error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:8:7
   |
LL |     ($($($i:ident)?)+) => {};
   |       ^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:13:7
   |
LL |     ($($($i:ident)?)*) => {};
   |       ^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:18:7
   |
LL |     ($($($i:ident)?)?) => {};
   |       ^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:23:7
   |
LL |     ($($($($i:ident)?)?)?) => {};
   |       ^^^^^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:28:7
   |
LL |     ($($($($i:ident)*)?)?) => {};
   |       ^^^^^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:33:7
   |
LL |     ($($($($i:ident)?)*)?) => {};
   |       ^^^^^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:38:7
   |
LL |     ($($($($i:ident)?)?)*) => {};
   |       ^^^^^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:43:7
   |
LL |     ($($($($i:ident)*)*)?) => {};
   |       ^^^^^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:48:7
   |
LL |     ($($($($i:ident)?)*)*) => {};
   |       ^^^^^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:53:7
   |
LL |     ($($($($i:ident)?)*)+) => {};
   |       ^^^^^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:58:7
   |
LL |     ($($($($i:ident)+)?)*) => {};
   |       ^^^^^^^^^^^^^^^^^^

error: repetition matches empty token tree
  --> $DIR/issue-57597.rs:63:7
   |
LL |     ($($($($i:ident)+)*)?) => {};
   |       ^^^^^^^^^^^^^^^^^^

error: aborting due to 12 previous errors