[Clang][NFC] Consolidate tests for default argument substitution

[zyn0217]

Follow-up on 8ac140f.

The test SemaTemplate/default-parm-init.cpp was introduced since the fix #80288 and mainly did the following things:

• Ensure the default arguments are properly substituted inside either the primary template & their explicit / out-of-line specializations.
• Ensure the strategy doesn't mess up the substitution of a lambda expression as a default argument.

The 1st is for the bug of #68490, yet it does some redundant work: each of the member functions is duplicated twice for the sizeof and alignof operators, respectively, and the principle under the hood are essentially the same. So this patch removes the duplication and reduces the 8 functions to 4 functions that reveal the same thing.

The 2nd is presumably testing that the fix in #80288 doesn't impact a complicated substitution. However, that seems unnecessary & unrelated to the original issue. And more importantly, we don't have any problems with that ever. Hence, I'll remove that test from this patch.

The test for default arguments is merged into SemaTemplate/default-arguments.cpp with a new namespace, and hopefully this could reduce the entropy of our testing cases.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Younan Zhang (zyn0217)

Changes

Follow-up on 8ac140f.

The test SemaTemplate/default-parm-init.cpp was introduced since the fix for #80288 and mainly did the following things:

• Ensure the default arguments are properly substituted inside either the primary template & their explicit / out-of-line specializations.
• Ensure the strategy doesn't mess up the substitution of a lambda expression as a default argument.

The 1st is for the bug of #68490, yet it does some redundant work: each of the member functions is duplicated twice for the sizeof and alignof operators, respectively, and the principal under the hood are essentially the same. So this patch removes the duplication and reduces the 8 functions to 4 functions that reveal the same thing.

The 2nd is presumably testing that the fix in #80288 doesn't impact a complicated substitution. However, that seems unnecessary & unrelated to the original issue. And more importantly, we don't have any problems with that ever. Hence, I'll remove that test from this patch.

The test for default arguments is merged into SemaTemplate/default-arguments.cpp with a new namespace, and hopefully this could reduce the entropy of our testing cases.

---

Full diff: https://github.com/llvm/llvm-project/pull/105617.diff

2 Files Affected:

• (modified) clang/test/SemaTemplate/default-arguments.cpp (+52)
• (removed) clang/test/SemaTemplate/default-parm-init.cpp (-190)

diff --git a/clang/test/SemaTemplate/default-arguments.cpp b/clang/test/SemaTemplate/default-arguments.cpp
index d5d9687cc90f49..3b1fbda414c12b 100644
--- a/clang/test/SemaTemplate/default-arguments.cpp
+++ b/clang/test/SemaTemplate/default-arguments.cpp
@@ -229,3 +229,55 @@ namespace unevaluated {
   template<int = 0> int f(int = a); // expected-warning 0-1{{extension}}
   int k = sizeof(f());
 }
+
+#if __cplusplus >= 201103L
+namespace GH68490 {
+
+template <typename T> struct S {
+  template <typename U>
+  constexpr int SizeOfU(int param = sizeof(U)) const;
+
+  template <typename U>
+  constexpr int SizeOfT(int param = sizeof(T)) const;
+};
+
+template <typename T> struct S<T *> {
+  template <typename U>
+  constexpr int SizeOfU(int param = sizeof(U)) const;
+
+  template <typename U>
+  constexpr int SizeOfT(int param = sizeof(T *)) const;
+};
+
+template <typename T>
+template <typename U>
+constexpr int S<T *>::SizeOfU(int param) const {
+  return param;
+}
+
+template <typename T>
+template <typename U>
+constexpr int S<T *>::SizeOfT(int param) const {
+  return param;
+}
+
+template <>
+template <typename T>
+constexpr int S<int>::SizeOfU(int param) const {
+  return param;
+}
+
+template <>
+template <typename T>
+constexpr int S<int>::SizeOfT(int param) const {
+  return param;
+}
+
+static_assert(S<int>().SizeOfU<char>() == sizeof(char), "");
+static_assert(S<int>().SizeOfT<char>() == sizeof(int), "");
+static_assert(S<short *>().SizeOfU<char>() == sizeof(char), "");
+static_assert(S<short *>().SizeOfT<char>() == sizeof(short *), "");
+
+} // namespace GH68490
+
+#endif
diff --git a/clang/test/SemaTemplate/default-parm-init.cpp b/clang/test/SemaTemplate/default-parm-init.cpp
deleted file mode 100644
index 73ba8998df6a98..00000000000000
--- a/clang/test/SemaTemplate/default-parm-init.cpp
+++ /dev/null
@@ -1,190 +0,0 @@
-// RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify %s
-// RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify %s
-// expected-no-diagnostics
-
-namespace std {
-
-template<typename Signature> class function;
-
-template<typename R, typename... Args> class invoker_base {
-public: 
-  virtual ~invoker_base() { } 
-  virtual R invoke(Args...) = 0; 
-  virtual invoker_base* clone() = 0;
-};
-
-template<typename F, typename R, typename... Args> 
-class functor_invoker : public invoker_base<R, Args...> {
-public: 
-  explicit functor_invoker(const F& f) : f(f) { } 
-  R invoke(Args... args) { return f(args...); } 
-  functor_invoker* clone() { return new functor_invoker(f); }
-
-private:
-  F f;
-};
-
-template<typename R, typename... Args>
-class function<R (Args...)> {
-public: 
-  typedef R result_type;
-  function() : invoker (0) { }
-  function(const function& other) : invoker(0) { 
-    if (other.invoker)
-      invoker = other.invoker->clone();
-  }
-
-  template<typename F> function(const F& f) : invoker(0) {
-    invoker = new functor_invoker<F, R, Args...>(f);
-  }
-
-  ~function() { 
-    if (invoker)
-      delete invoker;
-  }
-
-  function& operator=(const function& other) { 
-    function(other).swap(*this); 
-    return *this;
-  }
-
-  template<typename F> 
-  function& operator=(const F& f) {
-    function(f).swap(*this); 
-    return *this;
-  }
-
-  void swap(function& other) { 
-    invoker_base<R, Args...>* tmp = invoker; 
-    invoker = other.invoker; 
-    other.invoker = tmp;
-  }
-
-  result_type operator()(Args... args) const { 
-    return invoker->invoke(args...);
-  }
-
-private: 
-  invoker_base<R, Args...>* invoker;
-};
-
-}
-
-template<typename TemplateParam>
-struct Problem {
-  template<typename FunctionTemplateParam>
-  constexpr int FuncAlign(int param = alignof(FunctionTemplateParam));
-
-  template<typename FunctionTemplateParam>
-  constexpr int FuncSizeof(int param = sizeof(FunctionTemplateParam));
-
-  template<typename FunctionTemplateParam>
-  constexpr int FuncAlign2(int param = alignof(TemplateParam));
-
-  template<typename FunctionTemplateParam>
-  constexpr int FuncSizeof2(int param = sizeof(TemplateParam));
-};
-
-template<typename TemplateParam>
-struct Problem<TemplateParam*> {
-  template<typename FunctionTemplateParam>
-  constexpr int FuncAlign(int param = alignof(FunctionTemplateParam));
-
-  template<typename FunctionTemplateParam>
-  constexpr int FuncSizeof(int param = sizeof(FunctionTemplateParam));
-
-  template<typename FunctionTemplateParam>
-  constexpr int FuncAlign2(int param = alignof(TemplateParam));
-
-  template<typename FunctionTemplateParam>
-  constexpr int FuncSizeof2(int param = sizeof(TemplateParam));
-};
-
-template<typename TemplateParam>
-template<typename FunctionTemplateParam>
-constexpr int Problem<TemplateParam*>::FuncAlign(int param) {
-	return 2U*param;
-}
-
-template<typename TemplateParam>
-template<typename FunctionTemplateParam>
-constexpr int Problem<TemplateParam*>::FuncSizeof(int param) {
-    return 2U*param;
-}
-
-template<typename TemplateParam>
-template<typename FunctionTemplateParam>
-constexpr int Problem<TemplateParam*>::FuncAlign2(int param) {
-	return 2U*param;
-}
-
-template<typename TemplateParam>
-template<typename FunctionTemplateParam>
-constexpr int Problem<TemplateParam*>::FuncSizeof2(int param) {
-	return 2U*param;
-}
-
-template <>
-template<typename FunctionTemplateParam>
-constexpr int Problem<int>::FuncAlign(int param) {
-	return param;
-}
-
-template <>
-template<typename FunctionTemplateParam>
-constexpr int Problem<int>::FuncSizeof(int param) {
-	return param;
-}
-
-template <>
-template<typename FunctionTemplateParam>
-constexpr int Problem<int>::FuncAlign2(int param) {
-	return param;
-}
-
-template <>
-template<typename FunctionTemplateParam>
-constexpr int Problem<int>::FuncSizeof2(int param) {
-	return param;
-}
-
-void foo() {
-    Problem<int> p = {};
-    static_assert(p.FuncAlign<char>() == alignof(char));
-    static_assert(p.FuncSizeof<char>() == sizeof(char));
-    static_assert(p.FuncAlign2<char>() == alignof(int));
-    static_assert(p.FuncSizeof2<char>() == sizeof(int));
-    Problem<short*> q = {};
-    static_assert(q.FuncAlign<char>() == 2U * alignof(char));
-    static_assert(q.FuncSizeof<char>() == 2U * sizeof(char));
-    static_assert(q.FuncAlign2<char>() == 2U *alignof(short));
-    static_assert(q.FuncSizeof2<char>() == 2U * sizeof(short));
-}
-
-template <typename T>
-class A {
- public:
-  void run(
-    std::function<void(T&)> f1 = [](auto&&) {},
-    std::function<void(T&)> f2 = [](auto&&) {});
- private:
-  class Helper {
-   public:
-    explicit Helper(std::function<void(T&)> f2) : f2_(f2) {}
-    std::function<void(T&)> f2_;
-  };
-};
-
-template <typename T>
-void A<T>::run(std::function<void(T&)> f1,
-               std::function<void(T&)> f2) {
-  Helper h(f2);
-}
-
-struct B {};
-
-int main() {
-    A<B> a;
-    a.run([&](auto& l) {});
-    return 0;
-}

[zyn0217]

libcxx failures are unrelated.

[cor3ntin]

LGTM