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

go version go1.13.8 darwin/amd64

Does this issue reproduce with the latest release?

Yes

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

GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/big0ne/Library/Caches/go-build"
GOENV="/Users/big0ne/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/big0ne/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
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/ql/g_n75d6510s0lxhzzs70h5g40000gn/T/go-build587896349=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

I have struct like this:
type person struct { first string last string skills []string }

and I have two variables in this type:

` p1 := person{
first: "John",
last: "Stallone",
skills: []string{"Java", "Go"},
}

p2 := person{
	first:  "Mark",
	last:   "Stallone",
	skills: []string{"C++", "Python", "Go"},
}`

If I wanted create something like this:

persons := map[string]person{ "Stallone": p1, "Stallone": p2, }

it would be obvious error, but if I try this:

persons := map[string]person{ p1.last: p1, p2.last: p2, }

there is no problem.

And result may be confusing, because second key overwrites previous one. For example for this code:

for _, v := range persons { fmt.Println(v.first) fmt.Println(v.last) for i, val := range v.skills { fmt.Println(i+1, val) } fmt.Println("===") }

I get only one person with skills, when I have map with two values in there.

What did you expect to see?

Consistency would be better (so we should let developer write map with two keys all the time or we should block every try of duplication by raise an exception)

What did you see instead?

Mark Stallone 1 C++ 2 Python 3 Go