求教个简单的 C++ 语法问题

代码如下

#include<iostream> enum ExprValueType : uint8_t { MinInf = 1 }; int main(int argc, char* argv[]) { ExprValueType type = MinInf; std::cout <<"Hello world" << std::endl; std::cout << type << std::endl; return 0; } 

abc.cc:3:20: error: found ‘:’ in nested-name-specifier, expected ‘::’ 3 | enum ExprValueType : uint8_t { | ^ | :: abc.cc:3:6: error: ‘ExprValueType’ has not been declared 3 | enum ExprValueType : uint8_t { | ^~~~~~~~~~~~~ abc.cc:3:30: error: expected unqualified-id before ‘{’ token 3 | enum ExprValueType : uint8_t { | ^ abc.cc: In function ‘int main(int, char**)’: abc.cc:8:3: error: ‘ExprValueType’ was not declared in this scope 8 | ExprValueType type = MinInf; | ^~~~~~~~~~~~~ abc.cc:10:16: error: ‘type’ was not declared in this scope; did you mean ‘std::__cmp_cat::type’? 10 | std::cout << type << std::endl; | ^~~~ | std::__cmp_cat::type In file included from /usr/include/c++/13/bits/char_traits.h:56, from /usr/include/c++/13/ios:42, from /usr/include/c++/13/ostream:40, from /usr/include/c++/13/iostream:41, from abc.cc:1: /usr/include/c++/13/compare:49:11: note: ‘std::__cmp_cat::type’ declared here 49 | using type = signed char; | ^~~~ 

个人猜测是 gcc 版本的问题，于是在 https://gcc.godbolt.org/ 切换不同的编译器查看。

• 发现自 x86-64 gcc 13.1 开始会报错，之前版本（比如 x86-64 gcc 12.3）就不会报错。
• 同样 x86-64 clang 17.0.1 开始会报错，之前版本（比如 x86-64 clang 16.0.0 ）就不会报错。

于是产生了两个困惑

• 编译器最近是出了什么新的标准导致不支持 enum 的这种写法了吗？
• 如果想要在 x86-64 gcc 13.1 上跑起来，应该怎么改？