diff --git a/include/rapidjson/pointer.h b/include/rapidjson/pointer.h
index 6f4ef3892..355929ede 100644
--- a/include/rapidjson/pointer.h
+++ b/include/rapidjson/pointer.h
@@ -28,6 +28,12 @@ RAPIDJSON_DIAG_PUSH
 RAPIDJSON_DIAG_OFF(4512) // assignment operator could not be generated
 #endif
 
+#if defined(RAPIDJSON_CPLUSPLUS) && RAPIDJSON_CPLUSPLUS >= 201703L
+#define RAPIDJSON_IF_CONSTEXPR if constexpr
+#else
+#define RAPIDJSON_IF_CONSTEXPR if
+#endif
+
 RAPIDJSON_NAMESPACE_BEGIN
 
 static const SizeType kPointerInvalidIndex = ~SizeType(0);  //!< Represents an invalid index in GenericPointer::Token
@@ -291,7 +297,7 @@ class GenericPointer {
         SizeType length = static_cast<SizeType>(end - buffer);
         buffer[length] = '\0';
 
-        if (sizeof(Ch) == 1) {
+        RAPIDJSON_IF_CONSTEXPR (sizeof(Ch) == 1) {
             Token token = { reinterpret_cast<Ch*>(buffer), length, index };
             return Append(token, allocator);
         }