src/test/ui/proc-macro/auxiliary/issue-50061.rs

// force-host
// no-prefer-dynamic

#![crate_type = "proc-macro"]

extern crate proc_macro;
use proc_macro::TokenStream;

#[proc_macro_attribute]
pub fn check(_a: TokenStream, b: TokenStream) -> TokenStream {
    b.into_iter().collect()
}