1 files changed, 17 insertions, 0 deletions
diff --git a/tests/ui/fmt/raw-idents.rs b/tests/ui/fmt/raw-idents.rs
new file mode 100644
index 000000000..29a74c55a
--- /dev/null
+++ b/tests/ui/fmt/raw-idents.rs
@@ -0,0 +1,17 @@
+// Regression test for https://github.com/rust-lang/rust/issues/115466
+
+// The "identifier" in format strings is parsed as an IDENTIFIER_OR_KEYWORD, not an IDENTIFIER.
+// Test that there is an actionable diagnostic if a RAW_IDENTIFIER is used instead.
+
+fn main() {
+    let r#type = "foobar";
+    println!("It is {r#type}"); //~ ERROR: invalid format string: raw identifiers are not supported
+    println!(r##"It still is {r#type}"##); //~ ERROR: invalid format string: raw identifiers are not supported
+    println!(concat!("{r#", "type}")); //~ ERROR: invalid format string: raw identifiers are not supported
+    println!("{\x72\x23type:?}"); //~ ERROR: invalid format string: raw identifiers are not supported
+
+    // OK
+    println!("{type}");
+    println!("{let}", let = r#type);
+    println!("{let}", r#let = r#type);
+}