diff --git a/base/containers/id_map_unittest.cc b/base/containers/id_map_unittest.cc
index 78b866244fd53d..1dd69b6cf4375c 100644
--- a/base/containers/id_map_unittest.cc
+++ b/base/containers/id_map_unittest.cc
@@ -32,7 +32,7 @@ struct RepeatingKeyType {
 namespace std {
 template <>
 struct hash<::base::test::id_map::RepeatingKeyType> {
-  constexpr size_t operator()(
+  size_t operator()(
       const ::base::test::id_map::RepeatingKeyType& k) const noexcept {
     return std::hash<int>()(k.i);
   }