[wahern]

WG14 adopted variably modified types, a kind of dependent type. From a security standpoint it offers all the same qualities. It also in principle was easier to integrate from a backwards compatibility standpoint, with the exception of struct member analogs (which we now have but aren't yet standardized).

Maybe we would have been better off with Ritchie's counter proposal. But neither proposal was chiefly concerned with security, thus no proposals for, e.g., automatic bounds checking.

[wahern]

Just to be clear, I often think we would have been better off with Ritchie's proposal, assuming it would have seen at least as much adoption in implementations and usage as variably modified types, which sadly remained poor for many years after C99, and arguably still poor. But being better off doesn't mean being in a drastically better situation than we are today from a security perspective. The proposed alternatives were prerequisites for substantively improving security, but far from sufficient. And the delay in adopting and refining variably-modified types has cost much more than whatever marginal benefit Ritchie's proposal offered. Ditto for other gaps, like better facilities for handling arithmetic, e.g. overflow and mixed type comparisons. The first step in addressing overflow only came with C23 (overflow checking routines), and the latter only in the forthcoming C2y (typesafe, mixed-signedness min/max, etc).

[uecker]

The support for variably modified types is excellent, if you discount MSVC which is lacking support for modern C anyway (it seems to catch up a bit though).

[wahern]

Real-world usage certainly remains poor. Using pointers to VM types remains annoying, and I wish the committee would settle on a solution to the ordering of VM parameters. But, yeah, the VM types are solid in GCC and clang and should be used more.