A Numeric Type for Go?

When programmers complain about the lack of generics in Go, a common mitigation proposed is to use a interface. In many cases, it's possible to find an operation common to all the types to be supported; in the worst case, an empty interface can be used.

This doesn't satisfy many Go programmers, so a proposal for generic types has been made, containing the contract keyword:

    contract Ordinal(t T) {
        t < t
    }

So a contract looks basically like an interface, which doesn't require a type to implement a certain method, but to support the use of certain operations on it.

When I think of operations and types that apply to them in Go, the following categories come to my mind:

1. Equality, expressed by == and !=, which is supported by most Go expressions. 2. +, which adds up numbers and concatenates strings. 3. Other operations for arithmetics and comparison: -, *, /, %, <, >, <=, >=. 4. Accessors and qualifiers: . and []

Complaints about the lack of generics in Go are often heard from programmers that want to implement numeric libraries. They basically want a type, which support the operations of the first three categories, which are basically the numeric types: integer, floating point and complex numbers.

So an abstract "numeric" or "number" type could eliminate a lot of the use cases for contracts. Is this an option being considered? Or isn't there just any benefit over using the double type for numeric computations?