diff --git a/parallel_hashmap/phmap_utils.h b/parallel_hashmap/phmap_utils.h
index 9c570cf..7d45886 100644
--- a/parallel_hashmap/phmap_utils.h
+++ b/parallel_hashmap/phmap_utils.h
@@ -47,7 +47,7 @@ template <class T>  T phmap_max(T a, T b) { return a >= b ? a : b; }
 template <class T>
 struct Hash
 {
-    inline size_t operator()(const T& __v) noexcept
+    inline size_t operator()(const T& __v) const
     {
         return PHMAP_HASH_CLASS<T>()(__v);
     }