diff --git a/pkg/compiler/lib/src/dart2js.dart b/pkg/compiler/lib/src/dart2js.dart
index 5eeb420..98f2f79 100644
--- a/pkg/compiler/lib/src/dart2js.dart
+++ b/pkg/compiler/lib/src/dart2js.dart
@@ -447,7 +447,7 @@
     new OptionHandler(Flags.enableNativeNullAssertions, passThrough),
     new OptionHandler(Flags.trustTypeAnnotations, setTrustTypeAnnotations),
     new OptionHandler(Flags.trustPrimitives, passThrough),
-    new OptionHandler(Flags.trustJSInteropTypeAnnotations, passThrough),
+    new OptionHandler(Flags.trustJSInteropTypeAnnotations, ignoreOption),
     new OptionHandler(r'--help|/\?|/h', (_) => wantHelp = true),
     new OptionHandler('--packages=.+', setPackageConfig),
     new OptionHandler(Flags.noSourceMaps, passThrough),
diff --git a/pkg/compiler/lib/src/kernel/element_map_impl.dart b/pkg/compiler/lib/src/kernel/element_map_impl.dart
index a574666..ab22c77 100644
--- a/pkg/compiler/lib/src/kernel/element_map_impl.dart
+++ b/pkg/compiler/lib/src/kernel/element_map_impl.dart
@@ -1939,10 +1939,6 @@
 
   KernelBehaviorBuilder(this.elementEnvironment, this.commonElements,
       this.nativeBasicData, this.reporter, this.options);
-
-  @override
-  bool get trustJSInteropTypeAnnotations =>
-      options.trustJSInteropTypeAnnotations;
 }
 
 class KernelNativeMemberResolver implements NativeMemberResolver {
diff --git a/pkg/compiler/lib/src/native/behavior.dart b/pkg/compiler/lib/src/native/behavior.dart
index a01fac5..0457090 100644
--- a/pkg/compiler/lib/src/native/behavior.dart
+++ b/pkg/compiler/lib/src/native/behavior.dart
@@ -736,7 +736,6 @@
   CommonElements get commonElements;
   DiagnosticReporter get reporter;
   NativeBasicData get nativeBasicData;
-  bool get trustJSInteropTypeAnnotations;
   ElementEnvironment get elementEnvironment;
   CompilerOptions get options;
   DartTypes get dartTypes => commonElements.dartTypes;
@@ -817,21 +816,13 @@
           _behavior.typesInstantiated.add(type);
         }
 
-        if (!trustJSInteropTypeAnnotations || dartTypes.isTopType(type)) {
-          // By saying that only JS-interop types can be created, we prevent
-          // pulling in every other native type (e.g. all of dart:html) when a
-          // JS interop API returns dynamic or when we don't trust the type
-          // annotations. This means that to some degree we still use the return
-          // type to decide whether to include native types, even if we don't
-          // trust the type annotation.
-          ClassEntity cls = commonElements.jsJavaScriptObjectClass;
-          _behavior.typesInstantiated.add(elementEnvironment.getThisType(cls));
-        } else {
-          // Otherwise, when the declared type is a Dart type, we do not
-          // register an allocation because we assume it cannot be instantiated
-          // from within the JS-interop code. It must have escaped from another
-          // API.
-        }
+        // By saying that only JS-interop types can be created, we prevent
+        // pulling in every other native type (e.g. all of dart:html) when a
+        // JS interop API returns dynamic.  This means that to some degree we
+        // still use the return type to decide whether to include native types,
+        // even though we don't trust the type annotation.
+        ClassEntity cls = commonElements.jsJavaScriptObjectClass;
+        _behavior.typesInstantiated.add(elementEnvironment.getThisType(cls));
       }
     }
   }
@@ -868,9 +859,7 @@
       {bool isJsInterop}) {
     _behavior = new NativeBehavior();
     // TODO(sigmund,sra): consider doing something better for numeric types.
-    _addReturnType(!isJsInterop || trustJSInteropTypeAnnotations
-        ? type
-        : commonElements.dynamicType);
+    _addReturnType(!isJsInterop ? type : commonElements.dynamicType);
     _capture(type, isJsInterop);
     _overrideWithAnnotations(
         createsAnnotations, returnsAnnotations, lookupType);
@@ -898,15 +887,12 @@
     // Note: For dart:html and other internal libraries we maintain, we can
     // trust the return type and use it to limit what we enqueue. We have to
     // be more conservative about JS interop types and assume they can return
-    // anything (unless the user provides the experimental flag to trust the
-    // type of js-interop APIs). We do restrict the allocation effects and say
-    // that interop calls create only interop types (which may be unsound if
-    // an interop call returns a DOM type and declares a dynamic return type,
-    // but otherwise we would include a lot of code by default).
+    // anything. We do restrict the allocation effects and say that interop
+    // calls create only interop types (which may be unsound if an interop call
+    // returns a DOM type and declares a dynamic return type, but otherwise we
+    // would include a lot of code by default).
     // TODO(sigmund,sra): consider doing something better for numeric types.
-    _addReturnType(!isJsInterop || trustJSInteropTypeAnnotations
-        ? returnType
-        : commonElements.dynamicType);
+    _addReturnType(!isJsInterop ? returnType : commonElements.dynamicType);
     _capture(type, isJsInterop);
 
     for (DartType type in type.optionalParameterTypes) {
diff --git a/pkg/compiler/lib/src/options.dart b/pkg/compiler/lib/src/options.dart
index f9d0f30..f8c7901 100644
--- a/pkg/compiler/lib/src/options.dart
+++ b/pkg/compiler/lib/src/options.dart
@@ -281,9 +281,6 @@
   /// The compiler is run from the build bot.
   bool testMode = false;
 
-  /// Whether to trust JS-interop annotations. (experimental)
-  bool trustJSInteropTypeAnnotations = false;
-
   /// Whether to trust primitive types during inference and optimizations.
   bool trustPrimitives = false;
 
@@ -506,8 +503,6 @@
       .._legacyJavaScript = _hasOption(options, Flags.legacyJavaScript)
       .._noLegacyJavaScript = _hasOption(options, Flags.noLegacyJavaScript)
       ..testMode = _hasOption(options, Flags.testMode)
-      ..trustJSInteropTypeAnnotations =
-          _hasOption(options, Flags.trustJSInteropTypeAnnotations)
       ..trustPrimitives = _hasOption(options, Flags.trustPrimitives)
       ..useContentSecurityPolicy =
           _hasOption(options, Flags.useContentSecurityPolicy)
diff --git a/pkg/compiler/lib/src/ssa/builder_kernel.dart b/pkg/compiler/lib/src/ssa/builder_kernel.dart
index e093833..b3b3e6f 100644
--- a/pkg/compiler/lib/src/ssa/builder_kernel.dart
+++ b/pkg/compiler/lib/src/ssa/builder_kernel.dart
@@ -4967,11 +4967,6 @@
           new js.Template(null, js.objectLiteral(parameterNameMap));
 
       var nativeBehavior = new NativeBehavior()..codeTemplate = codeTemplate;
-      if (options.trustJSInteropTypeAnnotations) {
-        InterfaceType thisType =
-            _elementEnvironment.getThisType(constructor.enclosingClass);
-        nativeBehavior.typesReturned.add(thisType);
-      }
       registry.registerNativeMethod(element);
       // TODO(efortuna): Source information.
       return new HForeignCode(
@@ -4991,10 +4986,9 @@
         ? _elementEnvironment.getThisType(element.enclosingClass)
         : _elementEnvironment.getFunctionType(element).returnType;
     // Native behavior effects here are similar to native/behavior.dart.
-    // The return type is dynamic if we don't trust js-interop type
+    // The return type is dynamic because we don't trust js-interop type
     // declarations.
-    nativeBehavior.typesReturned.add(
-        options.trustJSInteropTypeAnnotations ? type : dartTypes.dynamicType());
+    nativeBehavior.typesReturned.add(dartTypes.dynamicType());
 
     // The allocation effects include the declared type if it is native (which
     // includes js interop types).
@@ -5003,14 +4997,13 @@
       nativeBehavior.typesInstantiated.add(type);
     }
 
-    // It also includes any other JS interop type if we don't trust the
-    // annotation or if is declared too broad.
-    if (!options.trustJSInteropTypeAnnotations ||
-        type == _commonElements.objectType ||
-        type is DynamicType) {
-      nativeBehavior.typesInstantiated.add(_elementEnvironment
-          .getThisType(_commonElements.jsJavaScriptObjectClass));
-    }
+    // It also includes any other JS interop type. Technically, a JS interop API
+    // could return anything, so the sound thing to do would be to assume that
+    // anything that may come from JS as instantiated. In order to prevent the
+    // resulting code bloat (e.g. from `dart:html`), we unsoundly assume that
+    // only JS interop types are returned.
+    nativeBehavior.typesInstantiated.add(_elementEnvironment
+        .getThisType(_commonElements.jsJavaScriptObjectClass));
 
     AbstractValue instructionType =
         _typeInferenceMap.typeFromNativeBehavior(nativeBehavior, closedWorld);
diff --git a/pkg/compiler/test/helpers/compiler_helper.dart b/pkg/compiler/test/helpers/compiler_helper.dart
index 562741f..eb7046a 100644
--- a/pkg/compiler/test/helpers/compiler_helper.dart
+++ b/pkg/compiler/test/helpers/compiler_helper.dart
@@ -37,7 +37,6 @@
     bool enableTypeAssertions: false,
     bool minify: false,
     bool disableInlining: true,
-    bool trustJSInteropTypeAnnotations: false,
     bool disableTypeInference: true,
     bool omitImplicitChecks: true,
     bool enableVariance: false,
@@ -58,9 +57,6 @@
   if (minify) {
     options.add(Flags.minify);
   }
-  if (trustJSInteropTypeAnnotations) {
-    options.add(Flags.trustJSInteropTypeAnnotations);
-  }
   if (disableInlining) {
     options.add(Flags.disableInlining);
   }
diff --git a/pkg/compiler/test/jsinterop/interop_anonymous_unreachable_test.dart b/pkg/compiler/test/jsinterop/interop_anonymous_unreachable_test.dart
index ded9c90..2e4e586 100644
--- a/pkg/compiler/test/jsinterop/interop_anonymous_unreachable_test.dart
+++ b/pkg/compiler/test/jsinterop/interop_anonymous_unreachable_test.dart
@@ -80,16 +80,6 @@
   Expect.isTrue(generated1.contains("UniqueLongNameForTesting_B"));
   Expect.isTrue(generated1.contains("UniqueLongNameForTesting_C"));
   Expect.isTrue(generated1.contains("UniqueLongNameForTesting_E"));
-
-  print(' - tree-shake when using flag -');
-  String generated2 = await compile(program,
-      trustJSInteropTypeAnnotations: true, returnAll: true);
-  Expect.isTrue(generated2.contains("UniqueLongNameForTesting_A"));
-  Expect.isTrue(generated2.contains("UniqueLongNameForTesting_D"));
-
-  Expect.isFalse(generated2.contains("UniqueLongNameForTesting_B"));
-  Expect.isFalse(generated2.contains("UniqueLongNameForTesting_C"));
-  Expect.isFalse(generated2.contains("UniqueLongNameForTesting_E"));
 }
 
 testTreeShakingNativeTypes() async {
@@ -122,14 +112,6 @@
   // but we exclude other native types like HTMLAudioElement
   Expect.isFalse(generated1.contains("HTMLAudioElement"));
 
-  print(' - allocation effect of dynamic excludes native types [flag] -');
-  // Trusting types doesn't make a difference.
-  String generated2 = await compile(program,
-      trustJSInteropTypeAnnotations: true, returnAll: true);
-  Expect.isTrue(generated2.contains("UniqueLongNameForTesting_A"));
-  Expect.isTrue(generated2.contains("UniqueLongNameForTesting_B"));
-  Expect.isFalse(generated2.contains("HTMLAudioElement"));
-
   print(' - declared native types are included in allocation effect -');
   String program2 = """
         import 'dart:html';
diff --git a/tests/lib/html/js_typed_interop_anonymous2_exp_test.dart b/tests/lib/html/js_typed_interop_anonymous2_exp_test.dart
deleted file mode 100644
index 2c827b8..0000000
--- a/tests/lib/html/js_typed_interop_anonymous2_exp_test.dart
+++ /dev/null
@@ -1,54 +0,0 @@
-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// SharedOptions=--experimental-trust-js-interop-type-annotations
-
-// Same test as js_typed_interop_anonymous2, but using the
-// --experimental-trust-js-interop-type-annotations flag.
-@JS()
-library js_typed_interop_anonymous2_exp_test;
-
-import 'dart:html';
-import 'dart:js' as js;
-
-import 'package:js/js.dart';
-import 'package:expect/minitest.dart';
-
-@JS()
-@anonymous
-class A {
-  external factory A({B? b});
-
-  external B? get b;
-}
-
-@JS()
-@anonymous
-class B {
-  external factory B({C? c});
-
-  external C? get c;
-}
-
-@JS()
-@anonymous
-class C {
-  external factory C();
-}
-
-// D is unreachable, and that is OK
-@JS()
-@anonymous
-class D {
-  external factory D();
-}
-
-main() {
-  test('simple', () {
-    var b = new B();
-    var a = new A(b: b);
-    expect(a.b, equals(b));
-    expect(b.c, isNull);
-  });
-}
diff --git a/tests/lib/html/js_typed_interop_anonymous_exp_test.dart b/tests/lib/html/js_typed_interop_anonymous_exp_test.dart
deleted file mode 100644
index e160bdd..0000000
--- a/tests/lib/html/js_typed_interop_anonymous_exp_test.dart
+++ /dev/null
@@ -1,35 +0,0 @@
-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// SharedOptions=--experimental-trust-js-interop-type-annotations
-
-// Same test as js_typed_interop_anonymous, but using the
-// --experimental-trust-js-interop-type-annotations flag.
-@JS()
-library js_typed_interop_anonymous_exp_test;
-
-import 'dart:html';
-import 'dart:js' as js;
-
-import 'package:js/js.dart';
-import 'package:expect/minitest.dart';
-
-@JS()
-@anonymous
-class Literal {
-  external factory Literal({int? x, String? y, num? z});
-
-  external int? get x;
-  external String? get y;
-  external num? get z;
-}
-
-main() {
-  test('simple', () {
-    var l = new Literal(x: 3, y: "foo");
-    expect(l.x, equals(3));
-    expect(l.y, equals("foo"));
-    expect(l.z, isNull);
-  });
-}
diff --git a/tests/lib/html/js_typed_interop_anonymous_unreachable_exp_test.dart b/tests/lib/html/js_typed_interop_anonymous_unreachable_exp_test.dart
deleted file mode 100644
index 046dcff..0000000
--- a/tests/lib/html/js_typed_interop_anonymous_unreachable_exp_test.dart
+++ /dev/null
@@ -1,34 +0,0 @@
-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// SharedOptions=--experimental-trust-js-interop-type-annotations
-
-// Same test as js_typed_interop_anonymous_unreachable, but using the
-// --experimental-trust-js-interop-type-annotations flag.
-@JS()
-library js_typed_interop_anonymous_unreachable_exp_test;
-
-import 'dart:html';
-import 'dart:js' as js;
-
-import 'package:js/js.dart';
-import 'package:expect/minitest.dart';
-
-@JS()
-@anonymous
-class Literal {
-  external factory Literal({required int x, required String y, required num z});
-
-  external int get x;
-  external String get y;
-  external num get z;
-}
-
-main() {
-  test('nothing to do', () {
-    // This test is empty, but it is a regression for Issue# 24974: dart2js
-    // would crash trying to compile code that used @anonymous and that was
-    // not reachable from main.
-  });
-}
diff --git a/tests/lib/html/js_typed_interop_side_cast_exp_test.dart b/tests/lib/html/js_typed_interop_side_cast_exp_test.dart
deleted file mode 100644
index be112c8..0000000
--- a/tests/lib/html/js_typed_interop_side_cast_exp_test.dart
+++ /dev/null
@@ -1,51 +0,0 @@
-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// SharedOptions=--experimental-trust-js-interop-type-annotations
-
-// Similar test to js_typed_interop_side_cast, but because we are using the
-// --experimental-trust-js-interop-type-annotations flag, we test a slightly
-// different behavior.
-@JS()
-library js_typed_interop_side_cast_exp_test;
-
-import 'package:js/js.dart';
-import 'package:expect/minitest.dart';
-
-@JS()
-@anonymous
-class A {
-  external int get x;
-  external factory A({required int x});
-}
-
-@JS()
-@anonymous
-class B {
-  external int get x;
-  external factory B({required int x});
-}
-
-@JS()
-@anonymous
-class C {
-  external int get x;
-  external factory C({required int x});
-}
-
-main() {
-  test('side-casts work for reachable types', () {
-    new C(x: 3); // make C reachable
-    dynamic a = new A(x: 3);
-    expect(a is C, isTrue);
-    C c = a;
-    expect(c.x, equals(3));
-  });
-
-  // Note: this test would fail without the experimental flag.
-  test('side-casts do not work for unreachable types', () {
-    dynamic a = new A(x: 3);
-    expect(a is B, isFalse); //# 01: ok
-  });
-}
diff --git a/tests/lib_2/html/js_typed_interop_anonymous2_exp_test.dart b/tests/lib_2/html/js_typed_interop_anonymous2_exp_test.dart
deleted file mode 100644
index ba4afc2..0000000
--- a/tests/lib_2/html/js_typed_interop_anonymous2_exp_test.dart
+++ /dev/null
@@ -1,54 +0,0 @@
-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-//
-// SharedOptions=--experimental-trust-js-interop-type-annotations
-
-// Same test as js_typed_interop_anonymous2, but using the
-// --experimental-trust-js-interop-type-annotations flag.
-@JS()
-library js_typed_interop_anonymous2_exp_test;
-
-import 'dart:html';
-import 'dart:js' as js;
-
-import 'package:js/js.dart';
-import 'package:expect/minitest.dart';
-
-@JS()
-@anonymous
-class A {
-  external factory A({B b});
-
-  external B get b;
-}
-
-@JS()
-@anonymous
-class B {
-  external factory B({C c});
-
-  external C get c;
-}
-
-@JS()
-@anonymous
-class C {
-  external factory C();
-}
-
-// D is unreachable, and that is OK
-@JS()
-@anonymous
-class D {
-  external factory D();
-}
-
-main() {
-  test('simple', () {
-    var b = new B();
-    var a = new A(b: b);
-    expect(a.b, equals(b));
-    expect(b.c, isNull);
-  });
-}
diff --git a/tests/lib_2/html/js_typed_interop_anonymous_exp_test.dart b/tests/lib_2/html/js_typed_interop_anonymous_exp_test.dart
deleted file mode 100644
index 362a41c..0000000
--- a/tests/lib_2/html/js_typed_interop_anonymous_exp_test.dart
+++ /dev/null
@@ -1,35 +0,0 @@
-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-//
-// SharedOptions=--experimental-trust-js-interop-type-annotations
-
-// Same test as js_typed_interop_anonymous, but using the
-// --experimental-trust-js-interop-type-annotations flag.
-@JS()
-library js_typed_interop_anonymous_exp_test;
-
-import 'dart:html';
-import 'dart:js' as js;
-
-import 'package:js/js.dart';
-import 'package:expect/minitest.dart';
-
-@JS()
-@anonymous
-class Literal {
-  external factory Literal({int x, String y, num z});
-
-  external int get x;
-  external String get y;
-  external num get z;
-}
-
-main() {
-  test('simple', () {
-    var l = new Literal(x: 3, y: "foo");
-    expect(l.x, equals(3));
-    expect(l.y, equals("foo"));
-    expect(l.z, isNull);
-  });
-}
diff --git a/tests/lib_2/html/js_typed_interop_anonymous_unreachable_exp_test.dart b/tests/lib_2/html/js_typed_interop_anonymous_unreachable_exp_test.dart
deleted file mode 100644
index 95c6141..0000000
--- a/tests/lib_2/html/js_typed_interop_anonymous_unreachable_exp_test.dart
+++ /dev/null
@@ -1,34 +0,0 @@
-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-//
-// SharedOptions=--experimental-trust-js-interop-type-annotations
-
-// Same test as js_typed_interop_anonymous_unreachable, but using the
-// --experimental-trust-js-interop-type-annotations flag.
-@JS()
-library js_typed_interop_anonymous_unreachable_exp_test;
-
-import 'dart:html';
-import 'dart:js' as js;
-
-import 'package:js/js.dart';
-import 'package:expect/minitest.dart';
-
-@JS()
-@anonymous
-class Literal {
-  external factory Literal({int x, String y, num z});
-
-  external int get x;
-  external String get y;
-  external num get z;
-}
-
-main() {
-  test('nothing to do', () {
-    // This test is empty, but it is a regression for Issue# 24974: dart2js
-    // would crash trying to compile code that used @anonymous and that was
-    // not reachable from main.
-  });
-}
diff --git a/tests/lib_2/html/js_typed_interop_side_cast_exp_test.dart b/tests/lib_2/html/js_typed_interop_side_cast_exp_test.dart
deleted file mode 100644
index a5061fb..0000000
--- a/tests/lib_2/html/js_typed_interop_side_cast_exp_test.dart
+++ /dev/null
@@ -1,51 +0,0 @@
-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-//
-// SharedOptions=--experimental-trust-js-interop-type-annotations
-
-// Similar test to js_typed_interop_side_cast, but because we are using the
-// --experimental-trust-js-interop-type-annotations flag, we test a slightly
-// different behavior.
-@JS()
-library js_typed_interop_side_cast_exp_test;
-
-import 'package:js/js.dart';
-import 'package:expect/minitest.dart';
-
-@JS()
-@anonymous
-class A {
-  external int get x;
-  external factory A({int x});
-}
-
-@JS()
-@anonymous
-class B {
-  external int get x;
-  external factory B({int x});
-}
-
-@JS()
-@anonymous
-class C {
-  external int get x;
-  external factory C({int x});
-}
-
-main() {
-  test('side-casts work for reachable types', () {
-    new C(x: 3); // make C reachable
-    dynamic a = new A(x: 3);
-    expect(a is C, isTrue);
-    C c = a;
-    expect(c.x, equals(3));
-  });
-
-  // Note: this test would fail without the experimental flag.
-  test('side-casts do not work for unreachable types', () {
-    dynamic a = new A(x: 3);
-    expect(a is B, isFalse); //# 01: ok
-  });
-}