[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 Andrew Pinski changed: What|Removed |Added Target Milestone|--- |11.0
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 --- Comment #11 from Andrew Pinski --- *** Bug 86228 has been marked as a duplicate of this bug. ***
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 Andrew Pinski changed: What|Removed |Added CC||zhonghao at pku dot org.cn --- Comment #10 from Andrew Pinski --- *** Bug 86579 has been marked as a duplicate of this bug. ***
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 Jonathan Wakely changed: What|Removed |Added See Also||https://gcc.gnu.org/bugzill ||a/show_bug.cgi?id=99701 --- Comment #9 from Jonathan Wakely --- (In reply to CVS Commits from comment #7) > 3) The overload descriptions for built-in operators were adjusted, >because objects of type std::nullptr_t cannot be used with relational >operators any more. This apparently wasn't completely done, see PR 99701.
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 Marek Polacek changed: What|Removed |Added Resolution|--- |FIXED Status|ASSIGNED|RESOLVED --- Comment #8 from Marek Polacek --- Implemented in GCC 11.
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699
--- Comment #7 from CVS Commits ---
The master branch has been updated by Marek Polacek :
https://gcc.gnu.org/g:ae8ed736addb2b005d54c0b3191ac599a04ec170
commit r11-467-gae8ed736addb2b005d54c0b3191ac599a04ec170
Author: Marek Polacek
Date: Wed May 13 15:52:42 2020 -0400
c++: Implement DR 1512, Pointer comparison vs qual convs [PR87699]
This patch resolves DR 1512 (and, by turn, DR 583). This entails:
1) Relational pointer comparisons against null pointer constants have
been made ill-formed:
void f(char *p) {
if (p > 0)
// ...
}
was always invalid in C but was -- accidentally -- allowed in C++.
2) This was ill-formed:
bool foo(int** x, const int** y) {
return x < y;
}
because 'int**' couldn't be converted to 'const int**'. This was
fixed by re-defining a generic composite pointer type. The composite
type of these two pointers will be 'const int *const *', to which
both pointers can be converted.
3) The overload descriptions for built-in operators were adjusted,
because objects of type std::nullptr_t cannot be used with relational
operators any more.
I fixed 1) by adjusting cp_build_binary_op; we already had a warning
for it so made it a hard error now.
Then 2) required tweaking composite_pointer_type_r. [expr.type] defines
the composite pointer type by using the "cv-combined type." We didn't
implement the [conv.qual]/3.3 part; previously the composite type of
'int**' and 'const int**' was 'const int**', so this didn't compile:
void f(const int **p, int **q) {
true ? p : q;
}
I wrote a more extensive test for this which uses decltype and some
template magic to check the composite type, see composite-ptr-type.C.
We still don't handle everything that [expr.type] requires us to,
but it's pretty close.
And finally 3) was handled in add_builtin_candidate. Turned out we
weren't creating built-in operator candidates when the type was
std::nullptr_t at all. We should, for == and !=. Tested in builtin4.C.
In passing, I'm fixing some of the comments too.
DR 1512
PR c++/87699
* call.c (add_builtin_candidate) : Create candidate
operator functions when type is std::nullptr_t for ==/!=.
* typeck.c (composite_pointer_type_r): Add bool a * parameter. Use
it
to maybe add "const" to the pointer type.
(composite_pointer_type): Update the call to
composite_pointer_type_r.
(cp_build_binary_op): Turn two warning_at into error_at. Print the
types.
* g++.dg/cpp0x/constexpr-array-ptr10.C: Change dg-warning to
dg-error
and adjust the expected messages in dg-error.
* g++.dg/expr/composite-ptr-type.C: New test.
* g++.dg/expr/ptr-comp1.C: New test.
* g++.dg/expr/ptr-comp2.C: New test.
* g++.dg/expr/ptr-comp3.C: New test.
* g++.dg/overload/builtin4.C: New test.
* g++.dg/warn/Wextra-3.C: Change dg-warning to dg-error.
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699
--- Comment #6 from Marek Polacek ---
See Daniel's testcase for why this is more important than it might seem:
template
bool test(T*)
{
return true;
}
int main()
{
test((int*)(nullptr));
}
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 Marek Polacek changed: What|Removed |Added CC||daniel.kruegler@googlemail. ||com --- Comment #5 from Marek Polacek --- *** Bug 94563 has been marked as a duplicate of this bug. ***
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 Marek Polacek changed: What|Removed |Added Assignee|beliveau0213 at gmail dot com |mpolacek at gcc dot gnu.org CC||mpolacek at gcc dot gnu.org --- Comment #4 from Marek Polacek --- Mine, for GCC 11.
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 Marek Polacek changed: What|Removed |Added Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |mpolacek at gcc dot gnu.org
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 Marek Polacek changed: What|Removed |Added CC||mpolacek at gcc dot gnu.org --- Comment #3 from Marek Polacek --- The warning is in place and triggers with -Wextra: warning (OPT_Wextra, "ordered comparison of pointer with integer zero"); I guess we should make it a permerror.
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 Martin Sebor changed: What|Removed |Added See Also||https://gcc.gnu.org/bugzill ||a/show_bug.cgi?id=81453 --- Comment #2 from Martin Sebor --- I raised bug 81453 for this against the C front end, but only to move the warning GCC issues with -Wextra to -Wall.
[Bug c++/87699] Implement CWG 1512
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87699 Jonathan Wakely changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2018-10-23 CC||msebor at gcc dot gnu.org Ever confirmed|0 |1 --- Comment #1 from Jonathan Wakely --- Confirmed. Martin, I thought this was a dup of an existing bug that you'd filed or commented on, but can't find anything. Am I imagining it?
