[clang-tools-extra] [clang-tidy][C++20] Add support for aggregate types within modernize-use-emplace (PR #131969)

[Baranov Victor via cfe-commits]

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@@ -0,0 +1,86 @@
+// RUN: %check_clang_tidy %s -std=c++20 modernize-use-emplace %t -- \
+// RUN:   -config="{CheckOptions: \
+// RUN:             {modernize-use-emplace.ContainersWithPushBack: \
+// RUN:                '::std::vector; ::std::list; ::std::deque; llvm::LikeASmallVector', \
+// RUN:              modernize-use-emplace.TupleTypes: \
+// RUN:                '::std::pair; std::tuple; ::test::Single', \
+// RUN:              modernize-use-emplace.TupleMakeFunctions: \
+// RUN:                '::std::make_pair; ::std::make_tuple; ::test::MakeSingle'}}"
+
+namespace std {
+template <typename E>
+class initializer_list {
+public:
+  const E *a, *b;
+  initializer_list() noexcept {}
+};
+
+template <typename T>
+class vector {
+public:
+  using value_type = T;
+
+  class iterator {};
+  class const_iterator {};
+  const_iterator begin() { return const_iterator{}; }
+
+  vector() = default;
+  vector(initializer_list<T>) {}
+
+  void push_back(const T &) {}
+  void push_back(T &&) {}
+
+  template <typename... Args>
+  void emplace_back(Args &&... args){};
+  template <typename... Args>
+  iterator emplace(const_iterator pos, Args &&...args);
+  ~vector();
+};
+
+} // namespace std
+
+struct InnerType {
+  InnerType() {}
+  InnerType(char const*) {}
+};
+
+//Not aggregate but we should still be able to directly initialize it with emplace_back
+struct NonTrivialNoCtor {
+  InnerType it;
+};
+
+struct Aggregate {
+  int a;
+  int b;
+};
+
+void testCXX20Cases() {
+  std::vector<Aggregate> v1;
+
+  v1.push_back(Aggregate{1, 2});
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vbvictor wrote:

 Consider adding tests with [designated initializers](https://en.cppreference.com/w/cpp/language/aggregate_initialization#Designated_initializers)

https://github.com/llvm/llvm-project/pull/131969