Function syntax::ext::base::expr_to_spanned_string [] [src]

pub fn expr_to_spanned_string(cx: &mut ExtCtxt,
                              expr: P<Expr>,
                              err_msg: &str)
                              -> Option<Spanned<(Symbol, StrStyle)>>
🔬 This is a nightly-only experimental API. (rustc_private)

Extract a string literal from the macro expanded version of expr, emitting err_msg if expr is not a string literal. This does not stop compilation on error, merely emits a non-fatal error and returns None.