Error Wrapping (Go 1.13+)

Go allows wrapping and unwrapping errors using fmt.Errorf

import "fmt"

func loadConfig() error {
    err := readFile()
    if err != nil {
        return fmt.Errorf("failed to load config: %w", err)
    }
    return nil
}

You can then use errors.Is or errors.As to check wrapped errors.