Re: [C++ PATCH] P0329R4: Designated Initialization

[Jason Merrill]

On Mon, Nov 13, 2017 at 5:53 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> +               /* If the element is an anonymous union object and the
> +                  initializer list is a designated-initializer-list, the
> +                  anonymous union object is initialized by the
> +                  designated-initializer-list { D }, where D is the
> +                  designated-initializer-clause naming a member of the
> +                  anonymous union object.  */
> +               next = build_constructor_single (type, ce->index, ce->value);

We need to use init_list_type_node for the CONSTRUCTOR so that
digest_init works properly.  Applying to trunk.

commit 9c34bc519821ca90cb37dce05744f404bb3a9991
Author: Jason Merrill <ja...@redhat.com>
Date:   Fri Mar 30 15:30:45 2018 -0400

    Fix designated initializer for anonymous union.
    
            * typeck2.c (process_init_constructor_record): Use
            init_list_type_node for the CONSTRUCTOR around an anonymous union
            designated initializer.

diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index 464e8a7c3b1..3aae0a362d5 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -1435,7 +1435,8 @@ process_init_constructor_record (tree type, tree init, int nested,
 		   designated-initializer-list { D }, where D is the
 		   designated-initializer-clause naming a member of the
 		   anonymous union object.  */
-		next = build_constructor_single (type, ce->index, ce->value);
+		next = build_constructor_single (init_list_type_node,
+						 ce->index, ce->value);
 	      else
 		{
 		  ce = NULL;
diff --git a/gcc/testsuite/g++.dg/cpp2a/desig9.C b/gcc/testsuite/g++.dg/cpp2a/desig9.C
new file mode 100644
index 00000000000..990a2aa20a5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/desig9.C
@@ -0,0 +1,13 @@
+// { dg-do compile }
+// { dg-options "" }
+
+struct A {
+  union {
+    int a;
+    char b;
+  };
+};
+
+struct A x = {
+  .a = 5,
+};