blob: 37f2a59e4499f9ab00fff69289e5c67c4369bc2f [file] [log] [blame]
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
type Exported interface {
type Implementation struct{}
func (p *Implementation) private() { println("main.Implementation.private()") }
func main() {
// nothing unusual here
var x Exported
x = new(Implementation)
x.private() // main.Implementation.private()
// same here - should be and is legal
var px p.Exported
px = p.X
// this assignment is correctly illegal:
// px.private undefined (cannot refer to unexported field or method private)
// px.private()
// this assignment is correctly illegal:
// *Implementation does not implement p.Exported (missing p.private method)
// px = new(Implementation)
// this assignment is correctly illegal:
// p.Exported does not implement Exported (missing private method)
// x = px
// this assignment unexpectedly compiles and then executes
x = px.(Exported) // ERROR "does not implement"
// this is a legitimate call, but because of the previous assignment,
// it invokes the method private in p!
x.private() // p.Implementation.private()