If you insist on point 3, you must also suggest a working alternative. As I've explained in a previous post, the assignment proposal is not equivalent in capability to the signature matching approach. Here is a challenge - how would you define a minimalistic version of the `Stack[T]` concept including only the `push` and `pop` operations where the `pop` operation takes a var output param and returns a bool, indicating that the stack was not empty and the pop was successful?
Regarding the implementation complexity, you can see from the code that only minor modifications is `sigmatch` were necessary - there is no backtracking if I understand correctly what you mean.
