I keep being impressed at subtle but meaningful things that Go does right.

The reason it feels like a kludge is that "comments" are normally understood to be non-impactful. Is a source transformation that removes all comments valid? If comments have no impact per the spec, yes. But that's not the case here.

In practice comments in go are defined to be able to carry semantic meaning extensibly. Whether they're safe to ignore depends on what meaning is given to the directives, e.g. conditional compilation directives.

(My personal theory is that early go had a somewhat misguided idea of simplicity, and preferred overloading existing concepts with special cases over introducing new keywords. Capitalization for visibility is another example of that.)

This is an impossible task. For a library function, you can't know whether or not the function is defer called.

Maybe this is not an important problem. But it would be better if the blog article mentions this.

It is just a demo.

   package main

   type T = [8]byte
   var a T

   //go:fix inline
   func foo() T {
      return T{}
   }

   func main() {
      if foo() == a {
      }
   }

    package main

    //go:fix inline
    func foo[T [8]byte | [4]uint16]() {
        var v T
        var n byte = 1 << len(v) >> len(v)
        if n == 0 {
            println("T is [8]byte")
        } else {
            println("T is [4]uint16]")
        }
    }

    func main() {
        foo[[8]byte]()
    }