more valueless_by_exception cases

Author: changkhothuychung

libcxx/include/__ranges/concat_view.h

@@ -522,7 +522,9 @@ class concat_view<_Views...>::__iterator {
        ...))
 
   {
-    return std::visit(
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+        !__it.__it_.valueless_by_exception(), "Trying to convert from a valueless iterator of concat_view.");
+    return __variant_detail::__visitation::__variant::__visit_value(
         [](const auto& __i) -> __concat_rvalue_reference_t<__maybe_const<_Const, _Views>...> {
           return ranges::iter_move(__i);
         },
@@ -539,7 +541,11 @@ class concat_view<_Views...>::__iterator {
     requires swappable_with<iter_reference_t<__iterator>, iter_reference_t<__iterator>> &&
              (... && indirectly_swappable<iterator_t<__maybe_const<_Const, _Views>>>)
   {
-    std::visit(
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+        !__x.__it_.valueless_by_exception(), "Trying to convert from a valueless iterator of concat_view.");
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+        !__y.__it_.valueless_by_exception(), "Trying to convert from a valueless iterator of concat_view.");
+    __variant_detail::__visitation::__variant::__visit_value(
         [&](const auto& __it1, const auto& __it2) {
           if constexpr (is_same_v<decltype(__it1), decltype(__it2)>) {
             ranges::iter_swap(__it1, __it2);

libcxx/test/std/ranges/range.adaptors/range.concat/iterator/ctor.pass.cpp

@@ -67,21 +67,6 @@ struct IterNoDefaultInitView : std::ranges::view_base {
   int* end();
 };
 
-struct ThrowOnCopyView : std::ranges::view_base {
-  int start_;
-  int* ptr_;
-  constexpr explicit ThrowOnCopyView(int* ptr = globalBuff, int start = 0) : start_(start), ptr_(ptr) {}
-  constexpr ThrowOnCopyView(ThrowOnCopyView&&) = default;
-  constexpr ThrowOnCopyView(const ThrowOnCopyView&) { throw 42; };
-  constexpr ThrowOnCopyView& operator=(ThrowOnCopyView&&) = default;
-  constexpr ThrowOnCopyView& operator=(const ThrowOnCopyView&) {
-    throw 42;
-    return *this;
-  };
-  constexpr int* begin() const { return ptr_ + start_; }
-  constexpr int* end() const { return ptr_ + 8; }
-};
-
 constexpr bool test() {
   std::ranges::concat_view<MoveOnlyView> concatView;
   auto iter = std::move(concatView).begin();

libcxx/test/std/ranges/range.adaptors/range.concat/iterator/decrement.pass.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 // REQUIRES: std-at-least-c++26
+// UNSUPPORTED: libcpp-hardening-mode=none, no-exceptions
 
 #include <ranges>
 
@@ -16,6 +17,7 @@
 #include <iterator>
 #include <utility>
 #include <vector>
+#include "check_assertion.h"
 #include "test_iterators.h"
 #include "test_macros.h"
 #include "../types.h"
@@ -81,6 +83,17 @@ constexpr void test() {
     assert(result == view.end());
     assert(it == (result - 1));
   }
+
+  {
+    //valueless by exception test
+    std::ranges::concat_view<ThrowOnCopyView> concatView_2;
+    std::ranges::iterator_t<std::ranges::concat_view<ThrowOnCopyView>> it1;
+    try {
+      it1 = concatView_2.begin();
+    } catch (...) {
+      TEST_LIBCPP_ASSERT_FAILURE([&] { (void)--*it1; }(), "valueless by exception");
+    }
+  }
 }
 
 int main(int, char**) {

libcxx/test/std/ranges/range.adaptors/range.concat/iterator/deref.pass.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 // REQUIRES: std-at-least-c++26
+// UNSUPPORTED: libcpp-hardening-mode=none, no-exceptions
 
 #include <ranges>
 
@@ -15,6 +16,7 @@
 #include <concepts>
 #include <cstddef>
 #include <utility>
+#include "check_assertion.h"
 #include "test_iterators.h"
 #include "test_macros.h"
 #include "../types.h"
@@ -36,6 +38,17 @@ constexpr void test() {
   int& result         = *iter;
   ASSERT_SAME_TYPE(int&, decltype(*iter));
   assert(&result == array.data());
+
+  {
+    //valueless by exception test
+    std::ranges::concat_view<ThrowOnCopyView> concatView_2;
+    std::ranges::iterator_t<std::ranges::concat_view<ThrowOnCopyView>> it1;
+    try {
+      it1 = concatView_2.begin();
+    } catch (...) {
+      TEST_LIBCPP_ASSERT_FAILURE([&] { (void)*it1; }(), "valueless by exception");
+    }
+  }
 }
 
 constexpr bool tests() {

libcxx/test/std/ranges/range.adaptors/range.concat/iterator/increment.pass.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 // REQUIRES: std-at-least-c++26
+// UNSUPPORTED: libcpp-hardening-mode=none, no-exceptions
 
 #include <ranges>
 
@@ -16,6 +17,7 @@
 #include <concepts>
 #include <type_traits>
 #include <utility>
+#include "check_assertion.h"
 #include "test_iterators.h"
 #include "test_macros.h"
 #include "../types.h"
@@ -61,6 +63,17 @@ constexpr void test() {
     ++it;
     assert(*it == array[4]);
   }
+
+  {
+    //valueless by exception test
+    std::ranges::concat_view<ThrowOnCopyView> concatView_2;
+    std::ranges::iterator_t<std::ranges::concat_view<ThrowOnCopyView>> it1;
+    try {
+      it1 = concatView_2.begin();
+    } catch (...) {
+      TEST_LIBCPP_ASSERT_FAILURE([&] { (void)++*it1; }(), "valueless by exception");
+    }
+  }
 }
 
 constexpr bool tests() {

libcxx/test/std/ranges/range.adaptors/range.concat/types.h

@@ -12,6 +12,8 @@
 #include <ranges>
 #include <utility>
 
+int globalArray[8] = {0, 1, 2, 3, 4, 5, 6, 7};
+
 struct TrackInitialization {
   constexpr explicit TrackInitialization(bool* moved, bool* copied) : moved_(moved), copied_(copied) {}
   constexpr TrackInitialization(TrackInitialization const& other) : moved_(other.moved_), copied_(other.copied_) {
@@ -41,4 +43,19 @@ struct minimal_view : std::ranges::view_base {
   decltype(base(std::declval<Sent>())) sent_;
 };
 
+struct ThrowOnCopyView : std::ranges::view_base {
+  int start_;
+  int* ptr_;
+  constexpr explicit ThrowOnCopyView(int* ptr = globalArray, int start = 0) : start_(start), ptr_(ptr) {}
+  constexpr ThrowOnCopyView(ThrowOnCopyView&&) = default;
+  constexpr ThrowOnCopyView(const ThrowOnCopyView&) { throw 42; };
+  constexpr ThrowOnCopyView& operator=(ThrowOnCopyView&&) = default;
+  constexpr ThrowOnCopyView& operator=(const ThrowOnCopyView&) {
+    throw 42;
+    return *this;
+  };
+  constexpr int* begin() const { return ptr_ + start_; }
+  constexpr int* end() const { return ptr_ + 8; }
+};
+
 #endif // TEST_STD_RANGES_RANGE_ADAPTORS_CONCAT_FILTER_TYPES_H