readability-reference-to-constructed-temporary

Detects C++ code where a reference variable is used to extend the lifetime of a temporary object that has just been constructed.

This construction is often the result of multiple code refactorings or a lack of developer knowledge, leading to confusion or subtle bugs. In most cases, what the developer really wanted to do is create a new variable rather than extending the lifetime of a temporary object.

Examples of problematic code include:

const std::string& str("hello");

struct Point { int x; int y; };
const Point& p = { 1, 2 };

In the first example, a const std::string& reference variable str is assigned a temporary object created by the std::string("hello") constructor. In the second example, a const Point& reference variable p is assigned an object that is constructed from an initializer list { 1, 2 }. Both of these examples extend the lifetime of the temporary object to the lifetime of the reference variable, which can make it difficult to reason about and may lead to subtle bugs or misunderstanding.

To avoid these issues, it is recommended to change the reference variable to a (const) value variable.