quote/
spanned.rs

1use crate::ToTokens;
2use proc_macro2::extra::DelimSpan;
3use proc_macro2::{Span, TokenStream};
4
5// Not public API other than via the syn crate. Use syn::spanned::Spanned.
6pub trait Spanned: private::Sealed {
7    fn __span(&self) -> Span;
8}
9
10impl Spanned for Span {
11    fn __span(&self) -> Span {
12        *self
13    }
14}
15
16impl Spanned for DelimSpan {
17    fn __span(&self) -> Span {
18        self.join()
19    }
20}
21
22impl<T: ?Sized + ToTokens> Spanned for T {
23    fn __span(&self) -> Span {
24        join_spans(self.into_token_stream())
25    }
26}
27
28fn join_spans(tokens: TokenStream) -> Span {
29    let mut iter = tokens.into_iter().map(|tt| tt.span());
30
31    let Some(first) = iter.next() else {
32        return Span::call_site();
33    };
34
35    iter.fold(None, |_prev, next| Some(next))
36        .and_then(|last| first.join(last))
37        .unwrap_or(first)
38}
39
40mod private {
41    use crate::ToTokens;
42    use proc_macro2::extra::DelimSpan;
43    use proc_macro2::Span;
44
45    pub trait Sealed {}
46    impl Sealed for Span {}
47    impl Sealed for DelimSpan {}
48    impl<T: ?Sized + ToTokens> Sealed for T {}
49}
quote/spanned.rs

quote/
spanned.rs
