[ynfnehf]

This usage of VLAs is once again mandatory for compilers to support, since C23. From Wikipedia: "Variably-modified types (but not VLAs which are automatic variables allocated on the stack) become a mandatory feature".

[pjmlp]

Oh well...

[ynfnehf]

At least it is still optional to allow for stack allocated VLAs. Which is the attack vector you mentioned.

[legalcorrection]

Tell me, what’s wrong with variably modified types specifically?

[mananaysiempre]

Sizeof, which used to be one of the very few things you could blindly do to an arbitrary (potentially UB-provoking) expression, can now have side effects.