assert tree.asAnnotatable().hasAnnotation("holeType");
IConstructor type = (IConstructor) tree.asAnnotatable().getAnnotation("holeType");
tree = (IConstructor) TreeAdapter.getArgs(tree).get(0);
IList args = TreeAdapter.getArgs(tree);
IConstructor nameTree = (IConstructor) args.get(4);
ISourceLocation src = TreeAdapter.getLocation(tree);
Expression result = new Tree.MetaVariable(tree, type, TreeAdapter.yield(nameTree));
result.setSourceLocation(src);
return result;
}