_const_type(
+                    anon_const.def_id,
+                    ty::EarlyBinder::bind(ty.skip_binder()),
+                );
+            }
+
+            alias_ty
         };
 
         match binding.kind {
diff --git a/compiler/rustc_hir_analysis/src/collect/type_of.rs b/compiler/rustc_hir_analysis/src/collect/type_of.rs
index a1345c2d81b..598dba922d0 100644
--- a/compiler/rustc_hir_analysis/src/collect/type_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/type_of.rs
@@ -79,37 +79,6 @@ fn anon_const_type_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Ty<'tcx> {
                 .expect("const parameter types cannot be generic");
         }
 
-        Node::TypeBinding(binding @ &TypeBinding { hir_id: binding_id, .. })
-            if let Node::TraitRef(trait_ref) = tcx.parent_hir_node(binding_id) =>
-        {
-            let Some(trait_def_id) = trait_ref.trait_def_id() else {
-                return Ty::new_error_with_message(
-                    tcx,
-                    tcx.def_span(def_id),
-                    "Could not find trait",
-                );
-            };
-            let assoc_items = tcx.associated_items(trait_def_id);
-            let assoc_item = assoc_items.find_by_name_and_kind(
-                tcx,
-                binding.ident,
-                ty::AssocKind::Const,
-                def_id.to_def_id(),
-            );
-            return if let Some(assoc_item) = assoc_item {
-                tcx.type_of(assoc_item.def_id)
-                    .no_bound_vars()
-                    .expect("const parameter types cannot be generic")
-            } else {
-                // FIXME(associated_const_equality): add a useful error message here.
-                Ty::new_error_with_message(
-                    tcx,
-                    tcx.def_span(def_id),
-                    "Could not find associated const on trait",
-                )
-            };
-        }
-
         // This match arm is for when the def_id appears in a GAT whose
         // path can't be resolved without typechecking e.g.
         //