diff --git a/src/goto-programs/builtin_functions.cpp b/src/goto-programs/builtin_functions.cpp
index b3d6d82f650..0cef3e382b4 100644
--- a/src/goto-programs/builtin_functions.cpp
+++ b/src/goto-programs/builtin_functions.cpp
@@ -580,7 +580,7 @@ void goto_convertt::do_cpp_new(
     if(new_array)
       new_call.arguments().push_back(count);
     new_call.arguments().push_back(object_size);
-    new_call.set("#type", lhs.type().subtype());
+    new_call.set(ID_C_cxx_alloc_type, lhs.type().subtype());
     new_call.lhs()=tmp_symbol_expr;
     new_call.add_source_location()=rhs.source_location();
 
@@ -612,7 +612,7 @@ void goto_convertt::do_cpp_new(
       new_call.arguments().push_back(count);
     new_call.arguments().push_back(object_size);
     new_call.arguments().push_back(rhs.op0()); // memory location
-    new_call.set("#type", lhs.type().subtype());
+    new_call.set(ID_C_cxx_alloc_type, lhs.type().subtype());
     new_call.lhs()=tmp_symbol_expr;
     new_call.add_source_location()=rhs.source_location();
 
diff --git a/src/pointer-analysis/value_set.cpp b/src/pointer-analysis/value_set.cpp
index 1a6c639ff92..b35952dc064 100644
--- a/src/pointer-analysis/value_set.cpp
+++ b/src/pointer-analysis/value_set.cpp
@@ -796,7 +796,7 @@ void value_sett::get_value_set_rec(
       assert(suffix=="");
 
       const typet &dynamic_type=
-        static_cast<const typet &>(expr.find("#type"));
+        static_cast<const typet &>(expr.find(ID_C_cxx_alloc_type));
 
       dynamic_object_exprt dynamic_object(dynamic_type);
       dynamic_object.set_instance(location_number);
diff --git a/src/pointer-analysis/value_set_fivr.cpp b/src/pointer-analysis/value_set_fivr.cpp
index e06d73b245b..45e721137e0 100644
--- a/src/pointer-analysis/value_set_fivr.cpp
+++ b/src/pointer-analysis/value_set_fivr.cpp
@@ -853,7 +853,7 @@ void value_set_fivrt::get_value_set_rec(
       assert(suffix=="");
 
       const typet &dynamic_type=
-        static_cast<const typet &>(expr.find("#type"));
+        static_cast<const typet &>(expr.find(ID_C_cxx_alloc_type));
 
       dynamic_object_exprt dynamic_object(dynamic_type);
       // let's make up a `unique' number for this object...
diff --git a/src/pointer-analysis/value_set_fivrns.cpp b/src/pointer-analysis/value_set_fivrns.cpp
index 4591bdd938d..c94afc8f95d 100644
--- a/src/pointer-analysis/value_set_fivrns.cpp
+++ b/src/pointer-analysis/value_set_fivrns.cpp
@@ -627,7 +627,7 @@ void value_set_fivrnst::get_value_set_rec(
       assert(suffix=="");
 
       const typet &dynamic_type=
-        static_cast<const typet &>(expr.find("#type"));
+        static_cast<const typet &>(expr.find(ID_C_cxx_alloc_type));
 
       dynamic_object_exprt dynamic_object(dynamic_type);
       // let's make up a `unique' number for this object...
diff --git a/src/util/irep_ids.def b/src/util/irep_ids.def
index 91379187bde..56153453d7c 100644
--- a/src/util/irep_ids.def
+++ b/src/util/irep_ids.def
@@ -205,6 +205,7 @@ IREP_ID_ONE(main)
 IREP_ID_ONE(expression)
 IREP_ID_ONE(free)
 IREP_ID_ONE(malloc)
+IREP_ID_TWO(C_cxx_alloc_type, #cxx_alloc_type)
 IREP_ID_ONE(cpp_new)
 IREP_ID_ONE(cpp_delete)
 IREP_ID_TWO(cpp_new_array, cpp_new[])