8203679: AssertionError in DeferredAttr with parenthesized method reference

Reviewed-by: mcimadamore

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/DeferredAttr.java

@@ -164,11 +164,18 @@ public class DeferredAttr extends JCTree.Visitor {
                     JCMemberReference result = new JCMemberReference(t.mode, t.name, expr, typeargs) {
                         @Override
                         public void setOverloadKind(OverloadKind overloadKind) {
-                            super.setOverloadKind(overloadKind);
-                            if (t.getOverloadKind() == null) {
+                            OverloadKind previous = t.getOverloadKind();
+                            if (previous == null) {
                                 t.setOverloadKind(overloadKind);
+                            } else {
+                                Assert.check(previous == overloadKind);
                             }
                         }
+
+                        @Override
+                        public OverloadKind getOverloadKind() {
+                            return t.getOverloadKind();
+                        }
                     };
                     result.pos = t.pos;
                     return result;

test/langtools/tools/javac/lambda/methodReference/MethodRefStuckParenthesized.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2018, Google LLC. 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 8203679
+ * @summary This is a negative regression test for an AssertionError in DeferredAttr.
+ * @compile/fail/ref=MethodRefStuckParenthesized.out -XDrawDiagnostics MethodRefStuckParenthesized.java
+ */
+
+public abstract class MethodRefStuckParenthesized {
+
+  interface I {
+    String v();
+  }
+
+  interface J {
+    String v();
+  }
+
+  abstract String v();
+
+  abstract void f(I v);
+
+  abstract <X extends J> J g(X x);
+
+  void test() {
+    f(g((this::v)));
+  }
+}

test/langtools/tools/javac/lambda/methodReference/MethodRefStuckParenthesized.out

@@ -0,0 +1,2 @@
+MethodRefStuckParenthesized.java:48:5: compiler.err.cant.apply.symbol: kindname.method, f, MethodRefStuckParenthesized.I, MethodRefStuckParenthesized.J, kindname.class, MethodRefStuckParenthesized, (compiler.misc.no.conforming.assignment.exists: (compiler.misc.infer.no.conforming.instance.exists: X, MethodRefStuckParenthesized.J, MethodRefStuckParenthesized.I))
+1 error