While this is a standalone proposal, it is motivated by the go2 generics proposal (issue and doc). The connection between this proposal and generics is presented here (originally here).
In go, one can convert any type to another with the same type definition: type A int; var _ = A(int(1)) is perfectly valid (play).
original github issue and discussion
This document presents a solution on how to introduce read only and immutability support in go2. It is split into two parts:
Golang compiles fast, and this is an important feature when it is compared to other languages. The draft design makes a small reference to compile time performance implementation and efficiency but I believe this has to be clarified further.
Let me address the quote "In other words, this design permits people to stop choosing slow programmers, and permits the implementation to decide between slow compilers (compile each set of type arguments separately) or slow execution times (use method calls for each operation on a value of a type argument)". "Slow programmers" is the current 'do it your own way approach', which is largely agreed is not good enough. But "slow execution times", also referred to as