[C++ PATCH] Reject invalid reference type non-static data members in unions (PR c++/78890)
Jason Merrill
jason@redhat.com
Thu Jan 5 20:52:00 GMT 2017
OK.
On Wed, Jan 4, 2017 at 5:07 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Wed, Jan 04, 2017 at 04:24:55PM -0500, Jason Merrill wrote:
>> On Mon, Jan 2, 2017 at 2:32 PM, Jakub Jelinek <jakub@redhat.com> wrote:
>> > 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;
>> > + }
>>
>> I don't think we need the old error anymore; in C++98 mode we will
>> have already complained about a static data member reference, so we
>> can drop the above and just keep the below.
>>
>> > + 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;
>> > + }
>
> Like this? Ok for trunk if bootstrap/regtest passes (just started them;
> make check-c++-all didn't show regressions)?
>
> 2017-01-04 Jakub Jelinek <jakub@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 2017-01-03 08:12:27.154511815 +0100
> +++ gcc/cp/class.c 2017-01-04 22:41:32.669279309 +0100
> @@ -3759,25 +3759,27 @@ 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);
> continue;
> }
> - if (TREE_CODE (type) == REFERENCE_TYPE)
> + if (TREE_CODE (type) == REFERENCE_TYPE
> + && TREE_CODE (x) == FIELD_DECL)
> {
> - error ("in C++98 %q+D may not have reference type %qT "
> - "because it is a member of a union", x, type);
> + 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 2017-01-03 08:12:26.878515378 +0100
> +++ gcc/testsuite/g++.dg/init/ref14.C 2017-01-04 22:40:35.789996635 +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 2017-01-03 08:12:26.862515585 +0100
> +++ gcc/testsuite/g++.dg/init/union1.C 2017-01-04 22:40:35.789996635 +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/pr78890-2.C.jj 2017-01-04 22:40:35.821996232 +0100
> +++ gcc/testsuite/g++.dg/cpp0x/pr78890-2.C 2017-01-04 22:40:35.821996232 +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 &> ();
> --- gcc/testsuite/g++.dg/cpp0x/union8.C.jj 2017-01-04 22:40:35.820996244 +0100
> +++ gcc/testsuite/g++.dg/cpp0x/union8.C 2017-01-04 22:40:35.820996244 +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/union6.C.jj 2017-01-03 08:12:26.926514759 +0100
> +++ gcc/testsuite/g++.dg/cpp0x/union6.C 2017-01-04 22:40:35.820996244 +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/pr78890-1.C.jj 2017-01-04 22:40:35.820996244 +0100
> +++ gcc/testsuite/g++.dg/cpp0x/pr78890-1.C 2017-01-04 22:40:35.820996244 +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;
> +}
>
>
> Jakub
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