env GOPRIVATE=test/main

garble -debugdir ./test1 build
exists 'test1/test/main/imported/imported.go' 'test1/main/main.go'
! grep ImportedFunc $WORK/test1/test/main/imported/imported.go
! grep ImportedFunc $WORK/test1/main/main.go

-- go.mod --
module test/main
-- main.go --
package main

import "test/main/imported"

func main() {
	imported.ImportedFunc()
}

-- imported/imported.go --
package imported

func ImportedFunc() {}