error: problems parsing template source at row 3, column 4 near:
       "// Help, I forgot how to write comments!"...
 --> tests/ui/match_with_extra.rs:3:10
  |
3 | #[derive(Template)]
  |          ^^^^^^^^
  |
  = note: this error originates in the derive macro `Template` (in Nightly builds, run with -Z macro-backtrace for more info)