libgo/go/cmd/vet/testdata/rangeloop.go

   1 // Copyright 2012 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 rangeloop checker.
   6
   7 package testdata
   8
   9 func RangeLoopTests() {
  10         var s []int
  11         for i, v := range s {
  12                 go func() {
  13                         println(i) // ERROR "loop variable i captured by func literal"
  14                         println(v) // ERROR "loop variable v captured by func literal"
  15                 }()
  16         }
  17         for i, v := range s {
  18                 defer func() {
  19                         println(i) // ERROR "loop variable i captured by func literal"
  20                         println(v) // ERROR "loop variable v captured by func literal"
  21                 }()
  22         }
  23         for i := range s {
  24                 go func() {
  25                         println(i) // ERROR "loop variable i captured by func literal"
  26                 }()
  27         }
  28         for _, v := range s {
  29                 go func() {
  30                         println(v) // ERROR "loop variable v captured by func literal"
  31                 }()
  32         }
  33         for i, v := range s {
  34                 go func() {
  35                         println(i, v)
  36                 }()
  37                 println("unfortunately, we don't catch the error above because of this statement")
  38         }
  39         for i, v := range s {
  40                 go func(i, v int) {
  41                         println(i, v)
  42                 }(i, v)
  43         }
  44         for i, v := range s {
  45                 i, v := i, v
  46                 go func() {
  47                         println(i, v)
  48                 }()
  49         }
  50         // If the key of the range statement is not an identifier
  51         // the code should not panic (it used to).
  52         var x [2]int
  53         var f int
  54         for x[0], f = range s {
  55                 go func() {
  56                         _ = f // ERROR "loop variable f captured by func literal"
  57                 }()
  58         }
  59         type T struct {
  60                 v int
  61         }
  62         for _, v := range s {
  63                 go func() {
  64                         _ = T{v: 1}
  65                         _ = []int{v: 1} // ERROR "loop variable v captured by func literal"
  66                 }()
  67         }
  68
  69         // ordinary for-loops
  70         for i := 0; i < 10; i++ {
  71                 go func() {
  72                         print(i) // ERROR "loop variable i captured by func literal"
  73                 }()
  74         }
  75         for i, j := 0, 1; i < 100; i, j = j, i+j {
  76                 go func() {
  77                         print(j) // ERROR "loop variable j captured by func literal"
  78                 }()
  79         }
  80         type cons struct {
  81                 car int
  82                 cdr *cons
  83         }
  84         var head *cons
  85         for p := head; p != nil; p = p.next {
  86                 go func() {
  87                         print(p.car) // ERROR "loop variable p captured by func literal"
  88                 }()
  89         }
  90 }