diff --git a/src/snmalloc/backend_helpers/pagemap.h b/src/snmalloc/backend_helpers/pagemap.h
index 460f70e..0466913 100644
--- a/src/snmalloc/backend_helpers/pagemap.h
+++ b/src/snmalloc/backend_helpers/pagemap.h
@@ -28,6 +28,10 @@ namespace snmalloc
      */
     using Entry = PagemapEntry;
 
+    static_assert(
+      std::is_same_v<PagemapEntry, typename ConcreteMap::EntryType>,
+      "BasicPagemap's PagemapEntry and ConcreteMap disagree!");
+
     /**
      * Instance of the concrete pagemap, accessible to the backend so that
      * it can call the init method whose type dependent on fixed_range.
diff --git a/src/snmalloc/ds/pagemap.h b/src/snmalloc/ds/pagemap.h
index d7115cb..a420249 100644
--- a/src/snmalloc/ds/pagemap.h
+++ b/src/snmalloc/ds/pagemap.h
@@ -48,6 +48,8 @@ namespace snmalloc
     size_t size{0};
 
   public:
+    using EntryType = T;
+
     /**
      * Ensure this range of pagemap is accessible
      */