[Clang] Reject this void explicit object parameters (CWG2915)
#108817
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@llvm/pr-subscribers-clang Author: Mital Ashok (MitalAshok) Changeshttps://cplusplus.github.io/CWG/issues/2915.html Previously, 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:
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>
|
MitalAshok
changed the title
this void explicit object parameters (CWG2915)
cor3ntin
approved these changes
Sep 16, 2024
We should always strive to keep unrelated changes separate. There are a lot of good reasons for this. The most basic is that if we have to revert then we lose both set of changes but clearly the unrelated DR documentation changes are NFC. |
|
@shafik: Since this is a generated file, it is very easy to regenerate after a revert with @Endilll: I've removed the other changes from |
hamphet
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Sep 18, 2024
…#108817) 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)
tmsri
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Sep 19, 2024
…#108817) 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)
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https://cplusplus.github.io/CWG/issues/2915.html
Previously,
struct A { void f(this void); };was accepted withA::fbeing 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)