diff --git a/compiler/lowerer.ts b/compiler/lowerer.ts
index 23e58a0..e939fde 100644
--- a/compiler/lowerer.ts
+++ b/compiler/lowerer.ts
@@ -116,6 +116,30 @@ export class Lowerer {
         this.program.add(Ops.Jump, this.breakStack.at(-1)!);
     }
 
+    private lowerBuiltinAnno(annoArgs: Expr[]) {
+        if (annoArgs.length !== 1) {
+            throw new Error("invalid # of arguments to builtin annotation");
+        }
+        const anno = annoArgs[0];
+        if (anno.kind.type !== "ident") {
+            throw new Error(
+                `unexpected argument type '${anno.kind.type}' expected 'ident'`,
+            );
+        }
+        const value = anno.kind.value;
+        switch (value) {
+            case "print": {
+                this.program.add(Ops.Builtin, Builtins.Print);
+                break;
+            }
+            default: {
+                throw new Error(
+                    `unrecognized builtin '${value}'`,
+                );
+            }
+        }
+    }
+
     private lowerFnStmt(stmt: Stmt) {
         if (stmt.kind.type !== "fn") {
             throw new Error();
@@ -135,24 +159,7 @@ export class Lowerer {
             this.locals.allocSym(ident);
         }
         if (stmt.kind.anno?.ident === "builtin") {
-            const anno = stmt.kind.anno.values[0];
-            if (!anno) {
-                throw new Error("builtin annotation without ident");
-            }
-            if (anno.kind.type !== "ident") {
-                throw new Error("builtin annotation without ident");
-            }
-            const value = anno.kind.value;
-            switch (value) {
-                case "print": {
-                    this.program.add(Ops.LoadLocal, 0);
-                    this.program.add(Ops.Builtin, Builtins.Print);
-                    break;
-                }
-                default: {
-                    throw new Error("unrecognized builtin");
-                }
-            }
+            this.lowerBuiltinAnno(stmt.kind.anno.values);
         } else {
             this.lowerExpr(stmt.kind.body);
         }