Be a bit more defensive about setting the temporary base location

during template instantiation. This code needs to eventually die, but
this little tweak fixes PR8629, where bad location information slipped
through to the location of a class template instantiation.

llvm-svn: 124199

clang/lib/Sema/TreeTransform.h

@@ -169,6 +169,8 @@ public:
                   DeclarationName Entity) : Self(Self) {
       OldLocation = Self.getDerived().getBaseLocation();
       OldEntity = Self.getDerived().getBaseEntity();
+      
+      if (Location.isValid())
         Self.getDerived().setBase(Location, Entity);
     }