pub fn original_sp(sp: Span, enclosing_sp: Span) -> Span
Return the span itself if it doesn't come from a macro expansion,
otherwise return the call site span up to the enclosing_sp by
following the expn_info chain.
Prefix searches with a type followed by a colon (e.g.
fn:) to restrict the search to a given type.
Accepted types are: fn, mod,
struct (or str), enum,
trait, typedef (or
tdef).