rust/src/test/ui/proc-macro/auxiliary/hygiene_example_codegen.rs

28 lines
848 B
Rust
Raw Normal View History

// force-host
2017-03-30 23:06:28 -05:00
// no-prefer-dynamic
#![feature(proc_macro_quote, proc_macro_hygiene)]
2017-03-30 23:06:28 -05:00
#![crate_type = "proc-macro"]
extern crate proc_macro as proc_macro_renamed; // This does not break `quote!`
use proc_macro_renamed::{TokenStream, quote};
#[proc_macro]
pub fn hello(input: TokenStream) -> TokenStream {
quote!(hello_helper!($input))
//^ `hello_helper!` always resolves to the following proc macro,
//| no matter where `hello!` is used.
}
#[proc_macro]
pub fn hello_helper(input: TokenStream) -> TokenStream {
quote! {
extern crate hygiene_example; // This is never a conflict error
let string = format!("hello {}", $input);
//^ `format!` always resolves to the prelude macro,
//| even if a different `format!` is in scope where `hello!` is used.
hygiene_example::print(&string)
}
}