From f8981b8ce216ab440cfb6497f5a672519e0b5880 Mon Sep 17 00:00:00 2001 From: Dimitry Andric Date: Sun, 28 Jan 2024 21:34:42 +0100 Subject: [PATCH] Merge commit 6e4930c67508 from llvm-project (by Alexander Kornienko): Revert "[SemaCXX] Implement CWG2137 (list-initialization from objects of the same type) (#77768)" This reverts commit 924701311aa79180e86ad8ce43d253f27d25ec7d. Causes compilation errors on valid code, see https://github.com/llvm/llvm-project/pull/77768#issuecomment-1908062472. In particular, this fixes bogus "call to constructor of 'SomeType' is ambiguous" errors. PR: 276104 MFC after: 1 month (cherry picked from commit ddbac700c256bec42c441b75a5cb5f74e9be601f) --- .../llvm-project/clang/lib/Sema/SemaInit.cpp | 40 +++++-------------- .../clang/lib/Sema/SemaOverload.cpp | 38 +++++------------- 2 files changed, 20 insertions(+), 58 deletions(-) diff --git a/contrib/llvm-project/clang/lib/Sema/SemaInit.cpp b/contrib/llvm-project/clang/lib/Sema/SemaInit.cpp index 91e4cb7b68a24..457fa377355a9 100644 --- a/contrib/llvm-project/clang/lib/Sema/SemaInit.cpp +++ b/contrib/llvm-project/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/contrib/llvm-project/clang/lib/Sema/SemaOverload.cpp b/contrib/llvm-project/clang/lib/Sema/SemaOverload.cpp index 030878899b812..c9eb678983563 100644 --- a/contrib/llvm-project/clang/lib/Sema/SemaOverload.cpp +++ b/contrib/llvm-project/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))