diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 060bc7669b72a5..edc05a0d208ded 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -234,11 +234,6 @@ C++2c Feature Support Resolutions to C++ Defect Reports ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -- Implemented `CWG2137 `_ which allows - list-initialization from objects of the same type. -- Implemented `CWG2311 `_: given a prvalue ``e`` of object type - ``T``, ``T{e}`` will try to resolve an initializer list constructor and will use it if successful (CWG2137). - Otherwise, if there is no initializer list constructor, the copy will be elided as if it was ``T(e)``. - Implemented `CWG2598 `_ and `CWG2096 `_, making unions (that have either no members or at least one literal member) literal types. diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp index 91e4cb7b68a24a..457fa377355a97 100644 --- a/clang/lib/Sema/SemaInit.cpp +++ b/clang/lib/Sema/SemaInit.cpp @@ -4200,7 +4200,7 @@ static OverloadingResult ResolveConstructorOverload( /// \param IsListInit Is this list-initialization? /// \param IsInitListCopy Is this non-list-initialization resulting from a /// list-initialization from {x} where x is the same -/// aggregate type as the entity? +/// type as the entity? static void TryConstructorInitialization(Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind, @@ -4230,14 +4230,6 @@ static void TryConstructorInitialization(Sema &S, Entity.getKind() != InitializedEntity::EK_LambdaToBlockConversionBlockElement); - bool CopyElisionPossible = false; - auto ElideConstructor = [&] { - // Convert qualifications if necessary. - Sequence.AddQualificationConversionStep(DestType, VK_PRValue); - if (ILE) - Sequence.RewrapReferenceInitList(DestType, ILE); - }; - // C++17 [dcl.init]p17: // - If the initializer expression is a prvalue and the cv-unqualified // version of the source type is the same class as the class of the @@ -4250,17 +4242,11 @@ static void TryConstructorInitialization(Sema &S, if (S.getLangOpts().CPlusPlus17 && !RequireActualConstructor && UnwrappedArgs.size() == 1 && UnwrappedArgs[0]->isPRValue() && S.Context.hasSameUnqualifiedType(UnwrappedArgs[0]->getType(), DestType)) { - if (ILE && !DestType->isAggregateType()) { - // CWG2311: T{ prvalue_of_type_T } is not eligible for copy elision - // Make this an elision if this won't call an initializer-list - // constructor. (Always on an aggregate type or check constructors first.) - assert(!IsInitListCopy && - "IsInitListCopy only possible with aggregate types"); - CopyElisionPossible = true; - } else { - ElideConstructor(); - return; - } + // Convert qualifications if necessary. + Sequence.AddQualificationConversionStep(DestType, VK_PRValue); + if (ILE) + Sequence.RewrapReferenceInitList(DestType, ILE); + return; } const RecordType *DestRecordType = DestType->getAs(); @@ -4305,12 +4291,6 @@ static void TryConstructorInitialization(Sema &S, S, Kind.getLocation(), Args, CandidateSet, DestType, Ctors, Best, CopyInitialization, AllowExplicit, /*OnlyListConstructors=*/true, IsListInit, RequireActualConstructor); - - if (CopyElisionPossible && Result == OR_No_Viable_Function) { - // No initializer list candidate - ElideConstructor(); - return; - } } // C++11 [over.match.list]p1: @@ -4592,9 +4572,9 @@ static void TryListInitialization(Sema &S, return; } - // C++11 [dcl.init.list]p3, per DR1467 and DR2137: - // - If T is an aggregate class and the initializer list has a single element - // of type cv U, where U is T or a class derived from T, the object is + // C++11 [dcl.init.list]p3, per DR1467: + // - If T is a class type and the initializer list has a single element of + // type cv U, where U is T or a class derived from T, the object is // initialized from that element (by copy-initialization for // copy-list-initialization, or by direct-initialization for // direct-list-initialization). @@ -4605,7 +4585,7 @@ static void TryListInitialization(Sema &S, // - Otherwise, if T is an aggregate, [...] (continue below). if (S.getLangOpts().CPlusPlus11 && InitList->getNumInits() == 1 && !IsDesignatedInit) { - if (DestType->isRecordType() && DestType->isAggregateType()) { + if (DestType->isRecordType()) { QualType InitType = InitList->getInit(0)->getType(); if (S.Context.hasSameUnqualifiedType(InitType, DestType) || S.IsDerivedFrom(InitList->getBeginLoc(), InitType, DestType)) { diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp index 030878899b8122..c9eb6789835633 100644 --- a/clang/lib/Sema/SemaOverload.cpp +++ b/clang/lib/Sema/SemaOverload.cpp @@ -1568,37 +1568,19 @@ TryUserDefinedConversion(Sema &S, Expr *From, QualType ToType, // called for those cases. if (CXXConstructorDecl *Constructor = dyn_cast(ICS.UserDefined.ConversionFunction)) { - QualType FromType; - SourceLocation FromLoc; - // C++11 [over.ics.list]p6, per DR2137: - // C++17 [over.ics.list]p6: - // If C is not an initializer-list constructor and the initializer list - // has a single element of type cv U, where U is X or a class derived - // from X, the implicit conversion sequence has Exact Match rank if U is - // X, or Conversion rank if U is derived from X. - if (const auto *InitList = dyn_cast(From); - InitList && InitList->getNumInits() == 1 && - !S.isInitListConstructor(Constructor)) { - const Expr *SingleInit = InitList->getInit(0); - FromType = SingleInit->getType(); - FromLoc = SingleInit->getBeginLoc(); - } else { - FromType = From->getType(); - FromLoc = From->getBeginLoc(); - } - QualType FromCanon = - S.Context.getCanonicalType(FromType.getUnqualifiedType()); + QualType FromCanon + = S.Context.getCanonicalType(From->getType().getUnqualifiedType()); QualType ToCanon = S.Context.getCanonicalType(ToType).getUnqualifiedType(); if (Constructor->isCopyConstructor() && (FromCanon == ToCanon || - S.IsDerivedFrom(FromLoc, FromCanon, ToCanon))) { + S.IsDerivedFrom(From->getBeginLoc(), FromCanon, ToCanon))) { // Turn this into a "standard" conversion sequence, so that it // gets ranked with standard conversion sequences. DeclAccessPair Found = ICS.UserDefined.FoundConversionFunction; ICS.setStandard(); ICS.Standard.setAsIdentityConversion(); - ICS.Standard.setFromType(FromType); + ICS.Standard.setFromType(From->getType()); ICS.Standard.setAllToTypes(ToType); ICS.Standard.CopyConstructor = Constructor; ICS.Standard.FoundCopyConstructor = Found; @@ -5324,18 +5306,18 @@ TryListConversion(Sema &S, InitListExpr *From, QualType ToType, IsDesignatedInit) return Result; - // Per DR1467 and DR2137: - // If the parameter type is an aggregate class X and the initializer list - // has a single element of type cv U, where U is X or a class derived from - // X, the implicit conversion sequence is the one required to convert the - // element to the parameter type. + // Per DR1467: + // If the parameter type is a class X and the initializer list has a single + // element of type cv U, where U is X or a class derived from X, the + // implicit conversion sequence is the one required to convert the element + // to the parameter type. // // Otherwise, if the parameter type is a character array [... ] // and the initializer list has a single element that is an // appropriately-typed string literal (8.5.2 [dcl.init.string]), the // implicit conversion sequence is the identity conversion. if (From->getNumInits() == 1 && !IsDesignatedInit) { - if (ToType->isRecordType() && ToType->isAggregateType()) { + if (ToType->isRecordType()) { QualType InitType = From->getInit(0)->getType(); if (S.Context.hasSameUnqualifiedType(InitType, ToType) || S.IsDerivedFrom(From->getBeginLoc(), InitType, ToType)) diff --git a/clang/test/CXX/drs/dr14xx.cpp b/clang/test/CXX/drs/dr14xx.cpp index 4c29d03a6e117a..d262f6f9dcab79 100644 --- a/clang/test/CXX/drs/dr14xx.cpp +++ b/clang/test/CXX/drs/dr14xx.cpp @@ -488,6 +488,16 @@ namespace dr1467 { // dr1467: 3.7 c++11 } } // nonaggregate + namespace SelfInitIsNotListInit { + struct S { + S(); + explicit S(S &); + S(const S &); + }; + S s1; + S s2 = {s1}; // ok, not list-initialization so we pick the non-explicit constructor + } + struct NestedInit { int a, b, c; }; NestedInit ni[1] = {{NestedInit{1, 2, 3}}}; diff --git a/clang/test/CXX/drs/dr21xx.cpp b/clang/test/CXX/drs/dr21xx.cpp index 87040246aa5cd4..a7e50df3f374be 100644 --- a/clang/test/CXX/drs/dr21xx.cpp +++ b/clang/test/CXX/drs/dr21xx.cpp @@ -11,16 +11,6 @@ // cxx98-error@-1 {{variadic macros are a C99 feature}} #endif -namespace std { - __extension__ typedef __SIZE_TYPE__ size_t; - - template struct initializer_list { - const E *p; size_t n; - initializer_list(const E *p, size_t n); - initializer_list(); - }; -} - namespace dr2100 { // dr2100: 12 template struct X {}; template struct A { @@ -142,41 +132,6 @@ namespace dr2126 { // dr2126: 12 #endif } -namespace dr2137 { // dr2137: 18 -#if __cplusplus >= 201103L - struct Q { - Q(); - Q(Q&&); - Q(std::initializer_list) = delete; // #dr2137-Qcons - }; - - Q x = Q { Q() }; - // since-cxx11-error@-1 {{call to deleted constructor of 'Q'}} - // since-cxx11-note@#dr2137-Qcons {{'Q' has been explicitly marked deleted here}} - - int f(Q); // #dr2137-f - int y = f({ Q() }); - // since-cxx11-error@-1 {{call to deleted constructor of 'Q'}} - // since-cxx11-note@#dr2137-Qcons {{'Q' has been explicitly marked deleted here}} - // since-cxx11-note@#dr2137-f {{passing argument to parameter here}} - - struct U { - U(); - U(const U&); - }; - - struct Derived : U { - Derived(); - Derived(const Derived&); - } d; - - int g(Derived); - int g(U(&&)[1]) = delete; - - int z = g({ d }); -#endif -} - namespace dr2140 { // dr2140: 9 #if __cplusplus >= 201103L union U { int a; decltype(nullptr) b; }; diff --git a/clang/test/CXX/drs/dr23xx.cpp b/clang/test/CXX/drs/dr23xx.cpp index d8556998315c77..03077ae9239a45 100644 --- a/clang/test/CXX/drs/dr23xx.cpp +++ b/clang/test/CXX/drs/dr23xx.cpp @@ -6,16 +6,6 @@ // RUN: %clang_cc1 -std=c++23 %s -verify=expected,since-cxx11,since-cxx14,since-cxx17,since-cxx20 -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s // RUN: %clang_cc1 -std=c++2c %s -verify=expected,since-cxx11,since-cxx14,since-cxx17,since-cxx20 -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s -namespace std { - __extension__ typedef __SIZE_TYPE__ size_t; - - template struct initializer_list { - const E *p; size_t n; - initializer_list(const E *p, size_t n); - initializer_list(); - }; -} - #if __cplusplus >= 201103L namespace dr2303 { // dr2303: 12 template @@ -57,81 +47,6 @@ void g() { } //namespace dr2303 #endif -namespace dr2311 { // dr2311: 18 open -#if __cplusplus >= 201707L -template -void test() { - // Ensure none of these try to call a move constructor. - T a = T{T(0)}; - T b{T(0)}; - auto c{T(0)}; - T d = {T(0)}; - auto e = {T(0)}; -#if __cplusplus >= 202302L - auto f = auto{T(0)}; -#endif - void(*fn)(T); - fn({T(0)}); -} - -struct NonMovable { - NonMovable(int); - NonMovable(NonMovable&&) = delete; -}; -struct NonMovableNonApplicableIList { - NonMovableNonApplicableIList(int); - NonMovableNonApplicableIList(NonMovableNonApplicableIList&&) = delete; - NonMovableNonApplicableIList(std::initializer_list); -}; -struct ExplicitMovable { - ExplicitMovable(int); - explicit ExplicitMovable(ExplicitMovable&&); -}; -struct ExplicitNonMovable { - ExplicitNonMovable(int); - explicit ExplicitNonMovable(ExplicitNonMovable&&) = delete; -}; -struct ExplicitNonMovableNonApplicableIList { - ExplicitNonMovableNonApplicableIList(int); - explicit ExplicitNonMovableNonApplicableIList(ExplicitNonMovableNonApplicableIList&&) = delete; - ExplicitNonMovableNonApplicableIList(std::initializer_list); -}; -struct CopyOnly { - CopyOnly(int); - CopyOnly(const CopyOnly&); - CopyOnly(CopyOnly&&) = delete; -}; -struct ExplicitCopyOnly { - ExplicitCopyOnly(int); - explicit ExplicitCopyOnly(const ExplicitCopyOnly&); - explicit ExplicitCopyOnly(ExplicitCopyOnly&&) = delete; -}; - -template void test(); -template void test(); -template void test(); -template void test(); -template void test(); -template void test(); -template void test(); - -struct any { - template - any(T&&); -}; - -template -struct X { - X(); - X(T) = delete; // #dr2311-X -}; - -X> x{ X>() }; -// since-cxx17-error@-1 {{call to deleted constructor of 'X>'}} -// since-cxx17-note@#dr2311-X {{'X' has been explicitly marked deleted here}} -#endif -} - // dr2331: na // dr2335 is in dr2335.cxx diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html index f0d835fc091cea..c9d21f096a34c6 100755 --- a/clang/www/cxx_dr_status.html +++ b/clang/www/cxx_dr_status.html @@ -12630,7 +12630,7 @@

C++ defect report implementation status

2137 CD4 List-initialization from object of same type - Clang 18 + Unknown 2138 @@ -13674,7 +13674,7 @@

C++ defect report implementation status

2311 open Missed case for guaranteed copy elision - Clang 18 + Not resolved 2312 diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/ctor.pair_U_V_move.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/ctor.pair_U_V_move.pass.cpp index 30fdb19fd3aebe..3b2d093eb34d49 100644 --- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/ctor.pair_U_V_move.pass.cpp +++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/ctor.pair_U_V_move.pass.cpp @@ -121,26 +121,7 @@ int main(int, char**) test_pair_rv(); test_pair_rv(); - /* For ExplicitTypes::CopyOnly, two of the viable candidates for initializing from a non-const xvalue are: - * pair(const pair&); // (defaulted copy constructor) - * template explicit pair(const pair&&); [U1 = ExplicitTypes::CopyOnly, U2 = int] - * This results in diverging behavior for test_convertible which uses copy-list-initialization - * Prior to CWG2137, this would have selected the first (non-explicit) ctor as explicit ctors would not be considered - * Afterwards, it should select the second since it is a better match, and then failed because it is explicit - * - * This may change with future defect reports, and some compilers only have partial support for CWG2137, - * so use std::is_convertible directly to avoid a copy-list-initialization - */ - { - using P1 = std::pair; - using P2 = std::pair; - using UP1 = std::pair&&; - using UP2 = std::pair&&; - static_assert(std::is_constructible::value, ""); - static_assert(std::is_convertible::value, ""); - static_assert(std::is_constructible::value, ""); - static_assert(std::is_convertible::value, ""); - } + test_pair_rv(); test_pair_rv(); test_pair_rv();