Mastering Go - Second Edition

You either use a Go package or you do not include it

Go has strict rules about package usage. Therefore, you cannot just include any package you might think that you will need and then not use it afterward.

Look at the following naive program, which is saved as packageNotUsed.go:

package main 
 
import ( 
    "fmt" 
    "os" 
) 
 
func main() { 
    fmt.Println("Hello there!") 
} 

In this book, you are going to see lots of error messages, error situations, and warnings. I believe that looking at code that fails to compile is also useful and sometimes even more valuable than just looking at Go code that compiles without any errors. The Go compiler usually displays useful error messages and warnings that will most likely help you to resolve an erroneous situation, ...