Javac crashes When compilin the following simple program:

class Foo<X> { X x; }
class Bug {
    public void m(Foo<String> f) {
        f.x += f.x;
    }
}

Here's the output:

/usr/lib/jvm/java-7-openjdk/bin/javac EchoImpl.java -XDverboseCompilePolicy
[attribute Foo]
[flow Foo]
[desugar Foo]
[generate code Foo]
[attribute Bug]
[flow Bug]
[desugar Bug]
[generate code Bug]
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: store unsupported: stack(object)
at com.sun.tools.javac.jvm.Items$Item.store(Items.java:212)
at com.sun.tools.javac.jvm.Items$AssignItem.drop(Items.java:715)
at com.sun.tools.javac.jvm.Gen.visitExec(Gen.java:1628)
at com.sun.tools.javac.tree.JCTree$JCExpressionStatement.accept(JCTree.java:1145)
at com.sun.tools.javac.jvm.Gen.genDef(Gen.java:683)
at com.sun.tools.javac.jvm.Gen.genStat(Gen.java:718)
at com.sun.tools.javac.jvm.Gen.genStat(Gen.java:704)
at com.sun.tools.javac.jvm.Gen.genStats(Gen.java:755)
at com.sun.tools.javac.jvm.Gen.visitBlock(Gen.java:1030)
at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:768)
at com.sun.tools.javac.jvm.Gen.genDef(Gen.java:683)
at com.sun.tools.javac.jvm.Gen.genStat(Gen.java:718)
at com.sun.tools.javac.jvm.Gen.genMethod(Gen.java:911)
at com.sun.tools.javac.jvm.Gen.visitMethodDef(Gen.java:884)
at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:655)
at com.sun.tools.javac.jvm.Gen.genDef(Gen.java:683)
at com.sun.tools.javac.jvm.Gen.genClass(Gen.java:2269)
at com.sun.tools.javac.main.JavaCompiler.genCode(JavaCompiler.java:695)
at com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1372)
at com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1340)
at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:848)
at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:810)
at com.sun.tools.javac.main.Main.compile(Main.java:400)
at com.sun.tools.javac.main.Main.compile(Main.java:318)
at com.sun.tools.javac.main.Main.compile(Main.java:309)
at com.sun.tools.javac.Main.compile(Main.java:82)
at com.sun.tools.javac.Main.main(Main.java:67)