From 0ea89b15782a4ee92bae0175a0a963752c39076c Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Mon, 20 Apr 2020 22:06:32 +0100
Subject: [PATCH] libstdc++: Fix tests that fail in C++20 mode
* testsuite/20_util/is_constructible/51185.cc: Make test class a
non-aggregate so that the test verifies the same thing in all -std
modes.
* testsuite/20_util/is_constructible/value-2.cc: Adjust expected
results for some types when paren-init for aggregates is supported.
---
libstdc++-v3/ChangeLog | 6 ++++
.../20_util/is_constructible/51185.cc | 9 +++++-
.../20_util/is_constructible/value-2.cc | 31 ++++++++++++++-----
3 files changed, 37 insertions(+), 9 deletions(-)
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 9f4c9d327c3a..932e2afe8125 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,11 @@
2020-04-20 Jonathan Wakely <jwakely@redhat.com>
+ * testsuite/20_util/is_constructible/51185.cc: Make test class a
+ non-aggregate so that the test verifies the same thing in all -std
+ modes.
+ * testsuite/20_util/is_constructible/value-2.cc: Adjust expected
+ results for some types when paren-init for aggregates is supported.
+
* include/std/version (__cpp_lib_three_way_comparison): Update value.
* libsupc++/compare (__cpp_lib_three_way_comparison): Likewise.
(__detail::__synth3way): Add noexcept-specifier.
diff --git a/libstdc++-v3/testsuite/20_util/is_constructible/51185.cc b/libstdc++-v3/testsuite/20_util/is_constructible/51185.cc
index d2750d8607e2..8605135ad5a7 100644
--- a/libstdc++-v3/testsuite/20_util/is_constructible/51185.cc
+++ b/libstdc++-v3/testsuite/20_util/is_constructible/51185.cc
@@ -20,7 +20,14 @@
#include <type_traits>
struct A { };
-struct B : A { };
+struct B : A {
+#if __cpp_aggregate_bases && __cpp_aggregate_paren_init
+ // A user-declared constructor prevents B from being an aggregate.
+ // Otherwise 'B&& b{A{}};' becomes valid in C++17 (__cpp_aggregate_bases),
+ // and 'B&& b(A{});' becomes valid in C++17 (__cpp_aggregate_paren_init).
+ B();
+#endif
+};
// libstdc++/51185
void f()
diff --git a/libstdc++-v3/testsuite/20_util/is_constructible/value-2.cc b/libstdc++-v3/testsuite/20_util/is_constructible/value-2.cc
index c54b749c0463..8ba50e1efe7c 100644
--- a/libstdc++-v3/testsuite/20_util/is_constructible/value-2.cc
+++ b/libstdc++-v3/testsuite/20_util/is_constructible/value-2.cc
@@ -216,12 +216,20 @@ static_assert(std::is_constructible<const B&&, D&&>::value, "Error");
static_assert(!std::is_constructible<B&, const D&>::value, "Error");
static_assert(!std::is_constructible<B&&, const D&&>::value, "Error");
+#if __cpp_aggregate_bases && __cpp_aggregate_paren_init
+// In C++20 an rvalue reference or const lvalue reference can bind to a
+// temporary of aggregate type that is initialized from a base class value.
+constexpr bool v = true;
+#else
+constexpr bool v = false;
+#endif
+
static_assert(!std::is_constructible<D&, B&>::value, "Error");
-static_assert(!std::is_constructible<D&&, B&&>::value, "Error");
+static_assert(v == std::is_constructible<D&&, B&&>::value, "Error");
static_assert(!std::is_constructible<D&, const B&>::value, "Error");
-static_assert(!std::is_constructible<D&&, const B&&>::value, "Error");
-static_assert(!std::is_constructible<const D&, B&>::value, "Error");
-static_assert(!std::is_constructible<const D&&, B&&>::value, "Error");
+static_assert(v == std::is_constructible<D&&, const B&&>::value, "Error");
+static_assert(v == std::is_constructible<const D&, B&>::value, "Error");
+static_assert(v == std::is_constructible<const D&&, B&&>::value, "Error");
static_assert(!std::is_constructible<B&&, B&>::value, "Error");
static_assert(!std::is_constructible<B&&, D&>::value, "Error");
@@ -754,14 +762,21 @@ static_assert(!std::is_constructible<FromArgs<std::initializer_list<int>&,
std::initializer_list<B>&>, std::initializer_list<int>,
std::initializer_list<B>>::value, "Error");
+#if __cpp_aggregate_paren_init
+// In C++20 arrays can be initialized using parentheses.
+constexpr bool w = true;
+#else
+constexpr bool w = false;
+#endif
+
static_assert(!std::is_constructible<FromArgs<std::initializer_list<int>>,
int, int>::value, "Error");
static_assert(!std::is_constructible<const
FromArgs<std::initializer_list<int>>, int, int>::value, "Error");
-static_assert(!std::is_constructible<B[2], B, B>::value, "Error");
-static_assert(!std::is_constructible<const B[2], B, B>::value, "Error");
-static_assert(!std::is_constructible<U[2], U, U>::value, "Error");
-static_assert(!std::is_constructible<const U[2], U, U>::value, "Error");
+static_assert(w == std::is_constructible<B[2], B, B>::value, "Error");
+static_assert(w == std::is_constructible<const B[2], B, B>::value, "Error");
+static_assert(w == std::is_constructible<U[2], U, U>::value, "Error");
+static_assert(w == std::is_constructible<const U[2], U, U>::value, "Error");
static_assert(!std::is_constructible<E, E, E>::value, "Error");
static_assert(!std::is_constructible<const E, E, E>::value, "Error");
--
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