Make parsing a semantic analysis a little more robust following Sema
failures that involve malformed types, e.g., "typename X::foo" where
"foo" isn't a type, or "std::vector<void>" that doens't instantiate
properly.

Similarly, be a bit smarter in our handling of ambiguities that occur
in Sema::getTypeName, to eliminate duplicate error messages about
ambiguous name lookup.

This eliminates two XFAILs in test/SemaCXX, one of which was crying
out to us, trying to tell us that we were producing repeated error
messages.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@68251 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index 7f68636..c442b84 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -755,7 +755,6 @@
       /// pointers used to reconstruct new'ed Decl*[] array containing
       /// found ambiguous decls. LookupResult is owner of this array.
       AmbiguousLookupStoresDecls
-
     } StoredKind;
 
     /// The first lookup result, whose contents depend on the kind of
@@ -939,6 +938,9 @@
 
     iterator begin();
     iterator end();
+
+    /// \brief Free the memory associated with this lookup.
+    void Destroy();
   };
 
 private: