use load_literal

compiler/gen_dev/src/lib.rs

@@ -491,9 +491,11 @@ where
                 debug_assert_eq!(
                     Layout::Builtin(Builtin::Bool),
                     *ret_layout,
-                    "NumIsZero: expected to have return layout of type I1"
+                    "NumIsZero: expected to have return layout of type Bool"
                 );
-                self.build_num_is_zero(sym, &args[0], &arg_layouts[0])
+
+                self.load_literal(&Symbol::DEV_TMP, &Literal::Int(0))?;
+                self.build_eq(sym, &args[0], &Symbol::DEV_TMP, &arg_layouts[0])
             }
             _ => Err(format!(
                 "the function, {:?}, is not yet implemented",

compiler/module/src/symbol.rs

@@ -880,6 +880,9 @@ define_builtins! {
 
         // the _ used in mono when a specialized symbol is deleted
         25 REMOVED_SPECIALIZATION: "#removed_specialization"
+
+        // used in dev backend
+        26 DEV_TMP: "#dev_tmp"
     }
     1 NUM: "Num" => {
         0 NUM_NUM: "Num" imported // the Num.Num type alias