32 lines
911 B
Rust
32 lines
911 B
Rust
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// force-host
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// no-prefer-dynamic
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#![feature(proc_macro_def_site)]
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#![feature(proc_macro_diagnostic)]
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#![feature(proc_macro_quote)]
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#![crate_type = "proc-macro"]
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extern crate proc_macro;
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use proc_macro::*;
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#[proc_macro]
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pub fn resolve_located_at(input: TokenStream) -> TokenStream {
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match &*input.into_iter().collect::<Vec<_>>() {
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[a, b, ..] => {
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// The error is reported at input `a`.
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let mut diag = Diagnostic::new(Level::Error, "expected error");
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diag.set_spans(Span::def_site().located_at(a.span()));
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diag.emit();
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// Resolves to `struct S;` at def site, but the error is reported at input `b`.
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let s = TokenTree::Ident(Ident::new("S", b.span().resolved_at(Span::def_site())));
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quote!({
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struct S;
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$s
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})
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}
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_ => panic!("unexpected input"),
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}
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}
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