Deprecate value_sett::location_number

This is set to zero and never modified, so there is no point in using
this field.

Author: romainbrenguier

src/pointer-analysis/value_set.cpp

@@ -741,7 +741,8 @@ void value_sett::get_value_set_rec(
         static_cast<const typet &>(expr.find(ID_C_cxx_alloc_type));
 
       dynamic_object_exprt dynamic_object(dynamic_type);
-      dynamic_object.set_instance(location_number);
+      PRECONDITION(location_number == 0);
+      dynamic_object.set_instance(0);
       dynamic_object.valid()=true_exprt();
 
       insert(dest, dynamic_object, 0);
@@ -753,7 +754,8 @@ void value_sett::get_value_set_rec(
       assert(expr_type.id()==ID_pointer);
 
       dynamic_object_exprt dynamic_object(expr_type.subtype());
-      dynamic_object.set_instance(location_number);
+      PRECONDITION(location_number == 0);
+      dynamic_object.set_instance(0);
       dynamic_object.valid()=true_exprt();
 
       insert(dest, dynamic_object, 0);

src/pointer-analysis/value_set.h

@@ -44,12 +44,11 @@ class namespacet;
 class value_sett
 {
 public:
-  value_sett():location_number(0)
+  value_sett()
   {
   }
 
-  value_sett(value_sett &&other)
-    : location_number(other.location_number), values(std::move(other.values))
+  value_sett(value_sett &&other) : values(std::move(other.values))
   {
   }
 
@@ -71,6 +70,7 @@ class value_sett
 
   /// Matches the location_number field of the instruction that corresponds
   /// to this value_sett instance in value_set_domaint's state map
+  DEPRECATED(SINCE(2019, 05, 22, "Always zero"))
   unsigned location_number;
 
   /// Global shared object numbering, used to abbreviate expressions stored