Function rustc_expand::base::get_single_str_from_tts

pub fn get_single_str_from_tts(
    cx: &mut ExtCtxt<'_>, 
    sp: Span, 
    tts: TokenStream, 
    name: &str
) -> Option<String>

Interpreting tts as a comma-separated sequence of expressions, expect exactly one string literal, or emit an error and return None.