diff --git a/noir-projects/aztec-nr/aztec/src/macros/dispatch.nr b/noir-projects/aztec-nr/aztec/src/macros/dispatch.nr
index c74441902c31..dae4af550228 100644
--- a/noir-projects/aztec-nr/aztec/src/macros/dispatch.nr
+++ b/noir-projects/aztec-nr/aztec/src/macros/dispatch.nr
@@ -35,7 +35,7 @@ pub comptime fn generate_public_dispatch(m: Module) -> Quoted {
             }
         };
 
-        let parameter_index = &mut 0;
+        let parameter_index: &mut u32 = &mut 0;
         let reads = parameters.map(|param: (Quoted, Type)| {
             let parameter_index_value = *parameter_index;
             let param_name = f"arg{parameter_index_value}".quoted_contents();