diff --git a/include/nlohmann/detail/meta/type_traits.hpp b/include/nlohmann/detail/meta/type_traits.hpp
index d2788bbd7..68f4f2434 100644
--- a/include/nlohmann/detail/meta/type_traits.hpp
+++ b/include/nlohmann/detail/meta/type_traits.hpp
@@ -684,6 +684,11 @@ inline constexpr bool value_in_range_of(T val)
 template<bool Value>
 using bool_constant = std::integral_constant<bool, Value>;
 
+#ifdef JSON_HAS_CPP_20
+template <typename T, typename BasicJsonType>
+concept CompatibleType = !is_basic_json<uncvref_t<T>>::value && is_compatible_type<BasicJsonType, uncvref_t<T>>::value;
+#endif
+
 ///////////////////////////////////////////////////////////////////////////////
 // is_c_string
 ///////////////////////////////////////////////////////////////////////////////
diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 2e733b5d2..84d41ab98 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -3694,11 +3694,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
 
     /// @brief comparison: equal
     /// @sa https://json.nlohmann.me/api/basic_json/operator_eq/
-    template < typename CompatibleType,
-               typename U = detail::uncvref_t<CompatibleType>,
-               detail::enable_if_t <
-                   !detail::is_basic_json<U>::value && detail::is_compatible_type<basic_json_t, U>::value, int > = 0 >
-    bool operator==(CompatibleType rhs) const noexcept
+    template <detail::CompatibleType<basic_json_t> T>
+    bool operator==(T rhs) const noexcept
     {
         return *this == basic_json(rhs);
     }