hamzasood created this revision.
This patch provides an implementation for P0704R1 <http://wg21.link/p0704r1>.
I also made it work pre-C++2a as an extension (with a warning) since that's how
Clang seems to deal with small additions like this. Hopefully someone more
knowledgable on the matter can clarify whether that's appropriate.
https://reviews.llvm.org/D36584
Files:
include/clang/Basic/DiagnosticGroups.td
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaExprCXX.cpp
test/CXX/expr/expr.mptr.oper/p6-0x.cpp
test/CXX/expr/expr.mptr.oper/p6-2a.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/CXX/expr/expr.mptr.oper/p6-2a.cpp
===================================================================
--- test/CXX/expr/expr.mptr.oper/p6-2a.cpp
+++ test/CXX/expr/expr.mptr.oper/p6-2a.cpp
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -std=c++2a -verify %s
+// expected-no-diagnostics
+
+struct X { void foo() const&; };
+
+void test() {
+ // Example from P0704R1.
+ X{}.foo();
+ (X{}.*&X::foo)();
+}
Index: test/CXX/expr/expr.mptr.oper/p6-0x.cpp
===================================================================
--- test/CXX/expr/expr.mptr.oper/p6-0x.cpp
+++ test/CXX/expr/expr.mptr.oper/p6-0x.cpp
@@ -12,14 +12,20 @@
// expression whose object expression is an lvalue, the program is
// ill-formed if the second operand is a pointer to member function
// with ref-qualifier &&.
-void test(X *xp, int (X::*pmf)(int), int (X::*l_pmf)(int) &,
- int (X::*r_pmf)(int) &&) {
+void test(X *xp, int (X::*pmf)(int), int (X::*const_l_pmf)(int) const&,
+ int (X::*l_pmf)(int) &, int (X::*r_pmf)(int) &&) {
// No ref-qualifier.
(lvalue<X>().*pmf)(17);
(xvalue<X>().*pmf)(17);
(prvalue<X>().*pmf)(17);
(xp->*pmf)(17);
+ // Const Lvalue ref-qualifier.
+ (lvalue<X>().*const_l_pmf)(17);
+ (xvalue<X>().*const_l_pmf)(17); // expected-warning {{C++2a extension}}
+ (prvalue<X>().*const_l_pmf)(17); // expected-warning {{C++2a extension}}
+ (xp->*const_l_pmf)(17);
+
// Lvalue ref-qualifier.
(lvalue<X>().*l_pmf)(17);
(xvalue<X>().*l_pmf)(17); // expected-error-re{{pointer-to-member function type 'int (X::*)(int){{( __attribute__\(\(thiscall\)\))?}} &' can only be called on an lvalue}}
Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -5162,22 +5162,32 @@
QualType Result = MemPtr->getPointeeType();
Result = Context.getCVRQualifiedType(Result, LHSType.getCVRQualifiers());
- // C++0x [expr.mptr.oper]p6:
+ // C++2a [expr.mptr.oper]p6:
// In a .* expression whose object expression is an rvalue, the program is
- // ill-formed if the second operand is a pointer to member function with
- // ref-qualifier &. In a ->* expression or in a .* expression whose object
- // expression is an lvalue, the program is ill-formed if the second operand
- // is a pointer to member function with ref-qualifier &&.
+ // ill-formed if the second operand is a pointer to member function whose
+ // ref-qualifier is &, unless its cv-qualifier-seq is const. In an ->*
+ // expression or in a .* expression whose object expression is an lvalue,
+ // the program is ill-formed if the second operand is a pointer to member
+ // function with ref-qualifier &&.
if (const FunctionProtoType *Proto = Result->getAs<FunctionProtoType>()) {
switch (Proto->getRefQualifier()) {
case RQ_None:
// Do nothing
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()) {
+ if (Proto->isConst() && !Proto->isVolatile())
+ Diag(Loc,
+ !getLangOpts().CPlusPlus2a
+ ? diag::
+ ext_const_amp_pointer_to_member_on_rvalue_cxx2a
+ : diag::
+ warn_cxx1z_compat_const_amp_pointer_to_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
@@ -4111,6 +4111,13 @@
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 warn_cxx1z_compat_const_amp_pointer_to_member_on_rvalue : Warning<
+ "invocation of a 'const&' qualified pointer-to-member function on an rvalue "
+ "is incompatible with C++ standards before C++2a">,
+ InGroup<CXXPre2aCompat>, DefaultIgnore;
+def ext_const_amp_pointer_to_member_on_rvalue_cxx2a : ExtWarn<
+ "invocation of a 'const&' qualified pointer-to-member function on an rvalue "
+ "is a C++2a extension">, InGroup<CXX2a>;
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
@@ -167,6 +167,9 @@
def CXXPre1zCompat : DiagGroup<"c++98-c++11-c++14-compat">;
def CXXPre1zCompatPedantic : DiagGroup<"c++98-c++11-c++14-compat-pedantic",
[CXXPre1zCompat]>;
+def CXXPre2aCompat : DiagGroup<"c++98-c++11-c++14-c++1z-compat">;
+def CXXPre2aCompatPedantic : DiagGroup<"c++98-c++11-c++14-c++1z-compat-pedantic",
+ [CXXPre2aCompat]>;
def CXX98CompatBindToTemporaryCopy :
DiagGroup<"c++98-compat-bind-to-temporary-copy">;
@@ -780,6 +783,10 @@
// earlier C++ versions.
def CXX1z : DiagGroup<"c++1z-extensions">;
+// A warning group for warnings about using C++2a features as extensions in
+// earlier C++ versions.
+def CXX2a : DiagGroup<"c++2a-extensions">;
+
def : DiagGroup<"c++0x-extensions", [CXX11]>;
def : DiagGroup<"c++1y-extensions", [CXX14]>;
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