Test causing an OOM

Author: ilya-biryukov

clang/test/Modules/pr83237.cppm

@@ -0,0 +1,39 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: split-file %s %t
+//
+// RUN: %clang_cc1 -std=c++20 %t/type_traits.cppm -emit-module-interface -o %t/type_traits.pcm
+// RUN: %clang_cc1 -std=c++20 %t/test.cpp -fprebuilt-module-path=%t -verify
+
+//--- type_traits.cppm
+export module type_traits;
+
+export template <typename T>
+constexpr bool is_pod_v = __is_pod(T);
+
+//--- test.cpp
+import type_traits;
+// Base is either void or wrapper<T>.
+template <class Base> struct wrapper : Base {};
+template <> struct wrapper<void> {};
+
+// wrap<0>::type<T> is wrapper<T>, wrap<1>::type<T> is wrapper<wrapper<T>>,
+// and so on.
+template <int N>
+struct wrap {
+  template <class Base>
+  using type = wrapper<typename wrap<N-1>::template type<Base>>;
+};
+
+template <>
+struct wrap<0> {
+  template <class Base>
+  using type = wrapper<Base>;
+};
+
+inline constexpr int kMaxRank = 40;
+template <int N, class Base = void>
+using rank = typename wrap<N>::template type<Base>;
+using rank_selector_t = rank<40>;
+
+static_assert(is_pod_v<rank_selector_t>, "Must be POD");