src/share/classes/com/sun/tools/javac/code/Source.java

@@ -235,10 +235,13 @@
         return compareTo(JDK1_8) >= 0;
     }
     public boolean allowFunctionalInterfaceMostSpecific() {
         return compareTo(JDK1_8) >= 0;
     }
+    public boolean allowPrivateSafeVarargs() {
+        return compareTo(JDK1_9) >= 0;
+    }
     public static SourceVersion toSourceVersion(Source source) {
         switch(source) {
         case JDK1_2:
             return RELEASE_2;
         case JDK1_3: