src/test/ui/annotate-snippet/auxiliary/multispan.rs

   1 // force-host
   2 // no-prefer-dynamic
   3
   4 #![crate_type = "proc-macro"]
   5 #![feature(proc_macro_diagnostic, proc_macro_span, proc_macro_def_site)]
   6
   7 extern crate proc_macro;
   8
   9 use proc_macro::{TokenStream, TokenTree, Span, Diagnostic};
  10
  11 fn parse(input: TokenStream) -> Result<(), Diagnostic> {
  12     let mut hi_spans = vec![];
  13     for tree in input {
  14         if let TokenTree::Ident(ref ident) = tree {
  15             if ident.to_string() == "hi" {
  16                 hi_spans.push(ident.span());
  17             }
  18         }
  19     }
  20
  21     if !hi_spans.is_empty() {
  22         return Err(Span::def_site()
  23                        .error("hello to you, too!")
  24                        .span_note(hi_spans, "found these 'hi's"));
  25     }
  26
  27     Ok(())
  28 }
  29
  30 #[proc_macro]
  31 pub fn hello(input: TokenStream) -> TokenStream {
  32     if let Err(diag) = parse(input) {
  33         diag.emit();
  34     }
  35
  36     TokenStream::new()
  37 }