1// Copyright 2013 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// This file contains tests for the useless-assignment checker.
6
7package assign
8
9import "math/rand"
10
11type ST struct {
12	x int
13	l []int
14}
15
16func (s *ST) SetX(x int, ch chan int) {
17	// Accidental self-assignment; it should be "s.x = x"
18	x = x // ERROR "self-assignment of x to x"
19	// Another mistake
20	s.x = s.x // ERROR "self-assignment of s.x to s.x"
21
22	s.l[0] = s.l[0] // ERROR "self-assignment of s.l.0. to s.l.0."
23
24	// Bail on any potential side effects to avoid false positives
25	s.l[num()] = s.l[num()]
26	rng := rand.New(rand.NewSource(0))
27	s.l[rng.Intn(len(s.l))] = s.l[rng.Intn(len(s.l))]
28	s.l[<-ch] = s.l[<-ch]
29}
30
31func num() int { return 2 }
32