Rollup merge of #89147 - b-naber:refs_in_check_const_value_eq, r=oli-obk

add case for checking const refs in check_const_value_eq

Previously in `check_const_value_eq` we destructured `ConstValue::ByRef` instances, this didn't account for `ty::Ref`s however, which led to an ICE.

Fixes https://github.com/rust-lang/rust/issues/88876
Fixes https://github.com/rust-lang/rust/issues/88384

r? `@oli-obk`

1 files changed, 9 insertions, 0 deletions

diff --git a/compiler/rustc_middle/src/ty/relate.rs b/compiler/rustc_middle/src/ty/relate.rs
index 9d1be212f5b..2c786538014 100644
--- a/compiler/rustc_middle/src/ty/relate.rs
+++ b/compiler/rustc_middle/src/ty/relate.rs
@@ -639,6 +639,15 @@ fn check_const_value_eq<R: TypeRelation<'tcx>>(
             get_slice_bytes(&tcx, a_val) == get_slice_bytes(&tcx, b_val)
         }
 
+        (ConstValue::ByRef { alloc: alloc_a, .. }, ConstValue::ByRef { alloc: alloc_b, .. })
+            if a.ty.is_ref() || b.ty.is_ref() =>
+        {
+            if a.ty.is_ref() && b.ty.is_ref() {
+                alloc_a == alloc_b
+            } else {
+                false
+            }
+        }
         (ConstValue::ByRef { .. }, ConstValue::ByRef { .. }) => {
             let a_destructured = tcx.destructure_const(relation.param_env().and(a));
             let b_destructured = tcx.destructure_const(relation.param_env().and(b));