splice() should take template instead of slist&

[vinipsmaker]

I have something like follows:

class Parent : public slist_base_hook<>
{
    // virtual destructor, etc
};

class Child : public Parent
{};

slist<Parent> storage;
slist<Child> temporaries;

I need to move all elements from temporaries to storage at the end of a function. I've tried to use splice(), but it doesn't work because it expects a slist of the same type as *this.

[igaztanaga]

Logically it could make sense to "upcast", as you suggest. In theory this operation could be also applied to other operations like move constructor or assignment. I'll need to further investigate the implicatons and if this could break container invariants in corner cases.