[C++ PATCH] Fix PR641, 11876 (Excessive friend declaration warning)
Kriang Lerdsuwanakij
lerdsuwa@users.sourceforge.net
Fri Aug 22 13:45:00 GMT 2003
Hi
Currently, friend declaration in code like
template <class T> class X {
friend class X<int>;
...
};
triggers a warning about X<int> is a friend of itself during
template instantiation of X<int>. I feel that cases like this
do not quite justify the warning. I propose the following patch
that only issue such diagnostics only during parsing. So
during template instantiation, we silently ignore the friend
declaration. With the above approach, we still provide a warning
for case like
class X {
friend class X;
};
Tested on i686-pc-linux-gnu. OK for mainline?
2003-08-22 Kriang Lerdsuwanakij <lerdsuwa@users.sourceforge.net>
PR c++/641, c++/11876
* friend.c (add_friend): Add complain parameter.
(make_friend_class): Likewise.
(do_friend): Adjust add_friend call.
* decl.c (grokdeclarator): Adjust make_friend_class call.
* parser.c (cp_parser_member_declaration): Likewise.
(cp_parser_template_declaration_after_exp): Likewise.
* pt.c (instantiate_class_template): Adjust make_friend_class
and add_friend call.
* cp-tree.h (make_friend_class): Adjust declaration.
(add_friend): Likewise.
2003-08-22 Kriang Lerdsuwanakij <lerdsuwa@users.sourceforge.net>
PR c++/641, c++/11876
* g++.dg/template/friend22.C: New test.
* g++.dg/template/friend23.C: Likewise.
diff -cprN gcc-main-save/gcc/cp/cp-tree.h gcc-main-new/gcc/cp/cp-tree.h
*** gcc-main-save/gcc/cp/cp-tree.h Thu Aug 14 19:58:57 2003
--- gcc-main-new/gcc/cp/cp-tree.h Mon Aug 18 22:29:24 2003
*************** extern tree cplus_expand_constant
*** 3838,3845 ****
/* friend.c */
extern int is_friend (tree, tree);
! extern void make_friend_class (tree, tree);
! extern void add_friend (tree, tree);
extern tree do_friend (tree, tree, tree, tree, tree, enum overload_flags, tree, int);
/* in init.c */
--- 3838,3845 ----
/* friend.c */
extern int is_friend (tree, tree);
! extern void make_friend_class (tree, tree, bool);
! extern void add_friend (tree, tree, bool);
extern tree do_friend (tree, tree, tree, tree, tree, enum overload_flags, tree, int);
/* in init.c */
diff -cprN gcc-main-save/gcc/cp/decl.c gcc-main-new/gcc/cp/decl.c
*** gcc-main-save/gcc/cp/decl.c Thu Aug 14 19:58:57 2003
--- gcc-main-new/gcc/cp/decl.c Mon Aug 18 22:30:35 2003
*************** grokdeclarator (tree declarator,
*** 11266,11272 ****
{
/* A friendly class? */
if (current_class_type)
! make_friend_class (current_class_type, TYPE_MAIN_VARIANT (type));
else
error ("trying to make class `%T' a friend of global scope",
type);
--- 11266,11273 ----
{
/* A friendly class? */
if (current_class_type)
! make_friend_class (current_class_type, TYPE_MAIN_VARIANT (type),
! /*complain=*/true);
else
error ("trying to make class `%T' a friend of global scope",
type);
diff -cprN gcc-main-save/gcc/cp/friend.c gcc-main-new/gcc/cp/friend.c
*** gcc-main-save/gcc/cp/friend.c Thu Jul 17 22:46:21 2003
--- gcc-main-new/gcc/cp/friend.c Mon Aug 18 22:29:23 2003
*************** is_friend (tree type, tree supplicant)
*** 127,136 ****
}
/* Add a new friend to the friends of the aggregate type TYPE.
! DECL is the FUNCTION_DECL of the friend being added. */
void
! add_friend (tree type, tree decl)
{
tree typedecl;
tree list;
--- 127,140 ----
}
/* Add a new friend to the friends of the aggregate type TYPE.
! DECL is the FUNCTION_DECL of the friend being added.
!
! If COMPLAIN is true, warning about duplicate friend is issued.
! We want to have this diagnostics during parsing but not
! when a template is being instantiated. */
void
! add_friend (tree type, tree decl, bool complain)
{
tree typedecl;
tree list;
*************** add_friend (tree type, tree decl)
*** 153,162 ****
{
if (decl == TREE_VALUE (friends))
{
! warning ("`%D' is already a friend of class `%T'",
! decl, type);
! cp_warning_at ("previous friend declaration of `%D'",
! TREE_VALUE (friends));
return;
}
}
--- 157,169 ----
{
if (decl == TREE_VALUE (friends))
{
! if (complain)
! {
! warning ("`%D' is already a friend of class `%T'",
! decl, type);
! cp_warning_at ("previous friend declaration of `%D'",
! TREE_VALUE (friends));
! }
return;
}
}
*************** add_friend (tree type, tree decl)
*** 192,201 ****
classes that are not defined. If a type has not yet been defined,
then the DECL_WAITING_FRIENDS contains a list of types
waiting to make it their friend. Note that these two can both
! be in use at the same time! */
void
! make_friend_class (tree type, tree friend_type)
{
tree classes;
int is_template_friend;
--- 199,212 ----
classes that are not defined. If a type has not yet been defined,
then the DECL_WAITING_FRIENDS contains a list of types
waiting to make it their friend. Note that these two can both
! be in use at the same time!
!
! If COMPLAIN is true, warning about duplicate friend is issued.
! We want to have this diagnostics during parsing but not
! when a template is being instantiated. */
void
! make_friend_class (tree type, tree friend_type, bool complain)
{
tree classes;
int is_template_friend;
*************** make_friend_class (tree type, tree frien
*** 227,234 ****
}
else if (same_type_p (type, friend_type))
{
! pedwarn ("class `%T' is implicitly friends with itself",
! type);
return;
}
else
--- 238,246 ----
}
else if (same_type_p (type, friend_type))
{
! if (complain)
! pedwarn ("class `%T' is implicitly friends with itself",
! type);
return;
}
else
*************** make_friend_class (tree type, tree frien
*** 275,282 ****
{
if (friend_type == probe)
{
! warning ("`%D' is already a friend of `%T'",
! probe, type);
break;
}
}
--- 287,295 ----
{
if (friend_type == probe)
{
! if (complain)
! warning ("`%D' is already a friend of `%T'",
! probe, type);
break;
}
}
*************** make_friend_class (tree type, tree frien
*** 284,291 ****
{
if (same_type_p (probe, friend_type))
{
! warning ("`%T' is already a friend of `%T'",
! probe, type);
break;
}
}
--- 297,305 ----
{
if (same_type_p (probe, friend_type))
{
! if (complain)
! warning ("`%T' is already a friend of `%T'",
! probe, type);
break;
}
}
*************** do_friend (tree ctype, tree declarator,
*** 369,375 ****
parameters. Instead, we rely on tsubst_friend_function
to check the validity of the declaration later. */
if (processing_template_decl)
! add_friend (current_class_type, decl);
/* A nested class may declare a member of an enclosing class
to be a friend, so we do lookup here even if CTYPE is in
the process of being defined. */
--- 383,389 ----
parameters. Instead, we rely on tsubst_friend_function
to check the validity of the declaration later. */
if (processing_template_decl)
! add_friend (current_class_type, decl, /*complain=*/true);
/* A nested class may declare a member of an enclosing class
to be a friend, so we do lookup here even if CTYPE is in
the process of being defined. */
*************** do_friend (tree ctype, tree declarator,
*** 378,384 ****
decl = check_classfn (ctype, decl);
if (decl)
! add_friend (current_class_type, decl);
}
else
error ("member `%D' declared as friend before type `%T' defined",
--- 392,398 ----
decl = check_classfn (ctype, decl);
if (decl)
! add_friend (current_class_type, decl, /*complain=*/true);
}
else
error ("member `%D' declared as friend before type `%T' defined",
*************** do_friend (tree ctype, tree declarator,
*** 446,452 ****
}
add_friend (current_class_type,
! is_friend_template ? DECL_TI_TEMPLATE (decl) : decl);
DECL_FRIEND_P (decl) = 1;
}
--- 460,467 ----
}
add_friend (current_class_type,
! is_friend_template ? DECL_TI_TEMPLATE (decl) : decl,
! /*complain=*/true);
DECL_FRIEND_P (decl) = 1;
}
diff -cprN gcc-main-save/gcc/cp/parser.c gcc-main-new/gcc/cp/parser.c
*** gcc-main-save/gcc/cp/parser.c Thu Aug 14 19:58:57 2003
--- gcc-main-new/gcc/cp/parser.c Mon Aug 18 22:30:35 2003
*************** cp_parser_member_declaration (cp_parser*
*** 11771,11777 ****
error ("friend declaration does not name a class or "
"function");
else
! make_friend_class (current_class_type, type);
}
/* If there is no TYPE, an error message will already have
been issued. */
--- 11771,11778 ----
error ("friend declaration does not name a class or "
"function");
else
! make_friend_class (current_class_type, type,
! /*complain=*/true);
}
/* If there is no TYPE, an error message will already have
been issued. */
*************** cp_parser_template_declaration_after_exp
*** 13567,13573 ****
if (member_p && !friend_p && decl)
decl = finish_member_template_decl (decl);
else if (friend_p && decl && TREE_CODE (decl) == TYPE_DECL)
! make_friend_class (current_class_type, TREE_TYPE (decl));
}
/* We are done with the current parameter list. */
--parser->num_template_parameter_lists;
--- 13568,13575 ----
if (member_p && !friend_p && decl)
decl = finish_member_template_decl (decl);
else if (friend_p && decl && TREE_CODE (decl) == TYPE_DECL)
! make_friend_class (current_class_type, TREE_TYPE (decl),
! /*complain=*/true);
}
/* We are done with the current parameter list. */
--parser->num_template_parameter_lists;
diff -cprN gcc-main-save/gcc/cp/pt.c gcc-main-new/gcc/cp/pt.c
*** gcc-main-save/gcc/cp/pt.c Thu Aug 14 19:58:57 2003
--- gcc-main-new/gcc/cp/pt.c Mon Aug 18 22:30:36 2003
*************** instantiate_class_template (tree type)
*** 5360,5373 ****
++processing_template_decl;
if (new_friend_type != error_mark_node)
! make_friend_class (type, new_friend_type);
if (TREE_CODE (friend_type) == TEMPLATE_DECL)
--processing_template_decl;
}
else
/* Build new DECL_FRIENDLIST. */
! add_friend (type, tsubst_friend_function (t, args));
}
}
--- 5360,5375 ----
++processing_template_decl;
if (new_friend_type != error_mark_node)
! make_friend_class (type, new_friend_type,
! /*complain=*/false);
if (TREE_CODE (friend_type) == TEMPLATE_DECL)
--processing_template_decl;
}
else
/* Build new DECL_FRIENDLIST. */
! add_friend (type, tsubst_friend_function (t, args),
! /*complain=*/false);
}
}
diff -cprN gcc-main-save/gcc/testsuite/g++.dg/template/friend22.C gcc-main-new/gcc/testsuite/g++.dg/template/friend22.C
*** gcc-main-save/gcc/testsuite/g++.dg/template/friend22.C Thu Jan 1 07:00:00 1970
--- gcc-main-new/gcc/testsuite/g++.dg/template/friend22.C Mon Aug 18 22:38:03 2003
***************
*** 0 ****
--- 1,15 ----
+ // { dg-do compile }
+
+ // Origin: Benoit Hudson <bh@techhouse.brown.edu>
+
+ // PR c++/641: Duplicate friend diagnostics
+
+ template <class T> class iterator { };
+ template <class T> class item {
+ friend class iterator<T>;
+ friend class iterator<const T>;
+ };
+
+ class A { };
+
+ item<const A> i;
diff -cprN gcc-main-save/gcc/testsuite/g++.dg/template/friend23.C gcc-main-new/gcc/testsuite/g++.dg/template/friend23.C
*** gcc-main-save/gcc/testsuite/g++.dg/template/friend23.C Thu Jan 1 07:00:00 1970
--- gcc-main-new/gcc/testsuite/g++.dg/template/friend23.C Mon Aug 18 22:38:09 2003
***************
*** 0 ****
--- 1,38 ----
+ // { dg-do compile }
+
+ // Origin: Alexandre Tolmos <ktulu@free.fr>
+
+ // PR c++/11876: Friend of its own class diagnostics
+
+ template <typename T>
+ class A
+ {
+ friend class A<int>;
+ friend class A<float>;
+ protected:
+ T _data;
+ inline A() : _data(0) {}
+ template <typename U>
+ inline A(const A<U>& r) : _data(r._data) {}
+ };
+
+ class B : public A<int>
+ {
+ public:
+ inline B() {}
+ inline B(const B& r) : A<int>(r) {}
+ };
+
+ class C : public A<float>
+ {
+ public:
+ inline C() {}
+ inline C(const B& r) : A<float>(r) {}
+ };
+
+ int main(int, char*[])
+ {
+ B b1, b2(b1);
+ C c(b1);
+ return 0;
+ }
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