8006692: jdk/test/java/util/Collections/BigBinarySearch.java fails to compile

Summary: Missing boxing cause spurious inference failure
Reviewed-by: jjg

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

@@ -321,8 +321,10 @@ public class Infer {
                             mt.getReturnType() : syms.objectType;
                 }
                 Type qtype1 = inferenceContext.asFree(mt.getReturnType(), types);
-                if (!types.isSubtype(qtype1,
-                        qtype1.hasTag(UNDETVAR) ? types.boxedTypeOrType(to) : to)) {
+                Warner retWarn = new Warner();
+                if (!resultInfo.checkContext.compatible(qtype1, qtype1.hasTag(UNDETVAR) ? types.boxedTypeOrType(to) : to, retWarn) ||
+                        //unchecked conversion is not allowed
+                        retWarn.hasLint(Lint.LintCategory.UNCHECKED)) {
                     throw inferenceException
                             .setMessage("infer.no.conforming.instance.exists",
                             inferenceContext.restvars(), mt.getReturnType(), to);

test/tools/javac/generics/inference/8006692/T8006692.java

+/*
+ * Copyright (c) 2013, 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 8006692
+ * @summary jdk/test/java/util/Collections/BigBinarySearch.java fails to compile
+ * @compile T8006692.java
+ */
+
+import java.util.*;
+
+class Test {
+    static void test(List<Integer> l, int i) {
+        equal(i, Collections.binarySearch(l, l.get(i)));
+    }
+    static void equal(Object x, Object y) {}
+}