diff --git a/sdk/lib/_internal/wasm/lib/bool.dart b/sdk/lib/_internal/wasm/lib/bool.dart
index 2aeab66110e..a949961f405 100644
--- a/sdk/lib/_internal/wasm/lib/bool.dart
+++ b/sdk/lib/_internal/wasm/lib/bool.dart
@@ -4,6 +4,18 @@
 
 part of "core_patch.dart";
 
+@patch
+class bool {
+  // Note: this needs to be in `bool`, cannot be overridden in `_BoxedBool`. I
+  // suspect the problem is there's an assumption in the front-end that `bool`
+  // has one implementation class (unlike `double`, `int`, `String`) which is
+  // the `bool` class itself. So when `runtimeType` is not overridden in
+  // `bool`, in code like `x.runtimeType` where `x` is `bool`, direct call
+  // metadata says that the member is `Object.runtimeType`.
+  @override
+  Type get runtimeType => bool;
+}
+
 @pragma("wasm:entry-point")
 class _BoxedBool extends bool {
   // A boxed bool contains an unboxed bool.