Attempt to refactor to avoid compile warning

Author: thomasspriggs

src/solvers/smt2_incremental/smt2_incremental_decision_procedure.cpp

@@ -164,7 +164,7 @@ exprt smt2_incremental_decision_proceduret::handle(const exprt &expr)
   return expr;
 }
 
-static optionalt<smt_identifier_termt> get_identifier(
+static optionalt<smt_termt> get_identifier(
   const exprt &expr,
   const std::unordered_map<exprt, smt_identifier_termt, irep_hash>
     &expression_handle_identifiers,
@@ -183,10 +183,8 @@ static optionalt<smt_identifier_termt> get_identifier(
 exprt smt2_incremental_decision_proceduret::get(const exprt &expr) const
 {
   log.debug() << "`get` - \n  " + expr.pretty(2, 0) << messaget::eom;
-  const auto identifier =
-    get_identifier(expr, expression_handle_identifiers, expression_identifiers);
   optionalt<smt_termt> descriptor =
-    identifier ? *identifier : optionalt<smt_termt>{};
+    get_identifier(expr, expression_handle_identifiers, expression_identifiers);
   if(!descriptor)
   {
     if(gather_dependent_expressions(expr).empty())