// run
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Ensure that range loops over maps with delete statements
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// have the requisite side-effects.
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package main
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import (
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"fmt"
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"os"
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)
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func checkcleared() {
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m := make(map[byte]int)
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m[1] = 1
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m[2] = 2
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for k := range m {
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delete(m, k)
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}
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l := len(m)
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if want := 0; l != want {
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fmt.Printf("len after map clear = %d want %d\n", l, want)
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os.Exit(1)
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}
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m[0] = 0 // To have non empty map and avoid internal map code fast paths.
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n := 0
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for range m {
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n++
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}
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if want := 1; n != want {
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fmt.Printf("number of keys found = %d want %d\n", n, want)
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os.Exit(1)
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}
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}
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func checkloopvars() {
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k := 0
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m := make(map[int]int)
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m[42] = 0
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for k = range m {
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delete(m, k)
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}
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if want := 42; k != want {
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fmt.Printf("var after range with side-effect = %d want %d\n", k, want)
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os.Exit(1)
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}
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}
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func checksideeffects() {
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var x int
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f := func() int {
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x++
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return 0
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}
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m := make(map[int]int)
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m[0] = 0
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m[1] = 1
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for k := range m {
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delete(m, k+f())
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}
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if want := 2; x != want {
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fmt.Printf("var after range with side-effect = %d want %d\n", x, want)
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os.Exit(1)
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}
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var n int
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m = make(map[int]int)
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m[0] = 0
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m[1] = 1
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for k := range m {
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delete(m, k)
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n++
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}
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if want := 2; n != want {
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fmt.Printf("counter for range with side-effect = %d want %d\n", n, want)
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os.Exit(1)
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}
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}
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func main() {
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checkcleared()
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checkloopvars()
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checksideeffects()
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}
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