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use crate::ToTokens;
use proc_macro2::{Span, TokenStream};
pub trait Spanned {
fn __span(&self) -> Span;
}
impl Spanned for Span {
fn __span(&self) -> Span {
*self
}
}
impl<T: ?Sized + ToTokens> Spanned for T {
fn __span(&self) -> Span {
join_spans(self.into_token_stream())
}
}
fn join_spans(tokens: TokenStream) -> Span {
let mut iter = tokens.into_iter().filter_map(|tt| {
let span = tt.span();
let debug = format!("{:?}", span);
if debug.ends_with("bytes(0..0)") {
None
} else {
Some(span)
}
});
let first = match iter.next() {
Some(span) => span,
None => return Span::call_site(),
};
iter.fold(None, |_prev, next| Some(next))
.and_then(|last| first.join(last))
.unwrap_or(first)
}