Incorrect slice indexing doesn't panic

[ofw]

Please answer these questions before submitting your issue. Thanks!

What version of Go are you using?

go1.11 darwin/amd64

Does this issue reproduce with the latest release?

yes. It is reproduced only with go 1.11

What operating system and processor architecture are you using?

GOARCH="amd64"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/Cellar/go/1.11/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.11/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/n3/mmrp5zqs4l32jk1bnxghymkh0000gn/T/go-build253851043=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

package main

import "fmt"

func main() {
	slice := make([]int, 0)
	if len(slice) > 10 {
		slice = append(slice, 1)
	}
	fmt.Println(slice[len(slice)-1])
}

What did you expect to see?

panic: runtime error: index out of range

goroutine 1 [running]:
main.main()
	/tmp/sandbox394962805/main.go:10 +0x20

What did you see instead?

0

Process finished with exit code 0

[ofw]

duplicates #27378