Fix code

src/Core/MultiEnum.h

@@ -83,13 +83,13 @@ struct MultiEnum
     template <typename ValueType, typename = std::enable_if_t<std::is_convertible_v<ValueType, StorageType>>>
     friend bool operator==(ValueType left, MultiEnum right)
     {
-        return right == left;
+        return right.operator==(left);
     }
 
     template <typename L>
     friend bool operator!=(L left, MultiEnum right)
     {
-        return !(right == left);
+        return !(right.operator==(left));
     }
 
 private:

tests/ci/ci_config.json

@@ -92,7 +92,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "gcc-10",
+            "compiler": "gcc-9",
             "build-type": "",
             "sanitizer": "",
             "package-type": "deb",