Hey everyone. Yeah, the issue is with VS 2017 15.9.0, which was released a couple days back on Nov 13.
I tested with 15.8.9, and things do compile.
Please uninstall 15.9.0 and install 15.8.9, as explained here (links for 15.8.9 therein)
https://docs.microsoft.com/en-us/visualstudio/productinfo/installing-an-earlier-release-of-vs2017
Also, note that you need Unreal version 4.18, not 4.21.
We’re looking into what is causing the error at Microsoft, please use anything <=15.8.9 till then. Thanks @Waarbubble for reporting the issue and the fix. Updating readme for the same.
Tagging @sytelus @lovettchris. this is the issue we discussed.
通过查看github上issue，发现是vs2017自己的错误，所以回退vs版本到15.89。
但是回退到15.89还是有问题，之后重新安装15.9版本。同时安装15.8版本。
在上面的操作后，UE4的4.20版本可以编译成功。但是4.21编译仍是失败，不过编译失败的原因是因为某些类找不到，与编译器无关(?待验证)。
以上截图为可以运行在4.20版本的vc++2017版本。
