2021-07-08 解决cannot find package “fmt“ in any of 问题

package main

import "fmt"

func main() {
	fmt.Println("Hello world!")
}

上述代码报错：

could not import fmt (cannot find package "fmt" in any of 
	/usr/local/Cellar/go/1.15.7/libexec/src/fmt (from $GOROOT)
	/Users/bytedance/go/src/fmt (from $GOPATH))

GOROOT配置错误：
如图可以看到我的 GOROOT 路径和上文报错路径不一致，可能是安装的时候有些混乱，所以需要按照报错提示重新配置一下。

GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/bytedance/Library/Caches/go-build"
GOENV="/Users/bytedance/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/bytedance/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="off"
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/jr/w6vq2s9x43340qv18sc7zlz00000gp/T/go-build690732439=/tmp/go-build -gno-record-gcc-switches -fno-common"

打开终端，按下述方法修改 GOROOT 配置：

vim ~/.bash_profile 
i

esc
:wq
source ~/.bash_profile
go env

GO111MODULE=""
GOARCH="amd64"
GOBIN="/Users/bytedance/go/bin"
GOCACHE="/Users/bytedance/Library/Caches/go-build"
GOENV="/Users/bytedance/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/bytedance/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/bytedance/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/Cellar/go/1.15.7/libexec"
GOSUMDB="off"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.15.7/libexec/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/jr/w6vq2s9x43340qv18sc7zlz00000gp/T/go-build286606926=/tmp/go-build -gno-record-gcc-switches -fno-common"

https://dave.cheney.net/2013/06/14/you-dont-need-to-set-goroot-really