diff --git a/src/Functions/FunctionsJSON.cpp b/src/Functions/FunctionsJSON.cpp
index 6889a0d44b9..cb55ba6b83b 100644
--- a/src/Functions/FunctionsJSON.cpp
+++ b/src/Functions/FunctionsJSON.cpp
@@ -1,3 +1,4 @@
+#include <type_traits>
 #include <boost/tti/has_member_function.hpp>
 
 #include <base/range.h>
@@ -38,7 +39,6 @@
 #include <Functions/SimdJSONParser.h>
 #include <Functions/RapidJSONParser.h>
 #include <Functions/FunctionHelpers.h>
-#include <Functions/FunctionsJSON.h>
 
 #include <Interpreters/Context.h>
 
@@ -58,6 +58,11 @@ namespace ErrorCodes
     extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
 }
 
+template <typename T>
+concept HasIndexOperator = requires (T t)
+{
+    t[0];
+};
 
 /// Functions to parse JSONs and extract values from it.
 /// The first argument of all these functions gets a JSON,
@@ -279,7 +284,7 @@ private:
             return true;
         }
 
-        if constexpr (FunctionJSONHelpersDetails::has_index_operator<typename JSONParser::Object>::value)
+        if constexpr (HasIndexOperator<typename JSONParser::Object>)
         {
             if (element.isObject())
             {
diff --git a/src/Functions/FunctionsJSON.h b/src/Functions/FunctionsJSON.h
deleted file mode 100644
index 4ef43eb637f..00000000000
--- a/src/Functions/FunctionsJSON.h
+++ /dev/null
@@ -1,17 +0,0 @@
-#pragma once
-
-#include <type_traits>
-
-namespace DB
-{
-
-namespace FunctionJSONHelpersDetails
-{
-    template <class T, class = void>
-    struct has_index_operator : std::false_type {};
-
-    template <class T>
-    struct has_index_operator<T, std::void_t<decltype(std::declval<T>()[0])>> : std::true_type {};
-}
-
-}