remove symbol initialization from code_declt

DECL instructions in goto programs do not offer the option to initialize the
symbol that is declared.  This removes the methods for that.

Author: kroening

src/util/std_code.h

@@ -311,47 +311,12 @@ class code_declt:public codet
     return symbol().get_identifier();
   }
 
-  /// Returns the initial value to which the declared variable is initialized,
-  /// or empty in the case where no initialisation is included.
-  /// \note: Initial values may be present in the front end but they must be
-  ///   separated into a separate assignment when used in a `goto_instructiont`.
-  optionalt<exprt> initial_value() const
-  {
-    if(operands().size() < 2)
-      return {};
-    return {op1()};
-  }
-
-  /// Sets the value to which this declaration initializes the declared
-  /// variable. Empty optional maybe passed to remove existing initialisation.
-  /// \note: Initial values may be present in the front end but they must be
-  ///   separated into a separate assignment when used in a `goto_instructiont`.
-  void set_initial_value(optionalt<exprt> initial_value)
-  {
-    if(!initial_value)
-    {
-      operands().resize(1);
-    }
-    else if(operands().size() < 2)
-    {
-      PRECONDITION(operands().size() == 1);
-      add_to_operands(std::move(*initial_value));
-    }
-    else
-    {
-      op1() = std::move(*initial_value);
-    }
-  }
-
   static void check(
     const codet &code,
     const validation_modet vm = validation_modet::INVARIANT)
   {
-    // will be size()==1 in the future
     DATA_CHECK(
-      vm,
-      code.operands().size() >= 1,
-      "declaration must have one or more operands");
+      vm, code.operands().size() == 1, "declaration must have one operand");
     DATA_CHECK(
       vm,
       code.op0().id() == ID_symbol,