diff --git a/src/base.rs b/src/base.rs
index 1ce920f3bdb..2415c2c90b2 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -779,7 +779,7 @@ fn is_fat_ptr<'tcx>(fx: &FunctionCx<'_, '_, 'tcx>, ty: Ty<'tcx>) -> bool {
                         NullOp::OffsetOf(fields) => {
                             layout.offset_of_subfield(fx, fields.iter()).bytes()
                         }
-                        NullOp::DebugAssertions => {
+                        NullOp::UbCheck(_) => {
                             let val = fx.tcx.sess.opts.debug_assertions;
                             let val = CValue::by_val(
                                 fx.bcx.ins().iconst(types::I8, i64::try_from(val).unwrap()),