Procedural macros can be defined inside non-module item in the root module

[petrochenkov]

Something like this even passes through proc macro registrar generation!

#![feature(proc_macro)]
#![crate_type = "proc-macro"]

extern crate proc_macro;
use proc_macro::*;

fn foo(arg: TokenStream) -> TokenStream {
    #[proc_macro]
    pub fn foo(arg: TokenStream) -> TokenStream { arg }
    
    arg
}

And registrar interprets the outer foo as the proc macro instead of the inner one.

[petrochenkov]

Fixed locally, will submit a PR today.