4 files changed, 45 insertions, 2 deletions
diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index 53fc3405bb..ffef288e71 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -613,6 +613,20 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
     ConsumeCodeCompletionToken();
   }
 
+  // C++03 [temp.explicit] 14.7.2/8:
+  //   The usual access checking rules do not apply to names used to specify
+  //   explicit instantiations.
+  //
+  // As an extension we do not perform access checking on the names used to
+  // specify explicit specializations either. This is important to allow
+  // specializing traits classes for private types.
+  bool SuppressingAccessChecks = false;
+  if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation ||
+      TemplateInfo.Kind == ParsedTemplateInfo::ExplicitSpecialization) {
+    Actions.ActOnStartSuppressingAccessChecks();
+    SuppressingAccessChecks = true;
+  }
+
   AttributeList *AttrList = 0;
   // If attributes exist after tag, parse them.
   if (Tok.is(tok::kw___attribute))
@@ -732,10 +746,18 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
       DS.SetTypeSpecError();
       SkipUntil(tok::semi, false, true);
       TemplateId->Destroy();
+      if (SuppressingAccessChecks)
+        Actions.ActOnStopSuppressingAccessChecks();
+
       return;
     }
   }
 
+  // As soon as we're finished parsing the class's template-id, turn access
+  // checking back on.
+  if (SuppressingAccessChecks)
+    Actions.ActOnStopSuppressingAccessChecks();
+
   // There are four options here.  If we have 'struct foo;', then this
   // is either a forward declaration or a friend declaration, which
   // have to be treated differently.  If we have 'struct foo {...' or
diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index eadc2ad253..d520a78abe 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -125,8 +125,8 @@ Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
     IdResolver(pp.getLangOptions()), StdNamespace(0), StdBadAlloc(0),
     GlobalNewDeleteDeclared(false), 
     CompleteTranslationUnit(CompleteTranslationUnit),
-    NumSFINAEErrors(0), NonInstantiationEntries(0), 
-    CurrentInstantiationScope(0), TyposCorrected(0),
+    NumSFINAEErrors(0), SuppressAccessChecking(false),
+    NonInstantiationEntries(0), CurrentInstantiationScope(0), TyposCorrected(0),
     AnalysisWarnings(*this)
 {
   TUScope = 0;
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index 9d5e290b2f..fcf5e94149 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -2797,6 +2797,12 @@ public:
 
   void HandleDelayedAccessCheck(DelayedDiagnostic &DD, Decl *Ctx);
 
+  /// A flag to suppress access checking.
+  bool SuppressAccessChecking;
+
+  void ActOnStartSuppressingAccessChecks();
+  void ActOnStopSuppressingAccessChecks();
+
   enum AbstractDiagSelID {
     AbstractNone = -1,
     AbstractReturnType,
diff --git a/lib/Sema/SemaAccess.cpp b/lib/Sema/SemaAccess.cpp
index 7845f6d0a9..e110e3dfa4 100644
--- a/lib/Sema/SemaAccess.cpp
+++ b/lib/Sema/SemaAccess.cpp
@@ -1024,6 +1024,9 @@ static Sema::AccessResult CheckAccess(Sema &S, SourceLocation Loc,
   if (Entity.getAccess() == AS_public)
     return Sema::AR_accessible;
 
+  if (S.SuppressAccessChecking)
+    return Sema::AR_accessible;
+
   // If we're currently parsing a top-level declaration, delay
   // diagnostics.  This is the only case where parsing a declaration
   // can actually change our effective context for the purposes of
@@ -1334,3 +1337,15 @@ void Sema::CheckLookupAccess(const LookupResult &R) {
     }
   }
 }
+
+void Sema::ActOnStartSuppressingAccessChecks() {
+  assert(!SuppressAccessChecking &&
+         "Tried to start access check suppression when already started.");
+  SuppressAccessChecking = true;
+}
+
+void Sema::ActOnStopSuppressingAccessChecks() {
+  assert(SuppressAccessChecking &&
+         "Tried to stop access check suprression when already stopped.");
+  SuppressAccessChecking = false;
+}