diff --git a/compiler/rustc_const_eval/src/interpret/call.rs b/compiler/rustc_const_eval/src/interpret/call.rs
index cdf706f3752a4..29f819cca1fb6 100644
--- a/compiler/rustc_const_eval/src/interpret/call.rs
+++ b/compiler/rustc_const_eval/src/interpret/call.rs
@@ -241,7 +241,8 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         interp_ok(caller == callee)
     }
 
-    fn check_argument_compat(
+    /// Returns a `bool` saying whether the two arguments are ABI-compatible.
+    pub fn check_argument_compat(
         &self,
         caller_abi: &ArgAbi<'tcx, Ty<'tcx>>,
         callee_abi: &ArgAbi<'tcx, Ty<'tcx>>,