lib/arrow/field-containable.rb in red-arrow-16.0.0 vs lib/arrow/field-containable.rb in red-arrow-17.0.0

@@ -27,10 +27,10 @@
         raise if index < 0
         index += n_fields if index < 0
         return nil if index < 0 or index >= n_fields
         get_field(index)
       else
-        message = "field name or index must be String, Symbol or Integer"
+        message = +"field name or index must be String, Symbol or Integer"
         message << ": <#{name_or_index.inspect}>"
         raise ArgumentError, message
       end
     end
   end