Comparison of returned errors with nil

Explore how functions returning different error types compare to nil, and predict what values will be printed to the console.

package main

import (
  "fmt"
)

type MyErr struct{}

func (me MyErr) Error() string {
  return "my err string"
}

func main() {
  fmt.Println(returnError() == nil)
  fmt.Println(returnErrorPtr() == nil)

  fmt.Println(returnCustomError() == nil)
  fmt.Println(returnCustomErrorPtr() == nil)

  fmt.Println(returnMyError() == nil)
}

func returnError() error {
  var err error
  return err
}

func returnErrorPtr() *error {
  var err *error
  return err
}

func returnCustomError() error {
  var customErr MyErr
  return customErr
}

func returnCustomErrorPtr() error {
  var customErr *MyErr
  return customErr
}

func returnMyError() *MyErr {
  return nil
}