Feature gate: #![feature(proc_macro_value)]

This feature provides methods on proc_macro::Literal to get their unescaped string equivalent.

Public API

For now, the only choice to get these values is to either copy-paste rustc's source code or use syn which has more or less the same code to achieve the same result.

After this change, one will be able to do:

// The one provided by `proc-macro`.
let literal_string = Literal::String { .. };

let unescaped_string_literal = literal_string.str_value().expect("failed to unescape");

Steps / History

• ACP
• Implementation
• Final comment period (FCP)¹
• Stabilization PR

Unresolved Questions

• Tests and/or shared code demonstrating that the new API parses the same set of (no more, no less) inputs with the same outputs as rustc would (cc Add _value API for number literals in proc-macro #154608 (comment)).