go/test/fixedbugs/issue23188.go
Ian Lance Taylor d49572eaf3 test: add order of evaluation test case that gccgo got wrong
Updates #23188

Change-Id: Idc5567546d1c4c592f997a4cebbbf483b85331e0
Reviewed-on: https://go-review.googlesource.com/123115
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-07-10 21:30:26 +00:00

32 lines
943 B
Go

// run
// Copyright 2018 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 order of evaluation of index operations.
package main
func main() {
arr := []int{1, 2}
// The spec says that in an assignment statement the operands
// of all index expressions and pointer indirections on the
// left, and the expressions on the right, are evaluated in
// the usual order. The usual order means function calls and
// channel operations are done first. Then the assignments are
// carried out one at a time. The operands of an index
// expression include both the array and the index. So this
// evaluates as
// tmp1 := arr
// tmp2 := len(arr) - 1
// tmp3 := len(arr)
// arr = arr[:tmp3-1]
// tmp1[tmp2] = 3
arr, arr[len(arr)-1] = arr[:len(arr)-1], 3
if len(arr) != 1 || arr[0] != 1 || arr[:2][1] != 3 {
panic(arr)
}
}