From b1a8b92f8f78536a00012e2e53a0d12ddbe6836d Mon Sep 17 00:00:00 2001
From: Marek Polacek <polacek@redhat.com>
Date: Fri, 28 Jan 2022 20:01:06 -0500
Subject: c++: Reject union std::initializer_list [PR102434]

Weird things are going to happen if you define your std::initializer_list
as a union.  In this case, we crash in output_constructor_regular_field.

Let's not allow such a definition in the first place.

	PR c++/102434

gcc/cp/ChangeLog:

	* class.cc (finish_struct): Don't allow union initializer_list.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/initlist128.C: New test.
---
 gcc/cp/class.cc | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'gcc/cp/class.cc')

diff --git a/gcc/cp/class.cc b/gcc/cp/class.cc
index 5db3722..6961557 100644
--- a/gcc/cp/class.cc
+++ b/gcc/cp/class.cc
@@ -7766,6 +7766,8 @@ finish_struct (tree t, tree attributes)
 		ok = true;
 	    }
 	}
+      /* It also cannot be a union.  */
+      ok &= NON_UNION_CLASS_TYPE_P (t);
       if (!ok)
 	fatal_error (input_location, "definition of %qD does not match "
 		     "%<#include <initializer_list>%>", TYPE_NAME (t));
-- 
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