error: Unknown argument(s) given to attribute `quantity`.

         = help: Use `#[quantity]`
       or  `#[quantity(<lhs_ident> * <rhs_ident>]`
       or  `#[quantity(<lhs_ident> / <rhs_ident>]`.

  --> tests/ui/invalid_args.rs:13:1
   |
13 | #[quantity(fn baz)]
   | ^^^^^^^^^^^^^^^^^^^
   |
   = note: this error originates in the attribute macro `quantity` (in Nightly builds, run with -Z macro-backtrace for more info)