TheRock/compiler/amd-llvm/clang-tools-extra/test/clang-tidy/checkers/performance/unnecessary-value-param-templates.cpp

// RUN: %check_clang_tidy  -std=c++14-or-later %s performance-unnecessary-value-param %t

struct ExpensiveToCopyType {
  virtual ~ExpensiveToCopyType();
};

template <typename T> void templateWithNonTemplatizedParameter(const ExpensiveToCopyType S, T V) {
  // CHECK-MESSAGES: [[@LINE-1]]:90: warning: the const qualified parameter 'S'
  // CHECK-MESSAGES: [[@LINE-2]]:95: warning: the parameter 'V'
  // CHECK-FIXES: template <typename T> void templateWithNonTemplatizedParameter(const ExpensiveToCopyType& S, const T& V) {
}

void instantiatedWithExpensiveValue() {
  templateWithNonTemplatizedParameter(
      ExpensiveToCopyType(), ExpensiveToCopyType());
  templateWithNonTemplatizedParameter(ExpensiveToCopyType(), 5);
}

template <typename T> void templateWithNonTemplatizedParameterCheapTemplate(const ExpensiveToCopyType S, T V) {
  // CHECK-MESSAGES: [[@LINE-1]]:103: warning: the const qualified parameter 'S'
  // CHECK-FIXES: template <typename T> void templateWithNonTemplatizedParameterCheapTemplate(const ExpensiveToCopyType& S, T V) {
}

void instantiatedWithCheapValue() {
  templateWithNonTemplatizedParameterCheapTemplate(ExpensiveToCopyType(), 5);
}

template <typename T> void nonInstantiatedTemplateWithConstValue(const T S) {}
template <typename T> void nonInstantiatedTemplateWithNonConstValue(T S) {}

template <typename T> void instantiatedTemplateSpecialization(T NoSpecS) {}
template <> void instantiatedTemplateSpecialization<int>(int SpecSInt) {}
// Updating template specialization would also require to update the main
// template and other specializations. Such specializations may be
// spreaded across different translation units.
// For that reason we only issue a warning, but do not propose fixes.
template <>
void instantiatedTemplateSpecialization<ExpensiveToCopyType>(
    ExpensiveToCopyType SpecSExpensiveToCopy) {
  // CHECK-MESSAGES: [[@LINE-1]]:25: warning: the parameter 'SpecSExpensiveToCopy'
  // CHECK-FIXES-NOT: const T& NoSpecS
  // CHECK-FIXES-NOT: const int& SpecSInt
  // CHECK-FIXES-NOT: const ExpensiveToCopyType& SpecSExpensiveToCopy
}

void instantiatedTemplateSpecialization() {
  instantiatedTemplateSpecialization(ExpensiveToCopyType());
}

template <typename T> void instantiatedTemplateWithConstValue(const T S) {
  // CHECK-MESSAGES: [[@LINE-1]]:71: warning: the const qualified parameter 'S'
  // CHECK-FIXES: template <typename T> void instantiatedTemplateWithConstValue(const T& S) {
}

void instantiatedConstValue() {
  instantiatedTemplateWithConstValue(ExpensiveToCopyType());
}

template <typename T> void instantiatedTemplateWithNonConstValue(T S) {
  // CHECK-MESSAGES: [[@LINE-1]]:68: warning: the parameter 'S'
  // CHECK-FIXES: template <typename T> void instantiatedTemplateWithNonConstValue(const T& S) {
}

void instantiatedNonConstValue() {
  instantiatedTemplateWithNonConstValue(ExpensiveToCopyType());
}

void lambdaConstValue() {
  auto fn = [](const ExpensiveToCopyType S) {
    // CHECK-MESSAGES: [[@LINE-1]]:42: warning: the const qualified parameter 'S'
    // CHECK-FIXES: auto fn = [](const ExpensiveToCopyType& S) {
  };
  fn(ExpensiveToCopyType());
}

void lambdaNonConstValue() {
  auto fn = [](ExpensiveToCopyType S) {
    // CHECK-MESSAGES: [[@LINE-1]]:36: warning: the parameter 'S'
    // CHECK-FIXES: auto fn = [](const ExpensiveToCopyType& S) {
  };
  fn(ExpensiveToCopyType());
}

void lambdaConstAutoValue() {
  auto fn = [](const auto S) {
    // CHECK-MESSAGES: [[@LINE-1]]:27: warning: the const qualified parameter 'S'
    // CHECK-FIXES: auto fn = [](const auto& S) {
  };
  fn(ExpensiveToCopyType());
}

void lambdaNonConstAutoValue() {
  auto fn = [](auto S) {
    // CHECK-MESSAGES: [[@LINE-1]]:21: warning: the parameter 'S'
    // CHECK-FIXES: auto fn = [](const auto& S) {
  };
  fn(ExpensiveToCopyType());
}

template <typename... Args>
void ParameterPack(Args... args) {
  // CHECK-MESSAGES: [[@LINE-1]]:28: warning: the parameter 'args' of type 'ExpensiveToCopyType'
  // CHECK-FIXES: void ParameterPack(const Args&... args) {
}

template <typename... Args>
void ParameterPackConst(Args const... args) {
  // CHECK-MESSAGES: [[@LINE-1]]:39: warning: the const qualified parameter 'args' of type 'const ExpensiveToCopyType'
  // CHECK-FIXES: void ParameterPackConst(Args const&... args) {
}

template <typename... Args>
void ParameterPackWithParams(const ExpensiveToCopyType E1, ExpensiveToCopyType E2, Args... args) {
  // CHECK-MESSAGES: [[@LINE-1]]:56: warning: the const qualified parameter 'E1'
  // CHECK-MESSAGES: [[@LINE-2]]:80: warning: the parameter 'E2'
  // CHECK-MESSAGES: [[@LINE-3]]:92: warning: the parameter 'args'
  // CHECK-FIXES: void ParameterPackWithParams(const ExpensiveToCopyType& E1, const ExpensiveToCopyType& E2, const Args&... args) {
}

template <typename... Args>
void PackWithNonExpensive(int x, Args... args) {}

void instantiatedParameterPack() {
  ExpensiveToCopyType E;
  ParameterPack(E);
  ParameterPackConst(E);
  ParameterPackWithParams(E, E, E);
  PackWithNonExpensive(5, 5);
}