Lambda是否有不同类型? [英] Do lambdas have different types?

问题描述

每个lambda都应具有唯一的未知类型.是否保证同一作用域中的两个lambda具有不同的类型?

Every lambda should have a unique unknown type.. is it guaranteed that two lambdas into the same scope have different types?

int main() {
   auto l1 = [](){};
   auto l2 = [](){};   
  static_assert(std::is_same<decltype(l1), decltype(l2)>::value == false, "Types cannot be equal!");
}

这可行，但是我想知道是否可以保证断言永远不会触发.

This works but I'd like to know if it's guaranteed that the assert will never fire.

推荐答案

是的，每个lambda表达式都会产生一个唯一的类型([expr.prim.lambda]/3):

Yes, each lambda expression produces a unique type ([expr.prim.lambda]/3):

lambda表达式的类型(这也是闭包对象的类型)是唯一，未命名的ununion类类型(称为闭包类型)，其属性如下所述.

The type of the lambda-expression (which is also the type of the closure object) is a unique, unnamed nonunion class type — called the closure type — whose properties are described below.

[已添加重点]

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