Implement C++ 10.3p16 - overrides involving deleted functions must match.

Only deleted functions may override deleted functions and non-deleted functions
may only override non-deleted functions.

llvm-svn: 166082

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -865,6 +865,12 @@ def note_pure_virtual_function : Note<
 def err_deleted_decl_not_first : Error<
   "deleted definition must be first declaration">;
 
+def err_deleted_override : Error<
+  "deleted function %0 cannot override a non-deleted function">;
+
+def err_non_deleted_override : Error<
+  "non-deleted function %0 cannot override a deleted function">;
+
 def warn_weak_vtable : Warning<
   "%0 has no out-of-line virtual method definitions; its vtable will be "
   "emitted in every translation unit">,

clang/lib/Sema/SemaDecl.cpp

@@ -4733,6 +4733,31 @@ static bool FindOverriddenMethod(const CXXBaseSpecifier *Specifier,
   return false;
 }
 
+namespace {
+  enum OverrideErrorKind { OEK_All, OEK_NonDeleted, OEK_Deleted };
+}
+/// \brief Report an error regarding overriding, along with any relevant
+/// overriden methods.
+///
+/// \param DiagID the primary error to report.
+/// \param MD the overriding method.
+/// \param OEK which overrides to include as notes.
+static void ReportOverrides(Sema& S, unsigned DiagID, const CXXMethodDecl *MD,
+                            OverrideErrorKind OEK = OEK_All) {
+  S.Diag(MD->getLocation(), DiagID) << MD->getDeclName();
+  for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
+                                      E = MD->end_overridden_methods();
+       I != E; ++I) {
+    // This check (& the OEK parameter) could be replaced by a predicate, but
+    // without lambdas that would be overkill. This is still nicer than writing
+    // out the diag loop 3 times.
+    if ((OEK == OEK_All) ||
+        (OEK == OEK_NonDeleted && !(*I)->isDeleted()) ||
+        (OEK == OEK_Deleted && (*I)->isDeleted()))
+      S.Diag((*I)->getLocation(), diag::note_overridden_virtual_function);
+  }
+}
+
 /// AddOverriddenMethods - See if a method overrides any in the base classes,
 /// and if so, check that it's a valid override and remember it.
 bool Sema::AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD) {
@@ -4741,6 +4766,8 @@ bool Sema::AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD) {
   FindOverriddenMethodData Data;
   Data.Method = MD;
   Data.S = this;
+  bool hasDeletedOverridenMethods = false;
+  bool hasNonDeletedOverridenMethods = false;
   bool AddedAny = false;
   if (DC->lookupInBases(&FindOverriddenMethod, &Data, Paths)) {
     for (CXXBasePaths::decl_iterator I = Paths.found_decls_begin(),
@@ -4750,12 +4777,21 @@ bool Sema::AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD) {
         if (!CheckOverridingFunctionReturnType(MD, OldMD) &&
             !CheckOverridingFunctionExceptionSpec(MD, OldMD) &&
             !CheckIfOverriddenFunctionIsMarkedFinal(MD, OldMD)) {
+          hasDeletedOverridenMethods |= OldMD->isDeleted();
+          hasNonDeletedOverridenMethods |= !OldMD->isDeleted();
           AddedAny = true;
         }
       }
     }
   }
-  
+
+  if (hasDeletedOverridenMethods && !MD->isDeleted()) {
+    ReportOverrides(*this, diag::err_non_deleted_override, MD, OEK_Deleted);
+  }
+  if (hasNonDeletedOverridenMethods && MD->isDeleted()) {
+    ReportOverrides(*this, diag::err_deleted_override, MD, OEK_NonDeleted);
+  }
+
   return AddedAny;
 }
 
@@ -6068,16 +6104,7 @@ bool Sema::CheckFunctionDeclaration(Scope *S, FunctionDecl *NewFD,
         if (AddOverriddenMethods(Method->getParent(), Method)) {
           // If the function was marked as "static", we have a problem.
           if (NewFD->getStorageClass() == SC_Static) {
-            Diag(NewFD->getLocation(), diag::err_static_overrides_virtual)
-              << NewFD->getDeclName();
-            for (CXXMethodDecl::method_iterator 
-                      Overridden = Method->begin_overridden_methods(),
-                   OverriddenEnd = Method->end_overridden_methods();
-                 Overridden != OverriddenEnd;
-                 ++Overridden) {
-              Diag((*Overridden)->getLocation(), 
-                   diag::note_overridden_virtual_function);
-            }
+            ReportOverrides(*this, diag::err_static_overrides_virtual, Method);
           }
         }
       }

clang/test/CXX/class.derived/class.abstract/p16.cpp

@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
+
+struct A {
+  virtual void a(); // expected-note{{overridden virtual function is here}}
+  virtual void b() = delete; // expected-note{{overridden virtual function is here}}
+};
+
+struct B: A {
+  virtual void a() = delete; // expected-error{{deleted function 'a' cannot override a non-deleted function}}
+  virtual void b(); // expected-error{{non-deleted function 'b' cannot override a deleted function}}
+};
+
+struct C: A {
+  virtual void a();
+  virtual void b() = delete;
+};