Add support for derived class special members hiding functions brought in from

a base class via a using-declaration. If a class has a using-declaration
declaring either a constructor or an assignment operator, eagerly declare its
special members in case they need to displace a shadow declaration from a
using-declaration.

llvm-svn: 269398

clang/include/clang/AST/DeclCXX.h

@@ -382,6 +382,14 @@ class CXXRecordDecl : public RecordDecl {
     /// provided default ctor also doesn't have an in-class initializer.
     unsigned HasUninitializedFields : 1;
 
+    /// \brief True if there are any member using-declarations that inherit
+    /// constructors from a base class.
+    unsigned HasInheritedConstructor : 1;
+
+    /// \brief True if there are any member using-declarations named
+    /// 'operator='.
+    unsigned HasInheritedAssignment : 1;
+
     /// \brief These flags are \c true if a defaulted corresponding special
     /// member can't be fully analyzed without performing overload resolution.
     /// @{
@@ -1308,6 +1316,18 @@ public:
     return data().HasNonLiteralTypeFieldsOrBases;
   }
 
+  /// \brief Determine whether this class has a using-declaration that names
+  /// a base class constructor.
+  bool hasInheritedConstructor() const {
+    return data().HasInheritedConstructor;
+  }
+
+  /// \brief Determine whether this class has a using-declaration that names
+  /// a base class assignment operator.
+  bool hasInheritedAssignment() const {
+    return data().HasInheritedAssignment;
+  }
+
   /// \brief Determine whether this class is considered trivially copyable per
   /// (C++11 [class]p6).
   bool isTriviallyCopyable() const;

clang/include/clang/Sema/Sema.h

@@ -4540,6 +4540,9 @@ public:
   /// class.
   void ForceDeclarationOfImplicitMembers(CXXRecordDecl *Class);
 
+  /// \brief Check a completed declaration of an implicit special member.
+  void CheckImplicitSpecialMemberDeclaration(Scope *S, FunctionDecl *FD);
+
   /// \brief Determine whether the given function is an implicitly-deleted
   /// special member function.
   bool isImplicitlyDeleted(FunctionDecl *FD);

clang/lib/AST/ASTImporter.cpp

@@ -2115,6 +2115,8 @@ bool ASTNodeImporter::ImportDefinition(RecordDecl *From, RecordDecl *To,
     ToData.HasUninitializedReferenceMember
       = FromData.HasUninitializedReferenceMember;
     ToData.HasUninitializedFields = FromData.HasUninitializedFields;
+    ToData.HasInheritedConstructor = FromData.HasInheritedConstructor;
+    ToData.HasInheritedAssignment = FromData.HasInheritedAssignment;
     ToData.NeedOverloadResolutionForMoveConstructor
       = FromData.NeedOverloadResolutionForMoveConstructor;
     ToData.NeedOverloadResolutionForMoveAssignment

clang/lib/AST/DeclCXX.cpp

@@ -53,6 +53,7 @@ CXXRecordDecl::DefinitionData::DefinitionData(CXXRecordDecl *D)
       HasPublicFields(false), HasMutableFields(false), HasVariantMembers(false),
       HasOnlyCMembers(true), HasInClassInitializer(false),
       HasUninitializedReferenceMember(false), HasUninitializedFields(false),
+      HasInheritedConstructor(false), HasInheritedAssignment(false),
       NeedOverloadResolutionForMoveConstructor(false),
       NeedOverloadResolutionForMoveAssignment(false),
       NeedOverloadResolutionForDestructor(false),
@@ -955,6 +956,15 @@ void CXXRecordDecl::addedMember(Decl *D) {
       data().Conversions.get(Ctx).addDecl(Ctx, Shadow, Shadow->getAccess());
     }
   }
+
+  if (UsingDecl *Using = dyn_cast<UsingDecl>(D)) {
+    if (Using->getDeclName().getNameKind() ==
+        DeclarationName::CXXConstructorName)
+      data().HasInheritedConstructor = true;
+
+    if (Using->getDeclName().getCXXOverloadedOperator() == OO_Equal)
+      data().HasInheritedAssignment = true;
+  }
 }
 
 void CXXRecordDecl::finishedDefaultedOrDeletedMember(CXXMethodDecl *D) {

clang/lib/Sema/SemaDeclCXX.cpp

@@ -6455,20 +6455,28 @@ void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) {
   if (!ClassDecl->hasUserDeclaredConstructor())
     ++ASTContext::NumImplicitDefaultConstructors;
 
+  // If this class inherited any constructors, declare the default constructor
+  // now in case it displaces one from a base class.
+  if (ClassDecl->needsImplicitDefaultConstructor() &&
+      ClassDecl->hasInheritedConstructor())
+    DeclareImplicitDefaultConstructor(ClassDecl);
+
   if (!ClassDecl->hasUserDeclaredCopyConstructor()) {
     ++ASTContext::NumImplicitCopyConstructors;
 
     // If the properties or semantics of the copy constructor couldn't be
     // determined while the class was being declared, force a declaration
     // of it now.
-    if (ClassDecl->needsOverloadResolutionForCopyConstructor())
+    if (ClassDecl->needsOverloadResolutionForCopyConstructor() ||
+        ClassDecl->hasInheritedConstructor())
       DeclareImplicitCopyConstructor(ClassDecl);
   }
 
   if (getLangOpts().CPlusPlus11 && ClassDecl->needsImplicitMoveConstructor()) {
     ++ASTContext::NumImplicitMoveConstructors;
 
-    if (ClassDecl->needsOverloadResolutionForMoveConstructor())
+    if (ClassDecl->needsOverloadResolutionForMoveConstructor() ||
+        ClassDecl->hasInheritedConstructor())
       DeclareImplicitMoveConstructor(ClassDecl);
   }
 
@@ -6480,7 +6488,8 @@ void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) {
     // it shows up in the right place in the vtable and that we diagnose
     // problems with the implicit exception specification.
     if (ClassDecl->isDynamicClass() ||
-        ClassDecl->needsOverloadResolutionForCopyAssignment())
+        ClassDecl->needsOverloadResolutionForCopyAssignment() ||
+        ClassDecl->hasInheritedAssignment())
       DeclareImplicitCopyAssignment(ClassDecl);
   }
 
@@ -6489,7 +6498,8 @@ void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) {
 
     // Likewise for the move assignment operator.
     if (ClassDecl->isDynamicClass() ||
-        ClassDecl->needsOverloadResolutionForMoveAssignment())
+        ClassDecl->needsOverloadResolutionForMoveAssignment() ||
+        ClassDecl->hasInheritedAssignment())
       DeclareImplicitMoveAssignment(ClassDecl);
   }
 
@@ -8898,10 +8908,11 @@ namespace {
 struct DeclaringSpecialMember {
   Sema &S;
   Sema::SpecialMemberDecl D;
+  Sema::ContextRAII SavedContext;
   bool WasAlreadyBeingDeclared;
 
   DeclaringSpecialMember(Sema &S, CXXRecordDecl *RD, Sema::CXXSpecialMember CSM)
-    : S(S), D(RD, CSM) {
+    : S(S), D(RD, CSM), SavedContext(S, RD) {
     WasAlreadyBeingDeclared = !S.SpecialMembersBeingDeclared.insert(D).second;
     if (WasAlreadyBeingDeclared)
       // This almost never happens, but if it does, ensure that our cache
@@ -8923,6 +8934,20 @@ struct DeclaringSpecialMember {
 };
 }
 
+void Sema::CheckImplicitSpecialMemberDeclaration(Scope *S, FunctionDecl *FD) {
+  // Look up any existing declarations, but don't trigger declaration of all
+  // implicit special members with this name.
+  DeclarationName Name = FD->getDeclName();
+  LookupResult R(*this, Name, SourceLocation(), LookupOrdinaryName,
+                 ForRedeclaration);
+  for (auto *D : FD->getParent()->lookup(Name))
+    if (auto *Acceptable = R.getAcceptableDecl(D))
+      R.addDecl(Acceptable);
+  R.resolveKind();
+
+  CheckFunctionDeclaration(S, FD, R, /*IsExplicitSpecialization*/false);
+}
+
 CXXConstructorDecl *Sema::DeclareImplicitDefaultConstructor(
                                                      CXXRecordDecl *ClassDecl) {
   // C++ [class.ctor]p5:
@@ -8971,13 +8996,16 @@ CXXConstructorDecl *Sema::DeclareImplicitDefaultConstructor(
   // constructors is easy to compute.
   DefaultCon->setTrivial(ClassDecl->hasTrivialDefaultConstructor());
 
-  if (ShouldDeleteSpecialMember(DefaultCon, CXXDefaultConstructor))
-    SetDeclDeleted(DefaultCon, ClassLoc);
-
   // Note that we have declared this constructor.
   ++ASTContext::NumImplicitDefaultConstructorsDeclared;
 
-  if (Scope *S = getScopeForContext(ClassDecl))
+  Scope *S = getScopeForContext(ClassDecl);
+  CheckImplicitSpecialMemberDeclaration(S, DefaultCon);
+
+  if (ShouldDeleteSpecialMember(DefaultCon, CXXDefaultConstructor))
+    SetDeclDeleted(DefaultCon, ClassLoc);
+
+  if (S)
     PushOnScopeChains(DefaultCon, S, false);
   ClassDecl->addDecl(DefaultCon);
 
@@ -9433,20 +9461,21 @@ CXXDestructorDecl *Sema::DeclareImplicitDestructor(CXXRecordDecl *ClassDecl) {
   FunctionProtoType::ExtProtoInfo EPI = getImplicitMethodEPI(*this, Destructor);
   Destructor->setType(Context.getFunctionType(Context.VoidTy, None, EPI));
 
-  AddOverriddenMethods(ClassDecl, Destructor);
-
   // We don't need to use SpecialMemberIsTrivial here; triviality for
   // destructors is easy to compute.
   Destructor->setTrivial(ClassDecl->hasTrivialDestructor());
 
-  if (ShouldDeleteSpecialMember(Destructor, CXXDestructor))
-    SetDeclDeleted(Destructor, ClassLoc);
-
   // Note that we have declared this destructor.
   ++ASTContext::NumImplicitDestructorsDeclared;
 
+  Scope *S = getScopeForContext(ClassDecl);
+  CheckImplicitSpecialMemberDeclaration(S, Destructor);
+
+  if (ShouldDeleteSpecialMember(Destructor, CXXDestructor))
+    SetDeclDeleted(Destructor, ClassLoc);
+
   // Introduce this destructor into its scope.
-  if (Scope *S = getScopeForContext(ClassDecl))
+  if (S)
     PushOnScopeChains(Destructor, S, false);
   ClassDecl->addDecl(Destructor);
 
@@ -10147,20 +10176,21 @@ CXXMethodDecl *Sema::DeclareImplicitCopyAssignment(CXXRecordDecl *ClassDecl) {
                                                nullptr);
   CopyAssignment->setParams(FromParam);
 
-  AddOverriddenMethods(ClassDecl, CopyAssignment);
-
   CopyAssignment->setTrivial(
     ClassDecl->needsOverloadResolutionForCopyAssignment()
       ? SpecialMemberIsTrivial(CopyAssignment, CXXCopyAssignment)
       : ClassDecl->hasTrivialCopyAssignment());
 
-  if (ShouldDeleteSpecialMember(CopyAssignment, CXXCopyAssignment))
-    SetDeclDeleted(CopyAssignment, ClassLoc);
-
   // Note that we have added this copy-assignment operator.
   ++ASTContext::NumImplicitCopyAssignmentOperatorsDeclared;
 
-  if (Scope *S = getScopeForContext(ClassDecl))
+  Scope *S = getScopeForContext(ClassDecl);
+  CheckImplicitSpecialMemberDeclaration(S, CopyAssignment);
+
+  if (ShouldDeleteSpecialMember(CopyAssignment, CXXCopyAssignment))
+    SetDeclDeleted(CopyAssignment, ClassLoc);
+
+  if (S)
     PushOnScopeChains(CopyAssignment, S, false);
   ClassDecl->addDecl(CopyAssignment);
 
@@ -10538,22 +10568,23 @@ CXXMethodDecl *Sema::DeclareImplicitMoveAssignment(CXXRecordDecl *ClassDecl) {
                                                nullptr);
   MoveAssignment->setParams(FromParam);
 
-  AddOverriddenMethods(ClassDecl, MoveAssignment);
-
   MoveAssignment->setTrivial(
     ClassDecl->needsOverloadResolutionForMoveAssignment()
       ? SpecialMemberIsTrivial(MoveAssignment, CXXMoveAssignment)
       : ClassDecl->hasTrivialMoveAssignment());
 
+  // Note that we have added this copy-assignment operator.
+  ++ASTContext::NumImplicitMoveAssignmentOperatorsDeclared;
+
+  Scope *S = getScopeForContext(ClassDecl);
+  CheckImplicitSpecialMemberDeclaration(S, MoveAssignment);
+
   if (ShouldDeleteSpecialMember(MoveAssignment, CXXMoveAssignment)) {
     ClassDecl->setImplicitMoveAssignmentIsDeleted();
     SetDeclDeleted(MoveAssignment, ClassLoc);
   }
 
-  // Note that we have added this copy-assignment operator.
-  ++ASTContext::NumImplicitMoveAssignmentOperatorsDeclared;
-
-  if (Scope *S = getScopeForContext(ClassDecl))
+  if (S)
     PushOnScopeChains(MoveAssignment, S, false);
   ClassDecl->addDecl(MoveAssignment);
 
@@ -10979,13 +11010,16 @@ CXXConstructorDecl *Sema::DeclareImplicitCopyConstructor(
       ? SpecialMemberIsTrivial(CopyConstructor, CXXCopyConstructor)
       : ClassDecl->hasTrivialCopyConstructor());
 
-  if (ShouldDeleteSpecialMember(CopyConstructor, CXXCopyConstructor))
-    SetDeclDeleted(CopyConstructor, ClassLoc);
-
   // Note that we have declared this constructor.
   ++ASTContext::NumImplicitCopyConstructorsDeclared;
 
-  if (Scope *S = getScopeForContext(ClassDecl))
+  Scope *S = getScopeForContext(ClassDecl);
+  CheckImplicitSpecialMemberDeclaration(S, CopyConstructor);
+
+  if (ShouldDeleteSpecialMember(CopyConstructor, CXXCopyConstructor))
+    SetDeclDeleted(CopyConstructor, ClassLoc);
+
+  if (S)
     PushOnScopeChains(CopyConstructor, S, false);
   ClassDecl->addDecl(CopyConstructor);
 
@@ -11156,15 +11190,18 @@ CXXConstructorDecl *Sema::DeclareImplicitMoveConstructor(
       ? SpecialMemberIsTrivial(MoveConstructor, CXXMoveConstructor)
       : ClassDecl->hasTrivialMoveConstructor());
 
+  // Note that we have declared this constructor.
+  ++ASTContext::NumImplicitMoveConstructorsDeclared;
+
+  Scope *S = getScopeForContext(ClassDecl);
+  CheckImplicitSpecialMemberDeclaration(S, MoveConstructor);
+
   if (ShouldDeleteSpecialMember(MoveConstructor, CXXMoveConstructor)) {
     ClassDecl->setImplicitMoveConstructorIsDeleted();
     SetDeclDeleted(MoveConstructor, ClassLoc);
   }
 
-  // Note that we have declared this constructor.
-  ++ASTContext::NumImplicitMoveConstructorsDeclared;
-
-  if (Scope *S = getScopeForContext(ClassDecl))
+  if (S)
     PushOnScopeChains(MoveConstructor, S, false);
   ClassDecl->addDecl(MoveConstructor);
 

clang/lib/Serialization/ASTReaderDecl.cpp

@@ -1466,6 +1466,8 @@ void ASTDeclReader::ReadCXXDefinitionData(
   Data.HasInClassInitializer = Record[Idx++];
   Data.HasUninitializedReferenceMember = Record[Idx++];
   Data.HasUninitializedFields = Record[Idx++];
+  Data.HasInheritedConstructor = Record[Idx++];
+  Data.HasInheritedAssignment = Record[Idx++];
   Data.NeedOverloadResolutionForMoveConstructor = Record[Idx++];
   Data.NeedOverloadResolutionForMoveAssignment = Record[Idx++];
   Data.NeedOverloadResolutionForDestructor = Record[Idx++];
@@ -1593,6 +1595,8 @@ void ASTDeclReader::MergeDefinitionData(
   MATCH_FIELD(HasInClassInitializer)
   MATCH_FIELD(HasUninitializedReferenceMember)
   MATCH_FIELD(HasUninitializedFields)
+  MATCH_FIELD(HasInheritedConstructor)
+  MATCH_FIELD(HasInheritedAssignment)
   MATCH_FIELD(NeedOverloadResolutionForMoveConstructor)
   MATCH_FIELD(NeedOverloadResolutionForMoveAssignment)
   MATCH_FIELD(NeedOverloadResolutionForDestructor)

clang/lib/Serialization/ASTWriter.cpp

@@ -5489,6 +5489,8 @@ void ASTRecordWriter::AddCXXDefinitionData(const CXXRecordDecl *D) {
   Record->push_back(Data.HasInClassInitializer);
   Record->push_back(Data.HasUninitializedReferenceMember);
   Record->push_back(Data.HasUninitializedFields);
+  Record->push_back(Data.HasInheritedConstructor);
+  Record->push_back(Data.HasInheritedAssignment);
   Record->push_back(Data.NeedOverloadResolutionForMoveConstructor);
   Record->push_back(Data.NeedOverloadResolutionForMoveAssignment);
   Record->push_back(Data.NeedOverloadResolutionForDestructor);

clang/test/CXX/dcl.dcl/basic.namespace/namespace.udecl/p12.cpp

@@ -1,3 +1,5 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++98 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
 // RUN: %clang_cc1 -fsyntax-only -verify %s
 
 // C++03 [namespace.udecl]p12:
@@ -161,3 +163,33 @@ namespace test4 {
     d.bar<int>(3); // expected-error {{'bar' is a protected member}}
   }
 }
+
+namespace test5 {
+  struct Derived;
+  struct Base {
+    void operator=(const Derived&);
+  };
+  struct Derived : Base {
+    // Hidden by implicit derived class operator.
+    using Base::operator=;
+  };
+  void f(Derived d) {
+    d = d;
+  }
+}
+
+#if __cplusplus >= 201103L
+namespace test6 {
+  struct Derived;
+  struct Base {
+    void operator=(Derived&&);
+  };
+  struct Derived : Base {
+    // Hidden by implicit derived class operator.
+    using Base::operator=;
+  };
+  void f(Derived d) {
+    d = Derived();
+  }
+}
+#endif

clang/test/SemaCUDA/implicit-member-target.cu

@@ -60,13 +60,14 @@ struct A3_with_device_ctors {
 
 struct B3_with_implicit_ctors : A3_with_device_ctors {
 };
+// expected-note@-2 2{{call to __device__ function from __host__ function}}
+// expected-note@-3 {{default constructor}}
 
-// expected-note@-3 {{copy constructor of 'B3_with_implicit_ctors' is implicitly deleted}}
 
 void hostfoo3() {
   B3_with_implicit_ctors b;  // this is OK because the inferred default ctor
                              // here is __host__
-  B3_with_implicit_ctors b2 = b; // expected-error {{call to implicitly-deleted copy constructor}}
+  B3_with_implicit_ctors b2 = b; // expected-error {{no matching constructor}}
 
 }
 

clang/test/SemaCXX/constructor-recovery.cpp

@@ -1,9 +1,9 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
 
-struct C {
+struct C { // expected-note 1+{{candidate}}
   virtual C() = 0; // expected-error{{constructor cannot be declared 'virtual'}}
 };
 
 void f() {
- C c;
+ C c; // expected-error {{no matching constructor}}
 }