Ideally, tools should consult this situation.

I'm not sure I understand what you mean by this.

I'm not sure how godoc works, but I suppose

package xxx

import "fmt"

func b() {
  fmt.Println("B")
}

func ExampleA() {
  fmt.Println("A")
}

func ExampleB() {
  b()
}

godoc can construct complete program for A.

package main

import "fmt"

func main() {
  fmt.Println("A")
}

But, it cannot construct complete program for B. It should emit

package main

import "fmt"

func b() {
  fmt.Println("B")
}

func main() {
  b()
}

I guess?

Change https://golang.org/cl/83615 mentions this issue: go/doc: make examples that depends on top-level decl playable