Causes cosmoc++ to segfault

cosmoc++ produces "internal compiler error: SIGSEGV" on this code if run
via:

    mmake ctl/unique_ptr.o

ctl/unique_ptr.cc

@@ -0,0 +1,19 @@
+// -*- mode:c++; indent-tabs-mode:nil; c-basic-offset:4; coding:utf-8 -*-
+// vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
+//
+// Copyright 2024 Justine Alexandra Roberts Tunney
+//
+// Permission to use, copy, modify, and/or distribute this software for
+// any purpose with or without fee is hereby granted, provided that the
+// above copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+// WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+// AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+// DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+// PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+// TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+#include "unique_ptr.h"

ctl/unique_ptr.h

@@ -0,0 +1,31 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef COSMOPOLITAN_CTL_UNIQUE_PTR_H_
+#define COSMOPOLITAN_CTL_UNIQUE_PTR_H_
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <__utility/swap.h>
+
+namespace ctl {
+
+template <typename T>
+using default_delete = decltype([](T* p) {
+    delete p;
+});
+
+template<typename T, typename D = default_delete<T>>
+struct unique_ptr
+{
+    T* p = 0;
+
+    using pointer = T*;
+    using element_type = T;
+    using deleter_type = D;
+
+    constexpr unique_ptr(nullptr_t = nullptr) { }
+    explicit unique_ptr(pointer p) : p(p) { }
+
+};
+
+} // namespace ctl
+#endif // COSMOPOLITAN_CTL_UNIQUE_PTR_H_