std::move behavior with const-qualified objects

Resource Transfer and Const-Correctness

C++ move semantics rely on the ability to modify the source object to transfer ownership of resources. The std::move function performs a cast to an rvalue reference, but the resulting type retains the const-qualification of the original object.

When a const T object is passed to std::move, the result is a const T&&. Most move constructors are defined to accept a non-const rvalue reference (T&&) to facilitate the mutation of the source.

This creates a scenario where the compiler must resolve the best match among available constructors when a const rvalue reference is provided. If the move constructor requires a non-const reference, the compiler may fall back to a copy constructor to maintain const-correctness.

• Does std::move on a const object always trigger a fallback to the copy constructor if no const T&& overload exists?
• What are the implications for performance when this silent fallback occurs in generic code?