Add a crash-on-valid unit test

Author: yuxuanchen1997

clang/test/SemaCXX/pr98102.cpp

@@ -0,0 +1,33 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++20 %s
+// expected-no-diagnostics
+
+template <bool v>
+struct BC {
+  static constexpr bool value = v;
+};
+
+template <typename T, typename Arg>
+struct Constructible : BC<__is_constructible(T, Arg)> {};
+
+template <typename T>
+using Requires = T::value;
+
+template <typename T>
+struct optional {
+  template <typename U, Requires<Constructible<T, U>> = true>
+  optional(U) {}
+};
+
+struct MO {};
+struct S : MO {};
+struct TB {
+  TB(optional<S>) {}
+};
+
+class TD : TB, MO {
+  using TB::TB;
+};
+
+void foo() {
+  static_assert(Constructible<TD, TD>::value);
+}