diff --git a/clang/tools/c-index-test/c-index-test.c b/clang/tools/c-index-test/c-index-test.c
index d0d5b2bce2f74c40af178172926964b2bd0d7977..44b90b13e1244a9e9591fad78e062726dcec9d53 100644
--- a/clang/tools/c-index-test/c-index-test.c
+++ b/clang/tools/c-index-test/c-index-test.c
@@ -2552,7 +2552,7 @@ static void printDiagnosticSet(CXDiagnosticSet Diags, unsigned indent) {
     printRanges(D, indent);
     printFixIts(D, indent);
     
-    // Print subdiagnostics.
+    /* Print subdiagnostics. */
     printDiagnosticSet(clang_getChildDiagnostics(D), indent+2);
 
     clang_disposeString(FileName);