How std::forward<T> preserves value category (lvalue vs rvalue) in generic code:

When a template argument is T&& in a deduced context (forwarding reference), T deduces to Widget& for lvalues and Widget for rvalues.

template<typename T>
void Wrapper(T&& arg) {
    // std::forward restores the original value category:
    // If arg was an rvalue, forwards as rvalue (enables move)
    // If arg was an lvalue, forwards as lvalue (preserves reference)
    TargetFunction(std::forward<T>(arg));
}

Without std::forward, named rvalue references inside functions are treated as lvalues, causing accidental copies instead of moves!

Remember: 'Named rvalues are lvalues'. Once an rvalue has a variable name inside a function scope, you must use std::forward to pass it along as an rvalue.

Perfect forwarding is the core engine behind std::make_unique, std::make_shared, and vector::emplace_back.