C++ :: Freeing Memory Without Destructing

Say we have this crude memory pool that is on the heap:

char* mpool = (char*)malloc(sizeof(char) * 4096);

And we used placement new to construct a couple objects in place:

char* next = mpool;
void* fooptr = new (next) FOO();
next += sizeof(FOO);
void* bazptr = new (next) Baz();
next += sizeof(Baz);

And at the end, let's say the memory is freed without having called the object destructors:

free(mpool);

What exactly happens? I haven't found any page that states what happens in this situation. Does it cause undefined behavior?