diff --git a/docs/no-react-deps.md b/docs/no-react-deps.md
index 9119d21..108e254 100644
--- a/docs/no-react-deps.md
+++ b/docs/no-react-deps.md
@@ -80,6 +80,11 @@ createEffect((prev) => {
   return (prev || 0) + 1;
 });
 
+createEffect((prev) => {
+  console.log(signal());
+  return prev ? prev + 1 : 1;
+}, undefined);
+
 const value = createMemo(() => computeExpensiveValue(a(), b()));
 
 const sum = createMemo((prev) => input() + prev, 0);
diff --git a/docs/reactivity.md b/docs/reactivity.md
index 4c56be9..07c6296 100644
--- a/docs/reactivity.md
+++ b/docs/reactivity.md
@@ -537,6 +537,11 @@ createEffect(() => {
   runWithOwner(owner, () => console.log(signal()));
 });
 
+const [signal] = createSignal();
+createEffect(() => {
+  runWithOwner(undefined, () => console.log(signal()));
+});
+
 const [signal] = createSignal();
 createEffect(() => {
   [1, 2].forEach(() => console.log(signal()));
diff --git a/src/utils.ts b/src/utils.ts
index 2983ae3..bb3e0f8 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -50,7 +50,9 @@ export function trace(node: T.Node, initialScope: TSESLint.Scope.Scope): T.Node
     if (!variable) return node;
 
     const def = variable.defs[0];
-    switch (def.type) {
+
+    // def is `undefined` for Identifier `undefined`
+    switch (def?.type) {
       case "FunctionName":
       case "ClassName":
       case "ImportBinding":
diff --git a/test/rules/no-react-deps.test.ts b/test/rules/no-react-deps.test.ts
index 300acd8..605de48 100644
--- a/test/rules/no-react-deps.test.ts
+++ b/test/rules/no-react-deps.test.ts
@@ -14,6 +14,10 @@ export const cases = run("no-react-deps", rule, {
       console.log(signal());
       return (prev || 0) + 1;
     });`,
+    `createEffect((prev) => {
+      console.log(signal());
+      return prev ? prev + 1 : 1;
+    }, undefined);`,
     `const value = createMemo(() => computeExpensiveValue(a(), b()));`,
     `const sum = createMemo((prev) => input() + prev, 0);`,
     `const args = [() => { console.log(signal()); }, [signal()]];
diff --git a/test/rules/reactivity.test.ts b/test/rules/reactivity.test.ts
index 23c24e3..f315828 100644
--- a/test/rules/reactivity.test.ts
+++ b/test/rules/reactivity.test.ts
@@ -95,6 +95,10 @@ export const cases = run("reactivity", rule, {
       const owner = getOwner();
       runWithOwner(owner, () => console.log(signal()));
     });`,
+    `const [signal] = createSignal();
+    createEffect(() => {
+      runWithOwner(undefined, () => console.log(signal()));
+    });`,
     // Sync callbacks
     `const [signal] = createSignal();
     createEffect(() => {