Avoid storing a constant description in dry run solvert

We may as well just return a literal in the function implementation if
the member variable will always be assigned the same literal value.

Author: thomasspriggs

src/solvers/smt2_incremental/smt_solver_process.cpp

@@ -20,7 +20,7 @@ smt_piped_solver_processt::smt_piped_solver_processt(
 {
 }
 
-const std::string &smt_piped_solver_processt::description()
+std::string smt_piped_solver_processt::description()
 {
   return command_line_description;
 }
@@ -87,9 +87,9 @@ smt_incremental_dry_run_solvert::smt_incremental_dry_run_solvert(
 {
 }
 
-const std::string &smt_incremental_dry_run_solvert::description()
+std::string smt_incremental_dry_run_solvert::description()
 {
-  return desc;
+  return "SMT2 incremental dry-run";
 }
 
 void smt_incremental_dry_run_solvert::send(const smt_commandt &smt_command)

src/solvers/smt2_incremental/smt_solver_process.h

@@ -17,7 +17,7 @@ class smt_commandt;
 class smt_base_solver_processt
 {
 public:
-  virtual const std::string &description() = 0;
+  virtual std::string description() = 0;
 
   /// \brief Converts given SMT2 command to SMT2 string and sends it to the
   ///    solver process.
@@ -44,7 +44,7 @@ class smt_piped_solver_processt : public smt_base_solver_processt
     message_handlert &message_handler,
     std::unique_ptr<std::ostream> out_stream);
 
-  const std::string &description() override;
+  std::string description() override;
 
   void send(const smt_commandt &smt_command) override;
 
@@ -81,7 +81,7 @@ class smt_incremental_dry_run_solvert : public smt_base_solver_processt
     std::ostream &out_stream,
     std::unique_ptr<std::ostream> file_stream);
 
-  const std::string &description() override;
+  std::string description() override;
 
   void send(const smt_commandt &smt_command) override;
 
@@ -98,9 +98,6 @@ class smt_incremental_dry_run_solvert : public smt_base_solver_processt
   std::unique_ptr<std::ostream> file_stream;
   /// The output stream reference to print the SMT formula to.
   std::ostream &out_stream;
-
-  /// Description of the current solver
-  const std::string desc = "SMT2 incremental dry-run";
 };
 
 #endif // CPROVER_SOLVERS_SMT2_INCREMENTAL_SMT_SOLVER_PROCESS_H

unit/solvers/smt2_incremental/smt2_incremental_decision_procedure.cpp

@@ -74,7 +74,7 @@ class smt_mock_solver_processt : public smt_base_solver_processt
   {
   }
 
-  const std::string &description() override
+  std::string description() override
   {
     UNREACHABLE;
   }