Comment by zozbot234

It's precisely when "you have frequently, even in the same expression, dozens of different kinds of additions, multiplications, divisions, etc., between scalars, vectors, matrices, tensors, complex numbers, various kinds of physical quantities, and so on" that operator overloading should be driven by custom syntax macros. (E.g. in a Rust-like language you might define math_expr!(...), float_expr!(...), matrix_expr!(...) etc. syntax macros, each with its own special semantics for operator symbols.) That way a program can directly express the variety of overloading that's relevant in any given context, as opposed to relying on fragile hacks like special __add__ and __mul__ "traits" that are dispatched in a type-dependent way.