[clang] [Clang] Reject "this void" (CWG2915) (PR #108817)
via cfe-commits
cfe-commits at lists.llvm.org
Mon Sep 16 05:04:25 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Mital Ashok (MitalAshok)
<details>
<summary>Changes</summary>
https://cplusplus.github.io/CWG/issues/2915.html
Previously, `struct A { void f(this void); };` was accepted with `A::f` being a member function with no non-object arguments, but it was still a little wonky because it was still considered an explicit object member function. Now, this is rejected immediately.
This applies to any language mode with explicit object parameters as this is a DR (C++23 and C++26)
---
Full diff: https://github.com/llvm/llvm-project/pull/108817.diff
5 Files Affected:
- (modified) clang/docs/ReleaseNotes.rst (+3)
- (modified) clang/include/clang/Basic/DiagnosticSemaKinds.td (+2)
- (modified) clang/lib/Sema/SemaType.cpp (+8)
- (modified) clang/test/CXX/drs/cwg29xx.cpp (+8)
- (modified) clang/www/cxx_dr_status.html (+63-5)
``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 485b75049927fe..9c87a0d002b4ac 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -170,6 +170,9 @@ Resolutions to C++ Defect Reports
in constant expressions. These comparisons always worked in non-constant expressions.
(`CWG2749: Treatment of "pointer to void" for relational comparisons <https://cplusplus.github.io/CWG/issues/2749.html>`_).
+- Reject explicit object parameters with type ``void`` (``this void``).
+ (`CWG2915: Explicit object parameters of type void <https://cplusplus.github.io/CWG/issues/2915.html>`_).
+
C Language Changes
------------------
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index d42558d2223aae..271f96e383e57d 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -4687,6 +4687,8 @@ def err_void_only_param : Error<
"'void' must be the first and only parameter if specified">;
def err_void_param_qualified : Error<
"'void' as parameter must not have type qualifiers">;
+def err_void_explicit_object_param : Error<
+ "explicit object parameter cannot have 'void' type">;
def err_ident_list_in_fn_declaration : Error<
"a parameter list without types is only allowed in a function definition">;
def ext_param_not_declared : ExtWarn<
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index e627fee51b66b8..7b99f5d13463fe 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5166,6 +5166,14 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
if (ParamTy.hasQualifiers())
S.Diag(DeclType.Loc, diag::err_void_param_qualified);
+ // Reject, but continue to parse 'float(this void)' as
+ // 'float(void)'.
+ if (Param->isExplicitObjectParameter()) {
+ S.Diag(Param->getLocation(),
+ diag::err_void_explicit_object_param);
+ Param->setExplicitObjectParameterLoc(SourceLocation());
+ }
+
// Do not add 'void' to the list.
break;
}
diff --git a/clang/test/CXX/drs/cwg29xx.cpp b/clang/test/CXX/drs/cwg29xx.cpp
index ca598bb39a6c31..e55e8e35e86f28 100644
--- a/clang/test/CXX/drs/cwg29xx.cpp
+++ b/clang/test/CXX/drs/cwg29xx.cpp
@@ -6,6 +6,14 @@
// RUN: %clang_cc1 -std=c++23 -pedantic-errors -verify=expected %s
// RUN: %clang_cc1 -std=c++2c -pedantic-errors -verify=expected %s
+namespace cwg2915 { // cwg2915: 20 tentatively ready 2024-08-16
+#if __cplusplus >= 202302L
+struct A {
+ void f(this void); // expected-error {{explicit object parameter cannot have 'void' type}}
+};
+#endif
+}
+
namespace cwg2917 { // cwg2917: 20 review 2024-07-30
template <typename>
class Foo;
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index f036fc5add2413..127bfe7e0e3724 100755
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -11809,11 +11809,11 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
<td>Reference list-initialization ignores conversion functions</td>
<td align="center">Not resolved</td>
</tr>
- <tr class="open" id="1997">
+ <tr id="1997">
<td><a href="https://cplusplus.github.io/CWG/issues/1997.html">1997</a></td>
- <td>drafting</td>
+ <td>DRWP</td>
<td>Placement new and previous initialization</td>
- <td align="center">Not resolved</td>
+ <td class="unknown" align="center">Unknown</td>
</tr>
<tr id="1998">
<td><a href="https://cplusplus.github.io/CWG/issues/1998.html">1998</a></td>
@@ -17346,11 +17346,15 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
<td><a href="https://cplusplus.github.io/CWG/issues/2915.html">2915</a></td>
<td>tentatively ready</td>
<td>Explicit object parameters of type <TT>void</TT></td>
- <td align="center">Not resolved</td>
+ <td align="center">
+ <details>
+ <summary>Not resolved</summary>
+ Clang 20 implements 2024-08-16 resolution
+ </details></td>
</tr>
<tr class="open" id="2916">
<td><a href="https://cplusplus.github.io/CWG/issues/2916.html">2916</a></td>
- <td>tentatively ready</td>
+ <td>review</td>
<td>Variable template partial specializations should not be declared <TT>static</TT></td>
<td align="center">Not resolved</td>
</tr>
@@ -17427,6 +17431,60 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
<td>open</td>
<td>Unclear status of translation unit with <TT>module</TT> keyword</td>
<td align="center">Not resolved</td>
+ </tr>
+ <tr class="open" id="2928">
+ <td><a href="https://cplusplus.github.io/CWG/issues/2928.html">2928</a></td>
+ <td>open</td>
+ <td>No ordering for initializing thread-local variables</td>
+ <td align="center">Not resolved</td>
+ </tr>
+ <tr class="open" id="2929">
+ <td><a href="https://cplusplus.github.io/CWG/issues/2929.html">2929</a></td>
+ <td>open</td>
+ <td>Lifetime of trivially-destructible static or thread-local objects</td>
+ <td align="center">Not resolved</td>
+ </tr>
+ <tr class="open" id="2930">
+ <td><a href="https://cplusplus.github.io/CWG/issues/2930.html">2930</a></td>
+ <td>open</td>
+ <td>Unclear term "copy/move operation" in specification of copy elision</td>
+ <td align="center">Not resolved</td>
+ </tr>
+ <tr class="open" id="2931">
+ <td><a href="https://cplusplus.github.io/CWG/issues/2931.html">2931</a></td>
+ <td>open</td>
+ <td>Restrictions on operator functions that are explicit object member functions</td>
+ <td align="center">Not resolved</td>
+ </tr>
+ <tr class="open" id="2932">
+ <td><a href="https://cplusplus.github.io/CWG/issues/2932.html">2932</a></td>
+ <td>open</td>
+ <td>Value range of empty enumeration</td>
+ <td align="center">Not resolved</td>
+ </tr>
+ <tr class="open" id="2933">
+ <td><a href="https://cplusplus.github.io/CWG/issues/2933.html">2933</a></td>
+ <td>open</td>
+ <td>Dangling references</td>
+ <td align="center">Not resolved</td>
+ </tr>
+ <tr class="open" id="2934">
+ <td><a href="https://cplusplus.github.io/CWG/issues/2934.html">2934</a></td>
+ <td>open</td>
+ <td>Unclear semantics of exception escaping from <TT>unhandled_exception</TT></td>
+ <td align="center">Not resolved</td>
+ </tr>
+ <tr class="open" id="2935">
+ <td><a href="https://cplusplus.github.io/CWG/issues/2935.html">2935</a></td>
+ <td>open</td>
+ <td>Destroying the coroutine state when initial-await-resume-called is false</td>
+ <td align="center">Not resolved</td>
+ </tr>
+ <tr class="open" id="2936">
+ <td><a href="https://cplusplus.github.io/CWG/issues/2936.html">2936</a></td>
+ <td>open</td>
+ <td>Local classes of templated functions should be part of the current instantiation</td>
+ <td align="center">Not resolved</td>
</tr></table>
</div>
``````````
</details>
https://github.com/llvm/llvm-project/pull/108817
More information about the cfe-commits
mailing list