tests/ui/proc-macro/auxiliary/resolved-located-at.rs

   1 // force-host
   2 // no-prefer-dynamic
   3
   4 #![feature(proc_macro_def_site)]
   5 #![feature(proc_macro_diagnostic)]
   6 #![feature(proc_macro_quote)]
   7 #![crate_type = "proc-macro"]
   8
   9 extern crate proc_macro;
  10 use proc_macro::*;
  11
  12 #[proc_macro]
  13 pub fn resolve_located_at(input: TokenStream) -> TokenStream {
  14     match &*input.into_iter().collect::<Vec<_>>() {
  15         [a, b, ..] => {
  16             // The error is reported at input `a`.
  17             let mut diag = Diagnostic::new(Level::Error, "expected error");
  18             diag.set_spans(Span::def_site().located_at(a.span()));
  19             diag.emit();
  20
  21             // Resolves to `struct S;` at def site, but the error is reported at input `b`.
  22             let s = TokenTree::Ident(Ident::new("S", b.span().resolved_at(Span::def_site())));
  23             quote!({
  24                 struct S;
  25
  26                 $s
  27             })
  28         }
  29         _ => panic!("unexpected input"),
  30     }
  31 }