I wish more language designers paid attention to how Ada did things. The language has some features that are very relevant to performance that even C++ or Rust

I wish more language designers paid attention to how Ada did things. The language has some features that are very relevant to performance that even C++ or Rust lacks. For example, Ada allows to return stack-allocate arrays with variable number of elements. One can emulate that in C++ with various arena classes, but the resulting code is not that efficient and the usage is much more complex.