diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index 5425c4f..24c5e09 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -79,8 +79,7 @@
     else
       assert(ModLen == 0 && ArgLen == 0 &&
              "Invalid modifier for DeclarationName argument");
-  } else {
-    assert(Kind == Diagnostic::ak_nameddecl);
+  } else if (Kind == Diagnostic::ak_nameddecl) {
     if (ModLen == 1 && Modifier[0] == 'q' && ArgLen == 0)
       S = reinterpret_cast<NamedDecl*>(Val)->getQualifiedNameAsString();
     else { 
@@ -88,6 +87,11 @@
            "Invalid modifier for NamedDecl* argument");
       S = reinterpret_cast<NamedDecl*>(Val)->getNameAsString();
     }
+  } else {
+    llvm::raw_string_ostream OS(S);
+    assert(Kind == Diagnostic::ak_nestednamespec);
+    reinterpret_cast<NestedNameSpecifier*> (Val)->print(OS, 
+                                                        Context.PrintingPolicy);
   }
   
   Output.push_back('\'');
diff --git a/lib/Sema/SemaCXXScopeSpec.cpp b/lib/Sema/SemaCXXScopeSpec.cpp
index 9c9bff8..3dac5d7 100644
--- a/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/lib/Sema/SemaCXXScopeSpec.cpp
@@ -79,17 +79,6 @@
         // The nested name specifier refers to a member of a class template.
         return RecordT->getDecl();
       }
-      
-      std::string NNSString;
-      {
-        llvm::raw_string_ostream OS(NNSString);
-        NNS->print(OS, Context.PrintingPolicy);
-      }
-      
-      // FIXME: Allow us to pass a nested-name-specifier to Diag?
-      Diag(SS.getRange().getBegin(), 
-           diag::err_template_qualified_declarator_no_match)
-        << NNSString << SS.getRange();
     }
     
     return 0;
@@ -298,6 +287,9 @@
                                            T.getTypePtr());
     }
     
+    // FIXME: It would be nice to maintain the namespace alias name, then
+    // see through that alias when resolving the nested-name-specifier down to
+    // a declaration context.
     if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD))
       return NestedNameSpecifier::Create(Context, Prefix,
                                          Alias->getNamespace());
@@ -404,8 +396,6 @@
   assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
   if (DeclContext *DC = computeDeclContext(SS, true))
     EnterDeclaratorContext(S, DC);
-  else
-    const_cast<CXXScopeSpec&>(SS).setScopeRep(0);
 }
 
 /// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
@@ -415,8 +405,8 @@
 /// defining scope.
 void Sema::ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
   assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
-  assert((SS.isInvalid() || S->getEntity() == computeDeclContext(SS, true)) && 
-         "Context imbalance!");
-  if (!SS.isInvalid())
+  if (SS.isInvalid())
+    return;
+  if (computeDeclContext(SS, true))
     ExitDeclaratorContext(S);
 }
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index d478c04..fec9a07 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1633,7 +1633,7 @@
         << D.getDeclSpec().getSourceRange() << D.getSourceRange();
     return DeclPtrTy();
   }
-  
+   
   // The scope passed in may not be a decl scope.  Zip up the scope tree until
   // we find one that is.
   while ((S->getFlags() & Scope::DeclScope) == 0 ||
@@ -1701,7 +1701,19 @@
                           D.getIdentifierLoc());
   } else { // Something like "int foo::x;"
     DC = computeDeclContext(D.getCXXScopeSpec(), true);
-    // FIXME: RequireCompleteDeclContext(D.getCXXScopeSpec()); ?
+    
+    if (!DC) {
+      // If we could not compute the declaration context, it's because the
+      // declaration context is dependent but does not refer to a class,
+      // class template, or class template partial specialization. Complain
+      // and return early, to avoid the coming semantic disaster.
+      Diag(D.getIdentifierLoc(), 
+           diag::err_template_qualified_declarator_no_match)
+        << (NestedNameSpecifier*)D.getCXXScopeSpec().getScopeRep()
+        << D.getCXXScopeSpec().getRange();
+      return DeclPtrTy();
+    }
+    
     PrevDecl = LookupQualifiedName(DC, Name, LookupOrdinaryName, true);
 
     // C++ 7.3.1.2p2: