assert value != null : Debug.show(symbol);
assert value != null : Debug.show(symbol) + " -> " + value;
    private Override loadOwnerOverridesThenGet(Symbol symbol) {        assert Debug.log("search override: ", symbol);        assert symbol.owner().isType() : Debug.show(symbol);        loadTemplateOverrides(symbol.owner());        Object value = overrides.get(symbol);        assert value != null : Debug.show(symbol);        return (Override)value;    }