GCC only works in the first case anyway: https://godbolt.org/z/jo57r1MW4 https://godbolt.org/z/jo57r1MW4 One could add in the other too, but language semantics

GCC only works in the first case anyway: https://godbolt.org/z/jo57r1MW4 https://godbolt.org/z/jo57r1MW4 One could add in the other too, but language semantics currently do not allow this. Changing the n later has no impact on the size of the arrays later and the compiler is perfectly able to remember the original size.