No, it doesn't match the "@dotted_name(arg_list)" pattern.

   decorator: "@" `dotted_name` ["(" [`argument_list` [","]] ")"] NEWLINE
   call: `primary` "(" [`argument_list` [","] | `comprehension`] ")"
   argument_list: `positional_arguments` ["," `starred_and_keywords`]
                :   ["," `keywords_arguments`]
                : | `starred_and_keywords` ["," `keywords_arguments`]
                : | `keywords_arguments`

The call syntax contains a special case for generator expression. The decorator expression syntax dosn't contain it. You should change the grammar rule to

   decorator: "@" `dotted_name` ["(" [`argument_list` [","] | `comprehension`] ")"] NEWLINE

for supporting this syntax. Please open a separate topic on Python-Dev for discussing this language change.