class Coerce(object):
    @staticmethod
    def bool(space, w_obj):
        return space.is_true(w_obj)

    @staticmethod
    def symbol(space, w_obj):
        if space.is_kind_of(w_obj, space.w_symbol):
            return space.symbol_w(w_obj)
        else:
            w_str = space.convert_type(w_obj, space.w_string, "to_str", raise_error=False)
            if w_str is space.w_nil:
                w_inspect_str = space.send(w_obj, space.newsymbol("inspect"))
                if not space.is_kind_of(w_inspect_str, space.w_string):
                    inspect_str = space.any_to_s(w_obj)
                else:
                    inspect_str = space.str_w(w_inspect_str)
                raise space.error(space.w_TypeError, "%s is not a symbol" % inspect_str)
            else:
                return space.str_w(w_str)

    @staticmethod
    def int(space, w_obj):
        if space.is_kind_of(w_obj, space.w_fixnum):
            return space.int_w(w_obj)
        else:
            return space.int_w(space.convert_type(w_obj, space.w_integer, "to_int"))

    @staticmethod
    def bigint(space, w_obj):
        return space.bigint_w(w_obj)

    @staticmethod
    def float(space, w_obj):
        if space.is_kind_of(w_obj, space.w_float):
            return space.float_w(w_obj)
        else:
            return space.float_w(space.send(w_obj, space.newsymbol("Float"), [w_obj]))

    @staticmethod
    def str(space, w_obj):
        if space.is_kind_of(w_obj, space.w_string) or space.is_kind_of(w_obj, space.w_symbol):
            return space.str_w(w_obj)
        else:
            return space.str_w(space.convert_type(w_obj, space.w_string, "to_str"))

    @staticmethod
    def path(space, w_obj):
        string = Coerce.str(space, w_obj)
        if '\0' in string:
            raise space.error(space.w_ArgumentError, "string contains null byte")
        else:
            return string

@@ -1,8 +1,55 @@
+from rpython.rlib.rstring import assert_str0%0A%0A%0A
 class Co
@@ -1808,12 +1808,14 @@
  if 
-'%5C0'
+%22%5Cx00%22
  in 
@@ -1937,15 +1937,28 @@
  return 
+assert_str0(
 string
+)
 %0A

make sure to mark this very clearly as str0