| 1 | // Copyright 2020 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 | |
| 7 | package testdata |
| 8 | |
| 9 | import "math/rand" |
| 10 | |
| 11 | type ST struct { |
| 12 | x int |
| 13 | l []int |
| 14 | } |
| 15 | |
| 16 | func (s *ST) SetX(x int, ch chan int) { |
| 17 | // Accidental self-assignment; it should be "s.x = x" |
| 18 | // want "self-assignment of x to x" |
| 19 | // Another mistake |
| 20 | // want "self-assignment of s.x to s.x" |
| 21 | |
| 22 | // want "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 | |
| 31 | func num() int { return 2 } |
| 32 | |
| 33 | func Index() { |
| 34 | s := []int{1} |
| 35 | // want "self-assignment" |
| 36 | |
| 37 | var a [5]int |
| 38 | // want "self-assignment" |
| 39 | |
| 40 | pa := &[2]int{1, 2} |
| 41 | // want "self-assignment" |
| 42 | |
| 43 | var pss *struct { // report self assignment despite nil dereference |
| 44 | s []int |
| 45 | } |
| 46 | // want "self-assignment" |
| 47 | |
| 48 | m := map[int]string{1: "a"} |
| 49 | m[0] = m[0] // bail on map self-assignments due to side effects |
| 50 | m[1] = m[1] // not modeling what elements must be in the map |
| 51 | (m[2]) = (m[2]) // even with parens |
| 52 | type Map map[string]bool |
| 53 | named := make(Map) |
| 54 | named["s"] = named["s"] // even on named maps. |
| 55 | var psm *struct { |
| 56 | m map[string]int |
| 57 | } |
| 58 | psm.m["key"] = psm.m["key"] // handles dereferences |
| 59 | } |
| 60 |
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