1 files changed, 117 insertions, 0 deletions
diff --git a/test/fixedbugs/issue22881.go b/test/fixedbugs/issue22881.go
new file mode 100644
index 0000000..645f2d4
--- /dev/null
+++ b/test/fixedbugs/issue22881.go
@@ -0,0 +1,117 @@
+// run
+
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Test to make sure RHS is evaluated before map insert is started.
+// The RHS panics in all of these cases.
+
+package main
+
+import "fmt"
+
+func main() {
+	for i, f := range []func(map[int]int){
+		f0, f1, f2, f3, f4, f5, f6, f7, f8,
+	} {
+		m := map[int]int{}
+		func() { // wrapper to scope the defer.
+			defer func() {
+				recover()
+			}()
+			f(m) // Will panic. Shouldn't modify m.
+			fmt.Printf("RHS didn't panic, case f%d\n", i)
+		}()
+		if len(m) != 0 {
+			fmt.Printf("map insert happened, case f%d\n", i)
+		}
+	}
+
+	// Append slice.
+	for i, f := range []func(map[int][]int){
+		fa0, fa1, fa2, fa3,
+	} {
+		m := map[int][]int{}
+		func() { // wrapper to scope the defer.
+			defer func() {
+				recover()
+			}()
+			f(m) // Will panic. Shouldn't modify m.
+			fmt.Printf("RHS didn't panic, case fa%d\n", i)
+		}()
+		if len(m) != 0 {
+			fmt.Printf("map insert happened, case fa%d\n", i)
+		}
+	}
+}
+
+func f0(m map[int]int) {
+	var p *int
+	m[0] = *p
+}
+
+func f1(m map[int]int) {
+	var p *int
+	m[0] += *p
+}
+
+func f2(m map[int]int) {
+	var p *int
+	sink, m[0] = sink, *p
+}
+
+func f3(m map[int]int) {
+	var p *chan int
+	m[0], sink = <-(*p)
+}
+
+func f4(m map[int]int) {
+	var p *interface{}
+	m[0], sink = (*p).(int)
+}
+
+func f5(m map[int]int) {
+	var p *map[int]int
+	m[0], sink = (*p)[0]
+}
+
+func f6(m map[int]int) {
+	var z int
+	m[0] /= z
+}
+
+func f7(m map[int]int) {
+	var a []int
+	m[0] = a[0]
+}
+
+func f8(m map[int]int) {
+	var z int
+	m[0] %= z
+}
+
+func fa0(m map[int][]int) {
+	var p *int
+	m[0] = append(m[0], *p)
+}
+
+func fa1(m map[int][]int) {
+	var p *int
+	sink, m[0] = !sink, append(m[0], *p)
+}
+
+func fa2(m map[int][]int) {
+	var p *int
+	m[0], _ = append(m[0], 0), *p
+}
+
+func fa3(m map[int][]int) {
+	// OSLICE has similar in-place-reassignment
+	// optimizations as OAPPEND, but we need to make sure
+	// to *not* optimize them, because we can't guarantee
+	// the slice indices are within bounds.
+	m[0] = m[0][:1]
+}
+
+var sink bool