4 #![crate_type = "proc-macro"]
7 extern crate proc_macro;
9 #[proc_macro_derive(A)]
10 pub unsafe extern "C" fn foo(a: i32, b: u32) -> u32 {
11 //~^ ERROR: mismatched derive proc macro signature
12 //~| mismatched derive proc macro signature
13 //~| mismatched derive proc macro signature
14 //~| proc macro functions may not be `extern
15 //~| proc macro functions may not be `unsafe