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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/102482] Winit-list-lifetime false positive for temporaries
 with std::initializer_list
Date: Wed, 29 Sep 2021 10:16:59 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102482

--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #6)
> The warning should not trigger if the constructor takes the initializer_l=
ist
> by non-const lvalue reference.

I think this change to cp/init.c:maybe_warn_list_ctor will check if the
initializer_list parameter is a non-const lvalue reference:

--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -750,7 +750,8 @@ maybe_warn_list_ctor (tree member, tree init)
     return;

   tree parms =3D FUNCTION_FIRST_USER_PARMTYPE (current_function_decl);
-  tree initlist =3D non_reference (TREE_VALUE (parms));
+  tree parm1 =3D TREE_VALUE (parms);
+  tree initlist =3D non_reference (parm1);
   tree targs =3D CLASSTYPE_TI_ARGS (initlist);
   tree elttype =3D TREE_VEC_ELT (targs, 0);

@@ -758,6 +759,10 @@ maybe_warn_list_ctor (tree member, tree init)
       (TREE_TYPE (memtype), elttype))
     return;

+  if (TYPE_REF_P (parm1) && !TYPE_REF_IS_RVALUE (parm1)
+      && !(cp_type_quals (initlist) & TYPE_QUAL_CONST))
+    return;
+
   tree begin =3D find_list_begin (init);
   if (!begin)
     return;=