1 // Copyright 2011 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package main 6 7 import ( 8 "./p" 9 ) 10 11 type Exported interface { 12 private() 13 } 14 15 type Implementation struct{} 16 17 func (p *Implementation) private() {} 18 19 20 func main() { 21 // nothing unusual here 22 var x Exported 23 x = new(Implementation) 24 x.private() // main.Implementation.private() 25 26 // same here - should be and is legal 27 var px p.Exported 28 px = p.X 29 30 // this assignment is correctly illegal: 31 // px.private undefined (cannot refer to unexported field or method private) 32 // px.private() 33 34 // this assignment is correctly illegal: 35 // *Implementation does not implement p.Exported (missing p.private method) 36 // px = new(Implementation) 37 38 // this assignment is correctly illegal: 39 // p.Exported does not implement Exported (missing private method) 40 // x = px 41 42 // this assignment unexpectedly compiles and then executes 43 defer func() { 44 recover() 45 }() 46 x = px.(Exported) 47 48 println("should not get this far") 49 50 // this is a legitimate call, but because of the previous assignment, 51 // it invokes the method private in p! 52 x.private() // p.Implementation.private() 53 } 54
