Now that templates instantiations are no longer emitted for all modules that even blink at them they seem to break due to being linkonce (if compiled with any optimization level > 0), so let's give them weak linkage instead. The difference is that unreferenced linkonce symbols can be deleted, while weak symbols need to be preserved.

void test(void delegate() spam)
{
    static void foo() // static is the problem
    {
        uint x;
        void peek() { x = 0; }
    }

    void bar()
    {
        spam();
    }
}