<ranges>: Diagnose the precondition added by LWG-3597

stl/inc/ranges

@@ -1333,7 +1333,12 @@ namespace ranges {
 
         constexpr explicit iota_view(_Wi _Value_) noexcept(
             is_nothrow_move_constructible_v<_Wi>&& is_nothrow_default_constructible_v<_Bo>) // strengthened
-            : _Value(_STD move(_Value_)) {}
+            : _Value(_STD move(_Value_)) {
+            if constexpr (totally_ordered_with<_Wi, _Bo>) {
+                _STL_ASSERT(_Value_ <= _Bound, "Per N4950 [range.iota.view]/6, the first argument must precede the "
+                                               "value-initialized bound when their types are totally ordered.");
+            }
+        }
 
         constexpr explicit iota_view(type_identity_t<_Wi> _Value_, type_identity_t<_Bo> _Bound_) noexcept(
             is_nothrow_move_constructible_v<_Wi>&& is_nothrow_move_constructible_v<_Bo>) // strengthened

tests/std/test.lst

@@ -455,6 +455,7 @@ tests\P0896R4_views_filter
 tests\P0896R4_views_filter_death
 tests\P0896R4_views_filter_iterator
 tests\P0896R4_views_iota
+tests\P0896R4_views_iota_death
 tests\P0896R4_views_join
 tests\P0896R4_views_lazy_split
 tests\P0896R4_views_reverse

tests/std/tests/P0896R4_views_iota_death/env.lst

@@ -0,0 +1,4 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+RUNALL_INCLUDE ..\strict_concepts_20_matrix.lst

tests/std/tests/P0896R4_views_iota_death/test.cpp

@@ -0,0 +1,68 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#define _CONTAINER_DEBUG_LEVEL 1
+
+#include <cassert>
+#include <cstddef>
+#include <ranges>
+#include <vector>
+
+#include <test_death.hpp>
+using namespace std;
+
+template <class I>
+void test_misordered_start_bound_int() {
+    ranges::iota_view{I{42}, I{1}};
+}
+
+template <class UI>
+void test_misordered_start_bound_uint_value_init() {
+    ranges::iota_view<UI, UI>{UI{42}};
+}
+
+template <class T>
+void test_misordered_start_bound_ptr() {
+    T arr[1]{};
+    ranges::iota_view{arr + 1, arr + 0};
+}
+
+int main(int argc, char* argv[]) {
+    std_testing::death_test_executive exec;
+
+#ifdef _DEBUG
+    struct S {};
+
+    exec.add_death_tests({
+        test_misordered_start_bound_int<signed char>, test_misordered_start_bound_int<unsigned char>,
+            test_misordered_start_bound_int<short>, test_misordered_start_bound_int<unsigned short>,
+            test_misordered_start_bound_int<int>, test_misordered_start_bound_int<unsigned int>,
+            test_misordered_start_bound_int<long>, test_misordered_start_bound_int<unsigned long>,
+            test_misordered_start_bound_int<long long>, test_misordered_start_bound_int<unsigned long long>,
+
+            test_misordered_start_bound_int<char>,
+#if __cpp_char8_t
+            test_misordered_start_bound_int<char8_t>,
+#endif // __cpp_char8_t
+            test_misordered_start_bound_int<char16_t>, test_misordered_start_bound_int<char32_t>,
+            test_misordered_start_bound_int<wchar_t>,
+
+            test_misordered_start_bound_uint_value_init<unsigned char>,
+            test_misordered_start_bound_uint_value_init<unsigned short>,
+            test_misordered_start_bound_uint_value_init<unsigned int>,
+            test_misordered_start_bound_uint_value_init<unsigned long>,
+            test_misordered_start_bound_uint_value_init<unsigned long long>,
+            test_misordered_start_bound_uint_value_init<unsigned long long>,
+#if __cpp_char8_t
+            test_misordered_start_bound_uint_value_init<char8_t>,
+#endif // __cpp_char8_t
+            test_misordered_start_bound_uint_value_init<char16_t>,
+            test_misordered_start_bound_uint_value_init<char32_t>, test_misordered_start_bound_uint_value_init<wchar_t>,
+
+            test_misordered_start_bound_ptr<char>, test_misordered_start_bound_ptr<int>,
+            test_misordered_start_bound_ptr<S>,
+    });
+#endif // _DEBUG
+
+    return exec.run(argc, argv);
+}