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go/test/fixedbugs/issue29190.go
Keith Randall 2493072db6 cmd/compile: avoid assignment conversion in append(a, b...)
There's no need for a and b to match types. The typechecker already
ensured that a and b are both slices with the same base type, or
a and b are (possibly named) []byte and string.

The optimization to treat append(b, make([], ...)) as a zeroing
slice extension doesn't fire when there's a OCONVNOP wrapping the make.
Fixes #53888

Change-Id: Ied871ed0bbb8e4a4b35d280c71acbab8103691bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/418475
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
2022-08-08 16:58:57 +00:00

38 lines
707 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.
package main
import (
"strings"
)
type T struct{}
const maxInt = int(^uint(0) >> 1)
func main() {
s := make([]T, maxInt)
shouldPanic("len out of range", func() { s = append(s, T{}) })
var oneElem = make([]T, 1)
shouldPanic("len out of range", func() { s = append(s, oneElem...) })
}
func shouldPanic(str string, f func()) {
defer func() {
err := recover()
if err == nil {
panic("did not panic")
}
s := err.(error).Error()
if !strings.Contains(s, str) {
panic("got panic " + s + ", want " + str)
}
}()
f()
}