A raw reference (a `T&`) is non-owning

Reason

There is nothing (in the C++ standard or in most code) to say otherwise and most raw references are non-owning. We want owners identified so that we can reliably and efficiently delete the objects pointed to by owning pointers.

Example

void f()
{
    int& r = *new int{7};  // bad: raw owning reference
    // ...
    delete &r;             // bad: violated the rule against deleting raw pointers
}

See also: The raw pointer rule

Enforcement

See the raw pointer rule