C++ PATCH for c++/48537 (ICE with value-initialization of union with deleted ctor)

[Jason Merrill]

The check for UNION_TYPE predates the C++0x extension of unions to allow 
members with constructors; now we can have a union that needs 
non-trivial initialization.

Tested x86_64-pc-linux-gnu, applying to trunk and 4.6.
commit 019dffcf98bb95ebbcb9180d76293b899d674ecf
Author: Jason Merrill <ja...@redhat.com>
Date:   Mon Apr 18 10:32:55 2011 -0700
        PR c++/48537
        * init.c (build_value_init): Handle UNION_TYPE the same.

diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 3280d9b..04d2bb2 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -343,7 +343,7 @@ build_value_init (tree type, tsubst_flags_t complain)
                                      NULL, type, LOOKUP_NORMAL,
                                      complain),
           complain);
-      else if (TREE_CODE (type) != UNION_TYPE && TYPE_NEEDS_CONSTRUCTING 
(type))
+      else if (TYPE_NEEDS_CONSTRUCTING (type))
        {
          /* This is a class that needs constructing, but doesn't have
             a user-provided constructor.  So we need to zero-initialize
diff --git a/gcc/testsuite/g++.dg/cpp0x/union4.C 
b/gcc/testsuite/g++.dg/cpp0x/union4.C
new file mode 100644
index 0000000..0705047
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/union4.C
@@ -0,0 +1,17 @@
+// PR c++/48537
+// { dg-options -std=c++0x }
+
+struct SFoo
+{
+  SFoo() =delete;              // { dg-error "declared" }
+};
+
+union UFoo                     // { dg-error "deleted" }
+{
+  SFoo foo;
+};
+
+int main()
+{
+  UFoo();                      // { dg-error "deleted" }
+}