1 files changed, 38 insertions, 0 deletions
diff --git a/tests/ui/proc-macro/auxiliary/subspan.rs b/tests/ui/proc-macro/auxiliary/subspan.rs
new file mode 100644
index 00000000000..f92adc04023
--- /dev/null
+++ b/tests/ui/proc-macro/auxiliary/subspan.rs
@@ -0,0 +1,38 @@
+// force-host
+// no-prefer-dynamic
+
+#![crate_type = "proc-macro"]
+#![feature(proc_macro_diagnostic, proc_macro_span)]
+
+extern crate proc_macro;
+
+use proc_macro::{TokenStream, TokenTree, Span, Diagnostic};
+
+fn parse(input: TokenStream) -> Result<(), Diagnostic> {
+    if let Some(TokenTree::Literal(lit)) = input.into_iter().next() {
+        let mut spans = vec![];
+        let string = lit.to_string();
+        for hi in string.matches("hi") {
+            let index = hi.as_ptr() as usize - string.as_ptr() as usize;
+            let subspan = lit.subspan(index..(index + hi.len())).unwrap();
+            spans.push(subspan);
+        }
+
+        if !spans.is_empty() {
+            Err(Span::call_site().error("found 'hi's").span_note(spans, "here"))
+        } else {
+            Ok(())
+        }
+    } else {
+        Err(Span::call_site().error("invalid input: expected string literal"))
+    }
+}
+
+#[proc_macro]
+pub fn subspan(input: TokenStream) -> TokenStream {
+    if let Err(diag) = parse(input) {
+        diag.emit();
+    }
+
+    TokenStream::new()
+}