go: runtime error on `go get` go1.11

What did you do?

1. dowload and install go1.11.linux-amd64.tar.gz
2. go get ./… dependencies for a project

What did you expect to see?

success

What did you see instead?

# runtime
/usr/local/go/src/runtime/map.go:64:2: bucketCntBits redeclared in this block
        previous declaration at /usr/local/go/src/runtime/hashmap.go:64:18
/usr/local/go/src/runtime/map.go:65:2: bucketCnt redeclared in this block
        previous declaration at /usr/local/go/src/runtime/hashmap.go:65:23
/usr/local/go/src/runtime/map.go:69:2: loadFactorNum redeclared in this block
        previous declaration at /usr/local/go/src/runtime/hashmap.go:69:18
/usr/local/go/src/runtime/map.go:70:2: loadFactorDen redeclared in this block
        previous declaration at /usr/local/go/src/runtime/hashmap.go:70:18
/usr/local/go/src/runtime/map.go:76:2: maxKeySize redeclared in this block
        previous declaration at /usr/local/go/src/runtime/hashmap.go:76:17
/usr/local/go/src/runtime/map.go:77:2: maxValueSize redeclared in this block
        previous declaration at /usr/local/go/src/runtime/hashmap.go:77:17
/usr/local/go/src/runtime/map.go:82:2: dataOffset redeclared in this block
        previous declaration at /usr/local/go/src/runtime/hashmap.go:85:4
/usr/local/go/src/runtime/map.go:91:2: empty redeclared in this block
        previous declaration at /usr/local/go/src/runtime/hashmap.go:91:19
/usr/local/go/src/runtime/map.go:92:2: evacuatedEmpty redeclared in this block
        previous declaration at /usr/local/go/src/runtime/hashmap.go:92:19
/usr/local/go/src/runtime/map.go:93:2: evacuatedX redeclared in this block
        previous declaration at /usr/local/go/src/runtime/hashmap.go:93:19
/usr/local/go/src/runtime/map.go:93:2: too many errors

System details

go version go1.11 linux/amd64
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/taya/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/taya/go:/home/taya/work/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
GOROOT/bin/go version: go version go1.11 linux/amd64
GOROOT/bin/go tool compile -V: compile version go1.11
uname -sr: Linux 4.15.0-33-generic
Distributor ID:	Ubuntu
Description:	Ubuntu 18.04.1 LTS
Release:	18.04
Codename:	bionic
/lib/x86_64-linux-gnu/libc.so.6: GNU C Library (Ubuntu GLIBC 2.27-3ubuntu1) stable release version 2.27.
gdb --version: GNU gdb (Ubuntu 8.1-0ubuntu3) 8.1.0.20180409-git