Define a symex_level2t::operator()

This is to be uniform with the other levels.

Author: romainbrenguier

src/goto-symex/goto_symex_state.cpp

@@ -260,7 +260,7 @@ void goto_symex_statet::set_l2_indices(
     return;
   level0(ssa_expr, ns, source.thread_nr);
   level1(ssa_expr);
-  ssa_expr.set_level_2(level2.current_count(ssa_expr.get_identifier()));
+  level2(ssa_expr);
 }
 
 template <goto_symex_statet::levelt level>

src/goto-symex/renaming_level.cpp

@@ -58,6 +58,11 @@ void symex_level1t::operator()(ssa_exprt &ssa_expr) const
   ssa_expr.set_level_1(it->second.second);
 }
 
+void symex_level2t::operator()(ssa_exprt &ssa_expr) const
+{
+  ssa_expr.set_level_2(current_count(ssa_expr.get_identifier()));
+}
+
 void symex_level1t::restore_from(
   const symex_renaming_levelt::current_namest &other)
 {

src/goto-symex/renaming_level.h

@@ -82,6 +82,8 @@ struct symex_level1t : public symex_renaming_levelt
 /// This is to ensure each variable is only assigned once.
 struct symex_level2t : public symex_renaming_levelt
 {
+  void operator()(ssa_exprt &ssa_expr) const;
+
   symex_level2t() = default;
   ~symex_level2t() override = default;
 };