Macro string_literal_replace 

string_literal_replace!() { /* proc-macro */ }

Replace contents of a string literal at compile-time.

assert_eq!(string_literal_replace!("hello, world!" ("hello" -> "goodbye")), "goodbye, world!");

This macro can chain with other macros that output string literals, like concat!:

assert_eq!(
    string_literal_replace!(concat!("hello", ", world!") ("hello" -> "goodbye")),
    "goodbye, world!"
);