-- go.mod --
module example.com
go 1.18

-- template/template.go --
package template

// Basic test of expression refactoring.
// (Types are not important in this case; it could be done with gofmt -r.)

import "time"

func before(t time.Time) time.Duration { return time.Now().Sub(t) }
func after(t time.Time) time.Duration  { return time.Since(t) }

-- in/b1/b1.go --
package b1

import "time"

var startup = time.Now()

func example() time.Duration {
	before := time.Now()
	time.Sleep(1)
	return time.Now().Sub(before)
}

func msSinceStartup() int64 {
	return int64(time.Now().Sub(startup) / time.Millisecond)
}

-- out/b1/b1.go --
package b1

import "time"

var startup = time.Now()

func example() time.Duration {
	before := time.Now()
	time.Sleep(1)
	return time.Since(before)
}

func msSinceStartup() int64 {
	return int64(time.Since(startup) / time.Millisecond)
}