Revert r184401 which reverted r183462.

The problem with r183462 was that we assumed that a diagnostic id of
zero would be silent.

This small correction to CheckDerivedToBaseConversion changes it's
behavior to omit the diagnostic when given a diagnostic id of zero.

This fix passes the test case added in r184402.

llvm-svn: 184631

1 files changed, 34 insertions, 25 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index cbe4a2829bb..caf7affd0cc 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -1311,7 +1311,7 @@ Sema::CheckBaseSpecifier(CXXRecordDecl *Class,
   assert(BaseDecl && "Record type has no declaration");
   BaseDecl = BaseDecl->getDefinition();
   assert(BaseDecl && "Base type is not incomplete, but has no definition");
-  CXXRecordDecl * CXXBaseDecl = cast<CXXRecordDecl>(BaseDecl);
+  CXXRecordDecl *CXXBaseDecl = cast<CXXRecordDecl>(BaseDecl);
   assert(CXXBaseDecl && "Base type is not a C++ type");
 
   // C++ [class]p3:
@@ -1590,26 +1590,28 @@ Sema::CheckDerivedToBaseConversion(QualType Derived, QualType Base,
     return false;
   }
   
-  // We know that the derived-to-base conversion is ambiguous, and
-  // we're going to produce a diagnostic. Perform the derived-to-base
-  // search just one more time to compute all of the possible paths so
-  // that we can print them out. This is more expensive than any of
-  // the previous derived-to-base checks we've done, but at this point
-  // performance isn't as much of an issue.
-  Paths.clear();
-  Paths.setRecordingPaths(true);
-  bool StillOkay = IsDerivedFrom(Derived, Base, Paths);
-  assert(StillOkay && "Can only be used with a derived-to-base conversion");
-  (void)StillOkay;
-  
-  // Build up a textual representation of the ambiguous paths, e.g.,
-  // D -> B -> A, that will be used to illustrate the ambiguous
-  // conversions in the diagnostic. We only print one of the paths
-  // to each base class subobject.
-  std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
-  
-  Diag(Loc, AmbigiousBaseConvID)
-  << Derived << Base << PathDisplayStr << Range << Name;
+  if (AmbigiousBaseConvID) {
+    // We know that the derived-to-base conversion is ambiguous, and
+    // we're going to produce a diagnostic. Perform the derived-to-base
+    // search just one more time to compute all of the possible paths so
+    // that we can print them out. This is more expensive than any of
+    // the previous derived-to-base checks we've done, but at this point
+    // performance isn't as much of an issue.
+    Paths.clear();
+    Paths.setRecordingPaths(true);
+    bool StillOkay = IsDerivedFrom(Derived, Base, Paths);
+    assert(StillOkay && "Can only be used with a derived-to-base conversion");
+    (void)StillOkay;
+
+    // Build up a textual representation of the ambiguous paths, e.g.,
+    // D -> B -> A, that will be used to illustrate the ambiguous
+    // conversions in the diagnostic. We only print one of the paths
+    // to each base class subobject.
+    std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
+
+    Diag(Loc, AmbigiousBaseConvID)
+    << Derived << Base << PathDisplayStr << Range << Name;
+  }
   return true;
 }
 
@@ -3790,10 +3792,17 @@ Sema::MarkBaseAndMemberDestructorsReferenced(SourceLocation Location,
 
     CXXDestructorDecl *Dtor = LookupDestructor(BaseClassDecl);
     assert(Dtor && "No dtor found for BaseClassDecl!");
-    CheckDestructorAccess(ClassDecl->getLocation(), Dtor,
-                          PDiag(diag::err_access_dtor_vbase)
-                            << VBase->getType(),
-                          Context.getTypeDeclType(ClassDecl));
+    if (CheckDestructorAccess(
+            ClassDecl->getLocation(), Dtor,
+            PDiag(diag::err_access_dtor_vbase)
+                << Context.getTypeDeclType(ClassDecl) << VBase->getType(),
+            Context.getTypeDeclType(ClassDecl)) ==
+        AR_accessible) {
+      CheckDerivedToBaseConversion(
+          Context.getTypeDeclType(ClassDecl), VBase->getType(),
+          diag::err_access_dtor_vbase, 0, ClassDecl->getLocation(),
+          SourceRange(), DeclarationName(), 0);
+    }
 
     MarkFunctionReferenced(Location, const_cast<CXXDestructorDecl*>(Dtor));
     DiagnoseUseOfDecl(Dtor, Location);