c++: Do not warn about lifetime of std::initializer_list<T>& [PR102482]

An initializer-list constructor taking a non-const lvalue cannot be
called with a temporary, so the array's lifetime probably doesn't end
with the full expression. -Winit-list-lifetime should not warn for that
case.

	PR c++/102482

gcc/cp/ChangeLog:

	* init.c (maybe_warn_list_ctor): Do not warn for a reference to
	a non-const std::initializer_list.

gcc/testsuite/ChangeLog:

	* g++.dg/warn/Winit-list5.C: New test.

1 files changed, 61 insertions, 0 deletions

diff --git a/gcc/testsuite/g++.dg/warn/Winit-list5.C b/gcc/testsuite/g++.dg/warn/Winit-list5.C
new file mode 100644
index 0000000..07b3a69
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Winit-list5.C
@@ -0,0 +1,61 @@
+// PR c++/102482
+// { dg-do compile { target c++11 } }
+// Test we don't warn for non-const lvalue refs.
+
+#include <initializer_list>
+
+struct X { };
+
+struct span
+{
+  span(std::initializer_list<int>& il)
+  : begin(il.begin()) // { dg-bogus "initializer_list" }
+  { }
+
+  const int* begin;
+};
+
+struct span_warn
+{
+  span_warn(std::initializer_list<int> il)
+  : begin(il.begin()) // { dg-warning "initializer_list" }
+  { }
+
+  const int* begin;
+};
+
+struct span_warn2
+{
+  span_warn2(std::initializer_list<int>&& il)
+  : begin(il.begin()) // { dg-warning "initializer_list" }
+  { }
+
+  const int* begin;
+};
+
+struct span_warn3
+{
+  span_warn3(std::initializer_list<int> const& il)
+  : begin(il.begin()) // { dg-warning "initializer_list" }
+  { }
+
+  const int* begin;
+};
+
+struct span_warn4
+{
+  span_warn4(std::initializer_list<int> const il)
+  : begin(il.begin()) // { dg-warning "initializer_list" }
+  { }
+
+  const int* begin;
+};
+
+struct span_warn5
+{
+  span_warn5(std::initializer_list<int> const&& il)
+  : begin(il.begin()) // { dg-warning "initializer_list" }
+  { }
+
+  const int* begin;
+};