online compiler and debugger for c/c++

/****************************************************************************** Welcome to GDB Online. GDB online is an online compiler and debugger tool for C, C++, Python, PHP, Ruby, C#, VB, Perl, Swift, Prolog, Javascript, Pascal, HTML, CSS, JS Code, Compile, Run and Debug online from anywhere in world. *******************************************************************************/ #include <stdio.h> constexpr int CONST = 1; template<int> using Void = void; template<typename PoisonDelayer> constexpr auto procurePoison(int i) { struct Poison { // error: use of parameter from containing function // constexpr auto operator()() const -> Void<(PoisonDelayer::delayStatic(i), 0)> {} // error: use of parameter from containing function // static constexpr auto drink() -> Void<(PoisonDelayer::delayStatic(i), 0)> {} } poison; return poison; } template<typename PoisonDelayer> constexpr auto procurePoisonFromObject(PoisonDelayer poisonDelayer, int i) { struct Poison { // error: use of parameter from containing function // constexpr auto operator()() const -> Void<(poisonDelayer(i), 0)> {} // error: use of parameter from containing function // static constexpr auto drink() -> Void<(poisonDelayer(i), 0)> {} } poison; return poison; } template<typename PoisonDelayer> struct PoisonOuterTemplate { const int& _i; // Internal compiler error / use of this in a constant expr // auto operator()() const -> Void<(PoisonDelayer::delayStatic(_i), 0)> {} }; template<typename PoisonDelayer> struct PoisonOuterTemplateStatic { static const int& _i; // error: the value of ‘PoisonOuterTemplateStatic::_i’ is not usable in a constant expression // static auto drink() const -> Void<(PoisonDelayer::delayStatic(_i), 0)> {} }; template<typename PoisonDelayer> const int& PoisonOuterTemplateStatic<PoisonDelayer>::_i = CONST; struct PoisonInnerTemplate { const int& _i; // Internal compiler error / use of this in a constexpr template<typename PoisonDelayer> auto drink() const -> Void<(PoisonDelayer::delayStatic(_i), 0)> {} }; struct PoisonInnerTemplateStatic { static const int& _i; // error: the value of ‘PoisonInnerTemplateStatic::_i’ is not usable in a constant expression // template<typename PoisonDelayer> // static auto drink() -> Void<(PoisonDelayer::delayStatic(_i), 0)> {} }; const int& PoisonInnerTemplateStatic::_i = CONST; template<typename PoisonDelayer> constexpr auto procurePoisonLambdaOuter(int i) { // error: use of parameter from containing function // auto lambda = []() -> Void<(PoisonDelayer::delayStatic(i), 0)> {}; // return lambda; return 0; } struct PoisonLambdaInner { static const int& _i; // error: the value of ‘PoisonLambdaInner::_i’ is not usable in a constant expression // template<typename PoisonDelayer> // static auto lambda = []() -> Void<(PoisonDelayer::delayStatic(_i), 0)> {}; }; const int& PoisonLambdaInner::_i = CONST; // error: use of parameter from containing function / i is not a constexpr constexpr auto poisonLambda = [](auto poisonDelayer, int i) { return []() -> Void<poisonDelayer(i)> {}; }; struct Delayer { static constexpr auto delayStatic(int input) { return input; } constexpr auto operator()(int input) { return input; } }; int main() { auto procurePoisonRes = procurePoison<Delayer>(1); auto procurePoisonFromObjectRes = procurePoisonFromObject(Delayer{}, 1); auto poisonOuterTemplate = PoisonOuterTemplate<Delayer>{CONST}; auto poisonOuterTemplateStatic = PoisonOuterTemplateStatic<Delayer>{}; auto poisonInnerTemplate = PoisonInnerTemplate{CONST}; auto poisonInnerTemplateStatic = PoisonInnerTemplateStatic{}; auto procurePoisonLambdaOuterRes = procurePoisonLambdaOuter<Delayer>(1); auto poisonLambdaInner = PoisonLambdaInner{}; // auto poisonLambdaRes = poisonLambda(Delayer{}, 1); return 0; }