internal javac cast exception when resolving varargs ambiguity

Compiling the following source code will cause an internal ClassCastException in javac.

Uncomment the cast of null to Long in order to compile without the crash.

public class Puke {
    public static void main(String[] args) {
        doit(/* (Long) */ null, new Exception());
    }

    public static void doit(Long l) {
    }

    public static void doit(Exception... exception) {
    }

    public static void doit(Long l, Exception... exception) {
    }
}

The crash error on 1.8.0-ea-b118 is:


java.lang.ClassCastException: com.sun.tools.javac.comp.Resolve$BadVarargsMethod cannot be cast to com.sun.tools.javac.comp.Resolve$AmbiguityError
        at com.sun.tools.javac.comp.Resolve$BasicLookupHelper.lookup(Resolve.java:3058)
        at com.sun.tools.javac.comp.Resolve.lookupMethod(Resolve.java:3307)
        at com.sun.tools.javac.comp.Resolve.lookupMethod(Resolve.java:3292)
        at com.sun.tools.javac.comp.Resolve.resolveMethod(Resolve.java:2361)
        at com.sun.tools.javac.comp.Attr.visitIdent(Attr.java:3129)
        at com.sun.tools.javac.tree.JCTree$JCIdent.accept(JCTree.java:2005)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:597)
        at com.sun.tools.javac.comp.Attr.visitApply(Attr.java:1828)
        at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1459)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:597)
        at com.sun.tools.javac.comp.Attr.attribExpr(Attr.java:646)
        at com.sun.tools.javac.comp.Attr.visitExec(Attr.java:1596)
        at com.sun.tools.javac.tree.JCTree$JCExpressionStatement.accept(JCTree.java:1290)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:597)
        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:666)
        at com.sun.tools.javac.comp.Attr.attribStats(Attr.java:682)
        at com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1127)
        at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:903)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:597)
        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:666)
        at com.sun.tools.javac.comp.Attr.visitMethodDef(Attr.java:1020)
        at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:772)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:597)
        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:666)
        at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:4287)
        at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4197)
        at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4131)
        at com.sun.tools.javac.comp.Attr.attrib(Attr.java:4106)
        at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1251)
        at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:904)
        at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:863)
        at com.sun.tools.javac.main.Main.compile(Main.java:523)
        at com.sun.tools.javac.main.Main.compile(Main.java:381)
        at com.sun.tools.javac.main.Main.compile(Main.java:370)
        at com.sun.tools.javac.main.Main.compile(Main.java:361)
        at com.sun.tools.javac.Main.compile(Main.java:56)
        at com.sun.tools.javac.Main.main(Main.java:42)