error: impossible to parse directory `not-a-locale` as a language identifier, (error: Parser error: Invalid subtag)
 --> tests/ui/fail/invalid-locale-directory/invalid-locale-directory.rs:1:1
  |
1 | l10n::init!();
  | ^^^^^^^^^^^^^
  |
  = note: this error originates in the macro `l10n::init` (in Nightly builds, run with -Z macro-backtrace for more info)