[clang] 0b021c4 - [clang] Claim conformance for CWG466 (#87748)
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Fri Apr 5 21:12:02 PDT 2024
Author: Vlad Serebrennikov
Date: 2024-04-06T08:11:58+04:00
New Revision: 0b021c4b603b4e076f9e54572a4eef3e43ab57c0
URL: https://github.com/llvm/llvm-project/commit/0b021c4b603b4e076f9e54572a4eef3e43ab57c0
DIFF: https://github.com/llvm/llvm-project/commit/0b021c4b603b4e076f9e54572a4eef3e43ab57c0.diff
LOG: [clang] Claim conformance for CWG466 (#87748)
[CWG466](https://cplusplus.github.io/CWG/issues/466.html) "cv-qualifiers
on pseudo-destructor type".
Richard claimed that we don't implement this DR because of one
ill-formed example being accepted: `a->CI::~VI();`. This example is
testing the behavior of calling a pseudo-destructor via a qualified
name, where components of qualified name denote the same `int` type, but
with different cv-qualifications.
Initially, the following wording from [expr.pseudo] quoted in CWG466 was
left intact:
> Furthermore, the two type-names in a pseudo-destructor-name of the
form
>
> `:: (opt) nested-name-specifier (opt) type-name ::~ type-name`
>
>shall designate the same scalar type.
According to this wording, the example is indeed ill-formed.
[P1131R2](https://wg21.link/p1131r2) merged wording for
pseudo-destructors into regular destructor wording. Among other things,
[expr.pseudo] was removed, and [expr.prim.id.qual]/2 was changed to
read:
> Where `type-name ::~ type-name` is used, the two type-names shall
refer to the same type (ignoring cv-qualifications);
I believe P1131R2 made the example well-formed.
However, this wording didn't survive
[P1787R6](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p1787r6.html)
"Declarations and where to find them". In that paper I don't see the
intent to make the example ill-formed again, so I assume it confirmed
status-quo via other wording. My _guess_ the new wording is
http://eel.is/c++draft/basic.lookup#qual.general-4.6:
> If a qualified name Q follows a ~:
> - <...>
> - The [type-name](http://eel.is/c++draft/dcl.type.simple#nt:type-name)
that is or contains Q shall refer to its (original) lookup context
(ignoring cv-qualification) under the interpretation established by at
least one (successful) lookup
performed[.](http://eel.is/c++draft/basic.lookup#qual.general-4.6.sentence-1)
Added:
Modified:
clang/test/CXX/drs/dr4xx.cpp
clang/www/cxx_dr_status.html
Removed:
################################################################################
diff --git a/clang/test/CXX/drs/dr4xx.cpp b/clang/test/CXX/drs/dr4xx.cpp
index 343c4ee6f3344e..34dd638c1d9b00 100644
--- a/clang/test/CXX/drs/dr4xx.cpp
+++ b/clang/test/CXX/drs/dr4xx.cpp
@@ -948,7 +948,7 @@ namespace dr460 { // dr460: yes
// dr464: na
// dr465: na
-namespace dr466 { // dr466: no
+namespace dr466 { // dr466: 2.8
typedef int I;
typedef const int CI;
typedef volatile int VI;
@@ -960,7 +960,7 @@ namespace dr466 { // dr466: no
a->CI::~CI();
a->VI::~VI();
- a->CI::~VI(); // FIXME: This is invalid; CI and VI are not the same scalar type.
+ a->CI::~VI(); // allowed by changes to [expr.id.prim.qual]/2 introduced in P1131R2
b->~I();
b->~CI();
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index 588c5b3e939d10..a4c133c13c493f 100755
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -2836,7 +2836,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
<td><a href="https://cplusplus.github.io/CWG/issues/466.html">466</a></td>
<td>CD1</td>
<td>cv-qualifiers on pseudo-destructor type</td>
- <td class="none" align="center">No</td>
+ <td class="full" align="center">Clang 2.8</td>
</tr>
<tr id="467">
<td><a href="https://cplusplus.github.io/CWG/issues/467.html">467</a></td>
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