Method returnLocalStdMove

lib/checkfunctions.cpp:706–734

Check for problems to compiler apply (Named) Return Value Optimization for local variable Technically we have different guarantees between standard versions details: https://en.cppreference.com/w/cpp/language/copy_elision

// Technically we have different guarantees between standard versions
// details: https://en.cppreference.com/w/cpp/language/copy_elision
void CheckFunctionsImpl::returnLocalStdMove()
{
    if (!mTokenizer->isCPP() || mSettings.standards.cpp < Standards::CPP11)
        return;

    if (!mSettings.severity.isEnabled(Severity::performance))
        return;

    logChecker("CheckFunctions::returnLocalStdMove"); // performance,c++11

    const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
    for (const Scope *scope : symbolDatabase->functionScopes) {
        // Expect return by-value
        if (Function::returnsReference(scope->function, /*unknown*/ true, /*includeRValueRef*/ true))
            continue;
        const auto rets = Function::findReturns(scope->function);
        for (const Token* ret : rets) {
            if (!Token::simpleMatch(ret->tokAt(-3), "std :: move ("))
                continue;
            const Token* retval = ret->astOperand2();
            // NRVO
            if (retval->variable() && retval->variable()->isLocal() && !retval->variable()->isVolatile())
                copyElisionError(retval);
            // RVO
            if (Token::Match(retval, "(|{") && !retval->isCast() && !(retval->valueType() && retval->valueType()->reference != Reference::None))
                copyElisionError(retval);
        }
    }
}

void CheckFunctionsImpl::copyElisionError(const Token *tok)
{