src/test/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_hygiene)]
   7 #![feature(proc_macro_quote)]
   8 #![crate_type = "proc-macro"]
   9
  10 extern crate proc_macro;
  11 use proc_macro::*;
  12
  13 #[proc_macro]
  14 pub fn resolve_located_at(input: TokenStream) -> TokenStream {
  15     match &*input.into_iter().collect::<Vec<_>>() {
  16         [a, b, ..] => {
  17             // The error is reported at input `a`.
  18             let mut diag = Diagnostic::new(Level::Error, "expected error");
  19             diag.set_spans(Span::def_site().located_at(a.span()));
  20             diag.emit();
  21
  22             // Resolves to `struct S;` at def site, but the error is reported at input `b`.
  23             let s = TokenTree::Ident(Ident::new("S", b.span().resolved_at(Span::def_site())));
  24             quote!({
  25                 struct S;
  26
  27                 $s
  28             })
  29         }
  30         _ => panic!("unexpected input"),
  31     }
  32 }