Why not just fix it? It's a trivial fix and has the added benefit that a zero-initialized DYN_ARR_OF(x) struct would be in a valid state, which is always nice.

Why not just fix it? It's a trivial fix and has the added benefit that a zero-initialized DYN_ARR_OF(x) struct would be in a valid state, which is always nice. A struct with several dynamic arrays can then much simpler to initialize, for example.