Implement storage of declaration iterator in scope_tree nodes

So it can be retrieved when producing the code for jumping into a
scope.

Author: thomasspriggs

src/goto-programs/scope_tree.cpp

@@ -13,7 +13,7 @@ void scope_treet::add(
   std::optional<goto_programt::targett> declaration)
 {
   auto previous_node = get_current_node();
-  auto new_node = scope_graph.add_node(destructor);
+  auto new_node = scope_graph.add_node(destructor, declaration);
   scope_graph.add_edge(previous_node, new_node);
   current_node = new_node;
 }
@@ -24,6 +24,13 @@ optionalt<codet> &scope_treet::get_destructor(node_indext index)
   return scope_graph[index].destructor_value;
 }
 
+optionalt<goto_programt::targett> &
+scope_treet::get_declaration(node_indext index)
+{
+  PRECONDITION(index < scope_graph.size());
+  return scope_graph[index].declaration_value;
+}
+
 const ancestry_resultt scope_treet::get_nearest_common_ancestor_info(
   node_indext left_index,
   node_indext right_index)
@@ -100,3 +107,11 @@ node_indext scope_treet::get_current_node() const
 {
   return current_node;
 }
+
+scope_treet::scope_nodet::scope_nodet(
+  codet destructor,
+  std::optional<goto_programt::targett> declaration)
+  : destructor_value(std::move(destructor)),
+    declaration_value(std::move(declaration))
+{
+}

src/goto-programs/scope_tree.h

@@ -107,6 +107,9 @@ class scope_treet
   /// Fetches the destructor value for the passed-in node index.
   optionalt<codet> &get_destructor(node_indext index);
 
+  /// Fetches the declaration value for the passed-in node index.
+  optionalt<goto_programt::targett> &get_declaration(node_indext index);
+
   /// Builds a vector of destructors that start from starting_index and ends
   /// at end_index.
   /// \param end_index Index of the first variable to keep.
@@ -147,11 +150,12 @@ class scope_treet
   public:
     scope_nodet() = default;
 
-    explicit scope_nodet(codet destructor)
-      : destructor_value(std::move(destructor))
-    {
-    }
+    explicit scope_nodet(
+      codet destructor,
+      std::optional<goto_programt::targett> declaration);
+
     optionalt<codet> destructor_value;
+    optionalt<goto_programt::targett> declaration_value;
   };
 
   grapht<scope_nodet> scope_graph;