libstdc++: Add valid range checks to std::span constructors [PR98421]

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/98421
	* include/std/span (span(Iter, size_type), span(Iter, Iter)):
	Add valid range checks.
	* testsuite/23_containers/span/cons_1_assert_neg.cc: New test.
	* testsuite/23_containers/span/cons_2_assert_neg.cc: New test.

2 files changed, 28 insertions, 0 deletions

diff --git a/libstdc++-v3/testsuite/23_containers/span/cons_1_assert_neg.cc b/libstdc++-v3/testsuite/23_containers/span/cons_1_assert_neg.cc
new file mode 100644
index 00000000000..2f555125453
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/span/cons_1_assert_neg.cc
@@ -0,0 +1,14 @@
+// { dg-options "-std=gnu++2a" }
+// { dg-do run { xfail *-*-* } }
+// { dg-require-effective-target c++2a }
+
+#undef _GLIBCXX_DEBUG
+#define _GLIBCXX_DEBUG
+#include <span>
+#include <vector>
+
+int main()
+{
+  std::vector<int> v(2);
+  std::span<int, std::dynamic_extent> s(v.begin(), 3);
+}
diff --git a/libstdc++-v3/testsuite/23_containers/span/cons_2_assert_neg.cc b/libstdc++-v3/testsuite/23_containers/span/cons_2_assert_neg.cc
new file mode 100644
index 00000000000..efef0e608ba
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/span/cons_2_assert_neg.cc
@@ -0,0 +1,14 @@
+// { dg-options "-std=gnu++2a" }
+// { dg-do run { xfail *-*-* } }
+// { dg-require-effective-target c++2a }
+
+#undef _GLIBCXX_DEBUG
+#define _GLIBCXX_DEBUG
+#include <span>
+#include <vector>
+
+int main()
+{
+  std::vector<int> v(2), w(1);
+  std::span<int, std::dynamic_extent> s(v.begin(), w.end());
+}