diff --git a/.github/workflows/perf.yml b/.github/workflows/perf.yml
index f8a0c9a5..e549b693 100644
--- a/.github/workflows/perf.yml
+++ b/.github/workflows/perf.yml
@@ -5,8 +5,9 @@ on:
   push:
     branches:
       - master
+      - check-signals
   pull_request:
-    branches: [master]
+    branches: [master, check-signals]
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
diff --git a/src/signal-polyfill.ts b/src/signal-polyfill.ts
new file mode 100644
index 00000000..536867d8
--- /dev/null
+++ b/src/signal-polyfill.ts
@@ -0,0 +1,116 @@
+//gist.github.com/lifeart/b6fc9ec2e111a12bb78a0558ef5afa11
+
+// one of possible signals implementations
+
+let USED_SIGNALS: Set<$Signal> | null = null;
+let inUntrackCall = false;
+const RELATED_WATCHERS: WeakMap<Computed, Set<Watcher>> = new WeakMap();
+const COMPUTED_SIGNALS: WeakMap<$Signal, Set<Computed>> = new WeakMap();
+
+class $Signal {
+  value: any;
+  constructor(value: any) {
+    this.value = value;
+  }
+  get() {
+    USED_SIGNALS?.add(this);
+    return this.value;
+  }
+  set(value: any) {
+    this.value = value;
+    const Watchers: Set<Watcher> = new Set();
+    COMPUTED_SIGNALS.get(this)?.forEach((computed) => {
+      computed.isValid = false;
+      for (const watcher of RELATED_WATCHERS.get(computed)!) {
+        Watchers.add(watcher);
+      }
+    });
+    Watchers.forEach((watcher) => {
+      watcher.callback();
+    });
+  }
+}
+
+function untrack(fn = () => {}) {
+  inUntrackCall = true;
+  try {
+    fn();
+  } catch(e) {
+    // EOL
+  } finally {
+    inUntrackCall = false;
+  }
+};
+
+class Computed {
+  fn: Function;
+  isValid = false;
+  result: any;
+  constructor(fn = () => {}) {
+    this.fn = fn;
+  }
+  get() {
+    if (this.isValid) {
+      return this.result;
+    }
+    const oldSignals = USED_SIGNALS;
+    USED_SIGNALS = inUntrackCall ? USED_SIGNALS : new Set();
+    try {
+      this.result = this.fn();
+      this.isValid = true;
+      return this.result;
+    } finally {
+      if (!inUntrackCall) {
+        USED_SIGNALS?.forEach((signal) => {
+          if (!COMPUTED_SIGNALS.has(signal)) {
+            COMPUTED_SIGNALS.set(signal, new Set());
+          }
+          COMPUTED_SIGNALS.get(signal)!.add(this);
+        });
+        USED_SIGNALS = oldSignals;
+      }
+    }
+  }
+}
+class Watcher {
+  constructor(callback: Function) {
+    this.callback = callback;
+  }
+  watched: Set<Computed> = new Set();
+  callback: Function;
+  isWatching = true;
+  watch(computed?: Computed) {
+    if (!computed) {
+      this.isWatching = true;
+      return;
+    }
+    if (!RELATED_WATCHERS.has(computed)) {
+      RELATED_WATCHERS.set(computed, new Set());
+    }
+    RELATED_WATCHERS.get(computed)!.add(this);
+    this.watched.add(computed);
+  }
+  unwatch(computed: Computed) {
+    this.watched.delete(computed);
+    RELATED_WATCHERS.get(computed)!.delete(this);
+  }
+  getPending() {
+    if (!this.isWatching) {
+      return [];
+    }
+    try {
+      return Array.from(this.watched).filter((computed) => !computed.isValid);
+    } finally {
+      this.isWatching = false;
+    }
+  }
+}
+
+export const Signal = {
+  State: $Signal,
+  Computed,
+  untrack,
+  subtle: {
+    Watcher,
+  },
+};
diff --git a/src/utils/dom.ts b/src/utils/dom.ts
index 2661636d..d745de4c 100644
--- a/src/utils/dom.ts
+++ b/src/utils/dom.ts
@@ -517,7 +517,6 @@ export function $_inElement(
       } else if (isTagLike(elementRef)) {
         appendRef = elementRef.value;
       } else {
-        // @ts-expect-error
         appendRef = elementRef;
       }
       const destructors: Destructors = [];
diff --git a/src/utils/glimmer-validator.ts b/src/utils/glimmer-validator.ts
index e1c64b14..ac1f6a02 100644
--- a/src/utils/glimmer-validator.ts
+++ b/src/utils/glimmer-validator.ts
@@ -41,7 +41,6 @@ export function trackedData<T extends object, K extends keyof T>(
   let hasInitializer = typeof initializer === 'function';
 
   function getter(self: T) {
-    // @ts-expect-error
     consumeTag(cellFor(self, key));
 
     let value;
diff --git a/src/utils/if.ts b/src/utils/if.ts
index ab38b0d0..1c7a07af 100644
--- a/src/utils/if.ts
+++ b/src/utils/if.ts
@@ -83,7 +83,6 @@ export function ifCondition(
       }
     },
     runExistingDestructors,
-    // @ts-expect-error
     opcodeFor(cell, (value) => {
       if (throwedError) {
         Promise.resolve().then(() => {
diff --git a/src/utils/list.ts b/src/utils/list.ts
index 04847e8e..6934c41e 100644
--- a/src/utils/list.ts
+++ b/src/utils/list.ts
@@ -110,7 +110,6 @@ export class BasicListComponent<T extends { id: number }> {
     if (!isTagLike(tag)) {
       if (isArray(tag)) {
         console.warn('iterator for @each should be a cell');
-        // @ts-expect-error
         tag = new Cell(tag, 'list tag');
       } else if (isFn(originalTag)) {
         tag = formula(() => deepFnValue(originalTag), 'list tag');
@@ -298,7 +297,6 @@ export class SyncListComponent<
   constructor(params: ListComponentArgs<T>, outlet: RenderTarget) {
     super(params, outlet);
     associateDestroyable(params.ctx, [
-      // @ts-expect-error
       opcodeFor(this.tag, (value) => {
         this.syncList(value as T[]);
       }),
@@ -333,7 +331,6 @@ export class AsyncListComponent<
   constructor(params: ListComponentArgs<any>, outlet: RenderTarget) {
     super(params, outlet);
     associateDestroyable(params.ctx, [
-      // @ts-expect-error
       opcodeFor(this.tag, async (value) => {
         await this.syncList(value as T[]);
       }),
diff --git a/src/utils/reactive.ts b/src/utils/reactive.ts
index 13c7e8c8..0e9d243c 100644
--- a/src/utils/reactive.ts
+++ b/src/utils/reactive.ts
@@ -4,7 +4,7 @@
   We explicitly update DOM only when it's needed and only if tags are changed.
 */
 import { isFn, isTag, isTagLike, debugContext } from '@/utils/shared';
-import { Signal } from "signal-polyfill";
+import { Signal } from "../signal-polyfill";
 
 
 export const asyncOpcodes = new WeakSet<tagOp>();
@@ -104,7 +104,7 @@ export function setIsRendering(value: boolean) {
 
 // "data" cell, it's value can be updated, and it's used to create derived cells
 export class Cell<T extends unknown = unknown> {
-  _value!: Signal.State<T>;
+  _value!: any;
   declare toHTML: () => string;
   [Symbol.toPrimitive]() {
     return this.value;
@@ -115,7 +115,6 @@ export class Cell<T extends unknown = unknown> {
     this._value = new Signal.State(value);
     if (IS_DEV_MODE) {
       this._debugName = debugContext(debugName);
-      // @ts-expect-error
       DEBUG_CELLS.add(this);
     }
   }
@@ -202,7 +201,6 @@ export function cellFor<T extends object, K extends keyof T>(
     obj[key],
     `${obj.constructor.name}.${String(key)}`,
   );
-  // @ts-expect-error
   refs.set(key, cellValue);
   cellsMap.set(obj, refs);
   Object.defineProperty(obj, key, {
diff --git a/src/utils/signals.ts b/src/utils/signals.ts
index 013a14da..64a89e33 100644
--- a/src/utils/signals.ts
+++ b/src/utils/signals.ts
@@ -1,4 +1,4 @@
-import { Signal } from "signal-polyfill";
+import { Signal } from "../signal-polyfill";
 import { isRehydrationScheduled } from "./rehydration";
 import { setIsRendering } from "./reactive";
 
diff --git a/src/utils/vm.ts b/src/utils/vm.ts
index a5d391ce..29703408 100644
--- a/src/utils/vm.ts
+++ b/src/utils/vm.ts
@@ -8,7 +8,7 @@ import {
   inNewTrackingFrame,
 } from './reactive';
 import { isFn } from './shared';
-import { Signal } from "signal-polyfill";
+import { Signal } from "../signal-polyfill";
 
 import { w } from './signals';
 type maybeDestructor = undefined | (() => void);