升级Go版本后编译出错：Load redeclared in this block

今天打算把Go升级到1.14.2，升级的方法就两步，

先上Go官方下载页面（ https://golang.org/dl/ ）下载macos对应的二进制包（1.14.13地址 https://studygolang.com/dl/golang/go1.14.13.linux-amd64.tar.gz ）

https://studygolang.com/dl/golang/go1.14.13.linux-amd64.tar.gz

下载好后把压缩包解压到相应的目录：

tar -C /usr/local -xzf go1.14.13.linux-amd64.tar.gz

因为是升级，不是初次安装，之前已经把PATH设置好了，就不用管了。

之后执行以下命令，查看Go版本：

# go version
go version go1.14.13 linux/amd64

看到已经是1.14.13了，美滋滋。

但是用Go编译自己的程序，输出一大段如下错误：

# runtime/internal/atomic
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:18:6: Load redeclared in this block
	previous declaration at /usr/local/go/src/runtime/internal/atomic/atomic_amd64.go:16:24
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:24:6: Loadp redeclared in this block
	previous declaration at /usr/local/go/src/runtime/internal/atomic/atomic_amd64.go:22:32
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:30:6: Load64 redeclared in this block
	previous declaration at /usr/local/go/src/runtime/internal/atomic/atomic_amd64.go:28:26
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:36:6: LoadAcq redeclared in this block
	previous declaration at /usr/local/go/src/runtime/internal/atomic/atomic_amd64.go:34:27
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:41:6: Xadd redeclared in this block
	previous declaration at /usr/local/go/src/runtime/internal/atomic/atomic_amd64.go:39:37
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:44:6: Xadd64 redeclared in this block
	previous declaration at /usr/local/go/src/runtime/internal/atomic/atomic_amd64.go:42:39
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:47:6: Xadduintptr redeclared in this block
	previous declaration at /usr/local/go/src/runtime/internal/atomic/atomic_amd64.go:45:47
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:50:6: Xchg redeclared in this block
	previous declaration at /usr/local/go/src/runtime/internal/atomic/atomic_amd64.go:48:36
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:53:6: Xchg64 redeclared in this block
	previous declaration at /usr/local/go/src/runtime/internal/atomic/atomic_amd64.go:51:38
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:56:6: Xchguintptr redeclared in this block
	previous declaration at /usr/local/go/src/runtime/internal/atomic/atomic_amd64.go:54:45
/usr/local/go/src/runtime/internal/atomic/atomic_amd64x.go:56:6: too many errors

错误提示中说，atomic中的很多内容都重定义了，打开目录/usr/local/go/src/runtime/internal/atomic/下的atomic_amd64x.go和atomic_amd64.go，发现内容都差不多。

猜想可能新版本的源码文件名变更了，由于我们的新版本是直接解压过去的，导致老版本和新版本的源码文件同时存在。

尝试将/usr/local/go整个删除，再次 tar -C /usr/local -xzf go1.14.13.linux-amd64.tar.gz 安装新版本。

之后用Go编译程序就没有错误了。

上/usr/local/go/src/runtime/internal/atomic目录看，只有atomic_amd64.go文件了，说明猜想正确。问题解决。

总结一下，安装Go时，如果选择安装在老版本目录，最好先把老版本完整删除掉。