diff --git a/modules/iris b/modules/iris
index 016870690..ce52ee9b7 160000
--- a/modules/iris
+++ b/modules/iris
@@ -1 +1 @@
-Subproject commit 0168706900e7bcc3f4d7d772a31fd660244720ce
+Subproject commit ce52ee9b7969458db0cef211d735fa55b8590350
diff --git a/test/x4/CMakeLists.txt b/test/x4/CMakeLists.txt
index 1fbf60563..0301d9447 100644
--- a/test/x4/CMakeLists.txt
+++ b/test/x4/CMakeLists.txt
@@ -4,11 +4,6 @@
 # Distributed under the Boost Software License, Version 1.0.
 # https://www.boost.org/LICENSE_1_0.txt
 
-add_library(x4_test_pch OBJECT pch.cpp)
-set_target_properties(x4_test_pch PROPERTIES CXX_EXTENSIONS OFF)
-target_link_libraries(x4_test_pch PRIVATE Iris::X4 iris_cxx_test)
-target_precompile_headers(x4_test_pch PUBLIC pch.hpp)
-
 function(x4_define_test_headers test_name)
     iris_define_test_headers(x4_${test_name} PRIVATE FILE_SET HEADERS FILES ${ARGN})
 endfunction()
@@ -16,7 +11,6 @@ endfunction()
 function(x4_define_test test_name)
     iris_define_test(x4_${test_name} ${ARGN})
     iris_define_test_headers(x4_${test_name} iris_x4_test.hpp)
-    target_precompile_headers(x4_${test_name}_test REUSE_FROM x4_test_pch)
     target_link_libraries(x4_${test_name}_test PRIVATE Iris::X4)
     set_target_properties(x4_${test_name}_test PROPERTIES FOLDER "test/x4")
 
diff --git a/test/x4/pch.cpp b/test/x4/pch.cpp
deleted file mode 100644
index e69de29bb..000000000
diff --git a/test/x4/pch.hpp b/test/x4/pch.hpp
deleted file mode 100644
index 15e146ccd..000000000
--- a/test/x4/pch.hpp
+++ /dev/null
@@ -1,25 +0,0 @@
-#ifndef IRIS_ZZ_X4_TEST_PCH_HPP
-#define IRIS_ZZ_X4_TEST_PCH_HPP
-
-#include <iris/alloy/tuple.hpp>
-#include <iris/alloy/adapt.hpp>
-
-#include <iris/rvariant.hpp>
-#include <iris/rvariant/rvariant_io.hpp>
-
-#include <iris/x4/char_encoding/unicode.hpp>
-
-#include <algorithm>
-#include <concepts>
-#include <iostream>
-#include <iterator>
-#include <memory>
-#include <optional>
-#include <ranges>
-#include <string>
-#include <string_view>
-#include <type_traits>
-#include <utility>
-#include <vector>
-
-#endif