6762569: Javac crashes with AssertionError in Types.containedBy

Summary: Types.containedBy should be more liberal with UndetVars
Reviewed-by: jjg

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

@@ -709,16 +709,13 @@ public class Types {
         case UNDETVAR:
             if (s.tag == WILDCARD) {
                 UndetVar undetvar = (UndetVar)t;
-
-                // Because of wildcard capture, s must be on the left
-                // hand side of an assignment.  Furthermore, t is an
-                // underconstrained type variable, for example, one
-                // that is only used in the return type of a method.
-                // If the type variable is truly underconstrained, it
-                // cannot have any low bounds:
-                assert undetvar.lobounds.isEmpty() : undetvar;
-
                 undetvar.inst = glb(upperBound(s), undetvar.inst);
+                // We should check instantiated type against any of the
+                // undetvar's lower bounds.
+                for (Type t2 : undetvar.lobounds) {
+                    if (!isSubtype(t2, undetvar.inst))
+                        return false;
+                }
                 return true;
             } else {
                 return isSameType(t, s);

test/tools/javac/generics/wildcards/6651719/T6651719b.java → test/tools/javac/generics/wildcards/6762569/T6762569a.java

@@ -23,14 +23,15 @@
 
 /*
  * @test
- * @bug     6651719
- * @summary Compiler crashes possibly during forward reference of TypeParameter
- * @compile T6651719b.java
+ * @bug     6762569
+ * @summary Javac crashes with AssertionError in Types.containedBy
+ * @compile T6762569a.java
  */
 import java.util.*;
 
-public class T6651719b {
+class T6762569a {
     <T> void m(T t, List<? super List<T>> list) {}
+
     void test(List<? super List<?>> list) {
         m("", list);
     }

test/tools/javac/generics/wildcards/6762569/T6762569b.java

+/*
+ * Copyright 2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ * @test
+ * @bug     6762569
+ * @summary Javac crashes with AssertionError in Types.containedBy
+ * @compile/fail T6762569b.java
+ */
+import java.util.*;
+
+class T6762569b {
+    <T> void m(T t, List<? super List<T>> list) {}
+
+    void test(List<? super List<? extends Number>> list) {
+        m("", list);
+    }
+}