New in this month's Overload magazine:

The power of ref-qualifiers

by Andreas Fertig

From the article:

... What I have illustrated is that there is an issue with range-based for-loops. In (1), we call GetKeeper().items() in the head of the range-based for-loop. By doing this, we create a dangling reference.

ref-qualifiers to the rescue

Now, this brings us to ref-qualifiers. They are often associated with move semantics, but we can use them without move. However, we will soon see why ref-qualifiers make the most sense with move semantics.

A version of Keeper with ref-qualifiers looks like Listing 2...