diff --git a/nac3core/src/codegen/model/ptr.rs b/nac3core/src/codegen/model/ptr.rs
index 740696de..10c0a97c 100644
--- a/nac3core/src/codegen/model/ptr.rs
+++ b/nac3core/src/codegen/model/ptr.rs
@@ -204,8 +204,8 @@ impl<'ctx, Item: Model<'ctx>> Instance<'ctx, Ptr<Item>> {
     ) {
         // Force extend `num_items` and `itemsize` to `i64` so their types would match.
         let itemsize = self.model.size_of(generator, ctx.ctx);
-        let itemsize = Int(Int64).z_extend_or_truncate(generator, ctx, itemsize);
-        let num_items = Int(Int64).z_extend_or_truncate(generator, ctx, num_items);
+        let itemsize = Int(SizeT).z_extend_or_truncate(generator, ctx, itemsize);
+        let num_items = Int(SizeT).z_extend_or_truncate(generator, ctx, num_items);
         let totalsize = itemsize.mul(ctx, num_items);
 
         let is_volatile = ctx.ctx.bool_type().const_zero(); // is_volatile = false