cmd/vet: should report json tag conflict for embedded struct #25593
Description
What version of Go are you using (go version)?
go version go1.10.2 linux/amd64
What operating system and processor architecture are you using (go env)?
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/powerman/.cache/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/powerman/go"
GORACE=""
GOROOT="/usr/lib/go"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="x86_64-pc-linux-gnu-gcc"
CXX="x86_64-pc-linux-gnu-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-build251037373=/tmp/go-build -gno-record-gcc-switches"
What did you do?
https://play.golang.org/p/zvagdPQx1Gf
What did you expect to see?
go vet should warn about using same json tag name in embedded struct.
It already warn about using same json tag name in same struct, so making it detect embedded fields looks like obvious enhancement.
May be related to #17609