diff --git a/examples/rust/custom-heap/src/entrypoint.rs b/examples/rust/custom-heap/src/entrypoint.rs
index 4f7df1a97f2..911619f22df 100644
--- a/examples/rust/custom-heap/src/entrypoint.rs
+++ b/examples/rust/custom-heap/src/entrypoint.rs
@@ -17,9 +17,9 @@ struct BumpAllocator;
 unsafe impl std::alloc::GlobalAlloc for BumpAllocator {
     #[inline]
     unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        const POS_PTR: *mut usize = HEAP_START_ADDRESS as *mut usize;
-        const TOP_ADDRESS: usize = HEAP_START_ADDRESS + HEAP_LENGTH;
-        const BOTTOM_ADDRESS: usize = HEAP_START_ADDRESS + size_of::<*mut u8>();
+        const POS_PTR: *mut usize = HEAP_START_ADDRESS as usize as *mut usize;
+        const TOP_ADDRESS: usize = HEAP_START_ADDRESS as usize + HEAP_LENGTH;
+        const BOTTOM_ADDRESS: usize = HEAP_START_ADDRESS as usize + size_of::<*mut u8>();
 
         let mut pos = *POS_PTR;
         if pos == 0 {