diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index 6679ec79c1dd..a4d839275c3e 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -21,6 +21,7 @@ pub enum Mode {
     CompileFail,
     ParseFail,
     RunFail,
+    /// This now behaves like a `ui` test that has an implict `// run-pass`.
     RunPass,
     RunPassValgrind,
     Pretty,