diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
index cb4209116ac65..7ab254e5f4b84 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
@@ -29,10 +29,9 @@ use rustc_errors::codes::*;
 use rustc_errors::{
     Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, FatalError, struct_span_code_err,
 };
-use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Namespace, Res};
 use rustc_hir::def_id::{DefId, LocalDefId};
-use rustc_hir::{GenericArg, GenericArgs, HirId};
+use rustc_hir::{self as hir, AnonConst, GenericArg, GenericArgs, HirId};
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::middle::stability::AllowUnstable;
@@ -2089,7 +2088,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 qpath.span(),
                 format!("Const::lower_const_arg: invalid qpath {qpath:?}"),
             ),
-            hir::ConstArgKind::Anon(anon) => self.lower_anon_const(anon.def_id),
+            hir::ConstArgKind::Anon(anon) => self.lower_anon_const(anon),
             hir::ConstArgKind::Infer(span) => self.ct_infer(None, span),
         }
     }
@@ -2180,27 +2179,22 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
     /// Literals and const generic parameters are eagerly converted to a constant, everything else
     /// becomes `Unevaluated`.
     #[instrument(skip(self), level = "debug")]
-    fn lower_anon_const(&self, def: LocalDefId) -> Const<'tcx> {
+    fn lower_anon_const(&self, anon: &AnonConst) -> Const<'tcx> {
         let tcx = self.tcx();
 
-        let body_id = match tcx.hir_node_by_def_id(def) {
-            hir::Node::AnonConst(ac) => ac.body,
-            node => span_bug!(
-                tcx.def_span(def.to_def_id()),
-                "from_anon_const can only process anonymous constants, not {node:?}"
-            ),
-        };
-
-        let expr = &tcx.hir().body(body_id).value;
+        let expr = &tcx.hir().body(anon.body).value;
         debug!(?expr);
 
-        let ty = tcx.type_of(def).no_bound_vars().expect("const parameter types cannot be generic");
+        let ty = tcx
+            .type_of(anon.def_id)
+            .no_bound_vars()
+            .expect("const parameter types cannot be generic");
 
         match self.try_lower_anon_const_lit(ty, expr) {
             Some(v) => v,
             None => ty::Const::new_unevaluated(tcx, ty::UnevaluatedConst {
-                def: def.to_def_id(),
-                args: ty::GenericArgs::identity_for_item(tcx, def.to_def_id()),
+                def: anon.def_id.to_def_id(),
+                args: ty::GenericArgs::identity_for_item(tcx, anon.def_id.to_def_id()),
             }),
         }
     }