diff --git a/unit/Makefile b/unit/Makefile
index fa46a11d30c..0f5bec6ec27 100644
--- a/unit/Makefile
+++ b/unit/Makefile
@@ -54,6 +54,7 @@ SRC += analyses/ai/ai.cpp \
        ansi-c/c_typecheck_base.cpp \
        big-int/big-int.cpp \
        compound_block_locations.cpp \
+       empty_namespace_test.cpp \
        get_goto_model_from_c_test.cpp \
        goto-cc/armcc_cmdline.cpp \
        goto-checker/properties/property_status.cpp \
diff --git a/unit/analyses/ai/ai_simplify_lhs.cpp b/unit/analyses/ai/ai_simplify_lhs.cpp
index 7e38f26f392..96e6b0cd735 100644
--- a/unit/analyses/ai/ai_simplify_lhs.cpp
+++ b/unit/analyses/ai/ai_simplify_lhs.cpp
@@ -9,21 +9,18 @@ Author: Diffblue Ltd.
 /// \file
 /// Unit tests for ai_domain_baset::ai_simplify_lhs
 
-#include <testing-utils/message.h>
-#include <testing-utils/use_catch.h>
-
-#include <analyses/ai_domain.h>
-
-#include <ansi-c/ansi_c_language.h>
-
 #include <util/arith_tools.h>
 #include <util/c_types.h>
 #include <util/config.h>
-#include <util/namespace.h>
 #include <util/simplify_expr.h>
-#include <util/symbol_table.h>
 #include <util/ui_message.h>
 
+#include <analyses/ai_domain.h>
+#include <ansi-c/ansi_c_language.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/message.h>
+#include <testing-utils/use_catch.h>
+
 class constant_simplification_mockt:public ai_domain_baset
 {
 public:
@@ -74,8 +71,7 @@ SCENARIO("ai_domain_baset::ai_simplify_lhs",
 {
   ansi_c_languaget language;
 
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   constant_simplification_mockt mock_ai_domain;
 
diff --git a/unit/analyses/does_remove_const/does_expr_lose_const.cpp b/unit/analyses/does_remove_const/does_expr_lose_const.cpp
index 91b48bb592d..c1e399b54c7 100644
--- a/unit/analyses/does_remove_const/does_expr_lose_const.cpp
+++ b/unit/analyses/does_remove_const/does_expr_lose_const.cpp
@@ -11,10 +11,8 @@ Author: Diffblue Ltd.
 
 #include <util/c_types.h>
 #include <util/mathematical_types.h>
-#include <util/namespace.h>
 #include <util/pointer_expr.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
 
 #include <goto-programs/goto_program.h>
 
@@ -26,8 +24,6 @@ Author: Diffblue Ltd.
 SCENARIO("does_expr_lose_const",
   "[core][analyses][does_remove_const][does_expr_remove_const]")
 {
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
   goto_programt program;
   does_remove_constt does_remove_const(program);
   does_remove_const_testt does_remove_const_test(does_remove_const);
diff --git a/unit/analyses/does_remove_const/does_type_preserve_const_correctness.cpp b/unit/analyses/does_remove_const/does_type_preserve_const_correctness.cpp
index 6dde902a93d..98f3ea25b52 100644
--- a/unit/analyses/does_remove_const/does_type_preserve_const_correctness.cpp
+++ b/unit/analyses/does_remove_const/does_type_preserve_const_correctness.cpp
@@ -9,25 +9,19 @@ Author: Diffblue Ltd.
 /// \file
 /// Does Remove Const Unit Tests
 
-#include <testing-utils/use_catch.h>
-
 #include <util/c_types.h>
 #include <util/mathematical_types.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
-
-#include <ansi-c/c_qualifiers.h>
 
 #include <goto-programs/goto_program.h>
 
-#include <analyses/does_remove_const/does_remove_const_util.h>
 #include <analyses/does_remove_const.h>
+#include <analyses/does_remove_const/does_remove_const_util.h>
+#include <ansi-c/c_qualifiers.h>
+#include <testing-utils/use_catch.h>
 
 SCENARIO("does_type_preserve_const_correctness",
   "[core][analyses][does_remove_const][does_type_preserve_const_correctness]")
 {
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
   goto_programt program;
   does_remove_constt does_remove_const(program);
   does_remove_const_testt does_remove_const_test(does_remove_const);
diff --git a/unit/analyses/does_remove_const/is_type_at_least_as_const_as.cpp b/unit/analyses/does_remove_const/is_type_at_least_as_const_as.cpp
index 0771edf69e9..a7fa63e5e13 100644
--- a/unit/analyses/does_remove_const/is_type_at_least_as_const_as.cpp
+++ b/unit/analyses/does_remove_const/is_type_at_least_as_const_as.cpp
@@ -9,25 +9,19 @@ Author: Diffblue Ltd.
 /// \file
 /// Does Remove Const Unit Tests
 
-#include <testing-utils/use_catch.h>
-
 #include <util/c_types.h>
 #include <util/mathematical_types.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
-
-#include <ansi-c/c_qualifiers.h>
 
 #include <goto-programs/goto_program.h>
 
-#include <analyses/does_remove_const/does_remove_const_util.h>
 #include <analyses/does_remove_const.h>
+#include <analyses/does_remove_const/does_remove_const_util.h>
+#include <ansi-c/c_qualifiers.h>
+#include <testing-utils/use_catch.h>
 
 SCENARIO("is_type_at_least_as_const",
   "[core][analyses][does_remove_const][is_type_at_least_as_const]")
 {
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
   goto_programt program;
   does_remove_constt does_remove_const(program);
   does_remove_const_testt does_remove_const_test(does_remove_const);
diff --git a/unit/analyses/variable-sensitivity/abstract_environment/to_predicate.cpp b/unit/analyses/variable-sensitivity/abstract_environment/to_predicate.cpp
index c53ac49c2ac..c5b3f7a4ef6 100644
--- a/unit/analyses/variable-sensitivity/abstract_environment/to_predicate.cpp
+++ b/unit/analyses/variable-sensitivity/abstract_environment/to_predicate.cpp
@@ -9,11 +9,11 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/constant_abstract_value.h> // IWYU pragma: keep
@@ -28,8 +28,7 @@ SCENARIO(
   config.context_tracking.last_write_context = false;
   auto object_factory =
     variable_sensitivity_object_factoryt::configured_with(config);
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("an abstract environment")
   {
diff --git a/unit/analyses/variable-sensitivity/abstract_object/index_range.cpp b/unit/analyses/variable-sensitivity/abstract_object/index_range.cpp
index 31a30119f05..424da3c94b9 100644
--- a/unit/analyses/variable-sensitivity/abstract_object/index_range.cpp
+++ b/unit/analyses/variable-sensitivity/abstract_object/index_range.cpp
@@ -9,13 +9,13 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/constant_abstract_value.h>
 #include <analyses/variable-sensitivity/interval_abstract_value.h>
 #include <analyses/variable-sensitivity/value_set_abstract_object.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 #include "analyses/variable-sensitivity/variable_sensitivity_test_helpers.h"
@@ -30,8 +30,7 @@ SCENARIO(
     vsd_configt::constant_domain());
   abstract_environmentt env{object_factory};
   env.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("an integer constant has an index_range")
   {
@@ -95,8 +94,7 @@ SCENARIO(
     vsd_configt::intervals());
   abstract_environmentt env{object_factory};
   env.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
   auto type = signedbv_typet(32);
 
   GIVEN("a top intervals's range is empty")
@@ -196,8 +194,7 @@ SCENARIO(
     vsd_configt::intervals());
   abstract_environmentt env{object_factory};
   env.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
   auto type = signedbv_typet(32);
 
   GIVEN("a TOP value_set is empty")
diff --git a/unit/analyses/variable-sensitivity/abstract_object/merge.cpp b/unit/analyses/variable-sensitivity/abstract_object/merge.cpp
index fb5b00fd275..88f57b3482a 100644
--- a/unit/analyses/variable-sensitivity/abstract_object/merge.cpp
+++ b/unit/analyses/variable-sensitivity/abstract_object/merge.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/abstract_object.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
@@ -93,13 +93,11 @@ SCENARIO(
       variable_sensitivity_object_factoryt::configured_with(config);
     abstract_environmentt environment{object_factory};
     environment.make_top();
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
 
     WHEN("merging TOP with 1")
     {
       auto top1 = make_top_object();
-      auto op2 = make_constant(val1, environment, ns);
+      auto op2 = make_constant(val1, environment, empty_namespace);
 
       auto result = abstract_objectt::merge(top1, op2, widen_modet::no);
 
@@ -138,7 +136,7 @@ SCENARIO(
     WHEN("merging BOTTOM with 1")
     {
       auto op1 = make_bottom_object();
-      auto op2 = make_constant(val1, environment, ns);
+      auto op2 = make_constant(val1, environment, empty_namespace);
 
       auto result = abstract_objectt::merge(op1, op2, widen_modet::no);
 
diff --git a/unit/analyses/variable-sensitivity/constant_abstract_value/meet.cpp b/unit/analyses/variable-sensitivity/constant_abstract_value/meet.cpp
index 26b500e73cd..eed4e4ef71e 100644
--- a/unit/analyses/variable-sensitivity/constant_abstract_value/meet.cpp
+++ b/unit/analyses/variable-sensitivity/constant_abstract_value/meet.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/constant_abstract_value.h> // IWYU pragma: keep
@@ -74,8 +74,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("meeting two constants")
   {
diff --git a/unit/analyses/variable-sensitivity/constant_abstract_value/merge.cpp b/unit/analyses/variable-sensitivity/constant_abstract_value/merge.cpp
index 10fffe551e5..17099429e22 100644
--- a/unit/analyses/variable-sensitivity/constant_abstract_value/merge.cpp
+++ b/unit/analyses/variable-sensitivity/constant_abstract_value/merge.cpp
@@ -9,11 +9,11 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/constant_abstract_value.h> // IWYU pragma: keep
@@ -48,8 +48,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("merging two constants")
   {
diff --git a/unit/analyses/variable-sensitivity/constant_abstract_value/to_predicate.cpp b/unit/analyses/variable-sensitivity/constant_abstract_value/to_predicate.cpp
index a5358355321..d82c5fbaa67 100644
--- a/unit/analyses/variable-sensitivity/constant_abstract_value/to_predicate.cpp
+++ b/unit/analyses/variable-sensitivity/constant_abstract_value/to_predicate.cpp
@@ -9,12 +9,12 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/constant_abstract_value.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 SCENARIO(
@@ -34,8 +34,6 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
 
   GIVEN("constant_abstract_value")
   {
@@ -51,13 +49,14 @@ SCENARIO(
     }
     WHEN("x = 2")
     {
-      auto obj = make_constant(val2, environment, ns);
+      auto obj = make_constant(val2, environment, empty_namespace);
       THEN_PREDICATE(obj, "x == 2");
     }
     WHEN("(1 + 2) = 3")
     {
       auto val1 = from_integer(1, type);
-      auto c3 = make_constant(from_integer(3, type), environment, ns);
+      auto c3 =
+        make_constant(from_integer(3, type), environment, empty_namespace);
 
       auto pred = c3->to_predicate(plus_exprt(val1, val2));
       THEN("predicate is (1 + 2) = 3")
diff --git a/unit/analyses/variable-sensitivity/constant_pointer_abstract_object/to_predicate.cpp b/unit/analyses/variable-sensitivity/constant_pointer_abstract_object/to_predicate.cpp
index ce37c9ca7cc..49419ca540e 100644
--- a/unit/analyses/variable-sensitivity/constant_pointer_abstract_object/to_predicate.cpp
+++ b/unit/analyses/variable-sensitivity/constant_pointer_abstract_object/to_predicate.cpp
@@ -9,12 +9,12 @@
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
 #include <util/pointer_expr.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/constant_pointer_abstract_object.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 SCENARIO(
@@ -35,8 +35,6 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
 
   GIVEN("constant_pointer_abstract_object")
   {
@@ -56,7 +54,7 @@ SCENARIO(
     {
       const auto address_of = address_of_exprt(val2_symbol);
       auto obj = std::make_shared<constant_pointer_abstract_objectt>(
-        address_of, environment, ns);
+        address_of, environment, empty_namespace);
       THEN_PREDICATE(obj, "x == &val2");
     }
   }
diff --git a/unit/analyses/variable-sensitivity/eval-member-access.cpp b/unit/analyses/variable-sensitivity/eval-member-access.cpp
index 3fd4c3537ad..dceb954181b 100644
--- a/unit/analyses/variable-sensitivity/eval-member-access.cpp
+++ b/unit/analyses/variable-sensitivity/eval-member-access.cpp
@@ -8,13 +8,13 @@
 
 #include <util/arith_tools.h>
 #include <util/mathematical_types.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/abstract_object.h>
 #include <analyses/variable-sensitivity/context_abstract_object.h>
 #include <analyses/variable-sensitivity/full_array_abstract_object.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 void test_array(
@@ -33,8 +33,7 @@ SCENARIO(
       vsd_configt::constant_domain())};
   environment.make_top(); // Domains are bottom on construction
 
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
+  const namespacet &ns = empty_namespace;
 
   GIVEN("An array of {1, 2, 3}")
   {
diff --git a/unit/analyses/variable-sensitivity/full_array_abstract_object/maximum_length.cpp b/unit/analyses/variable-sensitivity/full_array_abstract_object/maximum_length.cpp
index 8ec9733cf23..2ffa3e45ca2 100644
--- a/unit/analyses/variable-sensitivity/full_array_abstract_object/maximum_length.cpp
+++ b/unit/analyses/variable-sensitivity/full_array_abstract_object/maximum_length.cpp
@@ -6,16 +6,15 @@
 
 \*******************************************************************/
 
-#include "array_builder.h"
+#include <util/arith_tools.h>
+#include <util/bitvector_types.h>
 
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
-
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
-#include <util/arith_tools.h>
-#include <util/bitvector_types.h>
-#include <util/symbol_table.h>
+#include "array_builder.h"
 
 using abstract_object_ptrt = std::shared_ptr<const abstract_objectt>;
 
@@ -53,8 +52,7 @@ SCENARIO(
       variable_sensitivity_object_factoryt::configured_with(configuration);
     abstract_environmentt environment(object_factory);
     environment.make_top();
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
+    const namespacet &ns = empty_namespace;
     WHEN("maximum size is " + std::to_string(max_array_index))
     {
       WHEN("array = {1, 2, 3}, writes under maximum size")
diff --git a/unit/analyses/variable-sensitivity/full_array_abstract_object/merge.cpp b/unit/analyses/variable-sensitivity/full_array_abstract_object/merge.cpp
index 140279e4855..420cc7b1634 100644
--- a/unit/analyses/variable-sensitivity/full_array_abstract_object/merge.cpp
+++ b/unit/analyses/variable-sensitivity/full_array_abstract_object/merge.cpp
@@ -6,20 +6,20 @@
 
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-#include <typeinfo>
+#include <util/arith_tools.h>
+#include <util/bitvector_types.h>
+#include <util/namespace.h>
+#include <util/std_expr.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/abstract_object.h>
 #include <analyses/variable-sensitivity/full_array_abstract_object/array_builder.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
-#include <util/arith_tools.h>
-#include <util/bitvector_types.h>
-#include <util/namespace.h>
-#include <util/std_expr.h>
-#include <util/symbol_table.h>
+#include <typeinfo>
 
 SCENARIO(
   "merge_constant_array_abstract_object",
@@ -47,8 +47,7 @@ SCENARIO(
       vsd_configt::constant_domain());
     abstract_environmentt environment(object_factory);
     environment.make_top();
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
+    const namespacet &ns = empty_namespace;
 
     WHEN("Merging two constant array AOs with the same array")
     {
diff --git a/unit/analyses/variable-sensitivity/full_array_abstract_object/to_predicate.cpp b/unit/analyses/variable-sensitivity/full_array_abstract_object/to_predicate.cpp
index 263244fcbc1..e0b493be628 100644
--- a/unit/analyses/variable-sensitivity/full_array_abstract_object/to_predicate.cpp
+++ b/unit/analyses/variable-sensitivity/full_array_abstract_object/to_predicate.cpp
@@ -7,15 +7,12 @@
 \*******************************************************************/
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
-#include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
-
 #include <analyses/variable-sensitivity/full_array_abstract_object/array_builder.h>
+#include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
-
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
-#include <util/symbol_table.h>
-
 SCENARIO(
   "array to predicate",
   "[core][analyses][variable-sensitivity][full_array_abstract_object][to_"
@@ -25,8 +22,7 @@ SCENARIO(
     vsd_configt::constant_domain());
   abstract_environmentt environment(object_factory);
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("full_array_abstract_object to predicate")
   {
diff --git a/unit/analyses/variable-sensitivity/full_struct_abstract_object/merge.cpp b/unit/analyses/variable-sensitivity/full_struct_abstract_object/merge.cpp
index 4efe8b4f6ba..88f27cbbe14 100644
--- a/unit/analyses/variable-sensitivity/full_struct_abstract_object/merge.cpp
+++ b/unit/analyses/variable-sensitivity/full_struct_abstract_object/merge.cpp
@@ -6,19 +6,19 @@
 
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-#include <typeinfo>
+#include <util/mathematical_types.h>
+#include <util/namespace.h>
+#include <util/std_expr.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/abstract_object.h>
 #include <analyses/variable-sensitivity/full_struct_abstract_object/struct_builder.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
-#include <util/mathematical_types.h>
-#include <util/namespace.h>
-#include <util/std_expr.h>
-#include <util/symbol_table.h>
+#include <typeinfo>
 
 SCENARIO(
   "merge_full_struct_abstract_object",
@@ -45,8 +45,7 @@ SCENARIO(
       vsd_configt::constant_domain());
     abstract_environmentt environment(object_factory);
     environment.make_top();
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
+    const namespacet &ns = empty_namespace;
 
     WHEN("Merging two constant struct AOs with the same contents")
     {
diff --git a/unit/analyses/variable-sensitivity/full_struct_abstract_object/to_predicate.cpp b/unit/analyses/variable-sensitivity/full_struct_abstract_object/to_predicate.cpp
index 2ad91a4e383..e2d3aac03bc 100644
--- a/unit/analyses/variable-sensitivity/full_struct_abstract_object/to_predicate.cpp
+++ b/unit/analyses/variable-sensitivity/full_struct_abstract_object/to_predicate.cpp
@@ -7,14 +7,12 @@
 \*******************************************************************/
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
-#include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
-
 #include <analyses/variable-sensitivity/full_struct_abstract_object/struct_builder.h>
+#include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
-#include <util/symbol_table.h>
-
 SCENARIO(
   "struct to predicate",
   "[core][analyses][variable-sensitivity][full_struct_abstract_object][to_"
@@ -24,8 +22,7 @@ SCENARIO(
     vsd_configt::constant_domain());
   abstract_environmentt environment(object_factory);
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("full_struct_abstract_object to predicate")
   {
diff --git a/unit/analyses/variable-sensitivity/interval_abstract_value/extremes-go-top.cpp b/unit/analyses/variable-sensitivity/interval_abstract_value/extremes-go-top.cpp
index be191ecfc9f..05cdd081e93 100644
--- a/unit/analyses/variable-sensitivity/interval_abstract_value/extremes-go-top.cpp
+++ b/unit/analyses/variable-sensitivity/interval_abstract_value/extremes-go-top.cpp
@@ -8,8 +8,6 @@
 
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
@@ -17,6 +15,7 @@
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/interval_abstract_value.h> // IWYU pragma: keep
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 static void verify_extreme_interval(
@@ -39,8 +38,7 @@ SCENARIO(
 
   auto environment = abstract_environmentt{object_factory};
   environment.make_top();
-  auto symbol_table = symbol_tablet{};
-  auto ns = namespacet{symbol_table};
+  const namespacet &ns = empty_namespace;
 
   GIVEN("[min-max] signed goes TOP")
   {
diff --git a/unit/analyses/variable-sensitivity/interval_abstract_value/meet.cpp b/unit/analyses/variable-sensitivity/interval_abstract_value/meet.cpp
index 8d2d97029d4..c00b94ff09c 100644
--- a/unit/analyses/variable-sensitivity/interval_abstract_value/meet.cpp
+++ b/unit/analyses/variable-sensitivity/interval_abstract_value/meet.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/abstract_object.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
@@ -86,8 +86,7 @@ SCENARIO(
 
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("meeting two intervals")
   {
diff --git a/unit/analyses/variable-sensitivity/interval_abstract_value/merge.cpp b/unit/analyses/variable-sensitivity/interval_abstract_value/merge.cpp
index 8951fd2c0d8..42802d98f10 100644
--- a/unit/analyses/variable-sensitivity/interval_abstract_value/merge.cpp
+++ b/unit/analyses/variable-sensitivity/interval_abstract_value/merge.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/constant_abstract_value.h> // IWYU pragma: keep
@@ -52,8 +52,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("merging two intervals")
   {
diff --git a/unit/analyses/variable-sensitivity/interval_abstract_value/to_predicate.cpp b/unit/analyses/variable-sensitivity/interval_abstract_value/to_predicate.cpp
index 91941c97dd7..cdce7f95f6c 100644
--- a/unit/analyses/variable-sensitivity/interval_abstract_value/to_predicate.cpp
+++ b/unit/analyses/variable-sensitivity/interval_abstract_value/to_predicate.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/constant_abstract_value.h> // IWYU pragma: keep
@@ -44,8 +44,6 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
 
   GIVEN("interval_abstract_value")
   {
@@ -61,12 +59,12 @@ SCENARIO(
     }
     WHEN("[ 2 ]")
     {
-      auto obj = make_interval(val2, val2, environment, ns);
+      auto obj = make_interval(val2, val2, environment, empty_namespace);
       THEN_PREDICATE(obj, "x == 2");
     }
     WHEN("[ 0, 2 ]")
     {
-      auto obj = make_interval(val0, val2, environment, ns);
+      auto obj = make_interval(val0, val2, environment, empty_namespace);
       THEN_PREDICATE(obj, "0 <= x && x <= 2");
     }
   }
diff --git a/unit/analyses/variable-sensitivity/interval_abstract_value/widening_merge.cpp b/unit/analyses/variable-sensitivity/interval_abstract_value/widening_merge.cpp
index 4f0a7bdfd73..438b18fbbb6 100644
--- a/unit/analyses/variable-sensitivity/interval_abstract_value/widening_merge.cpp
+++ b/unit/analyses/variable-sensitivity/interval_abstract_value/widening_merge.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/interval_abstract_value.h> // IWYU pragma: keep
@@ -60,8 +60,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("interval merges which don't widen")
   {
diff --git a/unit/analyses/variable-sensitivity/value_expression_evaluation/assume.cpp b/unit/analyses/variable-sensitivity/value_expression_evaluation/assume.cpp
index f26e0da09b5..bf0786ee569 100644
--- a/unit/analyses/variable-sensitivity/value_expression_evaluation/assume.cpp
+++ b/unit/analyses/variable-sensitivity/value_expression_evaluation/assume.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/constant_abstract_value.h> // IWYU pragma: keep
@@ -170,8 +170,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   assume_testert assumeTester(environment, ns);
 
diff --git a/unit/analyses/variable-sensitivity/value_expression_evaluation/assume_prune.cpp b/unit/analyses/variable-sensitivity/value_expression_evaluation/assume_prune.cpp
index 18c7e0b86ca..0600cfd31ba 100644
--- a/unit/analyses/variable-sensitivity/value_expression_evaluation/assume_prune.cpp
+++ b/unit/analyses/variable-sensitivity/value_expression_evaluation/assume_prune.cpp
@@ -9,11 +9,11 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/constant_abstract_value.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/interval_abstract_value.h> // IWYU pragma: keep
@@ -81,8 +81,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   auto type = signedbv_typet(32);
   auto val0 = from_integer(0, type);
diff --git a/unit/analyses/variable-sensitivity/value_expression_evaluation/expression_evaluation.cpp b/unit/analyses/variable-sensitivity/value_expression_evaluation/expression_evaluation.cpp
index a33d432cb3f..75b5f081630 100644
--- a/unit/analyses/variable-sensitivity/value_expression_evaluation/expression_evaluation.cpp
+++ b/unit/analyses/variable-sensitivity/value_expression_evaluation/expression_evaluation.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/constant_abstract_value.h> // IWYU pragma: keep
@@ -44,8 +44,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("adding two constants")
   {
diff --git a/unit/analyses/variable-sensitivity/value_set_abstract_object/compacting.cpp b/unit/analyses/variable-sensitivity/value_set_abstract_object/compacting.cpp
index 1baefda7468..2af278484e9 100644
--- a/unit/analyses/variable-sensitivity/value_set_abstract_object/compacting.cpp
+++ b/unit/analyses/variable-sensitivity/value_set_abstract_object/compacting.cpp
@@ -13,8 +13,6 @@
 
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
@@ -22,6 +20,7 @@
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/interval_abstract_value.h> // IWYU pragma: keep
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 SCENARIO(
@@ -52,8 +51,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   auto environment = abstract_environmentt{object_factory};
   environment.make_top();
-  auto symbol_table = symbol_tablet{};
-  auto ns = namespacet{symbol_table};
+  const namespacet &ns = empty_namespace;
 
   GIVEN("compact values into existing interval")
   {
diff --git a/unit/analyses/variable-sensitivity/value_set_abstract_object/extremes-go-top.cpp b/unit/analyses/variable-sensitivity/value_set_abstract_object/extremes-go-top.cpp
index 32d87327c6d..a65188bef00 100644
--- a/unit/analyses/variable-sensitivity/value_set_abstract_object/extremes-go-top.cpp
+++ b/unit/analyses/variable-sensitivity/value_set_abstract_object/extremes-go-top.cpp
@@ -8,8 +8,6 @@
 
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 
@@ -17,6 +15,7 @@
 #include <analyses/variable-sensitivity/interval_abstract_value.h> // IWYU pragma: keep
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 SCENARIO(
@@ -28,8 +27,7 @@ SCENARIO(
 
   auto environment = abstract_environmentt{object_factory};
   environment.make_top();
-  auto symbol_table = symbol_tablet{};
-  auto ns = namespacet{symbol_table};
+  const namespacet &ns = empty_namespace;
 
   GIVEN("{FALSE, TRUE} goes TOP")
   {
diff --git a/unit/analyses/variable-sensitivity/value_set_abstract_object/meet.cpp b/unit/analyses/variable-sensitivity/value_set_abstract_object/meet.cpp
index e354520d407..58730924665 100644
--- a/unit/analyses/variable-sensitivity/value_set_abstract_object/meet.cpp
+++ b/unit/analyses/variable-sensitivity/value_set_abstract_object/meet.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/abstract_object.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/interval_abstract_value.h> // IWYU pragma: keep
@@ -76,8 +76,7 @@ SCENARIO(
 
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("meeting two value_sets")
   {
diff --git a/unit/analyses/variable-sensitivity/value_set_abstract_object/merge.cpp b/unit/analyses/variable-sensitivity/value_set_abstract_object/merge.cpp
index 31eb26d9148..c2513b7452a 100644
--- a/unit/analyses/variable-sensitivity/value_set_abstract_object/merge.cpp
+++ b/unit/analyses/variable-sensitivity/value_set_abstract_object/merge.cpp
@@ -8,8 +8,6 @@
 
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 
@@ -24,6 +22,7 @@
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/value_set_abstract_object.h> // IWYU pragma: keep
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 static merge_result<const value_set_abstract_objectt>
@@ -50,8 +49,7 @@ SCENARIO(
     vsd_configt::value_set());
   auto environment = abstract_environmentt{object_factory};
   environment.make_top();
-  auto symbol_table = symbol_tablet{};
-  auto ns = namespacet{symbol_table};
+  const namespacet &ns = empty_namespace;
 
   GIVEN("merging two value sets")
   {
diff --git a/unit/analyses/variable-sensitivity/value_set_abstract_object/to_predicate.cpp b/unit/analyses/variable-sensitivity/value_set_abstract_object/to_predicate.cpp
index e37287e2b30..4b6b5775e3a 100644
--- a/unit/analyses/variable-sensitivity/value_set_abstract_object/to_predicate.cpp
+++ b/unit/analyses/variable-sensitivity/value_set_abstract_object/to_predicate.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/interval_abstract_value.h> // IWYU pragma: keep
@@ -46,8 +46,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("value_set_abstract_object")
   {
diff --git a/unit/analyses/variable-sensitivity/value_set_abstract_object/widening_merge.cpp b/unit/analyses/variable-sensitivity/value_set_abstract_object/widening_merge.cpp
index 8f85268795d..e5808de6ac0 100644
--- a/unit/analyses/variable-sensitivity/value_set_abstract_object/widening_merge.cpp
+++ b/unit/analyses/variable-sensitivity/value_set_abstract_object/widening_merge.cpp
@@ -9,10 +9,10 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
+#include <testing-utils/empty_namespace.h>
 
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/interval_abstract_value.h> // IWYU pragma: keep
@@ -68,8 +68,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("value_set merges which don't widen")
   {
diff --git a/unit/analyses/variable-sensitivity/value_set_pointer_abstract_object/to_predicate.cpp b/unit/analyses/variable-sensitivity/value_set_pointer_abstract_object/to_predicate.cpp
index ed8cf002a4d..531a815eb02 100644
--- a/unit/analyses/variable-sensitivity/value_set_pointer_abstract_object/to_predicate.cpp
+++ b/unit/analyses/variable-sensitivity/value_set_pointer_abstract_object/to_predicate.cpp
@@ -9,9 +9,9 @@
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
 #include <util/pointer_expr.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
+#include <testing-utils/empty_namespace.h>
 // NOLINTNEXTLINE(whitespace/line_length)
 #include <analyses/variable-sensitivity/value_set_pointer_abstract_object.h> // IWYU pragma: keep
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
@@ -44,8 +44,7 @@ SCENARIO(
     variable_sensitivity_object_factoryt::configured_with(config);
   abstract_environmentt environment{object_factory};
   environment.make_top();
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("value_set_pointer_abstract_object")
   {
diff --git a/unit/analyses/variable-sensitivity/variable_sensitivity_domain/to_predicate.cpp b/unit/analyses/variable-sensitivity/variable_sensitivity_domain/to_predicate.cpp
index aa149ae0383..b5dec0c7563 100644
--- a/unit/analyses/variable-sensitivity/variable_sensitivity_domain/to_predicate.cpp
+++ b/unit/analyses/variable-sensitivity/variable_sensitivity_domain/to_predicate.cpp
@@ -9,11 +9,11 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/variable_sensitivity_domain.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_object_factory.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_test_helpers.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 SCENARIO(
@@ -26,8 +26,7 @@ SCENARIO(
   config.context_tracking.last_write_context = false;
   auto object_factory =
     variable_sensitivity_object_factoryt::configured_with(config);
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("to_predicate()")
   {
diff --git a/unit/analyses/variable-sensitivity/variable_sensitivity_test_helpers.cpp b/unit/analyses/variable-sensitivity/variable_sensitivity_test_helpers.cpp
index 07e0a7437c2..46a29323af5 100644
--- a/unit/analyses/variable-sensitivity/variable_sensitivity_test_helpers.cpp
+++ b/unit/analyses/variable-sensitivity/variable_sensitivity_test_helpers.cpp
@@ -11,9 +11,7 @@
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/mathematical_types.h>
-#include <util/namespace.h>
 #include <util/string_utils.h>
-#include <util/symbol_table.h>
 
 #include <analyses/variable-sensitivity/abstract_environment.h>
 #include <analyses/variable-sensitivity/constant_abstract_value.h>
@@ -21,6 +19,7 @@
 #include <analyses/variable-sensitivity/value_set_abstract_object.h>
 #include <analyses/variable-sensitivity/variable_sensitivity_domain.h>
 #include <ansi-c/ansi_c_language.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 std::shared_ptr<const constant_abstract_valuet>
@@ -182,12 +181,10 @@ std::string expr_to_str(const exprt &expr)
   if(expr.id() == ID_min_value)
     return "min";
 
-  auto st = symbol_tablet{};
-  auto ns = namespacet{st};
   auto expr_str = std::string{};
 
   auto lang = new_ansi_c_language();
-  lang->from_expr(expr, expr_str, ns);
+  lang->from_expr(expr, expr_str, empty_namespace);
 
   return expr_str;
 }
diff --git a/unit/ansi-c/expr2c.cpp b/unit/ansi-c/expr2c.cpp
index cfbed21dcb4..4f48d1dbb0e 100644
--- a/unit/ansi-c/expr2c.cpp
+++ b/unit/ansi-c/expr2c.cpp
@@ -6,23 +6,21 @@ Author: Diffblue
 
 \*******************************************************************/
 
-#include <ansi-c/expr2c.h>
-#include <testing-utils/use_catch.h>
 #include <util/arith_tools.h>
 #include <util/bitvector_expr.h>
 #include <util/bitvector_types.h>
 #include <util/config.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
+
+#include <ansi-c/expr2c.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
 TEST_CASE("rol_2_c_conversion_unsigned", "[core][ansi-c][expr2c]")
 {
   auto lhs = from_integer(31, unsignedbv_typet(32));
   auto rhs = from_integer(3, unsignedbv_typet(32));
   auto rol = shift_exprt(lhs, ID_rol, rhs);
-  CHECK(
-    expr2c(rol, namespacet{symbol_tablet{}}) ==
-    "31 << 3 % 32 | 31 >> 32 - 3 % 32");
+  CHECK(expr2c(rol, empty_namespace) == "31 << 3 % 32 | 31 >> 32 - 3 % 32");
 }
 
 TEST_CASE("rol_2_c_conversion_signed", "[core][ansi-c][expr2c]")
@@ -37,7 +35,7 @@ TEST_CASE("rol_2_c_conversion_signed", "[core][ansi-c][expr2c]")
   auto rhs = from_integer(3, signedbv_typet(8));
   auto rol = shift_exprt(lhs, ID_rol, rhs);
   CHECK(
-    expr2c(rol, namespacet{symbol_tablet{}}) ==
+    expr2c(rol, empty_namespace) ==
     "(unsigned char)31 << 3 % 8 | (unsigned char)31 >> 8 - 3 % 8");
 }
 
@@ -46,9 +44,7 @@ TEST_CASE("ror_2_c_conversion_unsigned", "[core][ansi-c][expr2c]")
   auto lhs = from_integer(31, unsignedbv_typet(32));
   auto rhs = from_integer(3, unsignedbv_typet(32));
   auto ror = shift_exprt(lhs, ID_ror, rhs);
-  CHECK(
-    expr2c(ror, namespacet{symbol_tablet{}}) ==
-    "31 >> 3 % 32 | 31 << 32 - 3 % 32");
+  CHECK(expr2c(ror, empty_namespace) == "31 >> 3 % 32 | 31 << 32 - 3 % 32");
 }
 
 TEST_CASE("ror_2_c_conversion_signed", "[core][ansi-c][expr2c]")
@@ -63,6 +59,6 @@ TEST_CASE("ror_2_c_conversion_signed", "[core][ansi-c][expr2c]")
   auto rhs = from_integer(3, integer_bitvector_typet(ID_signedbv, 32));
   auto ror = shift_exprt(lhs, ID_ror, rhs);
   CHECK(
-    expr2c(ror, namespacet{symbol_tablet{}}) ==
+    expr2c(ror, empty_namespace) ==
     "(unsigned int)31 >> 3 % 32 | (unsigned int)31 << 32 - 3 % 32");
 }
diff --git a/unit/empty_namespace_test.cpp b/unit/empty_namespace_test.cpp
new file mode 100644
index 00000000000..33f48a6db4f
--- /dev/null
+++ b/unit/empty_namespace_test.cpp
@@ -0,0 +1,30 @@
+/*******************************************************************\
+
+Module: Smoke test for empty_namespacet
+
+Author: Michael Tautschnig
+
+\*******************************************************************/
+
+/// \file
+/// Verify that the empty_namespace global is a usable
+/// const namespacet & whose symbol table is empty. The test exists to
+/// document the contract and to act as a regression test if anyone ever
+/// changes the inheritance order or the base-from-member cast in
+/// empty_namespacet's constructor.
+
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
+
+TEST_CASE(
+  "empty_namespace is a usable empty namespacet",
+  "[core][testing-utils]")
+{
+  const namespacet &ns = empty_namespace;
+
+  const symbolt *symbol = nullptr;
+  REQUIRE(ns.lookup("does_not_exist", symbol));
+  REQUIRE(symbol == nullptr);
+
+  REQUIRE(ns.smallest_unused_suffix("x") == 0);
+}
diff --git a/unit/goto-programs/goto_trace_output.cpp b/unit/goto-programs/goto_trace_output.cpp
index 729d5ca2b50..28b7d6f1c16 100644
--- a/unit/goto-programs/goto_trace_output.cpp
+++ b/unit/goto-programs/goto_trace_output.cpp
@@ -7,11 +7,11 @@ Author: Diffblue Ltd.
 \*******************************************************************/
 
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <goto-programs/goto_program.h>
 #include <goto-programs/goto_trace.h>
 
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 #include <sstream>
@@ -20,8 +20,6 @@ SCENARIO(
   "Output trace with nil lhs object",
   "[core][goto-programs][goto_trace]")
 {
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
   goto_programt::instructionst instructions;
   instructions.emplace_back(goto_program_instruction_typet::OTHER);
   goto_trace_stept step;
@@ -29,7 +27,7 @@ SCENARIO(
   step.type = goto_trace_stept::typet::ATOMIC_BEGIN;
 
   std::ostringstream oss;
-  step.output(ns, oss);
+  step.output(empty_namespace, oss);
 
   std::istringstream iss(oss.str());
   std::string line;
diff --git a/unit/goto-programs/xml_expr.cpp b/unit/goto-programs/xml_expr.cpp
index dac9d344111..0bd4a1af12e 100644
--- a/unit/goto-programs/xml_expr.cpp
+++ b/unit/goto-programs/xml_expr.cpp
@@ -6,25 +6,22 @@ Author: Michael Tautschnig
 
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/config.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <goto-programs/xml_expr.h>
 
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
+
 TEST_CASE("Constant expression to XML")
 {
   config.set_arch("none");
 
-  const symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
-
   const constant_exprt number_ubv = from_integer(0xFF, unsignedbv_typet(8));
-  const xmlt x_ubv = xml(number_ubv, ns);
+  const xmlt x_ubv = xml(number_ubv, empty_namespace);
 
   REQUIRE(x_ubv.get_attribute("binary") == "11111111");
 
@@ -33,7 +30,7 @@ TEST_CASE("Constant expression to XML")
   fixedbv_type.set_integer_bits(6);
 
   const constant_exprt number_fbv = from_integer(0x3, fixedbv_type);
-  const xmlt x_fbv = xml(number_fbv, ns);
+  const xmlt x_fbv = xml(number_fbv, empty_namespace);
 
   REQUIRE(x_fbv.get_attribute("binary") == "00001100");
 }
diff --git a/unit/goto-symex/is_constant.cpp b/unit/goto-symex/is_constant.cpp
index 29bb54a7d6f..27c441b9b43 100644
--- a/unit/goto-symex/is_constant.cpp
+++ b/unit/goto-symex/is_constant.cpp
@@ -9,22 +9,19 @@ Author: Diffblue Ltd.
 #include <util/bitvector_types.h>
 #include <util/namespace.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
 
 #include <goto-symex/goto_symex_can_forward_propagate.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 SCENARIO("goto-symex-is-constant", "[core][goto-symex][is_constant]")
 {
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
-
   signedbv_typet int_type(32);
   constant_exprt sizeof_constant("4", int_type);
   sizeof_constant.set(ID_C_c_sizeof_type, int_type);
   symbol_exprt non_constant("x", int_type);
 
-  goto_symex_can_forward_propagatet is_constant(ns);
+  goto_symex_can_forward_propagatet is_constant(empty_namespace);
 
   GIVEN("Sizeof expression multiplied by a non-constant")
   {
diff --git a/unit/goto-symex/shadow_memory_util.cpp b/unit/goto-symex/shadow_memory_util.cpp
index 1d315aa5d5b..05fe8720725 100644
--- a/unit/goto-symex/shadow_memory_util.cpp
+++ b/unit/goto-symex/shadow_memory_util.cpp
@@ -10,17 +10,16 @@
 #include <util/string_constant.h>
 
 #include <goto-symex/shadow_memory_util.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/invariant.h>
+#include <testing-utils/message.h>
 
 #include <array>
 
 /// Helper struct to hold useful test components.
 struct shadow_memory_util_test_environmentt
 {
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
   source_locationt loc{};
-  null_message_handlert null_message_handler{};
   messaget log{null_message_handler};
 
   static shadow_memory_util_test_environmentt make()
@@ -183,9 +182,9 @@ TEST_CASE(
         unsignedbv_typet{56});
 
       const exprt max_over_struct =
-        compute_max_over_bytes(bitvector, sm_type, test.ns);
+        compute_max_over_bytes(bitvector, sm_type, empty_namespace);
 
-      const exprt simplified = simplify_expr(max_over_struct, test.ns);
+      const exprt simplified = simplify_expr(max_over_struct, empty_namespace);
 
       REQUIRE(simplified == from_integer(max(values), sm_type));
     }
@@ -204,9 +203,9 @@ TEST_CASE(
       const array_exprt array_expr{array_operands, array_type};
 
       const exprt max_over_struct =
-        compute_max_over_bytes(array_expr, sm_type, test.ns);
+        compute_max_over_bytes(array_expr, sm_type, empty_namespace);
 
-      const exprt simplified = simplify_expr(max_over_struct, test.ns);
+      const exprt simplified = simplify_expr(max_over_struct, empty_namespace);
 
       REQUIRE(simplified == from_integer(max(values), sm_type));
     }
@@ -231,9 +230,9 @@ TEST_CASE(
       const struct_exprt struct_expr{struct_operands, struct_type};
 
       const exprt max_over_struct =
-        compute_max_over_bytes(struct_expr, sm_type, test.ns);
+        compute_max_over_bytes(struct_expr, sm_type, empty_namespace);
 
-      const exprt simplified = simplify_expr(max_over_struct, test.ns);
+      const exprt simplified = simplify_expr(max_over_struct, empty_namespace);
 
       REQUIRE(simplified == from_integer(max(values), sm_type));
     }
@@ -299,11 +298,11 @@ TEST_CASE(
           (values[4] << 32) + (values[5] << 40) + (values[6] << 48),
         unsignedbv_typet{56});
 
-      const exprt max_over_struct =
-        compute_or_over_bytes(bitvector, sm_type, test.ns, test.log, false);
+      const exprt max_over_struct = compute_or_over_bytes(
+        bitvector, sm_type, empty_namespace, test.log, false);
 
       const exprt simplified =
-        simplify_bit_or_exprt(simplify_expr(max_over_struct, test.ns));
+        simplify_bit_or_exprt(simplify_expr(max_over_struct, empty_namespace));
 
       REQUIRE(simplified == from_integer(compute_or(values), sm_type));
     }
@@ -321,11 +320,11 @@ TEST_CASE(
         from_integer(values[6], unsigned_char_type())};
       const array_exprt array_expr{array_operands, array_type};
 
-      const exprt max_over_struct =
-        compute_or_over_bytes(array_expr, sm_type, test.ns, test.log, false);
+      const exprt max_over_struct = compute_or_over_bytes(
+        array_expr, sm_type, empty_namespace, test.log, false);
 
       const exprt simplified =
-        simplify_bit_or_exprt(simplify_expr(max_over_struct, test.ns));
+        simplify_bit_or_exprt(simplify_expr(max_over_struct, empty_namespace));
 
       REQUIRE(simplified == from_integer(compute_or(values), sm_type));
     }
@@ -349,11 +348,11 @@ TEST_CASE(
         from_integer(fizz, char_type()), inner_struct_expr};
       const struct_exprt struct_expr{struct_operands, struct_type};
 
-      const exprt max_over_struct =
-        compute_or_over_bytes(struct_expr, sm_type, test.ns, test.log, false);
+      const exprt max_over_struct = compute_or_over_bytes(
+        struct_expr, sm_type, empty_namespace, test.log, false);
 
       const exprt simplified =
-        simplify_bit_or_exprt(simplify_expr(max_over_struct, test.ns));
+        simplify_bit_or_exprt(simplify_expr(max_over_struct, empty_namespace));
 
       REQUIRE(simplified == from_integer(compute_or(values), sm_type));
     }
diff --git a/unit/solvers/bdd/miniBDD/miniBDD.cpp b/unit/solvers/bdd/miniBDD/miniBDD.cpp
index 71a311e31a9..ee40fff6a6e 100644
--- a/unit/solvers/bdd/miniBDD/miniBDD.cpp
+++ b/unit/solvers/bdd/miniBDD/miniBDD.cpp
@@ -9,20 +9,19 @@ Author: Diffblue Ltd.
 /// \file
 /// Unit tests for miniBDD
 
-#include <testing-utils/message.h>
-#include <testing-utils/use_catch.h>
-
-#include <solvers/bdd/miniBDD/miniBDD.h>
-#include <solvers/flattening/boolbv.h>
-#include <solvers/prop/bdd_expr.h>
-
 #include <util/arith_tools.h>
 #include <util/bitvector_expr.h>
 #include <util/bitvector_types.h>
 #include <util/expanding_vector.h>
 #include <util/format_expr.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
+
+#include <solvers/bdd/miniBDD/miniBDD.h>
+#include <solvers/flattening/boolbv.h>
+#include <solvers/prop/bdd_expr.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/message.h>
+#include <testing-utils/use_catch.h>
 
 class bdd_propt : public propt
 {
@@ -202,11 +201,9 @@ SCENARIO("miniBDD", "[core][solver][miniBDD]")
 
   GIVEN("A bdd for x&!x==0")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
     mini_bdd_mgrt bdd_mgr;
     bdd_propt bdd_prop(bdd_mgr);
-    boolbvt boolbv(ns, bdd_prop, null_message_handler);
+    boolbvt boolbv(empty_namespace, bdd_prop, null_message_handler);
 
     unsignedbv_typet type(2);
     symbol_exprt var("x", type);
@@ -220,11 +217,9 @@ SCENARIO("miniBDD", "[core][solver][miniBDD]")
 
   GIVEN("A bdd for x+x==1")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
     mini_bdd_mgrt bdd_mgr;
     bdd_propt bdd_prop(bdd_mgr);
-    boolbvt boolbv(ns, bdd_prop, null_message_handler);
+    boolbvt boolbv(empty_namespace, bdd_prop, null_message_handler);
 
     unsignedbv_typet type(32);
     symbol_exprt var("x", type);
@@ -237,11 +232,9 @@ SCENARIO("miniBDD", "[core][solver][miniBDD]")
 
   GIVEN("A bdd for x*y==y*x")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
     mini_bdd_mgrt bdd_mgr;
     bdd_propt bdd_prop(bdd_mgr);
-    boolbvt boolbv(ns, bdd_prop, null_message_handler);
+    boolbvt boolbv(empty_namespace, bdd_prop, null_message_handler);
 
     unsignedbv_typet type(4);
     symbol_exprt var_x("x", type);
@@ -255,11 +248,9 @@ SCENARIO("miniBDD", "[core][solver][miniBDD]")
 
   GIVEN("A bdd for x*x==2")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
     mini_bdd_mgrt bdd_mgr;
     bdd_propt bdd_prop(bdd_mgr);
-    boolbvt boolbv(ns, bdd_prop, null_message_handler);
+    boolbvt boolbv(empty_namespace, bdd_prop, null_message_handler);
 
     unsignedbv_typet type(8);
     symbol_exprt var_x("x", type);
@@ -272,11 +263,9 @@ SCENARIO("miniBDD", "[core][solver][miniBDD]")
 
   GIVEN("A bdd for x*x==4")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
     mini_bdd_mgrt bdd_mgr;
     bdd_propt bdd_prop(bdd_mgr);
-    boolbvt boolbv(ns, bdd_prop, null_message_handler);
+    boolbvt boolbv(empty_namespace, bdd_prop, null_message_handler);
 
     unsignedbv_typet type(8);
     symbol_exprt var_x("x", type);
@@ -334,9 +323,6 @@ SCENARIO("miniBDD", "[core][solver][miniBDD]")
 
     or_exprt o(and_exprt(a, b), not_exprt(a));
 
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
-
     {
       std::ostringstream oss;
       oss << format(o);
diff --git a/unit/solvers/bdd/miniBDD/module_dependencies.txt b/unit/solvers/bdd/miniBDD/module_dependencies.txt
index 08156c972ba..21f20fa7016 100644
--- a/unit/solvers/bdd/miniBDD/module_dependencies.txt
+++ b/unit/solvers/bdd/miniBDD/module_dependencies.txt
@@ -1,4 +1,5 @@
 solvers/bdd/miniBDD
+solvers/flattening
 solvers/prop
 testing-utils
 util
diff --git a/unit/solvers/flattening/boolbv.cpp b/unit/solvers/flattening/boolbv.cpp
index a3ca65f32f5..9f0bde9234a 100644
--- a/unit/solvers/flattening/boolbv.cpp
+++ b/unit/solvers/flattening/boolbv.cpp
@@ -14,10 +14,10 @@ Author: Daniel Kroening
 #include <util/cout_message.h>
 #include <util/namespace.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
 
 #include <solvers/flattening/boolbv.h>
 #include <solvers/sat/satcheck.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 SCENARIO("boolbvt", "[core][solvers][flattening][boolbvt]")
@@ -28,9 +28,7 @@ SCENARIO("boolbvt", "[core][solvers][flattening][boolbvt]")
   GIVEN("A satisfiable bit-vector formula f")
   {
     satcheckt satcheck(message_handler);
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
-    boolbvt boolbv(ns, satcheck, message_handler);
+    boolbvt boolbv(empty_namespace, satcheck, message_handler);
 
     unsignedbv_typet u32(32);
     boolbv << equal_exprt(symbol_exprt("x", u32), from_integer(10, u32));
diff --git a/unit/solvers/flattening/boolbv_enumeration.cpp b/unit/solvers/flattening/boolbv_enumeration.cpp
index 521d99e8108..484db42896c 100644
--- a/unit/solvers/flattening/boolbv_enumeration.cpp
+++ b/unit/solvers/flattening/boolbv_enumeration.cpp
@@ -10,10 +10,10 @@ Author: Daniel Kroening, dkr@amazon.com
 
 #include <util/cout_message.h>
 #include <util/namespace.h>
-#include <util/symbol_table.h>
 
 #include <solvers/flattening/boolbv.h>
 #include <solvers/sat/satcheck.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 TEST_CASE(
@@ -23,9 +23,7 @@ TEST_CASE(
   console_message_handlert message_handler;
   message_handler.set_verbosity(0);
   satcheckt satcheck{message_handler};
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
-  boolbvt boolbv{ns, satcheck, message_handler};
+  boolbvt boolbv{empty_namespace, satcheck, message_handler};
   enumeration_typet enumeration;
   enumeration.elements().push_back(irept{"A"});
   enumeration.elements().push_back(irept{"B"});
diff --git a/unit/solvers/flattening/boolbv_onehot.cpp b/unit/solvers/flattening/boolbv_onehot.cpp
index c2ee0d45fcb..509652dfe39 100644
--- a/unit/solvers/flattening/boolbv_onehot.cpp
+++ b/unit/solvers/flattening/boolbv_onehot.cpp
@@ -14,10 +14,10 @@ Author: Daniel Kroening, dkr@amazon.com
 #include <util/cout_message.h>
 #include <util/namespace.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
 
 #include <solvers/flattening/boolbv.h>
 #include <solvers/sat/satcheck.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 TEST_CASE("onehot flattening", "[core][solvers][flattening][boolbvt][onehot]")
@@ -25,9 +25,7 @@ TEST_CASE("onehot flattening", "[core][solvers][flattening][boolbvt][onehot]")
   console_message_handlert message_handler;
   message_handler.set_verbosity(0);
   satcheckt satcheck{message_handler};
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
-  boolbvt boolbv{ns, satcheck, message_handler};
+  boolbvt boolbv{empty_namespace, satcheck, message_handler};
   unsignedbv_typet u8{8};
 
   GIVEN("A bit-vector that is one-hot")
diff --git a/unit/solvers/flattening/boolbv_update_bit.cpp b/unit/solvers/flattening/boolbv_update_bit.cpp
index b8b13336798..3fbc8bca877 100644
--- a/unit/solvers/flattening/boolbv_update_bit.cpp
+++ b/unit/solvers/flattening/boolbv_update_bit.cpp
@@ -15,10 +15,10 @@ Author: Daniel Kroening
 #include <util/cout_message.h>
 #include <util/namespace.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
 
 #include <solvers/flattening/boolbv.h>
 #include <solvers/sat/satcheck.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 SCENARIO(
@@ -31,9 +31,7 @@ SCENARIO(
   GIVEN("A satisfiable bit-vector formula f with update_bit")
   {
     satcheckt satcheck{message_handler};
-    symbol_tablet symbol_table;
-    namespacet ns{symbol_table};
-    boolbvt boolbv{ns, satcheck, message_handler};
+    boolbvt boolbv{empty_namespace, satcheck, message_handler};
 
     unsignedbv_typet u32{32};
     boolbv << equal_exprt(
diff --git a/unit/solvers/prop/bdd_expr.cpp b/unit/solvers/prop/bdd_expr.cpp
index 3567b34e4fd..e84672c9e7c 100644
--- a/unit/solvers/prop/bdd_expr.cpp
+++ b/unit/solvers/prop/bdd_expr.cpp
@@ -9,17 +9,15 @@ Author: Diffblue Ltd.
 /// \file
 /// Unit tests for bdd_expr
 
-#include <testing-utils/use_catch.h>
-
-#include <solvers/prop/bdd_expr.h>
 #include <util/namespace.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
+
+#include <solvers/prop/bdd_expr.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
 SCENARIO("bdd_expr", "[core][solver][prop][bdd_expr]")
 {
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
   bdd_exprt bdd_expr_converter;
 
   GIVEN("A bdd for x&!x")
diff --git a/unit/solvers/smt2_incremental/convert_expr_to_smt.cpp b/unit/solvers/smt2_incremental/convert_expr_to_smt.cpp
index ec94f96b9ea..aea2daf2762 100644
--- a/unit/solvers/smt2_incremental/convert_expr_to_smt.cpp
+++ b/unit/solvers/smt2_incremental/convert_expr_to_smt.cpp
@@ -9,7 +9,6 @@
 #include <util/namespace.h>
 #include <util/pointer_predicates.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
 
 #include <solvers/smt2_incremental/ast/smt_terms.h>
 #include <solvers/smt2_incremental/convert_expr_to_smt.h>
@@ -19,6 +18,7 @@
 #include <solvers/smt2_incremental/theories/smt_bit_vector_theory.h>
 #include <solvers/smt2_incremental/theories/smt_core_theory.h>
 #include <solvers/smt2_incremental/type_size_mapping.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/invariant.h>
 #include <testing-utils/use_catch.h>
 
@@ -469,12 +469,11 @@ TEST_CASE(
   {
     // (int32_t *)a + 2
     const auto pointer_arith_expr = plus_exprt{pointer_a, two_bvint_32bit};
-    const symbol_tablet symbol_table;
-    const namespacet ns{symbol_table};
-    track_expression_objects(pointer_arith_expr, ns, test.object_map);
+    track_expression_objects(
+      pointer_arith_expr, empty_namespace, test.object_map);
     associate_pointer_sizes(
       pointer_arith_expr,
-      ns,
+      empty_namespace,
       test.pointer_sizes,
       test.object_map,
       test.object_size_function.make_application,
@@ -545,12 +544,11 @@ TEST_CASE(
     // (int *)a - 2 is coming to us as (int *)a + (-2), so a design decision
     // was made to handle only that form.
     const auto pointer_arith_expr = plus_exprt{pointer_a, minus_two_bvint};
-    const symbol_tablet symbol_table;
-    const namespacet ns{symbol_table};
-    track_expression_objects(pointer_arith_expr, ns, test.object_map);
+    track_expression_objects(
+      pointer_arith_expr, empty_namespace, test.object_map);
     associate_pointer_sizes(
       pointer_arith_expr,
-      ns,
+      empty_namespace,
       test.pointer_sizes,
       test.object_map,
       test.object_size_function.make_application,
@@ -577,12 +575,11 @@ TEST_CASE(
     const auto two_bvint = from_integer(2, signedbv_typet{pointer_width});
     const auto pointer_arith_expr = minus_exprt{pointer_a, two_bvint};
 
-    const symbol_tablet symbol_table;
-    const namespacet ns{symbol_table};
-    track_expression_objects(pointer_arith_expr, ns, test.object_map);
+    track_expression_objects(
+      pointer_arith_expr, empty_namespace, test.object_map);
     associate_pointer_sizes(
       pointer_arith_expr,
-      ns,
+      empty_namespace,
       test.pointer_sizes,
       test.object_map,
       test.object_size_function.make_application,
@@ -615,12 +612,11 @@ TEST_CASE(
   {
     // (int32_t *)a - (int32_t *)b
     const auto pointer_subtraction = minus_exprt{pointer_b, pointer_a};
-    const symbol_tablet symbol_table;
-    const namespacet ns{symbol_table};
-    track_expression_objects(pointer_subtraction, ns, test.object_map);
+    track_expression_objects(
+      pointer_subtraction, empty_namespace, test.object_map);
     associate_pointer_sizes(
       pointer_subtraction,
-      ns,
+      empty_namespace,
       test.pointer_sizes,
       test.object_map,
       test.object_size_function.make_application,
@@ -1471,8 +1467,7 @@ TEST_CASE(
 {
   auto test =
     expr_to_smt_conversion_test_environmentt::make(test_archt::x86_64);
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
+  const namespacet &ns = empty_namespace;
   const symbol_exprt foo{"foo", unsignedbv_typet{32}};
   const symbol_exprt bar{"bar", unsignedbv_typet{32}};
   SECTION("Address of symbol")
@@ -1674,12 +1669,10 @@ TEST_CASE(
 {
   auto test =
     expr_to_smt_conversion_test_environmentt::make(test_archt::x86_64);
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
   const symbol_exprt foo{"foo", unsignedbv_typet{32}};
   const object_size_exprt object_size{
     address_of_exprt{foo}, unsignedbv_typet{64}};
-  track_expression_objects(object_size, ns, test.object_map);
+  track_expression_objects(object_size, empty_namespace, test.object_map);
   const auto foo_id = 2;
   CHECK(test.object_map.at(foo).unique_id == foo_id);
   const auto object_bits = config.bv_encoding.object_bits;
@@ -1699,11 +1692,9 @@ TEST_CASE(
 {
   auto test =
     expr_to_smt_conversion_test_environmentt::make(test_archt::x86_64);
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
   const symbol_exprt foo{"foo", unsignedbv_typet{32}};
   const is_dynamic_object_exprt is_dynamic_object{address_of_exprt{foo}};
-  track_expression_objects(is_dynamic_object, ns, test.object_map);
+  track_expression_objects(is_dynamic_object, empty_namespace, test.object_map);
   const auto foo_id = 2;
   CHECK(test.object_map.at(foo).unique_id == foo_id);
   const auto object_bits = config.bv_encoding.object_bits;
@@ -1723,8 +1714,6 @@ TEST_CASE(
 {
   auto test =
     expr_to_smt_conversion_test_environmentt::make(test_archt::x86_64);
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
   const typet value_type = signedbv_typet{8};
   const exprt array = symbol_exprt{
     "my_array", array_typet{value_type, from_integer(10, signed_size_type())}};
@@ -1756,10 +1745,10 @@ TEST_CASE(
   {
     const symbol_exprt symbol{"a_symbol", address_of_expr.type()};
     const equal_exprt assignment{symbol, address_of_expr};
-    track_expression_objects(assignment, ns, test.object_map);
+    track_expression_objects(assignment, empty_namespace, test.object_map);
     associate_pointer_sizes(
       assignment,
-      ns,
+      empty_namespace,
       test.pointer_sizes,
       test.object_map,
       test.object_size_function.make_application,
diff --git a/unit/solvers/smt2_incremental/object_tracking.cpp b/unit/solvers/smt2_incremental/object_tracking.cpp
index 910863f805d..c7793fb4052 100644
--- a/unit/solvers/smt2_incremental/object_tracking.cpp
+++ b/unit/solvers/smt2_incremental/object_tracking.cpp
@@ -9,6 +9,7 @@
 #include <util/symbol_table.h>
 
 #include <solvers/smt2_incremental/object_tracking.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 #include <string>
@@ -135,13 +136,11 @@ TEST_CASE("Tracking object base expressions", "[core][smt2_incremental]")
       actual_invalid_object_pointer->second.base_expression ==
       invalid_object_pointer);
   }
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
   SECTION("Check objects of compound expression not yet tracked")
   {
     CHECK_FALSE(objects_are_already_tracked(compound_expression, object_map));
   }
-  track_expression_objects(compound_expression, ns, object_map);
+  track_expression_objects(compound_expression, empty_namespace, object_map);
   SECTION("Tracking expression objects")
   {
     CHECK(object_map.size() == 5);
@@ -212,8 +211,6 @@ TEST_CASE("Tracking dynamic object status.", "[core][smt2_incremental]")
   config.ansi_c.mode = configt::ansi_ct::flavourt::GCC;
   config.ansi_c.set_arch_spec_x86_64();
   smt_object_mapt object_map = initial_smt_object_map();
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
   exprt base_object;
   bool expected_dynamic_status;
   using rowt =
@@ -224,7 +221,8 @@ TEST_CASE("Tracking dynamic object status.", "[core][smt2_incremental]")
     rowt{symbol_exprt{SYMEX_DYNAMIC_PREFIX "bar", unsignedbv_typet{8}}, true},
     rowt{from_integer(42, make_type_dynamic(signedbv_typet{16})), true});
   INFO("base_object is - " + base_object.pretty(1, 0));
-  track_expression_objects(address_of_exprt{base_object}, ns, object_map);
+  track_expression_objects(
+    address_of_exprt{base_object}, empty_namespace, object_map);
   const auto object = object_map.find(base_object);
   REQUIRE(object != object_map.end());
   REQUIRE(object->second.is_dynamic == expected_dynamic_status);
diff --git a/unit/solvers/strings/string_constraint_generator_valueof/get_numeric_value_from_character.cpp b/unit/solvers/strings/string_constraint_generator_valueof/get_numeric_value_from_character.cpp
index ea4b9b139f3..c2991a275e9 100644
--- a/unit/solvers/strings/string_constraint_generator_valueof/get_numeric_value_from_character.cpp
+++ b/unit/solvers/strings/string_constraint_generator_valueof/get_numeric_value_from_character.cpp
@@ -7,13 +7,12 @@ Author: Diffblue Ltd.
 
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
-#include <solvers/strings/string_constraint_generator.h>
-
 #include <util/namespace.h>
 #include <util/simplify_expr.h>
-#include <util/symbol_table.h>
+
+#include <solvers/strings/string_constraint_generator.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
 /// Get the simplified return value of get_numeric_value_from_character called
 /// with a radix
@@ -25,12 +24,10 @@ static exprt actual(
   const unsigned long radix_ul)
 {
   const constant_exprt chr = from_integer(character, char_type);
-  symbol_tablet symtab;
-  const namespacet ns(symtab);
   return simplify_expr(
     get_numeric_value_from_character(
       chr, char_type, int_type, strict_formatting, radix_ul),
-    ns);
+    empty_namespace);
 }
 
 SCENARIO(
diff --git a/unit/solvers/strings/string_constraint_generator_valueof/is_digit_with_radix.cpp b/unit/solvers/strings/string_constraint_generator_valueof/is_digit_with_radix.cpp
index f4833a812ab..a898e423cf2 100644
--- a/unit/solvers/strings/string_constraint_generator_valueof/is_digit_with_radix.cpp
+++ b/unit/solvers/strings/string_constraint_generator_valueof/is_digit_with_radix.cpp
@@ -7,13 +7,12 @@ Author: Diffblue Ltd.
 
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
-#include <solvers/strings/string_constraint_generator.h>
-
 #include <util/namespace.h>
 #include <util/simplify_expr.h>
-#include <util/symbol_table.h>
+
+#include <solvers/strings/string_constraint_generator.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
 /// Get the simplified return value of is_digit_with_radix called with a radix
 static exprt actual(
@@ -24,13 +23,11 @@ static exprt actual(
 {
   const typet char_type = unsignedbv_typet(16);
   const constant_exprt chr = from_integer(int_value, char_type);
-  symbol_tablet symtab;
-  const namespacet ns(symtab);
 
   return simplify_expr(
     is_digit_with_radix(
       std::move(chr), strict_formatting, radix_as_char, radix_ul),
-    ns);
+    empty_namespace);
 }
 
 /// Get the simplified return value of is_digit_with_radix called with a radix
diff --git a/unit/solvers/strings/string_format_builtin_function/length_for_format_specifier.cpp b/unit/solvers/strings/string_format_builtin_function/length_for_format_specifier.cpp
index 8148114e727..607a49d1350 100644
--- a/unit/solvers/strings/string_format_builtin_function/length_for_format_specifier.cpp
+++ b/unit/solvers/strings/string_format_builtin_function/length_for_format_specifier.cpp
@@ -7,16 +7,15 @@ Author: Diffblue Ltd.
 
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
-#include <solvers/strings/format_specifier.h>
-#include <solvers/strings/string_format_builtin_function.h>
-
 #include <util/pointer_expr.h>
 #include <util/range.h>
 #include <util/simplify_expr.h>
 #include <util/string_expr.h>
-#include <util/symbol_table.h>
+
+#include <solvers/strings/format_specifier.h>
+#include <solvers/strings/string_format_builtin_function.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
 // Create array_string_exprt from array of characters
 array_string_exprt from_char_vector(
@@ -49,8 +48,7 @@ SCENARIO(
   const std::size_t pointer_width = 16;
   const auto pointer_type = pointer_typet(char_type, pointer_width);
 
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
+  const namespacet &ns = empty_namespace;
   symbol_generatort fresh_symbol;
   array_poolt array_pool{fresh_symbol};
 
diff --git a/unit/solvers/strings/string_format_builtin_function/length_of_decimal_int.cpp b/unit/solvers/strings/string_format_builtin_function/length_of_decimal_int.cpp
index d2afe05f39b..7c39d2caa09 100644
--- a/unit/solvers/strings/string_format_builtin_function/length_of_decimal_int.cpp
+++ b/unit/solvers/strings/string_format_builtin_function/length_of_decimal_int.cpp
@@ -7,11 +7,11 @@ Author: Diffblue Ltd.
 
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
+#include <util/simplify_expr.h>
 
 #include <solvers/strings/string_format_builtin_function.h>
-#include <util/simplify_expr.h>
-#include <util/symbol_table.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
 SCENARIO(
   "length_of_decimal_int",
@@ -19,9 +19,6 @@ SCENARIO(
 {
   const typet type = signedbv_typet(32);
 
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   const std::vector<mp_integer> input_values = {
     0, 1, 10, 15, 999, 1000000001, -1, -21111111, -1234567890};
   const std::vector<int> oracles_for_base_10 = {1, 1, 2, 2, 3, 10, 2, 9, 11};
@@ -39,7 +36,8 @@ SCENARIO(
         THEN("length expression is " << oracle)
         {
           const int actual_int =
-            numeric_cast<int>(to_constant_expr(simplify_expr(actual, ns)))
+            numeric_cast<int>(
+              to_constant_expr(simplify_expr(actual, empty_namespace)))
               .value();
           REQUIRE(actual_int == oracle);
         }
@@ -58,8 +56,8 @@ SCENARIO(
         const int oracle = oracles_for_base_16[i];
         THEN("length expression is " << oracle)
         {
-          const int actual_int =
-            *numeric_cast<int>(to_constant_expr(simplify_expr(actual, ns)));
+          const int actual_int = *numeric_cast<int>(
+            to_constant_expr(simplify_expr(actual, empty_namespace)));
           REQUIRE(actual_int == oracle);
         }
       }
diff --git a/unit/solvers/strings/string_refinement/string_refinement.cpp b/unit/solvers/strings/string_refinement/string_refinement.cpp
index d86abcec0e5..468914e852c 100644
--- a/unit/solvers/strings/string_refinement/string_refinement.cpp
+++ b/unit/solvers/strings/string_refinement/string_refinement.cpp
@@ -7,16 +7,16 @@ Author: Romain Brenguier, romain.brenguier@diffblue.com
 
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
-#include <solvers/sat/satcheck.h>
-#include <solvers/strings/string_refinement.h>
 #include <util/arith_tools.h>
 #include <util/c_types.h>
 #include <util/config.h>
 #include <util/mathematical_types.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
+
+#include <solvers/sat/satcheck.h>
+#include <solvers/strings/string_refinement.h>
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
 SCENARIO("string refinement", "[core][solvers][strings][string_refinement]")
 {
@@ -27,9 +27,7 @@ SCENARIO("string refinement", "[core][solvers][strings][string_refinement]")
   null_message_handlert log{};
   info.message_handler = &log;
 
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
-  info.ns = &ns;
+  info.ns = &empty_namespace;
 
   satcheckt sat_solver{log};
   info.prop = &sat_solver;
diff --git a/unit/testing-utils/Makefile b/unit/testing-utils/Makefile
index abe4cc78c22..893b15f0a1f 100644
--- a/unit/testing-utils/Makefile
+++ b/unit/testing-utils/Makefile
@@ -1,5 +1,6 @@
 SRC = \
   call_graph_test_utils.cpp \
+  empty_namespace.cpp \
   free_form_cmdline.cpp \
   get_goto_model_from_c.cpp \
   invariant.cpp \
diff --git a/unit/testing-utils/empty_namespace.cpp b/unit/testing-utils/empty_namespace.cpp
new file mode 100644
index 00000000000..ac9ab758521
--- /dev/null
+++ b/unit/testing-utils/empty_namespace.cpp
@@ -0,0 +1,14 @@
+/*******************************************************************\
+
+Module: Unit test utilities
+
+Author: Diffblue Limited.
+
+\*******************************************************************/
+
+/// \file
+/// Global instance of \ref empty_namespacet.
+
+#include "empty_namespace.h"
+
+const empty_namespacet empty_namespace;
diff --git a/unit/testing-utils/empty_namespace.h b/unit/testing-utils/empty_namespace.h
new file mode 100644
index 00000000000..b5d156ccda1
--- /dev/null
+++ b/unit/testing-utils/empty_namespace.h
@@ -0,0 +1,37 @@
+/*******************************************************************\
+
+Module: Unit test utilities
+
+Author: Michael Tautschnig
+
+\*******************************************************************/
+
+/// \file
+/// An empty namespacet for unit tests that don't need symbols.
+
+#ifndef CPROVER_TESTING_UTILS_EMPTY_NAMESPACE_H
+#define CPROVER_TESTING_UTILS_EMPTY_NAMESPACE_H
+
+#include <util/namespace.h>
+#include <util/symbol_table.h>
+
+/// A namespacet that contains an empty symbol table, for use in tests that
+/// need a namespacet but don't actually look up any symbols.
+/// This avoids the boilerplate of declaring a symbol_tablet and namespacet
+/// in every test.
+class empty_namespacet : private symbol_tablet, public namespacet
+{
+public:
+  empty_namespacet() : namespacet{static_cast<symbol_tablet &>(*this)}
+  {
+  }
+
+  empty_namespacet(const empty_namespacet &) = delete;
+  empty_namespacet(empty_namespacet &&) = delete;
+  empty_namespacet &operator=(const empty_namespacet &) = delete;
+  empty_namespacet &operator=(empty_namespacet &&) = delete;
+};
+
+extern const empty_namespacet empty_namespace;
+
+#endif // CPROVER_TESTING_UTILS_EMPTY_NAMESPACE_H
diff --git a/unit/util/bitvector_expr.cpp b/unit/util/bitvector_expr.cpp
index bf4207fa11f..faac4794a7d 100644
--- a/unit/util/bitvector_expr.cpp
+++ b/unit/util/bitvector_expr.cpp
@@ -6,10 +6,10 @@
 #include <util/cout_message.h>
 #include <util/namespace.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
 
 #include <solvers/flattening/boolbv.h>
 #include <solvers/sat/satcheck.h>
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 TEST_CASE(
@@ -77,9 +77,7 @@ TEST_CASE("onehot expression lowering", "[core][util][expr]")
   console_message_handlert message_handler;
   message_handler.set_verbosity(0);
   satcheckt satcheck{message_handler};
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
-  boolbvt boolbv{ns, satcheck, message_handler};
+  boolbvt boolbv{empty_namespace, satcheck, message_handler};
   unsignedbv_typet u8{8};
 
   GIVEN("A bit-vector that is one-hot")
diff --git a/unit/util/interval/add.cpp b/unit/util/interval/add.cpp
index 45699877759..5119fea0fb3 100644
--- a/unit/util/interval/add.cpp
+++ b/unit/util/interval/add.cpp
@@ -3,13 +3,11 @@
  Author: DiffBlue Limited
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/interval.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
+
+#include <testing-utils/use_catch.h>
 
 #define V(X) (bvrep2integer(X.get(ID_value).c_str(), 32, true))
 #define V_(X) (bvrep2integer(X.c_str(), 32, true))
@@ -19,9 +17,6 @@ SCENARIO("add interval domain", "[core][analyses][interval][add]")
 {
   GIVEN("Two simple signed intervals")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
-
     WHEN("Both are positive [2,4]+[6,8]")
     {
       constant_interval_exprt left(CEV(2), CEV(4));
diff --git a/unit/util/interval/comparisons.cpp b/unit/util/interval/comparisons.cpp
index e31159a20d2..d37a24c3d07 100644
--- a/unit/util/interval/comparisons.cpp
+++ b/unit/util/interval/comparisons.cpp
@@ -3,13 +3,11 @@
  Author: DiffBlue Limited
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/interval.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
+
+#include <testing-utils/use_catch.h>
 
 #define V(X) (bvrep2integer(X.get(ID_value).c_str(), 32, true))
 #define V_(X) (bvrep2integer(X.c_str(), 32, true))
@@ -19,9 +17,6 @@ SCENARIO("comparison interval domain", "[core][analyses][interval][comparison]")
 {
   GIVEN("Two simple signed intervals")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
-
     WHEN("<, >, <=, >=, ==, != are tested on expressions")
     {
       THEN("Require correctness")
diff --git a/unit/util/interval/get_extreme.cpp b/unit/util/interval/get_extreme.cpp
index 58d6249859d..5d5a3609ed9 100644
--- a/unit/util/interval/get_extreme.cpp
+++ b/unit/util/interval/get_extreme.cpp
@@ -9,8 +9,8 @@
 #include <util/mp_arith.h>
 #include <util/namespace.h>
 #include <util/simplify_expr.h>
-#include <util/symbol_table.h>
 
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 #include <random>
@@ -23,8 +23,7 @@ SCENARIO("get extreme exprt value", "[core][analyses][interval][get_extreme]")
 {
   GIVEN("A selection of constant_exprts in a std::vector and map")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
+    const namespacet &ns = empty_namespace;
 
     std::vector<exprt> ve;
 
diff --git a/unit/util/interval/modulo.cpp b/unit/util/interval/modulo.cpp
index 895a995c4c1..972d4fdb55f 100644
--- a/unit/util/interval/modulo.cpp
+++ b/unit/util/interval/modulo.cpp
@@ -3,13 +3,11 @@
  Author: DiffBlue Limited
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/interval.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
+
+#include <testing-utils/use_catch.h>
 
 #define V(X) (bvrep2integer(X.get(ID_value).c_str(), 32, true))
 #define V_(X) (bvrep2integer(X.c_str(), 32, true))
@@ -38,9 +36,6 @@ SCENARIO("modulo interval domain", "[core][analyses][interval][modulo]")
   }
   GIVEN("Two simple signed intervals")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
-
     WHEN("Positive RHS")
     {
       THEN("Ensure result is consistent.")
diff --git a/unit/util/interval/multiply.cpp b/unit/util/interval/multiply.cpp
index 27274b47b16..92272aeeeaf 100644
--- a/unit/util/interval/multiply.cpp
+++ b/unit/util/interval/multiply.cpp
@@ -3,13 +3,11 @@
  Author: DiffBlue Limited
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/interval.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
+
+#include <testing-utils/use_catch.h>
 
 #define V(X) (bvrep2integer(X.get(ID_value).c_str(), 32, true))
 #define V_(X) (bvrep2integer(X.c_str(), 32, true))
@@ -19,9 +17,6 @@ SCENARIO("multiply interval domain", "[core][analyses][interval][multiply]")
 {
   GIVEN("A selection of constant_exprts in a std::vector and map")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
-
     WHEN("Single element multiplication")
     {
       constant_interval_exprt a = constant_interval_exprt::singleton(CEV(5));
diff --git a/unit/util/interval/subtract.cpp b/unit/util/interval/subtract.cpp
index be9da78d21d..7240abe6e66 100644
--- a/unit/util/interval/subtract.cpp
+++ b/unit/util/interval/subtract.cpp
@@ -3,13 +3,11 @@
  Author: DiffBlue Limited
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
 #include <util/arith_tools.h>
 #include <util/bitvector_types.h>
 #include <util/interval.h>
-#include <util/namespace.h>
-#include <util/symbol_table.h>
+
+#include <testing-utils/use_catch.h>
 
 #define V(X) (bvrep2integer(X.get(ID_value).c_str(), 32, true))
 #define V_(X) (bvrep2integer(X.c_str(), 32, true))
@@ -19,9 +17,6 @@ SCENARIO("subtract interval domain", "[core][analyses][interval][subtract]")
 {
   GIVEN("Two simple signed intervals")
   {
-    symbol_tablet symbol_table;
-    namespacet ns(symbol_table);
-
     WHEN("The result is positive [6,8]-[2,4]")
     {
       constant_interval_exprt left(CEV(6), CEV(8));
diff --git a/unit/util/lower_byte_operators.cpp b/unit/util/lower_byte_operators.cpp
index 4f3ac9ba9be..f8fa21b4adc 100644
--- a/unit/util/lower_byte_operators.cpp
+++ b/unit/util/lower_byte_operators.cpp
@@ -18,8 +18,8 @@
 #include <util/simplify_utils.h>
 #include <util/std_types.h>
 #include <util/string_constant.h>
-#include <util/symbol_table.h>
 
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 TEST_CASE("byte extract and bits", "[core][util][lowering][byte_extract]")
@@ -29,8 +29,7 @@ TEST_CASE("byte extract and bits", "[core][util][lowering][byte_extract]")
   cmdlinet cmdline;
   config.set(cmdline);
 
-  const symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   const unsignedbv_typet u16{16};
   const exprt sixteen_bits = from_integer(0x1234, u16);
@@ -99,8 +98,7 @@ SCENARIO("byte_extract_lowering", "[core][util][lowering][byte_extract]")
   cmdlinet cmdline;
   config.set(cmdline);
 
-  const symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("A byte_extract over a POD")
   {
@@ -367,8 +365,7 @@ SCENARIO("byte_update_lowering", "[core][util][lowering][byte_update]")
   cmdlinet cmdline;
   config.set(cmdline);
 
-  const symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   GIVEN("A byte_update of a POD")
   {
diff --git a/unit/util/pointer_offset_size.cpp b/unit/util/pointer_offset_size.cpp
index a091f1c7f42..70ce2df0aee 100644
--- a/unit/util/pointer_offset_size.cpp
+++ b/unit/util/pointer_offset_size.cpp
@@ -6,8 +6,6 @@ Author: Michael Tautschnig
 
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
 #include <util/arith_tools.h>
 #include <util/byte_operators.h>
 #include <util/c_types.h>
@@ -16,7 +14,9 @@ Author: Michael Tautschnig
 #include <util/namespace.h>
 #include <util/pointer_offset_size.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
+
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
 TEST_CASE("Build subexpression to access element at offset into array")
 {
@@ -25,8 +25,7 @@ TEST_CASE("Build subexpression to access element at offset into array")
   cmdlinet cmdline;
   config.set(cmdline);
 
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   const signedbv_typet t(32);
 
@@ -84,8 +83,7 @@ TEST_CASE("Build subexpression to access element at offset into struct")
   cmdlinet cmdline;
   config.set(cmdline);
 
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   const signedbv_typet t(32);
 
diff --git a/unit/util/simplify_expr.cpp b/unit/util/simplify_expr.cpp
index 663b5b19325..41347348cc2 100644
--- a/unit/util/simplify_expr.cpp
+++ b/unit/util/simplify_expr.cpp
@@ -22,15 +22,13 @@ Author: Michael Tautschnig
 #include <util/std_expr.h>
 #include <util/symbol_table.h>
 
+#include <testing-utils/empty_namespace.h>
 #include <testing-utils/use_catch.h>
 
 TEST_CASE("Simplify pointer_offset(address of array index)", "[core][util]")
 {
   config.set_arch("none");
 
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
-
   array_typet array_type(char_type(), from_integer(2, size_type()));
   symbol_exprt array("A", array_type);
   index_exprt index(array, from_integer(1, c_index_type()));
@@ -38,7 +36,7 @@ TEST_CASE("Simplify pointer_offset(address of array index)", "[core][util]")
 
   exprt p_o=pointer_offset(address_of);
 
-  exprt simp=simplify_expr(p_o, ns);
+  exprt simp = simplify_expr(p_o, empty_namespace);
 
   REQUIRE(simp.is_constant());
   const mp_integer offset_value =
@@ -53,24 +51,20 @@ TEST_CASE("Simplify byte extract", "[core][util]")
   cmdlinet cmdline;
   config.set(cmdline);
 
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
-
   // byte-extracting type T at offset 0 from an object of type T yields the
   // object
   symbol_exprt s("foo", size_type());
   byte_extract_exprt be =
     make_byte_extract(s, from_integer(0, c_index_type()), size_type());
 
-  exprt simp = simplify_expr(be, ns);
+  exprt simp = simplify_expr(be, empty_namespace);
 
   REQUIRE(simp == s);
 }
 
 TEST_CASE("expr2bits and bits2expr respect bit order", "[core][util]")
 {
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   exprt deadbeef = from_integer(0xdeadbeef, unsignedbv_typet(32));
 
@@ -122,9 +116,6 @@ TEST_CASE("Simplify extractbit", "[core][util]")
   const cmdlinet cmdline;
   config.set(cmdline);
 
-  const symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
-
   // binary: 1101 1110 1010 1101 1011 1110 1110 1111
   //         ^MSB                               LSB^
   //              bit23^                  bit4^
@@ -133,13 +124,13 @@ TEST_CASE("Simplify extractbit", "[core][util]")
   const exprt deadbeef = from_integer(0xdeadbeef, unsignedbv_typet(32));
 
   exprt eb1 = extractbit_exprt(deadbeef, 4);
-  bool unmodified = simplify(eb1, ns);
+  bool unmodified = simplify(eb1, empty_namespace);
 
   REQUIRE(!unmodified);
   REQUIRE(eb1 == false_exprt());
 
   exprt eb2 = extractbit_exprt(deadbeef, 23);
-  unmodified = simplify(eb2, ns);
+  unmodified = simplify(eb2, empty_namespace);
 
   REQUIRE(!unmodified);
   REQUIRE(eb2 == true_exprt());
@@ -152,13 +143,10 @@ TEST_CASE("Simplify extractbits", "[core][util]")
   const cmdlinet cmdline;
   config.set(cmdline);
 
-  const symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
-
   const exprt deadbeef = from_integer(0xdeadbeef, unsignedbv_typet(32));
 
   exprt eb = extractbits_exprt(deadbeef, 8, unsignedbv_typet(8));
-  bool unmodified = simplify(eb, ns);
+  bool unmodified = simplify(eb, empty_namespace);
 
   REQUIRE(!unmodified);
   REQUIRE(eb == from_integer(0xbe, unsignedbv_typet(8)));
@@ -166,8 +154,7 @@ TEST_CASE("Simplify extractbits", "[core][util]")
 
 TEST_CASE("Simplify shift", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   REQUIRE(
     simplify_expr(shl_exprt(from_integer(5, signedbv_typet(8)), 1), ns) ==
@@ -192,8 +179,7 @@ TEST_CASE("Simplify shift", "[core][util]")
 
 TEST_CASE("Simplify dynamic object comparison", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   dynamic_object_exprt dynamic_object(signedbv_typet(8));
   dynamic_object.set_instance(1);
@@ -238,23 +224,19 @@ TEST_CASE("Simplify pointer_object equality", "[core][util]")
   const cmdlinet cmdline;
   config.set(cmdline);
 
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
-
   exprt p_o_void =
     pointer_object(null_pointer_exprt{pointer_type(empty_typet{})});
   exprt p_o_int =
     pointer_object(null_pointer_exprt{pointer_type(signedbv_typet(32))});
 
-  exprt simp = simplify_expr(equal_exprt{p_o_void, p_o_int}, ns);
+  exprt simp = simplify_expr(equal_exprt{p_o_void, p_o_int}, empty_namespace);
 
   REQUIRE(simp == true);
 }
 
 TEST_CASE("Simplify cast from bool", "[core][util]")
 {
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   {
     // this checks that ((int)B)==1 turns into B
@@ -307,8 +289,7 @@ TEST_CASE("Simplify cast from bool", "[core][util]")
 
 TEST_CASE("simplify_expr boolean expressions", "[core][util]")
 {
-  symbol_tablet symbol_table;
-  namespacet ns{symbol_table};
+  const namespacet &ns = empty_namespace;
 
   SECTION("Binary boolean operations")
   {
@@ -520,24 +501,18 @@ TEST_CASE("Simplifying cast expressions", "[core][util]")
 
 TEST_CASE("Simplify bitor", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
-
   SECTION("Simplification for raw bitvector")
   {
     bv_typet bv{4};
     constant_exprt zero = from_integer(0, bv);
     symbol_exprt b{"B", bv};
 
-    REQUIRE(simplify_expr(bitor_exprt{b, zero}, ns) == b);
+    REQUIRE(simplify_expr(bitor_exprt{b, zero}, empty_namespace) == b);
   }
 }
 
 TEST_CASE("Simplify inequality", "[core][util]")
 {
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
-
   {
     // This checks that 3 < (B ? 4 : 5) simplifies to true, just like (B ? 4 :
     // 5) > 3 simplifies to true.
@@ -546,12 +521,12 @@ TEST_CASE("Simplify inequality", "[core][util]")
     if_exprt if_b{b, from_integer(4, sbv), from_integer(5, sbv)};
 
     binary_relation_exprt comparison_gt{if_b, ID_gt, from_integer(3, sbv)};
-    exprt simp = simplify_expr(comparison_gt, ns);
+    exprt simp = simplify_expr(comparison_gt, empty_namespace);
 
     REQUIRE(simp == true_exprt{});
 
     binary_relation_exprt comparison_lt{from_integer(3, sbv), ID_lt, if_b};
-    simp = simplify_expr(comparison_lt, ns);
+    simp = simplify_expr(comparison_lt, empty_namespace);
 
     REQUIRE(simp == true_exprt{});
   }
@@ -561,30 +536,27 @@ TEST_CASE("Simplify bitxor", "[core][util]")
 {
   config.set_arch("none");
 
-  const symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
-
   SECTION("Simplification for c_bool")
   {
     constant_exprt false_c_bool = from_integer(0, c_bool_type());
 
     REQUIRE(
-      simplify_expr(bitxor_exprt{false_c_bool, false_c_bool}, ns) ==
+      simplify_expr(
+        bitxor_exprt{false_c_bool, false_c_bool}, empty_namespace) ==
       false_c_bool);
   }
 }
 
 TEST_CASE("Simplify power", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   SECTION("Simplification for power")
   {
     symbol_exprt a{"a", integer_typet{}};
 
     REQUIRE(
-      simplify_expr(power_exprt{a, from_integer(1, integer_typet{})}, ns) == a);
+      simplify_expr(
+        power_exprt{a, from_integer(1, integer_typet{})}, empty_namespace) ==
+      a);
   }
 }
 
@@ -592,9 +564,6 @@ TEST_CASE("Simplify pointer cast of pointer arithmetic", "[core][util]")
 {
   config.set_arch("none");
 
-  symbol_tablet symbol_table;
-  namespacet ns(symbol_table);
-
   SECTION("Same element size: (char*)(unsigned_char_ptr + 1)")
   {
     // (char*)(ptr + 1) where ptr is unsigned char* should push the cast inside
@@ -604,7 +573,7 @@ TEST_CASE("Simplify pointer cast of pointer arithmetic", "[core][util]")
     plus_exprt ptr_plus_1{ptr, from_integer(1, pointer_diff_type())};
     typecast_exprt cast{ptr_plus_1, char_ptr_type};
 
-    exprt result = simplify_expr(cast, ns);
+    exprt result = simplify_expr(cast, empty_namespace);
 
     // Expected: (char*)ptr + 1
     plus_exprt expected{
@@ -621,7 +590,7 @@ TEST_CASE("Simplify pointer cast of pointer arithmetic", "[core][util]")
     plus_exprt ptr_plus_1{ptr, from_integer(1, pointer_diff_type())};
     typecast_exprt cast{ptr_plus_1, char_ptr_type};
 
-    exprt result = simplify_expr(cast, ns);
+    exprt result = simplify_expr(cast, empty_namespace);
 
     // Expected: (char*)ptr + 4
     plus_exprt expected{
@@ -632,8 +601,7 @@ TEST_CASE("Simplify pointer cast of pointer arithmetic", "[core][util]")
 
 TEST_CASE("Simplify quantifier", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
+  const namespacet &ns = empty_namespace;
 
   SECTION("Simplification for exists")
   {
@@ -656,57 +624,42 @@ TEST_CASE("Simplify quantifier", "[core][util]")
 
 TEST_CASE("Simplify all-zero constant in bitand", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   const unsignedbv_typet u8{8};
   const symbol_exprt x{"x", u8};
   const auto zero = from_integer(0, u8);
   const bitand_exprt band{x, zero};
-  REQUIRE(simplify_expr(band, ns) == zero);
+  REQUIRE(simplify_expr(band, empty_namespace) == zero);
 }
 
 TEST_CASE("Simplify all-ones constant in bitor", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   const unsignedbv_typet u8{8};
   const symbol_exprt x{"x", u8};
   const auto ones = from_integer(255, u8);
   const bitor_exprt bor{x, ones};
-  REQUIRE(simplify_expr(bor, ns) == ones);
+  REQUIRE(simplify_expr(bor, empty_namespace) == ones);
 }
 
 TEST_CASE("Simplify all-zero constant in bitand with bv_typet", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   const bv_typet bv8{8};
   const symbol_exprt x{"x", bv8};
   const auto zero = bv8.all_zeros_expr();
   const bitand_exprt band{x, zero};
-  REQUIRE(simplify_expr(band, ns) == zero);
+  REQUIRE(simplify_expr(band, empty_namespace) == zero);
 }
 
 TEST_CASE("Simplify all-ones constant in bitor with bv_typet", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   const bv_typet bv8{8};
   const symbol_exprt x{"x", bv8};
   const auto ones = bv8.all_ones_expr();
   const bitor_exprt bor{x, ones};
-  REQUIRE(simplify_expr(bor, ns) == ones);
+  REQUIRE(simplify_expr(bor, empty_namespace) == ones);
 }
 
 TEST_CASE("Simplify flatten nested OR", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   const symbol_exprt a{"a", bool_typet{}};
   const symbol_exprt b{"b", bool_typet{}};
   const symbol_exprt c{"c", bool_typet{}};
@@ -714,14 +667,11 @@ TEST_CASE("Simplify flatten nested OR", "[core][util]")
   // (a || (b || c)) should flatten to (a || b || c)
   const or_exprt inner{b, c};
   const or_exprt nested{a, inner};
-  REQUIRE(simplify_expr(nested, ns) == or_exprt{a, b, c});
+  REQUIRE(simplify_expr(nested, empty_namespace) == or_exprt{a, b, c});
 }
 
 TEST_CASE("Simplify flatten nested AND", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   const symbol_exprt a{"a", bool_typet{}};
   const symbol_exprt b{"b", bool_typet{}};
   const symbol_exprt c{"c", bool_typet{}};
@@ -729,43 +679,34 @@ TEST_CASE("Simplify flatten nested AND", "[core][util]")
   // (a && (b && c)) should flatten to (a && b && c)
   const and_exprt inner{b, c};
   const and_exprt nested{a, inner};
-  REQUIRE(simplify_expr(nested, ns) == and_exprt{a, b, c});
+  REQUIRE(simplify_expr(nested, empty_namespace) == and_exprt{a, b, c});
 }
 
 TEST_CASE("Simplify complementary pair in OR", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   const symbol_exprt a{"a", bool_typet{}};
 
   // (a || !a) should simplify to true
   const or_exprt expr{a, not_exprt{a}};
-  REQUIRE(simplify_expr(expr, ns) == true_exprt{});
+  REQUIRE(simplify_expr(expr, empty_namespace) == true_exprt{});
 }
 
 TEST_CASE("Simplify complementary pair in AND", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   const symbol_exprt a{"a", bool_typet{}};
 
   // (a && !a) should simplify to false
   const and_exprt expr{a, not_exprt{a}};
-  REQUIRE(simplify_expr(expr, ns) == false_exprt{});
+  REQUIRE(simplify_expr(expr, empty_namespace) == false_exprt{});
 }
 
 TEST_CASE("Simplify complementary pair in nested OR", "[core][util]")
 {
-  const symbol_tablet symbol_table;
-  const namespacet ns{symbol_table};
-
   const symbol_exprt a{"a", bool_typet{}};
   const symbol_exprt b{"b", bool_typet{}};
 
   // (a || (b || !a)) should simplify to true (after flattening)
   const or_exprt inner{b, not_exprt{a}};
   const or_exprt expr{a, inner};
-  REQUIRE(simplify_expr(expr, ns) == true_exprt{});
+  REQUIRE(simplify_expr(expr, empty_namespace) == true_exprt{});
 }
diff --git a/unit/util/std_expr.cpp b/unit/util/std_expr.cpp
index b21425164c9..91a1830af71 100644
--- a/unit/util/std_expr.cpp
+++ b/unit/util/std_expr.cpp
@@ -6,8 +6,6 @@ Author: Diffblue Ltd
 
 \*******************************************************************/
 
-#include <testing-utils/use_catch.h>
-
 #include <util/arith_tools.h>
 #include <util/c_types.h>
 #include <util/config.h>
@@ -16,7 +14,9 @@ Author: Diffblue Ltd
 #include <util/pointer_expr.h>
 #include <util/simplify_expr.h>
 #include <util/std_expr.h>
-#include <util/symbol_table.h>
+
+#include <testing-utils/empty_namespace.h>
+#include <testing-utils/use_catch.h>
 
 TEST_CASE("for a division expression...", "[unit][util][std_expr]")
 {
@@ -40,8 +40,7 @@ TEST_CASE("object descriptor expression", "[unit][util][std_expr]")
 {
   config.ansi_c.set_LP64();
 
-  symbol_tablet symbol_table;
-  const namespacet ns(symbol_table);
+  const namespacet &ns = empty_namespace;
 
   array_typet array_type(signed_int_type(), from_integer(2, size_type()));
   struct_typet struct_type({{"foo", array_type}});