diff --git a/src/liballoc_jemalloc/lib.rs b/src/liballoc_jemalloc/lib.rs
index a1401e65f38..c10af35a94b 100644
--- a/src/liballoc_jemalloc/lib.rs
+++ b/src/liballoc_jemalloc/lib.rs
@@ -228,7 +228,7 @@ mod contents {
         }
 
         let flags = align_to_flags(new_align);
-        let ptr = rallocx(ptr as *mut c_void, new_size, flags) as usize;
+        let ptr = rallocx(ptr as *mut c_void, new_size, flags) as *mut u8;
         let alloc_size = sallocx(ptr as *mut c_void, flags);
         if ptr.is_null() {
             let layout = Layout::from_size_align_unchecked(new_size, new_align);