When we emit an error during the implicit definition of a special

member function (default constructor, copy constructor, copy
assignment operator, destructor), emit a note showing where that
implicit definition was required.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@103619 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 54 insertions, 15 deletions

diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index fa8976fdc4..70e445ffae 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -3572,6 +3572,24 @@ public:
     }
   };
 
+  /// \brief RAII class that determines when any errors have occurred
+  /// between the time the instance was created and the time it was
+  /// queried.
+  class ErrorTrap {
+    Sema &SemaRef;
+    unsigned PrevErrors;
+
+  public:
+    explicit ErrorTrap(Sema &SemaRef)
+      : SemaRef(SemaRef), PrevErrors(SemaRef.getDiagnostics().getNumErrors()) {}
+
+    /// \brief Determine whether any errors have occurred since this
+    /// object instance was created.
+    bool hasErrorOccurred() const {
+      return SemaRef.getDiagnostics().getNumErrors() > PrevErrors;
+    }
+  };
+
   /// \brief A stack-allocated class that identifies which local
   /// variable declaration instantiations are present in this scope.
   ///
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 72a57c36bb..7320bc6b04 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -4146,12 +4146,15 @@ void Sema::DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
   assert(ClassDecl && "DefineImplicitDefaultConstructor - invalid constructor");
 
   ImplicitlyDefinedFunctionScope Scope(*this, Constructor);
-  if (SetBaseOrMemberInitializers(Constructor, 0, 0, /*AnyErrors=*/false)) {
+  ErrorTrap Trap(*this);
+  if (SetBaseOrMemberInitializers(Constructor, 0, 0, /*AnyErrors=*/false) ||
+      Trap.hasErrorOccurred()) {
     Diag(CurrentLocation, diag::note_member_synthesized_at) 
       << CXXConstructor << Context.getTagDeclType(ClassDecl);
     Constructor->setInvalidDecl();
   } else {
     Constructor->setUsed();
+    MaybeMarkVirtualMembersReferenced(CurrentLocation, Constructor);
   }
 }
 
@@ -4162,14 +4165,16 @@ void Sema::DefineImplicitDestructor(SourceLocation CurrentLocation,
   CXXRecordDecl *ClassDecl = Destructor->getParent();
   assert(ClassDecl && "DefineImplicitDestructor - invalid destructor");
 
+  if (Destructor->isInvalidDecl())
+    return;
+
   ImplicitlyDefinedFunctionScope Scope(*this, Destructor);
 
+  ErrorTrap Trap(*this);
   MarkBaseAndMemberDestructorsReferenced(Destructor->getLocation(),
                                          Destructor->getParent());
 
-  // FIXME: If CheckDestructor fails, we should emit a note about where the
-  // implicit destructor was needed.
-  if (CheckDestructor(Destructor)) {
+  if (CheckDestructor(Destructor) || Trap.hasErrorOccurred()) {
     Diag(CurrentLocation, diag::note_member_synthesized_at) 
       << CXXDestructor << Context.getTagDeclType(ClassDecl);
 
@@ -4178,6 +4183,7 @@ void Sema::DefineImplicitDestructor(SourceLocation CurrentLocation,
   }
 
   Destructor->setUsed();
+  MaybeMarkVirtualMembersReferenced(CurrentLocation, Destructor);
 }
 
 /// \brief Builds a statement that copies the given entity from \p From to
@@ -4396,6 +4402,7 @@ void Sema::DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
   CopyAssignOperator->setUsed();
 
   ImplicitlyDefinedFunctionScope Scope(*this, CopyAssignOperator);
+  ErrorTrap Trap(*this);
 
   // C++0x [class.copy]p30:
   //   The implicitly-defined or explicitly-defaulted copy assignment operator
@@ -4616,6 +4623,12 @@ void Sema::DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
       Invalid = true;
     else {
       Statements.push_back(Return.takeAs<Stmt>());
+
+      if (Trap.hasErrorOccurred()) {
+        Diag(CurrentLocation, diag::note_member_synthesized_at) 
+          << CXXCopyAssignment << Context.getTagDeclType(ClassDecl);
+        Invalid = true;
+      }
     }
   }
 
@@ -4628,6 +4641,8 @@ void Sema::DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
                                             /*isStmtExpr=*/false);
   assert(!Body.isInvalid() && "Compound statement creation cannot fail");
   CopyAssignOperator->setBody(Body.takeAs<Stmt>());
+
+  MaybeMarkVirtualMembersReferenced(CurrentLocation, CopyAssignOperator);
 }
 
 void Sema::DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
@@ -4642,8 +4657,10 @@ void Sema::DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
   assert(ClassDecl && "DefineImplicitCopyConstructor - invalid constructor");
 
   ImplicitlyDefinedFunctionScope Scope(*this, CopyConstructor);
+  ErrorTrap Trap(*this);
 
-  if (SetBaseOrMemberInitializers(CopyConstructor, 0, 0, /*AnyErrors=*/false)) {
+  if (SetBaseOrMemberInitializers(CopyConstructor, 0, 0, /*AnyErrors=*/false) ||
+      Trap.hasErrorOccurred()) {
     Diag(CurrentLocation, diag::note_member_synthesized_at) 
       << CXXCopyConstructor << Context.getTagDeclType(ClassDecl);
     CopyConstructor->setInvalidDecl();
@@ -4653,6 +4670,7 @@ void Sema::DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
                                                MultiStmtArg(*this, 0, 0), 
                                                /*isStmtExpr=*/false)
                                                               .takeAs<Stmt>());
+    MaybeMarkVirtualMembersReferenced(CurrentLocation, CopyConstructor);
   }
   
   CopyConstructor->setUsed();
diff --git a/test/CXX/class.access/p4.cpp b/test/CXX/class.access/p4.cpp
index 1cd8966136..e8afbe7a39 100644
--- a/test/CXX/class.access/p4.cpp
+++ b/test/CXX/class.access/p4.cpp
@@ -97,7 +97,7 @@ namespace test2 {
   A A::foo; // okay
   
   class B : A { }; // expected-error {{base class 'test2::A' has private constructor}}
-  B b;
+  B b; // expected-note{{implicit default constructor}}
   
   class C : virtual A { 
   public:
@@ -105,7 +105,7 @@ namespace test2 {
   };
 
   class D : C { }; // expected-error {{inherited virtual base class 'test2::A' has private constructor}}
-  D d;
+  D d; // expected-note{{implicit default constructor}}
 }
 
 // Implicit destructor calls.
@@ -143,13 +143,15 @@ namespace test3 {
   };
 
   class Derived3 : // expected-error 2 {{inherited virtual base class 'Base<2>' has private destructor}} \
-                   // expected-error 2 {{inherited virtual base class 'Base<3>' has private destructor}}
+                   // expected-error 2 {{inherited virtual base class 'Base<3>' has private destructor}} \
+    // expected-note 2{{implicit default constructor}}
     Base<0>,  // expected-error 2 {{base class 'Base<0>' has private destructor}}
     virtual Base<1>, // expected-error 2 {{base class 'Base<1>' has private destructor}}
     Base2, // expected-error 2 {{base class 'test3::Base2' has private destructor}}
     virtual Base3
-  {};
-  Derived3 d3;
+  {}; 
+  Derived3 d3; // expected-note {{implicit default constructor}}\
+               // expected-note{{implicit default destructor}}}
 }
 
 // Conversion functions.
@@ -205,13 +207,13 @@ namespace test5 {
   class Test1 { A a; }; // expected-error {{private member}}
   void test1() {
     Test1 a;
-    a = Test1();
+    a = Test1(); // expected-note{{implicit default copy}}
   }
 
   class Test2 : A {}; // expected-error {{private member}}
   void test2() {
     Test2 a;
-    a = Test2();
+    a = Test2(); // expected-note{{implicit default copy}}
   }
 }
 
@@ -224,12 +226,12 @@ namespace test6 {
 
   class Test1 { A a; }; // expected-error {{field of type 'test6::A' has private copy constructor}}
   void test1(const Test1 &t) {
-    Test1 a = t;
+    Test1 a = t; // expected-note{{implicit default copy}}
   }
 
   class Test2 : A {}; // expected-error {{base class 'test6::A' has private copy constructor}}
   void test2(const Test2 &t) {
-    Test2 a = t;
+    Test2 a = t; // expected-note{{implicit default copy}}
   }
 }
 
diff --git a/test/SemaCXX/default-assignment-operator.cpp b/test/SemaCXX/default-assignment-operator.cpp
index 4b5531e0c8..668c600366 100644
--- a/test/SemaCXX/default-assignment-operator.cpp
+++ b/test/SemaCXX/default-assignment-operator.cpp
@@ -101,7 +101,8 @@ namespace ProtectedCheck {
     X x;
   };
 
-  void f(Z z) { z = z; } // 
+  void f(Z z) { z = z; }  // expected-note{{implicit default copy assignment operator}}
+
 }
 
 namespace MultiplePaths {