1 // run 2 3 // Copyright 2017 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 to make sure RHS is evaluated before map insert is started. 8 // The RHS panics in all of these cases. 9 10 package main 11 12 import "fmt" 13 14 func main() { 15 for i, f := range []func(map[int]int){ 16 f0, f1, f2, f3, f4, f5, f6, f7, 17 } { 18 m := map[int]int{} 19 func() { // wrapper to scope the defer. 20 defer func() { 21 recover() 22 }() 23 f(m) // Will panic. Shouldn't modify m. 24 fmt.Printf("RHS didn't panic, case f%d\n", i) 25 }() 26 if len(m) != 0 { 27 fmt.Printf("map insert happened, case f%d\n", i) 28 } 29 } 30 } 31 32 func f0(m map[int]int) { 33 var p *int 34 m[0] = *p 35 } 36 37 func f1(m map[int]int) { 38 var p *int 39 m[0] += *p 40 } 41 42 func f2(m map[int]int) { 43 var p *int 44 sink, m[0] = sink, *p 45 } 46 47 func f3(m map[int]int) { 48 var p *chan int 49 m[0], sink = <-(*p) 50 } 51 52 func f4(m map[int]int) { 53 var p *interface{} 54 m[0], sink = (*p).(int) 55 } 56 57 func f5(m map[int]int) { 58 var p *map[int]int 59 m[0], sink = (*p)[0] 60 } 61 62 func f6(m map[int]int) { 63 var z int 64 m[0] /= z 65 } 66 67 func f7(m map[int]int) { 68 var a []int 69 m[0] = a[0] 70 } 71 72 var sink bool 73
