proc-macro-error2 2.0.1

Almost drop-in replacement to panics in proc-macros
Documentation 
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error: #[proc_macro_error] attribute can be used only with procedural macros

         = hint: if you are really sure that #[proc_macro_error] should be applied to this exact function, use #[proc_macro_error(allow_not_macro)]
 --> tests/ui/not_proc_macro.rs:3:1
  |
3 | #[proc_macro_error]
  | ^^^^^^^^^^^^^^^^^^^
  |
  = note: this error originates in the attribute macro `proc_macro_error` (in Nightly builds, run with -Z macro-backtrace for more info)