diff --git a/src/front/check2.ts b/src/front/check2.ts
new file mode 100644
index 0000000..77c384a
--- /dev/null
+++ b/src/front/check2.ts
@@ -0,0 +1,32 @@
+import { Syms } from "./resolve.ts";
+import * as ast from "../ast.ts";
+import { Ty } from "../ty.ts";
+
+export function checkFn(fn: ast.FnStmt, syms: Syms) {
+}
+
+export class FnTys {
+    constructor(
+        private nodeTys: Map<ast.Node, Ty>,
+    ) {}
+
+    get(node: ast.Node): Ty {
+        const ty = this.nodeTys.get(node);
+        if (ty === undefined) {
+            throw new Error(`no type for '${node.kind.tag}'`);
+        }
+        return ty;
+    }
+}
+
+class FnChecker {
+    private nodeTys = new Map<ast.Node, Ty>();
+
+    constructor(
+        private fn: ast.FnStmt,
+        private syms: Syms,
+    ) {}
+
+    check() {
+    }
+}
diff --git a/src/front/mod.ts b/src/front/mod.ts
index 84a7d34..25c8a8a 100644
--- a/src/front/mod.ts
+++ b/src/front/mod.ts
@@ -1,3 +1,4 @@
 export * from "./parse.ts";
 export * from "./resolve.ts";
 export * from "./check.ts";
+export * from "./check2.ts";