gcc/testsuite/go.test/test/indirect.go

   1 // run
   2
   3 // Copyright 2009 The Go Authors. All rights reserved.
   4 // Use of this source code is governed by a BSD-style
   5 // license that can be found in the LICENSE file.
   6
   7 // Test various safe uses of indirection.
   8
   9 package main
  10
  11 var m0 map[string]int
  12 var m1 *map[string]int
  13 var m2 *map[string]int = &m0
  14 var m3 map[string]int = map[string]int{"a": 1}
  15 var m4 *map[string]int = &m3
  16
  17 var s0 string
  18 var s1 *string
  19 var s2 *string = &s0
  20 var s3 string = "a"
  21 var s4 *string = &s3
  22
  23 var a0 [10]int
  24 var a1 *[10]int
  25 var a2 *[10]int = &a0
  26
  27 var b0 []int
  28 var b1 *[]int
  29 var b2 *[]int = &b0
  30 var b3 []int = []int{1, 2, 3}
  31 var b4 *[]int = &b3
  32
  33 func crash() {
  34         // these uses of nil pointers
  35         // would crash but should type check
  36         println("crash",
  37                 len(a1)+cap(a1))
  38 }
  39
  40 func nocrash() {
  41         // this is spaced funny so that
  42         // the compiler will print a different
  43         // line number for each len call if
  44         // it decides there are type errors.
  45         // it might also help in the traceback.
  46         x :=
  47                 len(m0) +
  48                         len(m3)
  49         if x != 1 {
  50                 println("wrong maplen")
  51                 panic("fail")
  52         }
  53
  54         x =
  55                 len(s0) +
  56                         len(s3)
  57         if x != 1 {
  58                 println("wrong stringlen")
  59                 panic("fail")
  60         }
  61
  62         x =
  63                 len(a0) +
  64                         len(a2)
  65         if x != 20 {
  66                 println("wrong arraylen")
  67                 panic("fail")
  68         }
  69
  70         x =
  71                 len(b0) +
  72                         len(b3)
  73         if x != 3 {
  74                 println("wrong slicelen")
  75                 panic("fail")
  76         }
  77
  78         x =
  79                 cap(b0) +
  80                         cap(b3)
  81         if x != 3 {
  82                 println("wrong slicecap")
  83                 panic("fail")
  84         }
  85 }
  86
  87 func main() { nocrash() }