[thelinked]

An interesting example of C++ not being able to introduce new keywords is the co-opting of auto in C++11 from a storage class to type deduction.

[ninkendo]

But they had a decent justification: the auto keyword literally did nothing in C++. The only place it was valid, it was also the default.

[danielweber]

IIRC they audited a bunch of projects to see if anyone was using auto somewhere besides test code explicitly for the auto-keyword, and found nothing.