| package main // OMIT | |
| import "fmt" | |
| type I interface { | |
| Key() string | |
| Value() string | |
| } | |
| type S struct{ I } // S has method sets of I. | |
| func (s S) Key() string { return "type S" } | |
| func main() { | |
| var s S | |
| fmt.Println("key", s.Key()) | |
| fmt.Println(s.Value()) // runtime error: invalid memory address or nil pointer deference // HL | |
| } |