--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/tools/javac/switchexpr/ExpressionSwitchFallThrough.java	Wed Aug 29 09:36:17 2018 +0200
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8206986
+ * @summary Check fall through in switch expressions.
+ * @compile --enable-preview -source 12 ExpressionSwitchFallThrough.java
+ * @run main/othervm --enable-preview ExpressionSwitchFallThrough
+ */
+
+import java.util.Objects;
+import java.util.function.Function;
+
+public class ExpressionSwitchFallThrough {
+    public static void main(String... args) {
+        new ExpressionSwitchFallThrough().run();
+    }
+
+    private void run() {
+        runTest(this::expression1);
+        runTest(this::expression2);
+    }
+
+    private void runTest(Function<T, String> print) {
+        check(T.A,  print, "ab");
+        check(T.B,  print, "b");
+        check(T.C,  print, "");
+    }
+
+    private String expression1(T t) {
+        String help = "";
+        return switch (t) {
+            case A: help = "a";
+            case B: help += "b";
+            default: break help;
+        };
+    }
+
+    private String expression2(T t) {
+        String help = "";
+        return switch (t) {
+            case A: help = "a";
+            case B: help += "b";
+            default: break help;
+        };
+    }
+
+    private void check(T t, Function<T, String> print, String expected) {
+        String result = print.apply(t);
+        if (!Objects.equals(result, expected)) {
+            throw new AssertionError("Unexpected result: " + result);
+        }
+    }
+
+    enum T {
+        A, B, C;
+    }
+}