diff --git a/src/corelib/CMakeLists.txt b/src/corelib/CMakeLists.txt
index 3333bc1a62..adfb67ffd6 100644
--- a/src/corelib/CMakeLists.txt
+++ b/src/corelib/CMakeLists.txt
@@ -310,7 +310,6 @@ qt_internal_add_module(Core
         tools/qvector.h
         tools/qversionnumber.cpp tools/qversionnumber.h
     NO_UNITY_BUILD_SOURCES
-        tools/qfreelist.cpp # Size0/Offset0 (also in qabstracteventdispatcher.cpp)
         # MinGW complains about `free-nonheap-object` in ~QSharedDataPointer()
         # despite the fact that appropriate checks are in place to avoid that!
         tools/qshareddata.cpp tools/qshareddata.h
diff --git a/src/corelib/tools/qfreelist.cpp b/src/corelib/tools/qfreelist.cpp
index 45bd3ba8ae..db15fac5d6 100644
--- a/src/corelib/tools/qfreelist.cpp
+++ b/src/corelib/tools/qfreelist.cpp
@@ -6,6 +6,7 @@
 QT_BEGIN_NAMESPACE
 
 // default sizes and offsets (no need to define these when customizing)
+namespace QFreeListDefaultConstantsPrivate {
 enum {
     Offset0 = 0x00000000,
     Offset1 = 0x00008000,
@@ -17,12 +18,13 @@ enum {
     Size2 = Offset3 - Offset2,
     Size3 = QFreeListDefaultConstants::MaxIndex - Offset3
 };
+}
 
 Q_CONSTINIT const int QFreeListDefaultConstants::Sizes[QFreeListDefaultConstants::BlockCount] = {
-    Size0,
-    Size1,
-    Size2,
-    Size3
+    QFreeListDefaultConstantsPrivate::Size0,
+    QFreeListDefaultConstantsPrivate::Size1,
+    QFreeListDefaultConstantsPrivate::Size2,
+    QFreeListDefaultConstantsPrivate::Size3
 };
 
 QT_END_NAMESPACE