My thought (which is apparently wrong) is that the `const int& x` refers to memory that might be freed during `vector::push_back`. Then, when we go to construct the new element that is a copy of `x`, it might be invalid to read `x`. No?
Is this related to how a reference-to-const on the stack can extend the lifetime of a temporary to which it's bound? I didn't think that function parameters had this property (i.e. an implicit copy).
My thought (which is apparently wrong) is that the `const int& x` refers to memory that might be freed during `vector::push_back`. Then, when we go to construct the new element that is a copy of `x`, it might be invalid to read `x`. No?
Is this related to how a reference-to-const on the stack can extend the lifetime of a temporary to which it's bound? I didn't think that function parameters had this property (i.e. an implicit copy).