Hi!
As mentioned in the PR, C++98 didn't allow static data members nor any
members with reference type, and r211318 guarded all that with cxx_dialect <
cxx11. Which is correct for the VAR_P check, but as C++11 and later
says that non-static data members of reference type are ill-formed in
unions, for C++11 and later we need to allow reference type on static data
members and disallow it on FIELD_DECLs.
On some testcases the invalid C++11+ would work fine, but on the attached
pr78890-1.C g++ ICEd.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2017-01-02 Jakub Jelinek <ja...@redhat.com>
PR c++/78890
* class.c (check_field_decls): Diagnose REFERENCE_TYPE fields in
unions even for C++11 and later.
* g++.dg/init/ref14.C: Expect error even in C++11 and later.
* g++.dg/init/union1.C: Likewise.
* g++.dg/cpp0x/union6.C: Expect errors.
* g++.dg/cpp0x/union8.C: New test.
* g++.dg/cpp0x/pr78890-1.C: New test.
* g++.dg/cpp0x/pr78890-2.C: New test.
--- gcc/cp/class.c.jj 2017-01-01 12:45:44.000000000 +0100
+++ gcc/cp/class.c 2017-01-02 10:03:43.119034899 +0100
@@ -3759,16 +3759,17 @@ check_field_decls (tree t, tree *access_
/* When this goes into scope, it will be a non-local reference. */
DECL_NONLOCAL (x) = 1;
- if (TREE_CODE (t) == UNION_TYPE
- && cxx_dialect < cxx11)
+ if (TREE_CODE (t) == UNION_TYPE)
{
/* [class.union] (C++98)
If a union contains a static data member, or a member of
reference type, the program is ill-formed.
- In C++11 this limitation doesn't exist anymore. */
- if (VAR_P (x))
+ In C++11 [class.union] says:
+ If a union contains a non-static data member of reference type
+ the program is ill-formed. */
+ if (VAR_P (x) && cxx_dialect < cxx11)
{
error ("in C++98 %q+D may not be static because it is "
"a member of a union", x);
@@ -3776,9 +3777,18 @@ check_field_decls (tree t, tree *access_
}
if (TREE_CODE (type) == REFERENCE_TYPE)
{
- error ("in C++98 %q+D may not have reference type %qT "
- "because it is a member of a union", x, type);
- continue;
+ if (cxx_dialect < cxx11)
+ {
+ error ("in C++98 %q+D may not have reference type %qT "
+ "because it is a member of a union", x, type);
+ continue;
+ }
+ else if (TREE_CODE (x) == FIELD_DECL)
+ {
+ error ("non-static data member %q+D in a union may not "
+ "have reference type %qT", x, type);
+ continue;
+ }
}
}
--- gcc/testsuite/g++.dg/init/ref14.C.jj 2014-06-09 11:01:13.000000000
+0200
+++ gcc/testsuite/g++.dg/init/ref14.C 2017-01-02 10:10:47.629616381 +0100
@@ -4,7 +4,7 @@
union A
{
- int &i; // { dg-error "may not have reference type" "" { target { ! c++11 }
} }
+ int &i; // { dg-error "may not have reference type" }
};
void foo()
--- gcc/testsuite/g++.dg/init/union1.C.jj 2014-06-09 11:01:13.000000000
+0200
+++ gcc/testsuite/g++.dg/init/union1.C 2017-01-02 10:11:05.667386144 +0100
@@ -1,5 +1,5 @@
// PR c++/14401
union U {
- int& i; // { dg-error "reference type" "" { target { ! c++11 } } }
+ int& i; // { dg-error "reference type" }
};
--- gcc/testsuite/g++.dg/cpp0x/union6.C.jj 2014-06-09 11:01:13.000000000
+0200
+++ gcc/testsuite/g++.dg/cpp0x/union6.C 2017-01-02 10:10:20.152967097 +0100
@@ -12,9 +12,9 @@ union Test2 {
const int Test2::kConstant = 10;
union Test3 {
- int& kConstant;
+ int& kConstant; // { dg-error "may not have reference type" }
};
union Test4 {
- const int& kConstant = 10;
+ const int& kConstant = 10; // { dg-error "may not have reference type" }
};
--- gcc/testsuite/g++.dg/cpp0x/union8.C.jj 2017-01-02 10:30:59.981111680
+0100
+++ gcc/testsuite/g++.dg/cpp0x/union8.C 2017-01-02 10:32:05.715270255 +0100
@@ -0,0 +1,26 @@
+// PR c++/78890
+// { dg-do compile { target c++11 } }
+
+union Test1 {
+ static int kConstant;
+};
+
+union Test2 {
+ static const int kConstant;
+};
+
+const int Test2::kConstant = 10;
+
+int k;
+
+union Test3 {
+ static int& kRef;
+};
+
+int& Test3::kRef = k;
+
+union Test4 {
+ static const int& kRef;
+};
+
+const int& Test4::kRef = 10;
--- gcc/testsuite/g++.dg/cpp0x/pr78890-1.C.jj 2017-01-02 10:24:42.406944789
+0100
+++ gcc/testsuite/g++.dg/cpp0x/pr78890-1.C 2017-01-02 10:24:38.101999895
+0100
@@ -0,0 +1,13 @@
+// PR c++/78890
+// { dg-do compile { target c++11 } }
+
+int
+main()
+{
+ union {
+ int a;
+ int &b = a; // { dg-error "may not have reference type" }
+ };
+ a = 1;
+ auto c = b + 1;
+}
--- gcc/testsuite/g++.dg/cpp0x/pr78890-2.C.jj 2017-01-02 10:24:45.619903662
+0100
+++ gcc/testsuite/g++.dg/cpp0x/pr78890-2.C 2017-01-02 10:24:26.960142515
+0100
@@ -0,0 +1,44 @@
+// PR c++/78890
+// { dg-do compile { target c++11 } }
+
+template <typename T>
+int
+foo ()
+{
+ union {
+ int a;
+ int &b = a; // { dg-error "may not have reference
type" }
+ };
+ a = 1;
+ auto c = b + 1;
+ return c;
+}
+
+template <typename T>
+T
+bar ()
+{
+ union {
+ T a;
+ T &b = a; // { dg-error "may not have reference type" }
+ };
+ a = 1;
+ auto c = b + 1;
+ return c;
+}
+
+template <typename T, typename U>
+T baz()
+{
+ union {
+ T a;
+ U b = a; // { dg-error "may not have reference type" }
+ };
+ a = 1;
+ auto c = b + 1;
+ return c;
+}
+
+int a = foo<int> ();
+int b = bar<int> ();
+int c = baz<int, int &> ();
Jakub
