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[C++ PATCH] Fix 21799
- From: Nathan Sidwell <nathan at codesourcery dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 08 Jul 2005 12:07:54 +0100
- Subject: [C++ PATCH] Fix 21799
This patch fixes 21799 a latent deduction bug exposed by my implementation of
DR214. We cannot deduce T as 'X const' against a pointer to constant member
function, for instance. The CV qualifiers must match exactly. I took the same
approach for a restrict qualifier.
booted & tested on i686-pc-linux-gnu, installed on mainline.
queued for 4.0.2
nathan
--
Nathan Sidwell :: http://www.codesourcery.com :: CodeSourcery LLC
nathan@codesourcery.com :: http://www.planetfall.pwp.blueyonder.co.uk
2005-07-08 Nathan Sidwell <nathan@codesourcery.com>
PR c++/21799
* pt.c (type_unification_real): Add is_method argument. Use it
for this pointer unification.
(fn_type_unification): Adjust type_unification_real call.
(unify): Likewise.
2005-07-08 Nathan Sidwell <nathan@codesourcery.com>
PR c++/21799
* g++.dg/template/unify8.C: New.
* g++.dg/template/unify9.C: New.
Index: pt.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/pt.c,v
retrieving revision 1.1012
diff -c -3 -p -r1.1012 pt.c
*** pt.c 7 Jul 2005 14:38:33 -0000 1.1012
--- pt.c 7 Jul 2005 14:57:02 -0000
*************** static tree add_outermost_template_args
*** 109,115 ****
static bool check_instantiated_args (tree, tree, tsubst_flags_t);
static int maybe_adjust_types_for_deduction (unification_kind_t, tree*, tree*);
static int type_unification_real (tree, tree, tree, tree,
! int, unification_kind_t);
static void note_template_header (int);
static tree convert_nontype_argument_function (tree, tree);
static tree convert_nontype_argument (tree, tree);
--- 109,115 ----
static bool check_instantiated_args (tree, tree, tsubst_flags_t);
static int maybe_adjust_types_for_deduction (unification_kind_t, tree*, tree*);
static int type_unification_real (tree, tree, tree, tree,
! int, unification_kind_t, int);
static void note_template_header (int);
static tree convert_nontype_argument_function (tree, tree);
static tree convert_nontype_argument (tree, tree);
*************** fn_type_unification (tree fn,
*** 9177,9183 ****
event. */
result = type_unification_real (DECL_INNERMOST_TEMPLATE_PARMS (fn),
targs, parms, args, /*subr=*/0,
! strict);
if (result == 0)
/* All is well so far. Now, check:
--- 9177,9183 ----
event. */
result = type_unification_real (DECL_INNERMOST_TEMPLATE_PARMS (fn),
targs, parms, args, /*subr=*/0,
! strict, 0);
if (result == 0)
/* All is well so far. Now, check:
*************** maybe_adjust_types_for_deduction (unific
*** 9285,9291 ****
If SUBR is 1, we're being called recursively (to unify the
arguments of a function or method parameter of a function
! template). */
static int
type_unification_real (tree tparms,
--- 9285,9293 ----
If SUBR is 1, we're being called recursively (to unify the
arguments of a function or method parameter of a function
! template). If IS_METHOD is true, XPARMS are the parms of a
! member function, and special rules apply to cv qualification
! deduction on the this parameter. */
static int
type_unification_real (tree tparms,
*************** type_unification_real (tree tparms,
*** 9293,9299 ****
tree xparms,
tree xargs,
int subr,
! unification_kind_t strict)
{
tree parm, arg;
int i;
--- 9295,9302 ----
tree xparms,
tree xargs,
int subr,
! unification_kind_t strict,
! int is_method)
{
tree parm, arg;
int i;
*************** type_unification_real (tree tparms,
*** 9345,9350 ****
--- 9348,9373 ----
template args from other function args. */
continue;
+ if (is_method)
+ {
+ /* The cv qualifiers on the this pointer argument must match
+ exactly. We cannot deduce a T as const X against a const
+ member function for instance. */
+ gcc_assert (TREE_CODE (parm) == POINTER_TYPE);
+ gcc_assert (TREE_CODE (arg) == POINTER_TYPE);
+ /* The restrict qualifier will be on the pointer. */
+ if (cp_type_quals (parm) != cp_type_quals (arg))
+ return 1;
+ parm = TREE_TYPE (parm);
+ arg = TREE_TYPE (arg);
+ if (cp_type_quals (parm) != cp_type_quals (arg))
+ return 1;
+
+ parm = TYPE_MAIN_VARIANT (parm);
+ arg = TYPE_MAIN_VARIANT (arg);
+ is_method = 0;
+ }
+
/* Conversions will be performed on a function argument that
corresponds with a function parameter that contains only
non-deducible template parameters and explicitly specified
*************** unify (tree tparms, tree targs, tree par
*** 10249,10255 ****
TREE_TYPE (arg), UNIFY_ALLOW_NONE))
return 1;
return type_unification_real (tparms, targs, TYPE_ARG_TYPES (parm),
! TYPE_ARG_TYPES (arg), 1, DEDUCE_EXACT);
case OFFSET_TYPE:
/* Unify a pointer to member with a pointer to member function, which
--- 10272,10279 ----
TREE_TYPE (arg), UNIFY_ALLOW_NONE))
return 1;
return type_unification_real (tparms, targs, TYPE_ARG_TYPES (parm),
! TYPE_ARG_TYPES (arg), 1, DEDUCE_EXACT,
! TREE_CODE (parm) == METHOD_TYPE);
case OFFSET_TYPE:
/* Unify a pointer to member with a pointer to member function, which
Index: testsuite/g++.dg/template/unify8.C
===================================================================
RCS file: testsuite/g++.dg/template/unify8.C
diff -N testsuite/g++.dg/template/unify8.C
*** /dev/null 1 Jan 1970 00:00:00 -0000
--- testsuite/g++.dg/template/unify8.C 8 Jul 2005 11:04:19 -0000
***************
*** 0 ****
--- 1,20 ----
+ // { dg-do link }
+
+ // Copyright (C) 2005 Free Software Foundation, Inc.
+ // Contributed by Nathan Sidwell 7 Jul 2005 <nathan@codesourcery.com>
+
+ // Origin:Wolfgang Bangerth <bangerth@dealii.org>
+ // PR 21799: deduction of cvqualifiers on member functions was wrong
+
+ template <class T> void f (T &, void (T::*)() );
+ template <class T> void f (const T &, void (T::*)() const) {}
+
+ struct X {
+ void g() const {}
+ };
+
+ const X *x;
+
+ int main () {
+ f (*x, &X::g);
+ }
Index: testsuite/g++.dg/template/unify9.C
===================================================================
RCS file: testsuite/g++.dg/template/unify9.C
diff -N testsuite/g++.dg/template/unify9.C
*** /dev/null 1 Jan 1970 00:00:00 -0000
--- testsuite/g++.dg/template/unify9.C 8 Jul 2005 11:04:19 -0000
***************
*** 0 ****
--- 1,17 ----
+ // Copyright (C) 2005 Free Software Foundation, Inc.
+ // Contributed by Nathan Sidwell 7 Jul 2005 <nathan@codesourcery.com>
+
+ // Origin:Wolfgang Bangerth <bangerth@dealii.org>
+ // PR 21799: deduction of cvqualifiers on member functions was wrong
+
+ template <class T> void f (T &, void (T::*)() );
+
+ struct X {
+ void g() const {}
+ };
+
+ const X *x;
+
+ int main () {
+ f (*x, &X::g); // { dg-error "no matching function" }
+ }