Wouldn’t uniform call syntax (like in D) solve most of the issues outlined above? I.e. it always boils down to “primitive types can’t have methods”; but uniform call syntax would let us call any function like a method on its first argument...

Or just allow methods to be defined on primitive types, like Rust.

Uniform call syntax is a superset of that, since you can’t have virtual methods on primitive types.

That's why I cannot wait for concepts