Rakete1111 updated this revision to Diff 111602.
Rakete1111 added a comment.
Thanks! Agreed, your wording is better than mine :)
https://reviews.llvm.org/D36855
Files:
include/clang/Basic/DiagnosticGroups.td
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaExprCXX.cpp
test/SemaCXX/cxx2a-pointer-to-const-ref-member.cpp
www/cxx_status.html
Index: www/cxx_status.html
===================================================================
--- www/cxx_status.html
+++ www/cxx_status.html
@@ -777,13 +777,12 @@
<h2 id="cxx20">C++2a implementation status</h2>
-<p>Clang does not yet support any of the proposed features of
-<!--<p>Clang has <b>experimental</b> support for some proposed features of-->
+<p>Clang has <b>experimental</b> support for some proposed features of
the C++ standard following C++17, provisionally named C++2a.
Note that support for these features may change or be removed without notice,
as the draft C++2a standard evolves.
-<!--<p>You can use Clang in C++2a mode with the <code>-std=c++2a</code> option.</p>-->
+<p>You can use Clang in C++2a mode with the <code>-std=c++2a</code> option.</p>
<details open>
<summary>List of features and minimum Clang version with support</summary>
@@ -803,7 +802,7 @@
<tr>
<td><tt>const&</tt>-qualified pointers to members</td>
<td><a href="http://wg21.link/p0704r1";>P0704R1</a></td>
- <td class="none" align="center">No</td>
+ <td class="svn" align="center">SVN</td>
</tr>
<tr>
<td>Allow <i>lambda-capture</i> <tt>[=, this]</tt></td>
Index: test/SemaCXX/cxx2a-pointer-to-const-ref-member.cpp
===================================================================
--- test/SemaCXX/cxx2a-pointer-to-const-ref-member.cpp
+++ test/SemaCXX/cxx2a-pointer-to-const-ref-member.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -std=c++2a %s -verify
+
+struct X {
+ void ref() & {}
+ void cref() const& {}
+};
+
+void test() {
+ X{}.ref(); // expected-error{{cannot initialize object parameter of type 'X' with an expression of type 'X'}}
+ X{}.cref(); // expected-no-error
+
+ (X{}.*&X::ref)(); // expected-error{{pointer-to-member function type 'void (X::*)() &' can only be called on an lvalue}}
+ (X{}.*&X::cref)(); // expected-no-error
+}
Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -5175,9 +5175,16 @@
break;
case RQ_LValue:
- if (!isIndirect && !LHS.get()->Classify(Context).isLValue())
- Diag(Loc, diag::err_pointer_to_member_oper_value_classify)
- << RHSType << 1 << LHS.get()->getSourceRange();
+ if (!isIndirect && !LHS.get()->Classify(Context).isLValue()) {
+ // C++2a allows functions with ref-qualifier & if they are also 'const'.
+ if (Proto->isConst())
+ Diag(Loc, getLangOpts().CPlusPlus2a
+ ? diag::warn_cxx17_compat_pointer_to_const_ref_member_on_rvalue
+ : diag::ext_pointer_to_const_ref_member_on_rvalue);
+ else
+ Diag(Loc, diag::err_pointer_to_member_oper_value_classify)
+ << RHSType << 1 << LHS.get()->getSourceRange();
+ }
break;
case RQ_RValue:
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -4088,6 +4088,13 @@
def err_pointer_to_member_oper_value_classify: Error<
"pointer-to-member function type %0 can only be called on an "
"%select{rvalue|lvalue}1">;
+def ext_pointer_to_const_ref_member_on_rvalue : Extension<
+ "invoking a pointer to a 'const &' member function on an rvalue is a C++2a extension">,
+ InGroup<CXX20>, SFINAEFailure;
+def warn_cxx17_compat_pointer_to_const_ref_member_on_rvalue : Warning<
+ "pointer-to-member function for const& member function on rvalues is "
+ "incompatible with C++ standards before C++2a">,
+ InGroup<CXXPre2aCompat>, DefaultIgnore;
def ext_ms_deref_template_argument: ExtWarn<
"non-type template argument containing a dereference operation is a "
"Microsoft extension">, InGroup<MicrosoftTemplate>;
Index: include/clang/Basic/DiagnosticGroups.td
===================================================================
--- include/clang/Basic/DiagnosticGroups.td
+++ include/clang/Basic/DiagnosticGroups.td
@@ -169,6 +169,9 @@
def CXXPre1zCompatPedantic : DiagGroup<"c++98-c++11-c++14-compat-pedantic",
[CXXPre1zCompat]>;
+// Warnings for C++2a code which is not compatible with prior C++ standards.
+def CXXPre2aCompat : DiagGroup<"c++98-c++11-c++14-c++17-compat">;
+
def CXX98CompatBindToTemporaryCopy :
DiagGroup<"c++98-compat-bind-to-temporary-copy">;
def CXX98CompatLocalTypeTemplateArgs :
@@ -180,7 +183,8 @@
[CXX98CompatLocalTypeTemplateArgs,
CXX98CompatUnnamedTypeTemplateArgs,
CXXPre14Compat,
- CXXPre1zCompat]>;
+ CXXPre1zCompat,
+ CXXPre2aCompat]>;
// Warnings for C++11 features which are Extensions in C++98 mode.
def CXX98CompatPedantic : DiagGroup<"c++98-compat-pedantic",
[CXX98Compat,
@@ -211,7 +215,8 @@
CXX11CompatReservedUserDefinedLiteral,
CXX11CompatDeprecatedWritableStr,
CXXPre14Compat,
- CXXPre1zCompat]>;
+ CXXPre1zCompat,
+ CXXPre2aCompat]>;
def : DiagGroup<"c++0x-compat", [CXX11Compat]>;
def CXX11CompatPedantic : DiagGroup<"c++11-compat-pedantic",
[CXXPre14CompatPedantic,
@@ -784,9 +789,14 @@
// earlier C++ versions.
def CXX17 : DiagGroup<"c++17-extensions">;
+// A warning group for warnings about using C++2a features as extensions in
+// earlier C++ versions.
+def CXX20 : DiagGroup<"c++20-extensions">;
+
def : DiagGroup<"c++0x-extensions", [CXX11]>;
def : DiagGroup<"c++1y-extensions", [CXX14]>;
def : DiagGroup<"c++1z-extensions", [CXX17]>;
+def : DiagGroup<"c++2a-extensions", [CXX20]>;
def DelegatingCtorCycles :
DiagGroup<"delegating-ctor-cycles">;
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