diff --git a/crates/js-sys/tests/wasm/RangeError.rs b/crates/js-sys/tests/wasm/RangeError.rs
index c3470d26318..18c7d7d071e 100644
--- a/crates/js-sys/tests/wasm/RangeError.rs
+++ b/crates/js-sys/tests/wasm/RangeError.rs
@@ -8,6 +8,7 @@ fn range_error() {
     let error = RangeError::new("out of range yo");
     assert!(error.is_instance_of::<RangeError>());
     assert!(error.is_instance_of::<Error>());
+    assert!(error.is_instance_of::<Object>());
 
     let base: &Error = error.as_ref();
     assert_eq!(JsValue::from(base.message()), "out of range yo");
diff --git a/crates/js-sys/tests/wasm/ReferenceError.rs b/crates/js-sys/tests/wasm/ReferenceError.rs
index 22e2518c2e8..218ad52ec9b 100644
--- a/crates/js-sys/tests/wasm/ReferenceError.rs
+++ b/crates/js-sys/tests/wasm/ReferenceError.rs
@@ -8,6 +8,7 @@ fn reference_error() {
     let error = ReferenceError::new("bad reference, fool");
     assert!(error.is_instance_of::<ReferenceError>());
     assert!(error.is_instance_of::<Error>());
+    assert!(error.is_instance_of::<Object>());
 
     let base: &Error = error.as_ref();
     assert_eq!(JsValue::from(base.message()), "bad reference, fool");
diff --git a/crates/js-sys/tests/wasm/SyntaxError.rs b/crates/js-sys/tests/wasm/SyntaxError.rs
index 57d863711d1..23a211f0416 100644
--- a/crates/js-sys/tests/wasm/SyntaxError.rs
+++ b/crates/js-sys/tests/wasm/SyntaxError.rs
@@ -8,6 +8,7 @@ fn syntax_error() {
     let error = SyntaxError::new("msg");
     assert!(error.is_instance_of::<SyntaxError>());
     assert!(error.is_instance_of::<Error>());
+    assert!(error.is_instance_of::<Object>());
 
     let base: &Error = error.as_ref();
     assert_eq!(JsValue::from(base.message()), "msg");
diff --git a/crates/js-sys/tests/wasm/TypeError.rs b/crates/js-sys/tests/wasm/TypeError.rs
index e82cf091835..ef7b09fbb98 100644
--- a/crates/js-sys/tests/wasm/TypeError.rs
+++ b/crates/js-sys/tests/wasm/TypeError.rs
@@ -8,6 +8,7 @@ fn type_error() {
     let error = TypeError::new("msg");
     assert!(error.is_instance_of::<TypeError>());
     assert!(error.is_instance_of::<Error>());
+    assert!(error.is_instance_of::<Object>());
 
     let base: &Error = error.as_ref();
     assert_eq!(JsValue::from(base.message()), "msg");
diff --git a/crates/js-sys/tests/wasm/UriError.rs b/crates/js-sys/tests/wasm/UriError.rs
index 86ff417ee1d..ddcafc4957f 100644
--- a/crates/js-sys/tests/wasm/UriError.rs
+++ b/crates/js-sys/tests/wasm/UriError.rs
@@ -8,6 +8,7 @@ fn uri_error() {
     let error = UriError::new("msg");
     assert!(error.is_instance_of::<UriError>());
     assert!(error.is_instance_of::<Error>());
+    assert!(error.is_instance_of::<Object>());
 
     let base: &Error = error.as_ref();
     assert_eq!(JsValue::from(base.message()), "msg");