[neonsunset]

This does not hard-crash on an empty array[0] but can still cause bad UB and eventually crash should it point past allocated memory page or to other random data (spec allows to have a byref that would point to the last element of array if it were one element longer, but such dereference out of bounds is still UB).

Covariance is unfortunate choice of arrays of T where T is class and is widely considered a mistake today. When you pass Memory<T> or Span<T>, there are no covariance checks involved as they disallow it.

It is also less of an issue in .NET in general because quite often T is a struct instead, which does not have covariance in the OOP meaning of the word (old-style int[] to uint[] casts are just reinterprets, they are frowned upon luckily and few codebases use them).

[0] https://sharplab.io/#v2:EYLgtghglgdgNAFxAJwK4wD4AEBMBGAWACgs...