What version of Go are you using (go version)?

$ go version
go version go1.10.3 linux/amd64

Does this issue reproduce with the latest release?

not sure

What operating system and processor architecture are you using (go env)?

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/niko/.cache/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/niko/go"
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
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 -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build605005347=/tmp/go-build -gno-record-gcc-switches"

What did you do?

play.golang.org link is below:
https://play.golang.org/p/SAooamwMWuc

line1: rear := result[id:]
line2: front := result[:id]
line3: temp := append(front, item)
line4: result = append(temp, rear...)

the bug of "append" is : before it execute the line 3, the rear equals to [-4, 2, 2], after it execute the line 4, the rear equals to [-3, 1, 3] for no reason which is really weird

What did you expect to see?

the expect result is : after it execute the line3, the variable rear won't change. and the codes ' purpose is to insert a item

What did you see instead?

before it execute the line 3, the rear equals to [-4, 2, 2], after it execute the line 3, the rear equals to [-3, 1, 3] for no reason which is really weird.