"delete" asserts in debug build, multiple inheritance (msvc 7.1)

Note: cross-posted [comp.lang.c++] and [microsoft.public.vc.language].
Feel free to set follow-ups as appropriate (I don't know at this point).

<code>
struct Foo
{
     virtual ~Foo() {} // Seemingly works without this destructor.
};

template< typename T >
struct Wrapper: T, Foo
{
     Wrapper(): T() {}
     virtual ~Wrapper() {} // This destructor doesn't seem to matter.
};

struct Naughty
{
     //virtual ~Naughty() {} // Seemingly works with this destructor.
};

int main()
{
     typedef Wrapper<Naughty> X; // This is irrelevant.
     X* p = new X;
     delete p; // !!! Blows up with MSVC 7.1 debug build.
}
</code>

<build>
     cl /nologo /GX /GR /MDd main.cpp
</build>

<effect>
     A big bad Bill-Box pops up, saying that there's DAMAGE: after block so
     and so (the allocated block). Debugger lands on line 1165 in [dbgheap.c],
     but evidently that box is produced by 1151, which at least matches the text.
     This is, naturally, in function _free_dbg, called after destructors have
     run successfully (at least, that's what I believe).
</effect>

Some help would be nice. The fixes indicated above makes the problem go away.
However, the original code that this example is condensed from, can't rely on
class Naughty having a virtual destructor (or rather, it can require that, but
it would be a little impractical, almost offensive, since no logical reason?).

Help, please,

- Alf

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