FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
interface A<T>
{
    T foo();
}

interface B<T>
{
   T foo();
}

interface C<T extends A<?> & B<?>> { }


An exception has occurred in the compiler (1.7.0-ea). Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport) after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.AssertionError: isSubtype 15
at com.sun.tools.javac.code.Types$5.visitType(Types.java:415)
at com.sun.tools.javac.code.Types$5.visitType(Types.java:396)
at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visitWildcardType(Types.java:3667)
at com.sun.tools.javac.code.Type$WildcardType.accept(Type.java:440)
at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visit(Types.java:3665)
at com.sun.tools.javac.code.Types.isSubtype(Types.java:392)
at com.sun.tools.javac.code.Types.isSubtype(Types.java:390)
at com.sun.tools.javac.code.Types.isSubtype(Types.java:368)
at com.sun.tools.javac.code.Types.isSubtypeUnchecked(Types.java:339)
at com.sun.tools.javac.code.Types.isConvertible(Types.java:277)
at com.sun.tools.javac.code.Types.isAssignable(Types.java:1601)
at com.sun.tools.javac.code.Types.covariantReturnType(Types.java:3073)
at com.sun.tools.javac.comp.Check.firstDirectIncompatibility(Check.java:1655)
at com.sun.tools.javac.comp.Check.firstIncompatibility(Check.java:1608)
at com.sun.tools.javac.comp.Check.checkCompatibleAbstracts(Check.java:1586)
at com.sun.tools.javac.comp.Check.checkCompatibleSupertypes(Check.java:2062)
at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:3154)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:3104)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:3040)
at com.sun.tools.javac.comp.Attr.attribBounds(Attr.java:562)
at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:3128)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:3104)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:3040)
at com.sun.tools.javac.comp.Attr.attrib(Attr.java:3014)
at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1182)
at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:870)
at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:829)
at com.sun.tools.javac.main.Main.compile(Main.java:415)
at com.sun.tools.javac.main.Main.compile(Main.java:329)
at com.sun.tools.javac.main.Main.compile(Main.java:320)
at com.sun.tools.javac.Main.compile(Main.java:76)
at com.sun.tools.javac.Main.main(Main.java:61)



REPRODUCIBILITY :
This bug can be reproduced always.