Merge

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

@@ -3624,7 +3624,8 @@ public class Types {
             for (Type erasedSupertype : mec) {
                 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
                 for (int i = startIdx + 1 ; i < ts.length ; i++) {
-                    lci = intersect(lci, List.of(asSuper(ts[i], erasedSupertype.tsym)));
+                    Type superType = asSuper(ts[i], erasedSupertype.tsym);
+                    lci = intersect(lci, superType != null ? List.of(superType) : List.<Type>nil());
                 }
                 candidates = candidates.appendList(lci);
             }

src/share/classes/com/sun/tools/javac/comp/Infer.java

@@ -784,7 +784,10 @@ public class Infer {
                     while (tmpTail.nonEmpty()) {
                         Type b1 = boundList.head;
                         Type b2 = tmpTail.head;
-                        if (b1 != b2) {
+                        /* This wildcard check is temporary workaround. This code may need to be
+                         * revisited once spec bug JDK-7034922 is fixed.
+                         */
+                        if (b1 != b2 && !b1.hasTag(WILDCARD) && !b2.hasTag(WILDCARD)) {
                             Pair<Type, Type> commonSupers = infer.getParameterizedSupers(b1, b2);
                             if (commonSupers != null) {
                                 List<Type> allParamsSuperBound1 = commonSupers.fst.allparams();

test/tools/javac/lambda/T8057800/NPEMethodReferenceAndGenericsTest.java

+/*
+ * Copyright (c) 2014, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 8057800
+ * @summary Method reference with generic type creates NPE when compiling
+ * @compile NPEMethodReferenceAndGenericsTest.java
+ */
+
+public class NPEMethodReferenceAndGenericsTest {
+    public <T> void foo(java.util.Comparator<? super T> comparator) {}
+
+    public <C extends Comparable<? super C>> void foo() {
+        foo(C::compareTo);
+    }
+}