Deducing this (C++23)

In a Nutshell

Write the first parameter of a member function as this Self or this Self&&, and the compiler deduces it automatically from the value category of the calling object (lvalue/rvalue/const)—eliminating the const/non-const/rvalue-reference overload trio.

Header

None (language feature)

Core API Cheat Sheet

Syntax	Description
void func(this Self&& self)	Rvalue-reference explicit object parameter
void func(this const Self& self)	const lvalue reference (read-only)
void func(this Self& self)	Non-const lvalue reference (mutable)
void func(this auto&& self)	Perfect forwarding—one definition covers all value categories
Combined with templates	template<class Self> void func(this Self&& self) templated explicit object parameter
CRTP simplification	Explicit object parameters can directly replace CRTP, reducing base-class overhead

Minimal Example

Expand codeCollapse22 lines

// Standard: C++23
#include <iostream>
#include <utility>

struct Wrapper {
    int value;

    // One function covers all three scenarios: const / non-const / rvalue
    template <typename Self>
    auto&& get(this Self&& self) {
        return std::forward<Self>(self).value;
    }
};

int main() {
    Wrapper w{42};
    const Wrapper cw{99};

    std::cout << w.get() << "\n";   // 42 (non-const lvalue)
    std::cout << cw.get() << "\n";  // 99 (const lvalue)
    std::cout << Wrapper{7}.get() << "\n"; // 7 (rvalue)
}

Embedded Applicability: Moderate

• Less boilerplate: one explicit object parameter replaces the const/non-const/rvalue overload trio
• Simplifies CRTP: types are deduced directly in the member function, eliminating base-class indirection overhead
• Especially useful for recursive lambdas and chained-call APIs
• A C++23 feature; compiler support is still rolling out (GCC 14.1+, Clang 18+, MSVC 19.34+)
• Embedded toolchains have long upgrade cycles, so it is not suitable in the short term for projects that need broad compatibility

Compiler Support

GCC	Clang	MSVC
14.1	18	19.34

See Also

• cppreference: Deducing this

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