[clang] [clang-tools-extra] [Clang] Implement CWG2813: Class member access with prvalues (PR #95112)
Mital Ashok via cfe-commits
cfe-commits at lists.llvm.org
Wed Jun 12 10:21:24 PDT 2024
https://github.com/MitalAshok updated https://github.com/llvm/llvm-project/pull/95112
>From e53dfbc9b2c6b7f30c1378731d7de284fa99d568 Mon Sep 17 00:00:00 2001
From: Mital Ashok <mital at mitalashok.co.uk>
Date: Tue, 11 Jun 2024 14:26:38 +0100
Subject: [PATCH 1/3] [Clang] Implement CWG2813
---
clang/docs/ReleaseNotes.rst | 5 ++
.../clang/Basic/DiagnosticSemaKinds.td | 3 +
clang/lib/Sema/SemaExprMember.cpp | 64 +++++++++++---
clang/lib/Sema/SemaOverload.cpp | 11 +--
clang/lib/Sema/SemaStmt.cpp | 14 ++-
.../test/AST/ast-dump-for-range-lifetime.cpp | 12 +--
.../dcl.attr/dcl.attr.nodiscard/p2.cpp | 86 ++++++++++++++-----
clang/test/CXX/drs/cwg28xx.cpp | 17 ++++
clang/test/CodeGenCXX/cxx2b-deducing-this.cpp | 1 -
clang/www/cxx_dr_status.html | 2 +-
10 files changed, 164 insertions(+), 51 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index cf1ba02cbc4b2..36bf1fdea3602 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -260,6 +260,11 @@ Resolutions to C++ Defect Reports
- Clang now requires a template argument list after a template keyword.
(`CWG96: Syntactic disambiguation using the template keyword <https://cplusplus.github.io/CWG/issues/96.html>`_).
+- Clang now allows calling explicit object member functions directly with prvalues
+ instead of always materializing a temporary, meaning by-value explicit object parameters
+ do not need to move from a temporary.
+ (`CWG2813: Class member access with prvalues <https://cplusplus.github.io/CWG/issues/2813.html>`_).
+
C Language Changes
------------------
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 193eae3bc41d6..008bf5fa0ccfc 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -9182,6 +9182,9 @@ def warn_unused_constructor : Warning<
def warn_unused_constructor_msg : Warning<
"ignoring temporary created by a constructor declared with %0 attribute: %1">,
InGroup<UnusedValue>;
+def warn_discarded_class_member_access : Warning<
+ "left operand of dot in this class member access is discarded and has no effect">,
+ InGroup<UnusedValue>;
def warn_side_effects_unevaluated_context : Warning<
"expression with side effects has no effect in an unevaluated context">,
InGroup<UnevaluatedExpression>;
diff --git a/clang/lib/Sema/SemaExprMember.cpp b/clang/lib/Sema/SemaExprMember.cpp
index 3ae1af26d0096..4679fe529ac91 100644
--- a/clang/lib/Sema/SemaExprMember.cpp
+++ b/clang/lib/Sema/SemaExprMember.cpp
@@ -1015,15 +1015,6 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
: !isDependentScopeSpecifier(SS) || computeDeclContext(SS)) &&
"dependent lookup context that isn't the current instantiation?");
- // C++1z [expr.ref]p2:
- // For the first option (dot) the first expression shall be a glvalue [...]
- if (!IsArrow && BaseExpr && BaseExpr->isPRValue()) {
- ExprResult Converted = TemporaryMaterializationConversion(BaseExpr);
- if (Converted.isInvalid())
- return ExprError();
- BaseExpr = Converted.get();
- }
-
const DeclarationNameInfo &MemberNameInfo = R.getLookupNameInfo();
DeclarationName MemberName = MemberNameInfo.getName();
SourceLocation MemberLoc = MemberNameInfo.getLoc();
@@ -1140,26 +1131,68 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
BaseExpr = BuildCXXThisExpr(Loc, BaseExprType, /*IsImplicit=*/true);
}
+ // C++17 [expr.ref]p2, per CWG2813:
+ // For the first option (dot), if the id-expression names a static member or
+ // an enumerator, the first expression is a discarded-value expression; if
+ // the id-expression names a non-static data member, the first expression
+ // shall be a glvalue.
+ auto MakeDiscardedValue = [&BaseExpr, IsArrow, this] {
+ assert(getLangOpts().CPlusPlus &&
+ "Static member / member enumerator outside of C++");
+ if (IsArrow)
+ return false;
+ ExprResult Converted = IgnoredValueConversions(BaseExpr);
+ if (Converted.isInvalid())
+ return true;
+ BaseExpr = Converted.get();
+ DiagnoseUnusedExprResult(BaseExpr,
+ diag::warn_discarded_class_member_access);
+ return false;
+ };
+ auto MakeGLValue = [&BaseExpr, IsArrow, this] {
+ if (IsArrow || !BaseExpr->isPRValue())
+ return false;
+ ExprResult Converted = TemporaryMaterializationConversion(BaseExpr);
+ if (Converted.isInvalid())
+ return true;
+ BaseExpr = Converted.get();
+ return false;
+ };
+
// Check the use of this member.
if (DiagnoseUseOfDecl(MemberDecl, MemberLoc))
return ExprError();
- if (FieldDecl *FD = dyn_cast<FieldDecl>(MemberDecl))
+ if (FieldDecl *FD = dyn_cast<FieldDecl>(MemberDecl)) {
+ if (MakeGLValue())
+ return ExprError();
return BuildFieldReferenceExpr(BaseExpr, IsArrow, OpLoc, SS, FD, FoundDecl,
MemberNameInfo);
+ }
- if (MSPropertyDecl *PD = dyn_cast<MSPropertyDecl>(MemberDecl))
+ if (MSPropertyDecl *PD = dyn_cast<MSPropertyDecl>(MemberDecl)) {
+ // Properties treated as non-static data members for the purpose of
+ // temporary materialization
+ if (MakeGLValue())
+ return ExprError();
return BuildMSPropertyRefExpr(*this, BaseExpr, IsArrow, SS, PD,
MemberNameInfo);
+ }
- if (IndirectFieldDecl *FD = dyn_cast<IndirectFieldDecl>(MemberDecl))
+ if (IndirectFieldDecl *FD = dyn_cast<IndirectFieldDecl>(MemberDecl)) {
+ if (MakeGLValue())
+ return ExprError();
// We may have found a field within an anonymous union or struct
// (C++ [class.union]).
return BuildAnonymousStructUnionMemberReference(SS, MemberLoc, FD,
FoundDecl, BaseExpr,
OpLoc);
+ }
+ // Static data member
if (VarDecl *Var = dyn_cast<VarDecl>(MemberDecl)) {
+ if (MakeDiscardedValue())
+ return ExprError();
return BuildMemberExpr(BaseExpr, IsArrow, OpLoc,
SS.getWithLocInContext(Context), TemplateKWLoc, Var,
FoundDecl, /*HadMultipleCandidates=*/false,
@@ -1174,6 +1207,9 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
valueKind = VK_PRValue;
type = Context.BoundMemberTy;
} else {
+ // Static member function
+ if (MakeDiscardedValue())
+ return ExprError();
valueKind = VK_LValue;
type = MemberFn->getType();
}
@@ -1186,6 +1222,8 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
assert(!isa<FunctionDecl>(MemberDecl) && "member function not C++ method?");
if (EnumConstantDecl *Enum = dyn_cast<EnumConstantDecl>(MemberDecl)) {
+ if (MakeDiscardedValue())
+ return ExprError();
return BuildMemberExpr(
BaseExpr, IsArrow, OpLoc, SS.getWithLocInContext(Context),
TemplateKWLoc, Enum, FoundDecl, /*HadMultipleCandidates=*/false,
@@ -1193,6 +1231,8 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
}
if (VarTemplateDecl *VarTempl = dyn_cast<VarTemplateDecl>(MemberDecl)) {
+ if (MakeDiscardedValue())
+ return ExprError();
if (!TemplateArgs) {
diagnoseMissingTemplateArguments(
SS, /*TemplateKeyword=*/TemplateKWLoc.isValid(), VarTempl, MemberLoc);
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 1b4bcdcb51160..3aa87dae54dd8 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -5922,7 +5922,9 @@ ExprResult Sema::PerformImplicitObjectArgumentInitialization(
DestType = ImplicitParamRecordType;
FromClassification = From->Classify(Context);
- // When performing member access on a prvalue, materialize a temporary.
+ // CWG2813 [expr.call]p6:
+ // If the function is an implicit object member function, the object
+ // expression of the class member access shall be a glvalue [...]
if (From->isPRValue()) {
From = CreateMaterializeTemporaryExpr(FromRecordType, From,
Method->getRefQualifier() !=
@@ -6457,11 +6459,6 @@ static Expr *GetExplicitObjectExpr(Sema &S, Expr *Obj,
VK_LValue, OK_Ordinary, SourceLocation(),
/*CanOverflow=*/false, FPOptionsOverride());
}
- if (Obj->Classify(S.getASTContext()).isPRValue()) {
- Obj = S.CreateMaterializeTemporaryExpr(
- ObjType, Obj,
- !Fun->getParamDecl(0)->getType()->isRValueReferenceType());
- }
return Obj;
}
@@ -15709,8 +15706,6 @@ ExprResult Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE,
CurFPFeatureOverrides(), Proto->getNumParams());
} else {
// Convert the object argument (for a non-static member function call).
- // We only need to do this if there was actually an overload; otherwise
- // it was done at lookup.
ExprResult ObjectArg = PerformImplicitObjectArgumentInitialization(
MemExpr->getBase(), Qualifier, FoundDecl, Method);
if (ObjectArg.isInvalid())
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 57465d4a77ac2..7effaa943a226 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -223,6 +223,7 @@ static bool DiagnoseNoDiscard(Sema &S, const WarnUnusedResultAttr *A,
}
void Sema::DiagnoseUnusedExprResult(const Stmt *S, unsigned DiagID) {
+ const unsigned OrigDiagID = DiagID;
if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S))
return DiagnoseUnusedExprResult(Label->getSubStmt(), DiagID);
@@ -387,9 +388,16 @@ void Sema::DiagnoseUnusedExprResult(const Stmt *S, unsigned DiagID) {
// Do not diagnose use of a comma operator in a SFINAE context because the
// type of the left operand could be used for SFINAE, so technically it is
// *used*.
- if (DiagID != diag::warn_unused_comma_left_operand || !isSFINAEContext())
- DiagIfReachable(Loc, S ? llvm::ArrayRef(S) : std::nullopt,
- PDiag(DiagID) << R1 << R2);
+ if (DiagID == diag::warn_unused_comma_left_operand && isSFINAEContext())
+ return;
+
+ // Don't diagnose discarded left of dot in static class member access
+ // because its type is "used" to determine the class to access
+ if (OrigDiagID == diag::warn_discarded_class_member_access)
+ return;
+
+ DiagIfReachable(Loc, S ? llvm::ArrayRef(S) : std::nullopt,
+ PDiag(DiagID) << R1 << R2);
}
void Sema::ActOnStartOfCompoundStmt(bool IsStmtExpr) {
diff --git a/clang/test/AST/ast-dump-for-range-lifetime.cpp b/clang/test/AST/ast-dump-for-range-lifetime.cpp
index 0e92b6990ed50..d66e2c090791e 100644
--- a/clang/test/AST/ast-dump-for-range-lifetime.cpp
+++ b/clang/test/AST/ast-dump-for-range-lifetime.cpp
@@ -262,19 +262,19 @@ void test7() {
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .g {{.*}}
// CHECK-NEXT: | `-CXXMemberCallExpr {{.*}} 'A':'P2718R0::A' lvalue
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .r {{.*}}
- // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'A':'P2718R0::A' xvalue extended by Var {{.*}} '__range1' 'A &&'
+ // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'A':'P2718R0::A' lvalue extended by Var {{.*}} '__range1' 'A &&'
// CHECK-NEXT: | `-CXXBindTemporaryExpr {{.*}} 'A':'P2718R0::A' (CXXTemporary {{.*}})
// CHECK-NEXT: | `-CXXMemberCallExpr {{.*}} 'A':'P2718R0::A'
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .g {{.*}}
// CHECK-NEXT: | `-CXXMemberCallExpr {{.*}} 'A':'P2718R0::A' lvalue
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .r {{.*}}
- // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'A':'P2718R0::A' xvalue extended by Var {{.*}} '__range1' 'A &&'
+ // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'A':'P2718R0::A' lvalue extended by Var {{.*}} '__range1' 'A &&'
// CHECK-NEXT: | `-CXXBindTemporaryExpr {{.*}} 'A':'P2718R0::A' (CXXTemporary {{.*}})
// CHECK-NEXT: | `-CXXMemberCallExpr {{.*}} 'A':'P2718R0::A'
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .g {{.*}}
// CHECK-NEXT: | `-CXXMemberCallExpr {{.*}} 'A':'P2718R0::A' lvalue
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .r {{.*}}
- // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'A':'P2718R0::A' xvalue extended by Var {{.*}} '__range1' 'A &&'
+ // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'A':'P2718R0::A' lvalue extended by Var {{.*}} '__range1' 'A &&'
// CHECK-NEXT: | `-CXXBindTemporaryExpr {{.*}} 'A':'P2718R0::A' (CXXTemporary {{.*}})
// CHECK-NEXT: | `-CallExpr {{.*}} 'A':'P2718R0::A'
// CHECK-NEXT: | `-ImplicitCastExpr {{.*}} 'A (*)()' <FunctionToPointerDecay>
@@ -429,19 +429,19 @@ void test13() {
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .g {{.*}}
// CHECK-NEXT: | `-CXXMemberCallExpr {{.*}} 'A':'P2718R0::A' lvalue
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .r {{.*}}
- // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'A':'P2718R0::A' xvalue extended by Var {{.*}} '__range1' 'A &&'
+ // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'A':'P2718R0::A' lvalue extended by Var {{.*}} '__range1' 'A &&'
// CHECK-NEXT: | `-CXXBindTemporaryExpr {{.*}} 'A':'P2718R0::A' (CXXTemporary {{.*}})
// CHECK-NEXT: | `-CXXMemberCallExpr {{.*}} 'A':'P2718R0::A'
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .g {{.*}}
// CHECK-NEXT: | `-CXXMemberCallExpr {{.*}} 'A':'P2718R0::A' lvalue
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .r {{.*}}
- // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'A':'P2718R0::A' xvalue extended by Var {{.*}} '__range1' 'A &&'
+ // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'A':'P2718R0::A' lvalue extended by Var {{.*}} '__range1' 'A &&'
// CHECK-NEXT: | `-CXXBindTemporaryExpr {{.*}} 'A':'P2718R0::A' (CXXTemporary {{.*}})
// CHECK-NEXT: | `-CXXMemberCallExpr {{.*}} 'A':'P2718R0::A'
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .g {{.*}}
// CHECK-NEXT: | `-CXXMemberCallExpr {{.*}} 'A':'P2718R0::A' lvalue
// CHECK-NEXT: | `-MemberExpr {{.*}} '<bound member function type>' .r {{.*}}
- // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'P2718R0::A' xvalue extended by Var {{.*}} '__range1' 'A &&'
+ // CHECK-NEXT: | `-MaterializeTemporaryExpr {{.*}} 'P2718R0::A' lvalue extended by Var {{.*}} '__range1' 'A &&'
// CHECK-NEXT: | `-CXXBindTemporaryExpr {{.*}} 'P2718R0::A' (CXXTemporary {{.*}})
// CHECK-NEXT: | `-CallExpr {{.*}} 'P2718R0::A'
// CHECK-NEXT: | `-ImplicitCastExpr {{.*}} 'P2718R0::A (*)()' <FunctionToPointerDecay>
diff --git a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp
index e2397c12e2e99..a088c9ab93b0e 100644
--- a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp
+++ b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp
@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify -Wc++20-extensions %s
-// RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify -Wc++17-extensions %s
-// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify -DEXT -Wc++17-extensions -Wc++20-extensions %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify=expected -Wc++20-extensions %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify=expected,cxx11-17 -Wc++17-extensions %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify=expected,cxx11-17,cxx11 -Wc++17-extensions -Wc++20-extensions %s
struct [[nodiscard]] S {};
S get_s();
@@ -124,21 +124,67 @@ void usage() {
}
}; // namespace p1771
-#ifdef EXT
-// expected-warning at 5 {{use of the 'nodiscard' attribute is a C++17 extension}}
-// expected-warning at 9 {{use of the 'nodiscard' attribute is a C++17 extension}}
-// expected-warning at 12 {{use of the 'nodiscard' attribute is a C++17 extension}}
-// expected-warning at 13 {{use of the 'nodiscard' attribute is a C++17 extension}}
-// expected-warning at 29 {{use of the 'nodiscard' attribute is a C++17 extension}}
-// expected-warning at 65 {{use of the 'nodiscard' attribute is a C++20 extension}}
-// expected-warning at 67 {{use of the 'nodiscard' attribute is a C++20 extension}}
-// expected-warning at 71 {{use of the 'nodiscard' attribute is a C++20 extension}}
-// expected-warning at 73 {{use of the 'nodiscard' attribute is a C++20 extension}}
-// expected-warning at 74 {{use of the 'nodiscard' attribute is a C++20 extension}}
-// expected-warning at 84 {{use of the 'nodiscard' attribute is a C++20 extension}}
-// expected-warning at 86 {{use of the 'nodiscard' attribute is a C++17 extension}}
-// expected-warning at 87 {{use of the 'nodiscard' attribute is a C++20 extension}}
-// expected-warning at 91 {{use of the 'nodiscard' attribute is a C++17 extension}}
-// expected-warning at 92 {{use of the 'nodiscard' attribute is a C++20 extension}}
-// expected-warning at 95 {{use of the 'nodiscard' attribute is a C++20 extension}}
+namespace discarded_member_access {
+struct X {
+ union {
+ int variant_member;
+ };
+ struct {
+ int anonymous_struct_member;
+ };
+ int data_member;
+ static int static_data_member;
+ enum {
+ unscoped_enum
+ };
+ enum class scoped_enum_t {
+ scoped_enum
+ };
+ using enum scoped_enum_t;
+ // cxx11-17-warning at -1 {{using enum declaration is a C++20 extension}}
+
+ void implicit_object_member_function();
+ static void static_member_function();
+#if __cplusplus >= 202302L
+ void explicit_object_member_function(this X self);
#endif
+};
+
+[[nodiscard]] X get_X();
+// cxx11-warning at -1 {{use of the 'nodiscard' attribute is a C++17 extension}}
+void f() {
+ (void) get_X().variant_member;
+ (void) get_X().anonymous_struct_member;
+ (void) get_X().data_member;
+ (void) get_X().static_data_member;
+ // expected-warning at -1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+ (void) get_X().unscoped_enum;
+ // expected-warning at -1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+ (void) get_X().scoped_enum;
+ // expected-warning at -1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+ (void) get_X().implicit_object_member_function();
+ (void) get_X().static_member_function();
+ // expected-warning at -1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+#if __cplusplus >= 202302L
+ (void) get_X().explicit_object_member_function();
+#endif
+}
+} // namespace discarded_member_access
+
+
+// cxx11-warning at 5 {{use of the 'nodiscard' attribute is a C++17 extension}}
+// cxx11-warning at 9 {{use of the 'nodiscard' attribute is a C++17 extension}}
+// cxx11-warning at 12 {{use of the 'nodiscard' attribute is a C++17 extension}}
+// cxx11-warning at 13 {{use of the 'nodiscard' attribute is a C++17 extension}}
+// cxx11-warning at 29 {{use of the 'nodiscard' attribute is a C++17 extension}}
+// cxx11-warning at 65 {{use of the 'nodiscard' attribute is a C++20 extension}}
+// cxx11-warning at 67 {{use of the 'nodiscard' attribute is a C++20 extension}}
+// cxx11-warning at 71 {{use of the 'nodiscard' attribute is a C++20 extension}}
+// cxx11-warning at 73 {{use of the 'nodiscard' attribute is a C++20 extension}}
+// cxx11-warning at 74 {{use of the 'nodiscard' attribute is a C++20 extension}}
+// cxx11-warning at 84 {{use of the 'nodiscard' attribute is a C++20 extension}}
+// cxx11-warning at 86 {{use of the 'nodiscard' attribute is a C++17 extension}}
+// cxx11-warning at 87 {{use of the 'nodiscard' attribute is a C++20 extension}}
+// cxx11-warning at 91 {{use of the 'nodiscard' attribute is a C++17 extension}}
+// cxx11-warning at 92 {{use of the 'nodiscard' attribute is a C++20 extension}}
+// cxx11-warning at 95 {{use of the 'nodiscard' attribute is a C++20 extension}}
diff --git a/clang/test/CXX/drs/cwg28xx.cpp b/clang/test/CXX/drs/cwg28xx.cpp
index da81eccc8dc22..c712240fd8120 100644
--- a/clang/test/CXX/drs/cwg28xx.cpp
+++ b/clang/test/CXX/drs/cwg28xx.cpp
@@ -6,6 +6,23 @@
// RUN: %clang_cc1 -std=c++23 -pedantic-errors -verify=expected,since-cxx20,since-cxx23 %s
// RUN: %clang_cc1 -std=c++2c -pedantic-errors -verify=expected,since-cxx20,since-cxx23,since-cxx26 %s
+namespace cwg2813 { // cwg2813: 19
+#if __cplusplus >= 202302L
+struct X {
+ X() = default;
+
+ X(const X&) = delete;
+ X& operator=(const X&) = delete;
+
+ void f(this X self) { }
+};
+
+void f() {
+ X{}.f();
+}
+#endif
+}
+
namespace cwg2819 { // cwg2819: 19 tentatively ready 2023-12-01
#if __cpp_constexpr >= 202306L
constexpr void* p = nullptr;
diff --git a/clang/test/CodeGenCXX/cxx2b-deducing-this.cpp b/clang/test/CodeGenCXX/cxx2b-deducing-this.cpp
index f9f9fbd7397f8..66f4a45cde9b6 100644
--- a/clang/test/CodeGenCXX/cxx2b-deducing-this.cpp
+++ b/clang/test/CodeGenCXX/cxx2b-deducing-this.cpp
@@ -31,7 +31,6 @@ void test_lambda() {
//CHECK: define dso_local void @{{.*}}test_lambda{{.*}}() #0 {
//CHECK: entry:
//CHECK: %agg.tmp = alloca %class.anon, align 1
-//CHECK: %ref.tmp = alloca %class.anon, align 1
//CHECK: %call = call noundef i32 @"_ZZ11test_lambdavENH3$_0clIS_EEiT_"()
//CHECK: ret void
//CHECK: }
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index 5e2ab06701703..ee37d20345732 100755
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -16687,7 +16687,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
<td><a href="https://cplusplus.github.io/CWG/issues/2813.html">2813</a></td>
<td>DR</td>
<td>Class member access with prvalues</td>
- <td class="unknown" align="center">Unknown</td>
+ <td class="unreleased" align="center">Clang 19</td>
</tr>
<tr class="open" id="2814">
<td><a href="https://cplusplus.github.io/CWG/issues/2814.html">2814</a></td>
>From edac756d0ea826f19e5c7fda2910eb286a53ca56 Mon Sep 17 00:00:00 2001
From: Mital Ashok <mital at mitalashok.co.uk>
Date: Tue, 11 Jun 2024 17:07:45 +0100
Subject: [PATCH 2/3] fix clangd AST test
---
.../clangd/unittests/DumpASTTests.cpp | 41 +++++++++++++++++--
1 file changed, 37 insertions(+), 4 deletions(-)
diff --git a/clang-tools-extra/clangd/unittests/DumpASTTests.cpp b/clang-tools-extra/clangd/unittests/DumpASTTests.cpp
index 304682118c871..cb2c17ad4ef0d 100644
--- a/clang-tools-extra/clangd/unittests/DumpASTTests.cpp
+++ b/clang-tools-extra/clangd/unittests/DumpASTTests.cpp
@@ -49,7 +49,7 @@ declaration: Function - root
)"},
{R"cpp(
namespace root {
-struct S { static const int x = 0; };
+struct S { static const int x = 0; ~S(); };
int y = S::x + root::S().x;
}
)cpp",
@@ -60,10 +60,12 @@ declaration: Namespace - root
type: Qualified - const
type: Builtin - int
expression: IntegerLiteral - 0
+ declaration: CXXDestructor
+ type: Record - S
+ type: FunctionProto
+ type: Builtin - void
declaration: CXXConstructor
declaration: CXXConstructor
- declaration: CXXConstructor
- declaration: CXXDestructor
declaration: Var - y
type: Builtin - int
expression: ExprWithCleanups
@@ -74,7 +76,7 @@ declaration: Namespace - root
type: Record - S
expression: ImplicitCast - LValueToRValue
expression: Member - x
- expression: MaterializeTemporary - rvalue
+ expression: CXXBindTemporary
expression: CXXTemporaryObject - S
type: Elaborated
specifier: Namespace - root::
@@ -82,6 +84,37 @@ declaration: Namespace - root
)"},
{R"cpp(
namespace root {
+struct S { static const int x = 0; };
+int y = S::x + root::S().x;
+}
+ )cpp",
+ R"(
+declaration: Namespace - root
+ declaration: CXXRecord - S
+ declaration: Var - x
+ type: Qualified - const
+ type: Builtin - int
+ expression: IntegerLiteral - 0
+ declaration: CXXConstructor
+ declaration: CXXConstructor
+ declaration: CXXConstructor
+ declaration: CXXDestructor
+ declaration: Var - y
+ type: Builtin - int
+ expression: BinaryOperator - +
+ expression: ImplicitCast - LValueToRValue
+ expression: DeclRef - x
+ specifier: TypeSpec
+ type: Record - S
+ expression: ImplicitCast - LValueToRValue
+ expression: Member - x
+ expression: CXXTemporaryObject - S
+ type: Elaborated
+ specifier: Namespace - root::
+ type: Record - S
+ )"},
+ {R"cpp(
+namespace root {
template <typename T> int tmpl() {
(void)tmpl<unsigned>();
return T::value;
>From a353728d94fb390057facf3a248e895c19e83956 Mon Sep 17 00:00:00 2001
From: Mital Ashok <mital at mitalashok.co.uk>
Date: Wed, 12 Jun 2024 18:21:15 +0100
Subject: [PATCH 3/3] Run [[nodiscard]] test in C++23
---
clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp
index a088c9ab93b0e..fb767641cdf33 100644
--- a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp
+++ b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp
@@ -1,6 +1,7 @@
-// RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify=expected -Wc++20-extensions %s
-// RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify=expected,cxx11-17 -Wc++17-extensions %s
// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify=expected,cxx11-17,cxx11 -Wc++17-extensions -Wc++20-extensions %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify=expected,cxx11-17 -Wc++17-extensions %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify=expected -Wc++20-extensions %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++23 -verify=expected %s
struct [[nodiscard]] S {};
S get_s();
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