On 3/10/23 14:07, Marek Polacek wrote:
std::span is a view and therefore should be treated as a reference
wrapper class for the purposes of -Wdangling-reference. I'm not sure
there's a pattern that we could check for.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK.
PR c++/107532
gcc/cp/ChangeLog:
* call.cc (reference_like_class_p): Check for std::span.
gcc/testsuite/ChangeLog:
* g++.dg/warn/Wdangling-reference10.C: New test.
---
gcc/cp/call.cc | 1 +
gcc/testsuite/g++.dg/warn/Wdangling-reference10.C | 12 ++++++++++++
2 files changed, 13 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/warn/Wdangling-reference10.C
diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
index 3dfa12a0733..c01e7b82457 100644
--- a/gcc/cp/call.cc
+++ b/gcc/cp/call.cc
@@ -13800,6 +13800,7 @@ reference_like_class_p (tree ctype)
tree name = DECL_NAME (tdecl);
return (name
&& (id_equal (name, "reference_wrapper")
+ || id_equal (name, "span")
|| id_equal (name, "ref_view")));
}
for (tree fields = TYPE_FIELDS (ctype);
diff --git a/gcc/testsuite/g++.dg/warn/Wdangling-reference10.C
b/gcc/testsuite/g++.dg/warn/Wdangling-reference10.C
new file mode 100644
index 00000000000..733fb8cce63
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wdangling-reference10.C
@@ -0,0 +1,12 @@
+// PR c++/107532
+// { dg-do compile { target c++20 } }
+// { dg-options "-Wdangling-reference" }
+
+#include <span>
+#include <vector>
+
+void f(const std::vector<int>& v)
+{
+ const int& r = std::span<const int>(v)[0]; // { dg-bogus "dangling
reference" }
+ (void) r;
+}
base-commit: 20d790aa3ea5b0d240032cab997b8e0938cac62c
