6948381: javac Null Pointer Exception in Types.makeCompoundType

Summary: Race condition between symbol completion and attribution of import statements causes NPE when creating intersection type
Reviewed-by: jjg

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

@@ -1861,13 +1861,16 @@ public class Types {
 
     /**
      * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
-     * third parameter is computed directly.  Note that this test
-     * might cause a symbol completion.  Hence, this version of
+     * third parameter is computed directly, as follows: if all
+     * all bounds are interface types, the computed supertype is Object,
+     * otherwise the supertype is simply left null (in this case, the supertype
+     * is assumed to be the head of the bound list passed as second argument).
+     * Note that this check might cause a symbol completion. Hence, this version of
      * setBounds may not be called during a classfile read.
      */
     public void setBounds(TypeVar t, List<Type> bounds) {
         Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
-            supertype(bounds.head) : null;
+            syms.objectType : null;
         setBounds(t, bounds, supertype);
         t.rank_field = -1;
     }

test/tools/javac/6948381/T6948381.java

+/*
+ * Copyright 2010 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 6948381
+ * @summary javac Null Pointer Exception in Types.makeCompoundType
+ * @compile npe/A.java npe/B.java
+ */

test/tools/javac/6948381/npe/A.java

+/*
+ * Copyright 2010 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.
+ */
+
+package npe;
+
+import npe.B.*;
+
+public interface A {}

test/tools/javac/6948381/npe/B.java

+/*
+ * Copyright 2010 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.
+ */
+
+package npe;
+
+public interface B<T extends A & java.io.Serializable> {}