bug fixes on flattening

reconstruct/ast.py

@@ -207,7 +207,10 @@ class projection(ast_node):
                         this_type = enlist(this_type)
                         proj_expr = enlist(proj_expr)
                     for t, n, pexpr, cp in zip(this_type, name, proj_expr, compound):
-                        t = VectorT(t) if cp else t
+                        if cp:
+                            # Force postporcessing for compound columns
+                            t = VectorT(t)
+                            self.has_postproc = True
                         offset = len(col_exprs)
                         if n not in self.var_table:
                             self.var_table[n] = offset

server/types.h

@@ -428,7 +428,7 @@ using get_first = typename get_first_impl<T...>::first;
 template <class T>
 struct value_type_rec_impl { typedef T type; };
 template <template <class...> class VT, class ...V>
-struct value_type_rec_impl<VT<V...>> { typedef typename value_type_rec_impl<get_first<int>>::type type; };
+struct value_type_rec_impl<VT<V...>> { typedef typename value_type_rec_impl<get_first<V...>>::type type; };
 template <class T>
 using value_type_r = typename value_type_rec_impl<T>::type;