--- old/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/TypeEnter.java	2020-08-04 13:26:19.185000000 -0700
+++ new/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/TypeEnter.java	2020-08-04 13:26:18.381000000 -0700
@@ -1000,6 +1000,7 @@
             // Add default constructor if needed.
             DefaultConstructorHelper helper = getDefaultConstructorHelper(env);
             if (helper != null) {
+                chk.checkDefaultConstructor(sym, tree.pos());
                 defaultConstructor = defaultConstructor(make.at(tree.pos), helper);
                 tree.defs = tree.defs.prepend(defaultConstructor);
             }