<rdar://problem/13267210> Ensure that Sema::CompareReferenceRelationship returns consistent results with invalid types.

When Sema::RequireCompleteType() is given a class template
specialization type that then fails to instantiate, it returns
'true'. On subsequent invocations, it can return false. Make sure that
this difference doesn't change the result of
Sema::CompareReferenceRelationship, which is expected to remain stable
while we're checking an initialization sequence.

llvm-svn: 178088

clang/lib/Sema/SemaDeclCXX.cpp

@@ -1311,29 +1311,25 @@ void Sema::ActOnBaseSpecifiers(Decl *ClassDecl, CXXBaseSpecifier **Bases,
                        (CXXBaseSpecifier**)(Bases), NumBases);
 }
 
-static CXXRecordDecl *GetClassForType(QualType T) {
-  if (const RecordType *RT = T->getAs<RecordType>())
-    return cast<CXXRecordDecl>(RT->getDecl());
-  else if (const InjectedClassNameType *ICT = T->getAs<InjectedClassNameType>())
-    return ICT->getDecl();
-  else
-    return 0;
-}
-
 /// \brief Determine whether the type \p Derived is a C++ class that is
 /// derived from the type \p Base.
 bool Sema::IsDerivedFrom(QualType Derived, QualType Base) {
   if (!getLangOpts().CPlusPlus)
     return false;
   
-  CXXRecordDecl *DerivedRD = GetClassForType(Derived);
+  CXXRecordDecl *DerivedRD = Derived->getAsCXXRecordDecl();
   if (!DerivedRD)
     return false;
   
-  CXXRecordDecl *BaseRD = GetClassForType(Base);
+  CXXRecordDecl *BaseRD = Base->getAsCXXRecordDecl();
   if (!BaseRD)
     return false;
-  
+
+  // If either the base or the derived type is invalid, don't try to
+  // check whether one is derived from the other.
+  if (BaseRD->isInvalidDecl() || DerivedRD->isInvalidDecl())
+    return false;
+
   // FIXME: instantiate DerivedRD if necessary.  We need a PoI for this.
   return DerivedRD->hasDefinition() && DerivedRD->isDerivedFrom(BaseRD);
 }
@@ -1344,11 +1340,11 @@ bool Sema::IsDerivedFrom(QualType Derived, QualType Base, CXXBasePaths &Paths) {
   if (!getLangOpts().CPlusPlus)
     return false;
   
-  CXXRecordDecl *DerivedRD = GetClassForType(Derived);
+  CXXRecordDecl *DerivedRD = Derived->getAsCXXRecordDecl();
   if (!DerivedRD)
     return false;
   
-  CXXRecordDecl *BaseRD = GetClassForType(Base);
+  CXXRecordDecl *BaseRD = Base->getAsCXXRecordDecl();
   if (!BaseRD)
     return false;
   

clang/lib/Sema/SemaOverload.cpp

@@ -3937,6 +3937,15 @@ CompareDerivedToBaseConversions(Sema &S,
   return ImplicitConversionSequence::Indistinguishable;
 }
 
+/// \brief Determine whether the given type is valid, e.g., it is not an invalid
+/// C++ class.
+static bool isTypeValid(QualType T) {
+  if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
+    return !Record->isInvalidDecl();
+
+  return true;
+}
+
 /// CompareReferenceRelationship - Compare the two types T1 and T2 to
 /// determine whether they are reference-related,
 /// reference-compatible, reference-compatible with added
@@ -3970,7 +3979,8 @@ Sema::CompareReferenceRelationship(SourceLocation Loc,
   if (UnqualT1 == UnqualT2) {
     // Nothing to do.
   } else if (!RequireCompleteType(Loc, OrigT2, 0) &&
-           IsDerivedFrom(UnqualT2, UnqualT1))
+             isTypeValid(UnqualT1) && isTypeValid(UnqualT2) &&
+             IsDerivedFrom(UnqualT2, UnqualT1))
     DerivedToBase = true;
   else if (UnqualT1->isObjCObjectOrInterfaceType() &&
            UnqualT2->isObjCObjectOrInterfaceType() &&

clang/test/SemaCXX/constructor-initializer.cpp

@@ -232,13 +232,15 @@ namespace PR7402 {
 // <rdar://problem/8308215>: don't crash.
 // Lots of questionable recovery here;  errors can change.
 namespace test3 {
-  class A : public std::exception {}; // expected-error {{undeclared identifier}} expected-error {{expected class name}} expected-note 2 {{candidate}}
+  class A : public std::exception {}; // expected-error {{undeclared identifier}} expected-error {{expected class name}} expected-note 4 {{candidate}}
   class B : public A {
   public:
     B(const String& s, int e=0) // expected-error {{unknown type name}} 
       : A(e), m_String(s) , m_ErrorStr(__null) {} // expected-error {{no matching constructor}} expected-error {{does not name}}
     B(const B& e)
-      : A(e), m_String(e.m_String), m_ErrorStr(__null) { // expected-error {{does not name}} expected-error {{no member named 'm_String' in 'test3::B'}}
+      : A(e), m_String(e.m_String), m_ErrorStr(__null) { // expected-error {{does not name}} \
+      // expected-error {{no member named 'm_String' in 'test3::B'}} \
+      // expected-error {{no matching}}
     }
   };
 }

clang/test/SemaTemplate/derived.cpp

@@ -10,3 +10,21 @@ void test() {
   Foo2(vector2<int*>());  // expected-error{{no matching function for call to 'Foo2'}}
   Foo(vector<int*>());  // expected-error{{no matching function for call to 'Foo'}}
 }
+
+namespace rdar13267210 {
+  template < typename T > class A {
+    BaseTy; // expected-error{{C++ requires a type specifier for all declarations}}
+  };
+
+  template < typename T, int N > class C: A < T > {};
+
+  class B {
+    C<long, 16> ExternalDefinitions;
+    C<long, 64> &Record;
+
+    void AddSourceLocation(A<long> &R); // expected-note{{passing argument to parameter 'R' here}}
+    void AddTemplateKWAndArgsInfo() {
+      AddSourceLocation(Record); // expected-error{{non-const lvalue reference to type}}
+    }
+  };
+}