diff --git a/compiler/rustc_type_ir/src/infer_ctxt.rs b/compiler/rustc_type_ir/src/infer_ctxt.rs
index 7957bacda5677..7d8c6bdca8800 100644
--- a/compiler/rustc_type_ir/src/infer_ctxt.rs
+++ b/compiler/rustc_type_ir/src/infer_ctxt.rs
@@ -63,6 +63,7 @@ impl TypingModeErasedStatus for MayBeErased {}
     feature = "nightly",
     derive(Encodable_NoContext, Decodable_NoContext, StableHash_NoContext)
 )]
+#[cfg_attr(feature = "nightly", rustc_must_match_exhaustively)]
 pub enum TypingMode<I: Interner, S: TypingModeErasedStatus = MayBeErased> {
     /// When checking whether impls overlap, we check whether any obligations
     /// are guaranteed to never hold when unifying the impls. This requires us