error C2338: You've instantiated std::aligned_storage<Len, Align> with an extended alignment (in other words, Align >

报的完整错误为：

error C2338: You've instantiated std::aligned_storage<Len, Align> with an extended alignment (in other words, Align > alignof(max_align_t)).
Before VS 2017 15.8, the member type would non-conformingly have an alignment of only alignof(max_align_t).
VS 2017 15.8 was fixed to handle this correctly, but the fix inherently changes layout and breaks binary compatibility (*only* for uses of
aligned_storage with extended alignments). Please define either (1) _ENABLE_EXTENDED_ALIGNED_STORAGE to acknowledge that you understand this
message and that you actually want a type with an extended alignment, or (2) _DISABLE_EXTENDED_ALIGNED_STORAGE to silence this message and
get the old non-conformant behavior.

　　

　　

大概意思就是：VS2017 15.8版本修复了老版本有关对齐存储部分缺陷，但修复本身也有缺陷。如果不想编译时报这个问题，就在预编译时定义一个宏 _ENABLE_EXTENDED_ALIGNED_STORAGE 或者 _DISABLE_EXTENDED_ALIGNED_STORAGE（博主的理解是按照修复后的逻辑处理就定义带enable那个，按照老版本的逻辑处理就定义带disable那个）

参考解决方法：

打开 项目属性页 -- > C/C++  --> Preprocessor --> Preprocessor Definitions

里面添加，_DISABLE_EXTENDED_ALIGNED_STORAGE

即可。

参考文章

error C2338: You've instantiated std::aligned_storage《Len, Align》 with an extended alignment.（讨论）