3 use proc_macro::{Delimiter, Group, Ident, Spacing, Span, TokenTree};
5 fn concat(tokens: &[TokenTree], group_span: Span) -> TokenTree {  in concat()
8     let mut span = None;  in concat()  localVariable
12             Some(TokenTree::Literal(lit)) => segments.push((lit.to_string(), lit.span())),  in concat()
18                 segments.push((value, ident.span()));  in concat()
27                     // Set the overall span of concatenated token as current span  in concat()
28                     "span" => {  in concat()
30                             span.is_none(),  in concat()
31                             "span modifier should only appear at most once"  in concat()
33                         span = Some(sp);  in concat()
46     TokenTree::Ident(Ident::new(&pasted, span.unwrap_or(group_span)))  in concat()
53             let span = group.span();  in expand()  localVariable
62                 *token = concat(&stream[1..stream.len() - 1], span);  in expand()
67                 group.set_span(span);  in expand()