[Bug c++/67561] [C++14] ICE in tsubst_copy (nested auto lambdas may be involved)

[bisqwit at iki dot fi]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67561

--- Comment #1 from Joel Yliluoma <bisqwit at iki dot fi> ---
Further reduced example:

    template<typename PlotFunc>
    void DrawView(PlotFunc GetPlotFunc)
    {
        GetPlotFunc(1)(2);
    }

    void CalculateLightmap()
    {
        auto LightmapRenderer = [](unsigned round)
        {
            return [round](const auto& view)
            {
                return [=](auto prop)
                {
                    round + 0;
                };
            };
        };

        DrawView(LightmapRenderer(0));
    }

Replacing the [=] with [] or [&] retains the error. Replacing it with [round]
removes the error.