diff --git a/src/test_lib_json/main.cpp b/src/test_lib_json/main.cpp
index e8bc7bc..d0f5364 100644
--- a/src/test_lib_json/main.cpp
+++ b/src/test_lib_json/main.cpp
@@ -351,7 +351,7 @@
 }
 
 JSONTEST_FIXTURE_LOCAL(ValueTest, resizePopulatesAllMissingElements) {
-  int n = 10;
+  Json::ArrayIndex n = 10;
   Json::Value v;
   v.resize(n);
   JSONTEST_ASSERT_EQUAL(n, v.size());