diff --git a/CHANGELOG.md b/CHANGELOG.md
index e867036a579..52323af9b24 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,15 @@
 
 ### Language
 
+Dart 3.4 makes improvements to the type analysis of conditional expressions
+(`e1 ? e2 : e3`), if-null expressions (`e1 ?? e2`), if-null assignments
+(`e1 ??= e2`), and switch expressions (`switch (e) { p1 => e1, ... }`). To take
+advantage of these improvements, set your package's
+[SDK constraint][language version] lower bound to 3.4 or greater
+(`sdk: '^3.4.0'`).
+
+[language version]: https://dart.dev/guides/language/evolution
+
 - **Breaking Change** [#54640][]: The pattern context type schema for
   cast patterns has been changed from `Object?` to `_` (the unknown
   type), to align with the specification. This change is not expected
diff --git a/pkg/_fe_analyzer_shared/lib/src/experiments/flags.dart b/pkg/_fe_analyzer_shared/lib/src/experiments/flags.dart
index 5d0a15b5ec7..b8e4d2786e7 100644
--- a/pkg/_fe_analyzer_shared/lib/src/experiments/flags.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/experiments/flags.dart
@@ -82,10 +82,10 @@ enum ExperimentalFlag {
 
   inferenceUpdate3(
       name: 'inference-update-3',
-      isEnabledByDefault: false,
+      isEnabledByDefault: true,
       isExpired: false,
-      experimentEnabledVersion: defaultLanguageVersion,
-      experimentReleasedVersion: defaultLanguageVersion),
+      experimentEnabledVersion: const Version(3, 4),
+      experimentReleasedVersion: const Version(3, 4)),
 
   inlineClass(
       name: 'inline-class',
diff --git a/pkg/analyzer/lib/src/dart/analysis/experiments.g.dart b/pkg/analyzer/lib/src/dart/analysis/experiments.g.dart
index e278e8438cb..223cf32d896 100644
--- a/pkg/analyzer/lib/src/dart/analysis/experiments.g.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/experiments.g.dart
@@ -250,7 +250,7 @@ class ExperimentalFeatures {
     documentation:
         'Better handling of conditional expressions, and switch expressions.',
     experimentalReleaseVersion: null,
-    releaseVersion: null,
+    releaseVersion: Version.parse('3.4.0'),
   );
 
   static final inline_class = ExperimentalFeature(
@@ -459,7 +459,7 @@ class IsEnabledByDefault {
   static const bool inference_update_2 = true;
 
   /// Default state of the experiment "inference-update-3"
-  static const bool inference_update_3 = false;
+  static const bool inference_update_3 = true;
 
   /// Default state of the experiment "inline-class"
   static const bool inline_class = true;
diff --git a/pkg/analyzer/test/src/dart/analysis/analysis_context_collection_test.dart b/pkg/analyzer/test/src/dart/analysis/analysis_context_collection_test.dart
index 9ab28dcaa14..520feec6675 100644
--- a/pkg/analyzer/test/src/dart/analysis/analysis_context_collection_test.dart
+++ b/pkg/analyzer/test/src/dart/analysis/analysis_context_collection_test.dart
@@ -342,6 +342,7 @@ analysisOptions
     generic-metadata
     inference-update-1
     inference-update-2
+    inference-update-3
     inline-class
     named-arguments-anywhere
     non-nullable
@@ -414,6 +415,7 @@ analysisOptions
     generic-metadata
     inference-update-1
     inference-update-2
+    inference-update-3
     inline-class
     named-arguments-anywhere
     non-nullable
diff --git a/pkg/analyzer/test/src/dart/resolution/assignment_test.dart b/pkg/analyzer/test/src/dart/resolution/assignment_test.dart
index 94372645bd4..fd920db079c 100644
--- a/pkg/analyzer/test/src/dart/resolution/assignment_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/assignment_test.dart
@@ -319,6 +319,7 @@ AssignmentExpression
 
   test_ifNull_lubUsedEvenIfItDoesNotSatisfyContext() async {
     await assertNoErrorsInCode('''
+// @dart=3.3
 f(Object? o1, Object? o2, List<num> listNum) {
   if (o1 is Iterable<int>? && o2 is Iterable<num>) {
     o2 = (o1 ??= listNum);
diff --git a/pkg/analyzer/test/src/dart/resolution/binary_expression_test.dart b/pkg/analyzer/test/src/dart/resolution/binary_expression_test.dart
index 7c8434101b0..4bd9e66590a 100644
--- a/pkg/analyzer/test/src/dart/resolution/binary_expression_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/binary_expression_test.dart
@@ -266,6 +266,7 @@ BinaryExpression
 
   test_ifNull_lubUsedEvenIfItDoesNotSatisfyContext() async {
     await assertNoErrorsInCode('''
+// @dart=3.3
 class A {}
 class B1 extends A {}
 class B2 extends A {}
diff --git a/pkg/analyzer/test/src/dart/resolution/conditional_expression_test.dart b/pkg/analyzer/test/src/dart/resolution/conditional_expression_test.dart
index 2162108397f..724b83d3493 100644
--- a/pkg/analyzer/test/src/dart/resolution/conditional_expression_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/conditional_expression_test.dart
@@ -107,6 +107,7 @@ ConditionalExpression
 
   test_ifNull_lubUsedEvenIfItDoesNotSatisfyContext() async {
     await assertNoErrorsInCode('''
+// @dart=3.3
 class A {}
 class B1 extends A {}
 class B2 extends A {}
diff --git a/pkg/analyzer/test/src/task/strong/inferred_type_test.dart b/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
index ca5cdbb2577..86fbcb1488f 100644
--- a/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
+++ b/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
@@ -1999,19 +1999,16 @@ void main() {
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           387,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 457, 38),
       error(
           CompileTimeErrorCode
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           519,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 540, 32),
       error(
           CompileTimeErrorCode
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           594,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 620, 32),
     ]);
     await disposeAnalysisContextCollection();
 
@@ -2031,19 +2028,16 @@ void main() {
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           389,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 459, 40),
       error(
           CompileTimeErrorCode
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           523,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 544, 34),
       error(
           CompileTimeErrorCode
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           600,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 626, 34),
     ]);
     await disposeAnalysisContextCollection();
 
@@ -2063,19 +2057,16 @@ void main() {
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           391,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 461, 38),
       error(
           CompileTimeErrorCode
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           525,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 546, 32),
       error(
           CompileTimeErrorCode
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           602,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 628, 32),
     ]);
     await disposeAnalysisContextCollection();
 
@@ -2098,22 +2089,16 @@ void main() {
                   .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
               393,
               1),
-          error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 463,
-              40),
           error(
               CompileTimeErrorCode
                   .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
               529,
               1),
-          error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 550,
-              34),
           error(
               CompileTimeErrorCode
                   .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
               608,
               1),
-          error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 634,
-              34),
         ]);
     await disposeAnalysisContextCollection();
 
@@ -2133,19 +2118,16 @@ void main() {
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           387,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 457, 40),
       error(
           CompileTimeErrorCode
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           521,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 542, 34),
       error(
           CompileTimeErrorCode
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           598,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 624, 34),
     ]);
     await disposeAnalysisContextCollection();
 
@@ -2165,19 +2147,16 @@ void main() {
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           385,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 455, 38),
       error(
           CompileTimeErrorCode
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           517,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 538, 32),
       error(
           CompileTimeErrorCode
               .NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE,
           592,
           1),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_CLOSURE, 618, 32),
     ]);
     await disposeAnalysisContextCollection();
   }
@@ -2364,8 +2343,6 @@ $downwards<int> g3(bool x) async {
           contextMessages: [message(dartAsyncFile, 506, 4)]),
       error(CompileTimeErrorCode.MISSING_DEFAULT_VALUE_FOR_PARAMETER, 223, 7),
       error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_METHOD, 236, 4),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_FUNCTION, 285, 29),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_FUNCTION, 352, 29),
       error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_FUNCTION, 464, 1),
     ]);
     await disposeAnalysisContextCollection();
@@ -2375,8 +2352,6 @@ $downwards<int> g3(bool x) async {
           contextMessages: [message(dartAsyncFile, 506, 4)]),
       error(CompileTimeErrorCode.MISSING_DEFAULT_VALUE_FOR_PARAMETER, 223, 7),
       error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_METHOD, 236, 4),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_FUNCTION, 285, 31),
-      error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_FUNCTION, 354, 31),
       error(CompileTimeErrorCode.RETURN_OF_INVALID_TYPE_FROM_FUNCTION, 470, 1),
     ]);
     await disposeAnalysisContextCollection();
diff --git a/pkg/front_end/lib/src/api_prototype/experimental_flags_generated.dart b/pkg/front_end/lib/src/api_prototype/experimental_flags_generated.dart
index 615fcd33327..02db7c1b7cb 100644
--- a/pkg/front_end/lib/src/api_prototype/experimental_flags_generated.dart
+++ b/pkg/front_end/lib/src/api_prototype/experimental_flags_generated.dart
@@ -141,11 +141,11 @@ class ExperimentalFlag {
 
   static const ExperimentalFlag inferenceUpdate3 = const ExperimentalFlag(
       name: 'inference-update-3',
-      isEnabledByDefault: false,
+      isEnabledByDefault: true,
       isExpired: false,
-      enabledVersion: defaultLanguageVersion,
-      experimentEnabledVersion: defaultLanguageVersion,
-      experimentReleasedVersion: defaultLanguageVersion);
+      enabledVersion: const Version(3, 4),
+      experimentEnabledVersion: const Version(3, 4),
+      experimentReleasedVersion: const Version(3, 4));
 
   static const ExperimentalFlag inlineClass = const ExperimentalFlag(
       name: 'inline-class',
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2.dart b/pkg/front_end/testcases/inference/future_then_conditional2.dart
index 82987f2b132..d1ac21533cf 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2.dart
+++ b/pkg/front_end/testcases/inference/future_then_conditional2.dart
@@ -24,7 +24,6 @@ void test(MyFuture<bool> f) {
   });
   Future<int> t5 = f. /*@typeArgs=int*/ /*@target=MyFuture.then*/ then(
       /*@returnType=FutureOr<int>*/ (/*@type=bool*/ x) =>
-      // error:INVALID_CAST_FUNCTION_EXPR
           x ? 2 : new Future<int>.value(3));
   Future<int> t6 = f. /*@typeArgs=int*/ /*@target=MyFuture.then*/ then(
       /*@returnType=FutureOr<int>*/ (/*@type=bool*/ x) {
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2.dart.strong.expect b/pkg/front_end/testcases/inference/future_then_conditional2.dart.strong.expect
index 466dd7023f1..568ce3faac1 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2.dart.strong.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2.dart.strong.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2.dart.strong.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2.dart.strong.transformed.expect
index bffe4c4de73..532f57dbc8b 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2.dart.strong.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.expect b/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.expect
index 466dd7023f1..568ce3faac1 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.modular.expect b/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.modular.expect
index 466dd7023f1..568ce3faac1 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.modular.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.transformed.expect
index bffe4c4de73..532f57dbc8b 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2.dart.weak.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.strong.expect b/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.strong.expect
index d5f6018fc50..ead1e744c11 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.strong.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.strong.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.strong.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.strong.transformed.expect
index 0195ceb6779..05adeef3a72 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.strong.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.expect b/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.expect
index d5f6018fc50..ead1e744c11 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.modular.expect b/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.modular.expect
index d5f6018fc50..ead1e744c11 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.modular.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.transformed.expect
index 0195ceb6779..05adeef3a72 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_2.dart.weak.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_2.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_2.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.strong.expect b/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.strong.expect
index 45752c363d0..9faa298b9c4 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.strong.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.strong.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   self::MyFuture<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.strong.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.strong.transformed.expect
index 136e80af684..0f81d0b2091 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.strong.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   self::MyFuture<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.expect b/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.expect
index 45752c363d0..9faa298b9c4 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   self::MyFuture<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.modular.expect b/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.modular.expect
index 45752c363d0..9faa298b9c4 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.modular.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   self::MyFuture<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.transformed.expect
index 136e80af684..0f81d0b2091 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_3.dart.weak.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_3.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   self::MyFuture<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_3.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.strong.expect b/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.strong.expect
index 30ea48f7af3..f891d54914b 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.strong.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.strong.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   self::MyFuture<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.strong.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.strong.transformed.expect
index e10a8544031..499b6538736 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.strong.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   self::MyFuture<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.expect b/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.expect
index 30ea48f7af3..f891d54914b 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   self::MyFuture<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.modular.expect b/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.modular.expect
index 30ea48f7af3..f891d54914b 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.modular.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   self::MyFuture<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.transformed.expect
index e10a8544031..499b6538736 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_4.dart.weak.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_4.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::bool> f) → void {
   self::MyFuture<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  self::MyFuture<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   self::MyFuture<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_4.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.strong.expect b/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.strong.expect
index 04e8e1d0de0..df14585a0ed 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.strong.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.strong.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(asy::Future<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t2 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
-  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
+  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t6 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.strong.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.strong.transformed.expect
index 4a7568d52a1..165033e3953 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.strong.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(asy::Future<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t2 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
-  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
+  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t6 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.expect b/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.expect
index 04e8e1d0de0..df14585a0ed 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(asy::Future<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t2 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
-  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
+  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t6 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.modular.expect b/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.modular.expect
index 04e8e1d0de0..df14585a0ed 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.modular.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(asy::Future<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t2 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
-  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
+  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t6 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.transformed.expect
index 4a7568d52a1..165033e3953 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_5.dart.weak.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//         ? 2
-//         ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new MyFuture<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_5.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(asy::Future<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t2 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:24:9: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-        ? 2
-        ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
-  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:30:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new MyFuture<int>.value(3));
-            ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
+  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t6 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_5.dart:33:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new MyFuture<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : new self::MyFuture::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : new self::MyFuture::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.strong.expect b/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.strong.expect
index 36390d877fa..7e3245b27df 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.strong.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.strong.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(asy::Future<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t2 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
-  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
+  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t6 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.strong.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.strong.transformed.expect
index 4b5c87721ec..564b8245b47 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.strong.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(asy::Future<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t2 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
-  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
+  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t6 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.expect b/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.expect
index 36390d877fa..7e3245b27df 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(asy::Future<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t2 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
-  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
+  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t6 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.modular.expect b/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.modular.expect
index 36390d877fa..7e3245b27df 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.modular.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(asy::Future<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t2 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
-  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
+  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t6 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.transformed.expect
index 4b5c87721ec..564b8245b47 100644
--- a/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_conditional2_6.dart.weak.transformed.expect
@@ -1,23 +1,4 @@
 library test;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-//                                                 ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ? 2 : new Future<int>.value(3));
-//             ^
-//
-// pkg/front_end/testcases/inference/future_then_conditional2_6.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -45,21 +26,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(asy::Future<core::bool> f) → void {
   asy::Future<core::int> t1 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ => x ?{core::int} 2 : await asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t2 = f.{asy::Future::then}<core::int>((core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ? 2 : new Future<int>.value(3);
-                                                ^" in (await x /* runtimeCheckType= asy::Future<core::bool> */ ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} core::int;
+    return await x /* runtimeCheckType= asy::Future<core::bool> */ ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
-  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ? 2 : new Future<int>.value(3));
-            ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
+  asy::Future<core::int> t5 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> => x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3)){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
   asy::Future<core::int> t6 = f.{asy::Future::then}<core::int>((core::bool x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_conditional2_6.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ? 2 : new Future<int>.value(3);
-                                          ^" in (x ?{core::Object} 2 : asy::Future::value<core::int>(3)) as{TypeError} FutureOr<core::int>;
+    return x ?{FutureOr<core::int>} 2 : asy::Future::value<core::int>(3);
   }){((core::bool) → FutureOr<core::int>, {onError: core::Function?}) → asy::Future<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_ifNull2.dart.strong.expect b/pkg/front_end/testcases/inference/future_then_ifNull2.dart.strong.expect
index df464d51ad8..6d104648342 100644
--- a/pkg/front_end/testcases/inference/future_then_ifNull2.dart.strong.expect
+++ b/pkg/front_end/testcases/inference/future_then_ifNull2.dart.strong.expect
@@ -10,30 +10,14 @@ library test;
 //     return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
 //                                         ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
-//                                                 ^
-//
 // pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:11: Warning: Operand of null-aware operation '??' has type 'int' which excludes null.
 //           x ?? new Future<int>.value(3));
 //           ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ?? new Future<int>.value(3));
-//             ^
-//
 // pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:41: Warning: Operand of null-aware operation '??' has type 'int' which excludes null.
 //     return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
 //                                         ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -61,21 +45,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::int> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::int x) → asy::Future<core::int> async /* emittedValueType= core::int */ => let final core::int #t1 = x in #t1 == null ?{core::int} await asy::Future::value<core::int>(3) : #t1){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::int x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
-                                                ^" in (let final core::int #t2 = await x /* runtimeCheckType= asy::Future<core::int> */ in #t2 == null ?{core::Object} asy::Future::value<core::int>(3) : #t2) as{TypeError} core::int;
+    return let final core::int #t2 = await x /* runtimeCheckType= asy::Future<core::int> */ in #t2 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t2;
   }){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ?? new Future<int>.value(3));
-            ^" in (let final core::int #t3 = x in #t3 == null ?{core::Object} asy::Future::value<core::int>(3) : #t3) as{TypeError} FutureOr<core::int>){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> => let final core::int #t3 = x in #t3 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t3){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
-                                          ^" in (let final core::int #t4 = x in #t4 == null ?{core::Object} asy::Future::value<core::int>(3) : #t4) as{TypeError} FutureOr<core::int>;
+    return let final core::int #t4 = x in #t4 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t4;
   }){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_ifNull2.dart.strong.transformed.expect b/pkg/front_end/testcases/inference/future_then_ifNull2.dart.strong.transformed.expect
index e5a2ea55431..5c369a7163f 100644
--- a/pkg/front_end/testcases/inference/future_then_ifNull2.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_ifNull2.dart.strong.transformed.expect
@@ -10,30 +10,14 @@ library test;
 //     return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
 //                                         ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
-//                                                 ^
-//
 // pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:11: Warning: Operand of null-aware operation '??' has type 'int' which excludes null.
 //           x ?? new Future<int>.value(3));
 //           ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ?? new Future<int>.value(3));
-//             ^
-//
 // pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:41: Warning: Operand of null-aware operation '??' has type 'int' which excludes null.
 //     return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
 //                                         ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -61,21 +45,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::int> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::int x) → asy::Future<core::int> async /* emittedValueType= core::int */ => let final core::int #t1 = x in #t1 == null ?{core::int} await asy::Future::value<core::int>(3) : #t1){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::int x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
-                                                ^" in (let final core::int #t2 = await x /* runtimeCheckType= asy::Future<core::int> */ in #t2 == null ?{core::Object} asy::Future::value<core::int>(3) : #t2) as{TypeError} core::int;
+    return let final core::int #t2 = await x /* runtimeCheckType= asy::Future<core::int> */ in #t2 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t2;
   }){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ?? new Future<int>.value(3));
-            ^" in (let final core::int #t3 = x in #t3 == null ?{core::Object} asy::Future::value<core::int>(3) : #t3) as{TypeError} FutureOr<core::int>){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> => let final core::int #t3 = x in #t3 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t3){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
-                                          ^" in (let final core::int #t4 = x in #t4 == null ?{core::Object} asy::Future::value<core::int>(3) : #t4) as{TypeError} FutureOr<core::int>;
+    return let final core::int #t4 = x in #t4 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t4;
   }){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.expect b/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.expect
index df464d51ad8..6d104648342 100644
--- a/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.expect
+++ b/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.expect
@@ -10,30 +10,14 @@ library test;
 //     return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
 //                                         ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
-//                                                 ^
-//
 // pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:11: Warning: Operand of null-aware operation '??' has type 'int' which excludes null.
 //           x ?? new Future<int>.value(3));
 //           ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ?? new Future<int>.value(3));
-//             ^
-//
 // pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:41: Warning: Operand of null-aware operation '??' has type 'int' which excludes null.
 //     return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
 //                                         ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -61,21 +45,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::int> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::int x) → asy::Future<core::int> async /* emittedValueType= core::int */ => let final core::int #t1 = x in #t1 == null ?{core::int} await asy::Future::value<core::int>(3) : #t1){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::int x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
-                                                ^" in (let final core::int #t2 = await x /* runtimeCheckType= asy::Future<core::int> */ in #t2 == null ?{core::Object} asy::Future::value<core::int>(3) : #t2) as{TypeError} core::int;
+    return let final core::int #t2 = await x /* runtimeCheckType= asy::Future<core::int> */ in #t2 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t2;
   }){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ?? new Future<int>.value(3));
-            ^" in (let final core::int #t3 = x in #t3 == null ?{core::Object} asy::Future::value<core::int>(3) : #t3) as{TypeError} FutureOr<core::int>){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> => let final core::int #t3 = x in #t3 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t3){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
-                                          ^" in (let final core::int #t4 = x in #t4 == null ?{core::Object} asy::Future::value<core::int>(3) : #t4) as{TypeError} FutureOr<core::int>;
+    return let final core::int #t4 = x in #t4 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t4;
   }){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.modular.expect b/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.modular.expect
index df464d51ad8..6d104648342 100644
--- a/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.modular.expect
@@ -10,30 +10,14 @@ library test;
 //     return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
 //                                         ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
-//                                                 ^
-//
 // pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:11: Warning: Operand of null-aware operation '??' has type 'int' which excludes null.
 //           x ?? new Future<int>.value(3));
 //           ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ?? new Future<int>.value(3));
-//             ^
-//
 // pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:41: Warning: Operand of null-aware operation '??' has type 'int' which excludes null.
 //     return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
 //                                         ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -61,21 +45,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::int> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::int x) → asy::Future<core::int> async /* emittedValueType= core::int */ => let final core::int #t1 = x in #t1 == null ?{core::int} await asy::Future::value<core::int>(3) : #t1){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::int x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
-                                                ^" in (let final core::int #t2 = await x /* runtimeCheckType= asy::Future<core::int> */ in #t2 == null ?{core::Object} asy::Future::value<core::int>(3) : #t2) as{TypeError} core::int;
+    return let final core::int #t2 = await x /* runtimeCheckType= asy::Future<core::int> */ in #t2 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t2;
   }){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ?? new Future<int>.value(3));
-            ^" in (let final core::int #t3 = x in #t3 == null ?{core::Object} asy::Future::value<core::int>(3) : #t3) as{TypeError} FutureOr<core::int>){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> => let final core::int #t3 = x in #t3 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t3){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
-                                          ^" in (let final core::int #t4 = x in #t4 == null ?{core::Object} asy::Future::value<core::int>(3) : #t4) as{TypeError} FutureOr<core::int>;
+    return let final core::int #t4 = x in #t4 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t4;
   }){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.transformed.expect
index e5a2ea55431..5c369a7163f 100644
--- a/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_then_ifNull2.dart.weak.transformed.expect
@@ -10,30 +10,14 @@ library test;
 //     return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
 //                                         ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
-//                                                 ^
-//
 // pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:11: Warning: Operand of null-aware operation '??' has type 'int' which excludes null.
 //           x ?? new Future<int>.value(3));
 //           ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//           x ?? new Future<int>.value(3));
-//             ^
-//
 // pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:41: Warning: Operand of null-aware operation '??' has type 'int' which excludes null.
 //     return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
 //                                         ^
 //
-// pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
-//  - 'Object' is from 'dart:core'.
-//     return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
-//                                           ^
-//
 import self as self;
 import "dart:core" as core;
 import "dart:async" as asy;
@@ -61,21 +45,11 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
 static method test(self::MyFuture<core::int> f) → void {
   asy::Future<core::int> t1 = f.{self::MyFuture::then}<core::int>((core::int x) → asy::Future<core::int> async /* emittedValueType= core::int */ => let final core::int #t1 = x in #t1 == null ?{core::int} await asy::Future::value<core::int>(3) : #t1){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t2 = f.{self::MyFuture::then}<core::int>((core::int x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:23:49: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    return /*info:DOWN_CAST_COMPOSITE*/ await x ?? new Future<int>.value(3);
-                                                ^" in (let final core::int #t2 = await x /* runtimeCheckType= asy::Future<core::int> */ in #t2 == null ?{core::Object} asy::Future::value<core::int>(3) : #t2) as{TypeError} core::int;
+    return let final core::int #t2 = await x /* runtimeCheckType= asy::Future<core::int> */ in #t2 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t2;
   }){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
-  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> => invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:28:13: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-          x ?? new Future<int>.value(3));
-            ^" in (let final core::int #t3 = x in #t3 == null ?{core::Object} asy::Future::value<core::int>(3) : #t3) as{TypeError} FutureOr<core::int>){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
+  asy::Future<core::int> t5 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> => let final core::int #t3 = x in #t3 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t3){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
   asy::Future<core::int> t6 = f.{self::MyFuture::then}<core::int>((core::int x) → FutureOr<core::int> {
-    return invalid-expression "pkg/front_end/testcases/inference/future_then_ifNull2.dart:31:43: Error: A value of type 'Object' can't be returned from a function with return type 'FutureOr<int>'.
- - 'Object' is from 'dart:core'.
-    return /*info:DOWN_CAST_COMPOSITE*/ x ?? new Future<int>.value(3);
-                                          ^" in (let final core::int #t4 = x in #t4 == null ?{core::Object} asy::Future::value<core::int>(3) : #t4) as{TypeError} FutureOr<core::int>;
+    return let final core::int #t4 = x in #t4 == null ?{FutureOr<core::int>} asy::Future::value<core::int>(3) : #t4;
   }){((core::int) → FutureOr<core::int>, {onError: core::Function?}) → self::MyFuture<core::int>};
 }
 static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.strong.expect b/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.strong.expect
index aac1575f739..e884bd75934 100644
--- a/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.strong.expect
+++ b/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.strong.expect
@@ -2,18 +2,6 @@ library test;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/inference/future_union_async_conditional2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//       ? 42
-//       ^
-//
-// pkg/front_end/testcases/inference/future_union_async_conditional2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     ? 42
-//     ^
-//
 // pkg/front_end/testcases/inference/future_union_async_conditional2.dart:28:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
 //  - 'Object' is from 'dart:core'.
 //  - 'Future' is from 'dart:async'.
@@ -45,18 +33,10 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
     return this.{self::MyFuture::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[timeLimit]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C10: onTimeout}))){(core::Invocation) → dynamic} as{TypeError,ForDynamic} asy::Future<self::MyFuture::T%>;
 }
 static method g1(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-      ? 42
-      ^" in (x ?{core::Object} 42 : asy::Future::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : asy::Future::value<core::int>(42);
 }
 static method g2(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ 
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    ? 42
-    ^" in (x ?{core::Object} 42 : asy::Future::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : asy::Future::value<core::int>(42);
 static method g3(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
   core::Object y = x ?{core::Object} 42 : asy::Future::value<core::int>(42);
   return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:28:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
diff --git a/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.strong.transformed.expect b/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.strong.transformed.expect
index f373bdf145b..23e57f67a3c 100644
--- a/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.strong.transformed.expect
@@ -2,18 +2,6 @@ library test;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/inference/future_union_async_conditional2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//       ? 42
-//       ^
-//
-// pkg/front_end/testcases/inference/future_union_async_conditional2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     ? 42
-//     ^
-//
 // pkg/front_end/testcases/inference/future_union_async_conditional2.dart:28:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
 //  - 'Object' is from 'dart:core'.
 //  - 'Future' is from 'dart:async'.
@@ -45,18 +33,10 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
     return this.{self::MyFuture::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C3, core::List::unmodifiable<dynamic>(core::_GrowableList::_literal1<dynamic>(timeLimit)), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C10: onTimeout}))){(core::Invocation) → dynamic} as{TypeError,ForDynamic} asy::Future<self::MyFuture::T%>;
 }
 static method g1(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-      ? 42
-      ^" in (x ?{core::Object} 42 : asy::Future::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : asy::Future::value<core::int>(42);
 }
 static method g2(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ 
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    ? 42
-    ^" in (x ?{core::Object} 42 : asy::Future::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : asy::Future::value<core::int>(42);
 static method g3(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
   core::Object y = x ?{core::Object} 42 : asy::Future::value<core::int>(42);
   return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:28:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
diff --git a/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.expect b/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.expect
index aac1575f739..e884bd75934 100644
--- a/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.expect
+++ b/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.expect
@@ -2,18 +2,6 @@ library test;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/inference/future_union_async_conditional2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//       ? 42
-//       ^
-//
-// pkg/front_end/testcases/inference/future_union_async_conditional2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     ? 42
-//     ^
-//
 // pkg/front_end/testcases/inference/future_union_async_conditional2.dart:28:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
 //  - 'Object' is from 'dart:core'.
 //  - 'Future' is from 'dart:async'.
@@ -45,18 +33,10 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
     return this.{self::MyFuture::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[timeLimit]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C10: onTimeout}))){(core::Invocation) → dynamic} as{TypeError,ForDynamic} asy::Future<self::MyFuture::T%>;
 }
 static method g1(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-      ? 42
-      ^" in (x ?{core::Object} 42 : asy::Future::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : asy::Future::value<core::int>(42);
 }
 static method g2(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ 
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    ? 42
-    ^" in (x ?{core::Object} 42 : asy::Future::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : asy::Future::value<core::int>(42);
 static method g3(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
   core::Object y = x ?{core::Object} 42 : asy::Future::value<core::int>(42);
   return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:28:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
diff --git a/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.modular.expect b/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.modular.expect
index aac1575f739..e884bd75934 100644
--- a/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.modular.expect
@@ -2,18 +2,6 @@ library test;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/inference/future_union_async_conditional2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//       ? 42
-//       ^
-//
-// pkg/front_end/testcases/inference/future_union_async_conditional2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     ? 42
-//     ^
-//
 // pkg/front_end/testcases/inference/future_union_async_conditional2.dart:28:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
 //  - 'Object' is from 'dart:core'.
 //  - 'Future' is from 'dart:async'.
@@ -45,18 +33,10 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
     return this.{self::MyFuture::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[timeLimit]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C10: onTimeout}))){(core::Invocation) → dynamic} as{TypeError,ForDynamic} asy::Future<self::MyFuture::T%>;
 }
 static method g1(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-      ? 42
-      ^" in (x ?{core::Object} 42 : asy::Future::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : asy::Future::value<core::int>(42);
 }
 static method g2(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ 
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    ? 42
-    ^" in (x ?{core::Object} 42 : asy::Future::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : asy::Future::value<core::int>(42);
 static method g3(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
   core::Object y = x ?{core::Object} 42 : asy::Future::value<core::int>(42);
   return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:28:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
diff --git a/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.transformed.expect
index f373bdf145b..23e57f67a3c 100644
--- a/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_union_async_conditional2.dart.weak.transformed.expect
@@ -2,18 +2,6 @@ library test;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/inference/future_union_async_conditional2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//       ? 42
-//       ^
-//
-// pkg/front_end/testcases/inference/future_union_async_conditional2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     ? 42
-//     ^
-//
 // pkg/front_end/testcases/inference/future_union_async_conditional2.dart:28:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
 //  - 'Object' is from 'dart:core'.
 //  - 'Future' is from 'dart:async'.
@@ -45,18 +33,10 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
     return this.{self::MyFuture::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C3, core::List::unmodifiable<dynamic>(core::_GrowableList::_literal1<dynamic>(timeLimit)), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C10: onTimeout}))){(core::Invocation) → dynamic} as{TypeError,ForDynamic} asy::Future<self::MyFuture::T%>;
 }
 static method g1(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-      ? 42
-      ^" in (x ?{core::Object} 42 : asy::Future::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : asy::Future::value<core::int>(42);
 }
 static method g2(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ 
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    ? 42
-    ^" in (x ?{core::Object} 42 : asy::Future::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : asy::Future::value<core::int>(42);
 static method g3(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
   core::Object y = x ?{core::Object} 42 : asy::Future::value<core::int>(42);
   return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional2.dart:28:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
diff --git a/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.strong.expect b/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.strong.expect
index 88b59c8de77..79cf45b1e58 100644
--- a/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.strong.expect
+++ b/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.strong.expect
@@ -2,18 +2,6 @@ library test;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//       ? 42
-//       ^
-//
-// pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     ? 42
-//     ^
-//
 // pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:29:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
 //  - 'Object' is from 'dart:core'.
 //  - 'Future' is from 'dart:async'.
@@ -45,18 +33,10 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
     return this.{self::MyFuture::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[timeLimit]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C10: onTimeout}))){(core::Invocation) → dynamic} as{TypeError,ForDynamic} asy::Future<self::MyFuture::T%>;
 }
 static method g1(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-      ? 42
-      ^" in (x ?{core::Object} 42 : new self::MyFuture::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : new self::MyFuture::value<core::int>(42);
 }
 static method g2(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ 
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    ? 42
-    ^" in (x ?{core::Object} 42 : new self::MyFuture::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : new self::MyFuture::value<core::int>(42);
 static method g3(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
   core::Object y = x ?{core::Object} 42 : new self::MyFuture::value<dynamic>(42);
   return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:29:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
diff --git a/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.strong.transformed.expect b/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.strong.transformed.expect
index f665fb968b6..ab03ea28bc3 100644
--- a/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.strong.transformed.expect
@@ -2,18 +2,6 @@ library test;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//       ? 42
-//       ^
-//
-// pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     ? 42
-//     ^
-//
 // pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:29:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
 //  - 'Object' is from 'dart:core'.
 //  - 'Future' is from 'dart:async'.
@@ -45,18 +33,10 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
     return this.{self::MyFuture::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C3, core::List::unmodifiable<dynamic>(core::_GrowableList::_literal1<dynamic>(timeLimit)), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C10: onTimeout}))){(core::Invocation) → dynamic} as{TypeError,ForDynamic} asy::Future<self::MyFuture::T%>;
 }
 static method g1(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-      ? 42
-      ^" in (x ?{core::Object} 42 : new self::MyFuture::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : new self::MyFuture::value<core::int>(42);
 }
 static method g2(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ 
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    ? 42
-    ^" in (x ?{core::Object} 42 : new self::MyFuture::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : new self::MyFuture::value<core::int>(42);
 static method g3(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
   core::Object y = x ?{core::Object} 42 : new self::MyFuture::value<dynamic>(42);
   return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:29:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
diff --git a/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.expect b/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.expect
index 88b59c8de77..79cf45b1e58 100644
--- a/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.expect
+++ b/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.expect
@@ -2,18 +2,6 @@ library test;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//       ? 42
-//       ^
-//
-// pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     ? 42
-//     ^
-//
 // pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:29:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
 //  - 'Object' is from 'dart:core'.
 //  - 'Future' is from 'dart:async'.
@@ -45,18 +33,10 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
     return this.{self::MyFuture::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[timeLimit]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C10: onTimeout}))){(core::Invocation) → dynamic} as{TypeError,ForDynamic} asy::Future<self::MyFuture::T%>;
 }
 static method g1(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-      ? 42
-      ^" in (x ?{core::Object} 42 : new self::MyFuture::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : new self::MyFuture::value<core::int>(42);
 }
 static method g2(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ 
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    ? 42
-    ^" in (x ?{core::Object} 42 : new self::MyFuture::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : new self::MyFuture::value<core::int>(42);
 static method g3(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
   core::Object y = x ?{core::Object} 42 : new self::MyFuture::value<dynamic>(42);
   return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:29:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
diff --git a/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.modular.expect b/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.modular.expect
index 88b59c8de77..79cf45b1e58 100644
--- a/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.modular.expect
@@ -2,18 +2,6 @@ library test;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//       ? 42
-//       ^
-//
-// pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     ? 42
-//     ^
-//
 // pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:29:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
 //  - 'Object' is from 'dart:core'.
 //  - 'Future' is from 'dart:async'.
@@ -45,18 +33,10 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
     return this.{self::MyFuture::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[timeLimit]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C10: onTimeout}))){(core::Invocation) → dynamic} as{TypeError,ForDynamic} asy::Future<self::MyFuture::T%>;
 }
 static method g1(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-      ? 42
-      ^" in (x ?{core::Object} 42 : new self::MyFuture::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : new self::MyFuture::value<core::int>(42);
 }
 static method g2(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ 
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    ? 42
-    ^" in (x ?{core::Object} 42 : new self::MyFuture::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : new self::MyFuture::value<core::int>(42);
 static method g3(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
   core::Object y = x ?{core::Object} 42 : new self::MyFuture::value<dynamic>(42);
   return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:29:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
diff --git a/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.transformed.expect
index f665fb968b6..ab03ea28bc3 100644
--- a/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart.weak.transformed.expect
@@ -2,18 +2,6 @@ library test;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//       ? 42
-//       ^
-//
-// pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
-//  - 'Object' is from 'dart:core'.
-//  - 'Future' is from 'dart:async'.
-//     ? 42
-//     ^
-//
 // pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:29:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
 //  - 'Object' is from 'dart:core'.
 //  - 'Future' is from 'dart:async'.
@@ -45,18 +33,10 @@ class MyFuture<T extends core::Object? = dynamic> extends core::Object implement
     return this.{self::MyFuture::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C3, core::List::unmodifiable<dynamic>(core::_GrowableList::_literal1<dynamic>(timeLimit)), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C10: onTimeout}))){(core::Invocation) → dynamic} as{TypeError,ForDynamic} asy::Future<self::MyFuture::T%>;
 }
 static method g1(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:19:7: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-      ? 42
-      ^" in (x ?{core::Object} 42 : new self::MyFuture::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : new self::MyFuture::value<core::int>(42);
 }
 static method g2(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ 
-  return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:24:5: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
- - 'Object' is from 'dart:core'.
- - 'Future' is from 'dart:async'.
-    ? 42
-    ^" in (x ?{core::Object} 42 : new self::MyFuture::value<core::int>(42)) as{TypeError} core::int;
+  return x ?{FutureOr<core::int>} 42 : new self::MyFuture::value<core::int>(42);
 static method g3(core::bool x) → asy::Future<core::int> async /* emittedValueType= core::int */ {
   core::Object y = x ?{core::Object} 42 : new self::MyFuture::value<dynamic>(42);
   return invalid-expression "pkg/front_end/testcases/inference/future_union_async_conditional_2_2.dart:29:39: Error: A value of type 'Object' can't be returned from an async function with return type 'Future<int>'.
diff --git a/runtime/vm/experimental_features.cc b/runtime/vm/experimental_features.cc
index ff67a54103b..0bd06934e2b 100644
--- a/runtime/vm/experimental_features.cc
+++ b/runtime/vm/experimental_features.cc
@@ -17,7 +17,7 @@ namespace dart {
 bool GetExperimentalFeatureDefault(ExperimentalFeature feature) {
   constexpr bool kFeatureValues[] = {
       true, true, true, true, true, true, true, true, true, true, true,
-      true, true, true, true, true, true, true, true, true, true,
+      true, true, true, true, true, true, true, true, true, true, true,
   };
   ASSERT(static_cast<size_t>(feature) < ARRAY_SIZE(kFeatureValues));
   return kFeatureValues[static_cast<int>(feature)];
@@ -25,6 +25,7 @@ bool GetExperimentalFeatureDefault(ExperimentalFeature feature) {
 
 const char* GetExperimentalFeatureName(ExperimentalFeature feature) {
   constexpr const char* kFeatureNames[] = {
+      "inference-update-3",
       "inline-class",
       "inference-update-2",
       "sealed-class",
diff --git a/runtime/vm/experimental_features.h b/runtime/vm/experimental_features.h
index 7e85347428f..64338256648 100644
--- a/runtime/vm/experimental_features.h
+++ b/runtime/vm/experimental_features.h
@@ -12,6 +12,7 @@
 namespace dart {
 
 enum class ExperimentalFeature {
+  inference_update_3,
   inline_class,
   inference_update_2,
   sealed_class,
diff --git a/tools/experimental_features.yaml b/tools/experimental_features.yaml
index 123029bfb1c..b55ef9a8e60 100644
--- a/tools/experimental_features.yaml
+++ b/tools/experimental_features.yaml
@@ -128,9 +128,6 @@ features:
   resource-identifiers:
     help: "Output arguments used by static functions."
 
-  inference-update-3: # See https://github.com/dart-lang/language/issues/1618
-    help: "Better handling of conditional expressions, and switch expressions."
-
 # Experiment flag only used for testing.
   test-experiment:
     help: >-
@@ -144,6 +141,20 @@ features:
 # Shipped flags should be marked retired the following stable release.
 #
 
+  inference-update-3: # See https://github.com/dart-lang/language/issues/1618
+    enabledIn: '3.4.0'
+    validation: |
+      class A {}
+      class B1 implements A {}
+      class B2 implements A {}
+      class C1 implements B1, B2 {}
+      class C2 implements B1, B2 {}
+      B1 test(bool b, C1 c1, C2 c2) => b ? c1 : c2;
+      main() {
+        print('feature enabled');
+      }
+    help: "Better handling of conditional expressions, and switch expressions."
+
   inline-class:
     enabledIn: '3.3.0'
     validation: |