diff --git a/alloc/aligned/foreign.hpp b/alloc/aligned/foreign.hpp
index 898fc8b3..60590503 100644
--- a/alloc/aligned/foreign.hpp
+++ b/alloc/aligned/foreign.hpp
@@ -76,17 +76,17 @@ namespace cruft::alloc::aligned {
 
 
         decltype(auto)
-        deallocate (u08 *ptr, std::size_t bytes, std::size_t alignment)
+        deallocate (void *ptr, std::size_t bytes, std::size_t alignment)
         {
             CHECK_MOD (m_alignment, alignment);
-            return m_successor.deallocate (ptr - m_offset, bytes, alignment);
+            return m_successor.deallocate (reinterpret_cast<u08*> (ptr) - m_offset, bytes, alignment);
         }
 
 
         decltype(auto)
-        deallocate (u08 *ptr, std::size_t bytes)
+        deallocate (void *ptr, std::size_t bytes)
         {
-            return m_successor.deallocate (ptr - m_offset, bytes, m_alignment);
+            return m_successor.deallocate (reinterpret_cast<u08*> (ptr) - m_offset, bytes, m_alignment);
         }