coverage: Add a specific test for `#[rustfmt::skip]`

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/coverage/rustfmt-skip.rs b/tests/coverage/rustfmt-skip.rs
new file mode 100644
index 00000000000..6f6874c9aa0
--- /dev/null
+++ b/tests/coverage/rustfmt-skip.rs
@@ -0,0 +1,17 @@
+//@ edition: 2024
+
+// The presence of `#[rustfmt::skip]` on a function should not cause macros
+// within that function to mysteriously not be instrumented.
+//
+// This test detects problems that can occur when building an expansion tree
+// based on `ExpnData::parent` instead of `ExpnData::call_site`, for example.
+
+#[rustfmt::skip]
+fn main() {
+    // Ensure a gap between the body start and the first statement.
+    println!(
+        // Keep this on a separate line, to distinguish instrumentation of
+        // `println!` from instrumentation of its arguments.
+        "hello"
+    );
+}