[C++ Patch] PR 60184

[Paolo Carlini]

Hi,

this rejects-valid issue, as submitted, has only the testcase:

union Test {
   static constexpr int kConstant = 10;
};

which seems easy to handle by adjusting check_field_decls. While doing 
that, I also noticed that the same piece of C++98 which went away in 
C++11, thus allowing static members in unions, also mentioned 
reference-types, which therefore, should be now also allowed (current 
ICC agrees, current clang disagrees). Tested x86_64-linux.

Thanks,
Paolo.

////////////////////
-------------- next part --------------
/cp
2014-06-06  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/60184
	* class.c (check_field_decls): In C++11 mode do not reject constexpr
	static members and reference-type members of unions.

/testsuite
2014-06-06  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/60184
	* g++.dg/cpp0x/constexpr-union6.C: New.
	* g++.dg/cpp0x/union6.C: Likewise.
	* g++.dg/init/ref14.C: Adjust.
	* g++.dg/init/union1.C: Likewise.
-------------- next part --------------
Index: cp/class.c
===================================================================
--- cp/class.c	(revision 211309)
+++ cp/class.c	(working copy)
@@ -3480,21 +3480,25 @@ check_field_decls (tree t, tree *access_decls,
       /* When this goes into scope, it will be a non-local reference.  */
       DECL_NONLOCAL (x) = 1;
 
-      if (TREE_CODE (t) == UNION_TYPE)
+      if (TREE_CODE (t) == UNION_TYPE
+	  && cxx_dialect < cxx11)
 	{
-	  /* [class.union]
+	  /* [class.union] (C++98)
 
 	     If a union contains a static data member, or a member of
-	     reference type, the program is ill-formed.  */
+	     reference type, the program is ill-formed.
+
+	     In C++11 this limitation doesn't exist anymore.  */
 	  if (VAR_P (x))
 	    {
-	      error ("%q+D may not be static because it is a member of a union", x);
+	      error ("in C++98 %q+D may not be static because it is "
+		     "a member of a union", x);
 	      continue;
 	    }
 	  if (TREE_CODE (type) == REFERENCE_TYPE)
 	    {
-	      error ("%q+D may not have reference type %qT because"
-		     " it is a member of a union",
+	      error ("in C++98 %q+D may not have reference type %qT "
+		     "because it is a member of a union",
 		     x, type);
 	      continue;
 	    }
Index: testsuite/g++.dg/cpp0x/constexpr-union6.C
===================================================================
--- testsuite/g++.dg/cpp0x/constexpr-union6.C	(revision 0)
+++ testsuite/g++.dg/cpp0x/constexpr-union6.C	(working copy)
@@ -0,0 +1,10 @@
+// PR c++/60184
+// { dg-do compile { target c++11 } }
+
+union Test1 {
+  static constexpr int kConstant = 10;
+};
+
+union Test2 {
+  static constexpr const int& kConstant = Test1::kConstant;
+};
Index: testsuite/g++.dg/cpp0x/union6.C
===================================================================
--- testsuite/g++.dg/cpp0x/union6.C	(revision 0)
+++ testsuite/g++.dg/cpp0x/union6.C	(working copy)
@@ -0,0 +1,20 @@
+// PR c++/60184
+// { dg-do compile { target c++11 } }
+
+union Test1 {
+  static int kConstant;
+};
+
+union Test2 {
+  static const int kConstant;
+};
+
+const int Test2::kConstant = 10;
+
+union Test3 {
+  int& kConstant;
+};
+
+union Test4 {
+  const int& kConstant = 10;
+};
Index: testsuite/g++.dg/init/ref14.C
===================================================================
--- testsuite/g++.dg/init/ref14.C	(revision 211309)
+++ testsuite/g++.dg/init/ref14.C	(working copy)
@@ -4,7 +4,7 @@
 
 union A
 {
-  int &i; // { dg-error "may not have reference type" }
+  int &i; // { dg-error "may not have reference type" "" { target { ! c++11 } } }
 };
 
 void foo()
Index: testsuite/g++.dg/init/union1.C
===================================================================
--- testsuite/g++.dg/init/union1.C	(revision 211309)
+++ testsuite/g++.dg/init/union1.C	(working copy)
@@ -1,5 +1,5 @@
 // PR c++/14401
 
 union U {
-  int& i; // { dg-error "" }
+  int& i; // { dg-error "reference type" "" { target { ! c++11 } } }
 };