Nil Interfaces

What will be printed when the code below is executed?And explain why println(InitType() == nil) cannot be compiled? 

  1. package main
  3. type S struct{}
  5. func (s S) F() {}
  7. type IF interface {
  8.     F()
  9. }
  11. func InitType() S {
  12.     var s S
  13.     return s
  14. }
  16. func InitPointer() *S {
  17.     var s *S
  18.     return s
  19. }
  20. func InitEfaceType() interface{} {
  21.     var s S
  22.     return s
  23. }
  25. func InitEfacePointer() interface{} {
  26.     var s *S
  27.     return s
  28. }
  30. func InitIfaceType() IF {
  31.     var s S
  32.     return s
  33. }
  35. func InitIfacePointer() IF {
  36.     var s *S
  37.     return s
  38. }
  40. func main() {
  41.     //println(InitType() == nil)
  42.     println(InitPointer() == nil)
  43.     println(InitEfaceType() == nil)
  44.     println(InitEfacePointer() == nil)
  45.     println(InitIfaceType() == nil)
  46.     println(InitIfacePointer() == nil)
  47. }

Answer

  1. true
  2. false
  3. false
  4. false
  5. false