As I mentioned, it's not just for avoiding cryptic error messages, though I am not sure if we're even referring the same thing as this is a completely different

As I mentioned, it's not just for avoiding cryptic error messages, though I am not sure if we're even referring the same thing as this is a completely different one from linker errors. Believe me, improving the output doesn't help that much. Hundreds of C++ compiler developer have been trying that for tens of years. None of them has succeed to the level of making a novice understands what's going on when they give sort(list) to the compiler. To iterate my point, it serves as a "contract" between users and the code author. Without this, any user of a generic function will implicitly depend on its implementation, which creates tight coupling. Cryptic error messages or unintentional breakage are just undesired side effects from not having this clear boundary. So, the interface of generic functions needs to be explained to its users anyway; then why not making this understandable to compiler and prevent users from making such mistakes?