env GOPRIVATE=test/main

garble build
exec ./main
! stdout 'main.go|other_file_name|is sorted'

[short] stop # no need to verify this with -short

go build
exec ./main
stdout 'main.go'
stdout 'other_file_name'
stdout ':19: main'
stdout 'initLines is sorted'
stdout 'varLines is sorted'

-- go.mod --
module test/main

go 1.15
-- main.go --
package main

import (
	"fmt"
	"runtime"
	"sort"
)

var _, globalFile, globalLine, _ = runtime.Caller(0)

func init() {
	_, file, line, _ := runtime.Caller(0)
	fmt.Printf("%s:%d: init\n", file, line)
}

func main() {
	fmt.Printf("%s:%d: global\n", globalFile, globalLine)

	_, file, line, _ := runtime.Caller(0)
	fmt.Printf("%s:%d: main\n", file, line)

	funcDecl()
	funcVar()

	// initLines is filled by ten consecutive funcs.
	// If we are not shuffling or obfuscating line numbers,
	// this list will be sorted.
	// If we are, it's extremely unlikely it would remain sorted.
	if sort.IsSorted(sort.IntSlice(initLines)) {
		fmt.Println("initLines is sorted")
	}

	// Same as the above, but with vars.
	if sort.IsSorted(sort.IntSlice(varLines)) {
		fmt.Println("varLines is sorted")
	}
}
-- other_file_name.go --
package main

import (
	"fmt"
	"runtime"
)

func funcDecl() {
	_, file, line, _ := runtime.Caller(0)
	fmt.Printf("%s:%d: func\n", file, line)
}

var funcVar = func() {
	_, file, line, _ := runtime.Caller(0)
	fmt.Printf("%s:%d: func var\n", file, line)
}

var initLines []int

func curLine() int {
	_, _, line, _ := runtime.Caller(1)
	return line
}

func init() { initLines = append(initLines, curLine()) }
func init() { initLines = append(initLines, curLine()) }
func init() { initLines = append(initLines, curLine()) }
func init() { initLines = append(initLines, curLine()) }
func init() { initLines = append(initLines, curLine()) }
func init() { initLines = append(initLines, curLine()) }
func init() { initLines = append(initLines, curLine()) }
func init() { initLines = append(initLines, curLine()) }
func init() { initLines = append(initLines, curLine()) }
func init() { initLines = append(initLines, curLine()) }

var varLine0 = curLine()
var varLine1 = curLine()
var varLine2 = curLine()
var varLine3 = curLine()
var varLine4 = curLine()
var varLine5 = curLine()
var varLine6 = curLine()
var varLine7 = curLine()
var varLine8 = curLine()
var varLine9 = curLine()

var varLines = []int{
	varLine0, varLine1, varLine2, varLine3, varLine4,
	varLine5, varLine6, varLine7, varLine8, varLine9,
}