error: no rules expected the token `[`
  --> $DIR/macro-doc-comments-2.rs:6:5
   |
LL | macro_rules! inner {
   | ------------------ when calling this macro
...
LL |     /// Outer
   |     ^^^^^^^^^
   |     |
   |     no rules expected this token in macro call
   |     outer doc comments expand to `#[doc = "..."]`, which is what this macro attempted to match
   |
note: while trying to match `!`
  --> $DIR/macro-doc-comments-2.rs:2:7
   |
LL |     (#![$inner:meta]) => ()
   |       ^

error: aborting due to previous error