[vm] Removes support for --causal-async-stacks

All existing embedders have been opted into --lazy-async-stacks, the
VM also uses it as it's default in all configurations.

After this CL, any user of --causal-async-stacks will get an error
message when trying to use it.
=> In any such case, please simply remove the flag.

TEST=Exhaustive CQ.

Bug: https://github.com/dart-lang/sdk/issues/37668
Change-Id: Ia440afcf2dba464aa8b8cf381b93bbac8eb9f8dc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/172564
Commit-Queue: Clement Skau <cskau@google.com>
Reviewed-by: Clement Skau <cskau@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>

pkg/front_end/lib/src/fasta/source/source_loader.dart

@@ -1547,8 +1547,6 @@ _asyncErrorWrapperHelper(continuation) {}
 
 void _asyncStarMoveNextHelper(var stream) {}
 
-_asyncStackTraceHelper(async_op) {}
-
 _asyncThenWrapperHelper(continuation) {}
 
 _awaitHelper(object, thenCallback, errorCallback, awaiter) {}

pkg/front_end/test/flutter_gallery_leak_tester.dart

@@ -179,7 +179,6 @@ main(List<String> args) async {
     "--incremental",
     "--target=flutter",
     "--debugger-module-names",
-    "-Ddart.developer.causal_async_stacks=true",
     "--output-dill",
     "$rootPath/flutter_server_tmp.dill",
     "--packages",

pkg/front_end/testcases/extensions/async_extensions.dart.strong.transformed.expect

@@ -29,7 +29,6 @@ static method Extension|asyncMethod(final core::int* #this) → dynamic /* origi
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -44,7 +43,6 @@ static method Extension|asyncMethod(final core::int* #this) → dynamic /* origi
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -56,7 +54,6 @@ static method Extension|get#asyncMethod(final core::int* #this) → () →* dyna
 static method Extension|asyncStarMethod(final core::int* #this) → dynamic /* originally async* */ {
   asy::_AsyncStarStreamController<dynamic>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -74,7 +71,6 @@ static method Extension|asyncStarMethod(final core::int* #this) → dynamic /* o
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<dynamic>(:async_op);

pkg/front_end/testcases/extensions/deferred_explicit_access.dart.strong.transformed.expect

@@ -18,7 +18,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -45,7 +44,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -102,4 +100,4 @@ Extra constant evaluation status:
 Evaluated: VariableGet @ org-dartlang-testcase:///deferred_explicit_access.dart:12:31 -> IntConstant(0)
 Evaluated: VariableGet @ org-dartlang-testcase:///deferred_explicit_access.dart:12:45 -> IntConstant(42)
 Evaluated: VariableGet @ org-dartlang-testcase:///deferred_explicit_access.dart:12:45 -> IntConstant(42)
-Extra constant evaluation: evaluated: 96, effectively constant: 3
+Extra constant evaluation: evaluated: 93, effectively constant: 3

pkg/front_end/testcases/extensions/deferred_import_hidden.dart.strong.transformed.expect

@@ -10,7 +10,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -36,7 +35,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/async_function.dart.strong.transformed.expect

@@ -11,7 +11,6 @@ static method asyncString() → asy::Future<core::String*>* /* originally async
   final asy::_Future<core::String*>* :async_future = new asy::_Future::•<core::String*>();
   core::bool* :is_sync = false;
   FutureOr<core::String*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -29,7 +28,6 @@ static method asyncString() → asy::Future<core::String*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -40,7 +38,6 @@ static method asyncString2() → asy::Future<core::String*>* /* originally async
   final asy::_Future<core::String*>* :async_future = new asy::_Future::•<core::String*>();
   core::bool* :is_sync = false;
   FutureOr<core::String*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -58,7 +55,6 @@ static method asyncString2() → asy::Future<core::String*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -110,7 +106,6 @@ static method syncStarString2() → core::Iterable<core::String*>* /* originally
 static method asyncStarString() → asy::Stream<core::String*>* /* originally async* */ {
   asy::_AsyncStarStreamController<core::String*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -144,7 +139,6 @@ static method asyncStarString() → asy::Stream<core::String*>* /* originally as
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::String*>(:async_op);
@@ -154,7 +148,6 @@ static method asyncStarString() → asy::Stream<core::String*>* /* originally as
 static method asyncStarString2() → asy::Stream<core::String*>* /* originally async* */ {
   asy::_AsyncStarStreamController<core::String*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -179,7 +172,6 @@ static method asyncStarString2() → asy::Stream<core::String*>* /* originally a
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::String*>(:async_op);
@@ -190,7 +182,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -209,7 +200,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/async_nested.dart.strong.transformed.expect

@@ -31,7 +31,6 @@ static method main() → void /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -69,7 +68,6 @@ static method main() → void /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/await.dart.strong.transformed.expect

@@ -8,7 +8,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -27,7 +26,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/await_complex.dart.strong.transformed.expect

@@ -60,7 +60,6 @@ static method staticMembers() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -107,7 +106,6 @@ static method staticMembers() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -118,7 +116,6 @@ static method topLevelMembers() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -160,7 +157,6 @@ static method topLevelMembers() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -171,7 +167,6 @@ static method instanceMembers() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -214,7 +209,6 @@ static method instanceMembers() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -225,7 +219,6 @@ static method others() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -268,7 +261,6 @@ static method others() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -279,7 +271,6 @@ static method conditionals() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -342,7 +333,6 @@ static method conditionals() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -353,7 +343,6 @@ static method asserts() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -417,7 +406,6 @@ static method asserts() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -428,7 +416,6 @@ static method controlFlow() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -562,7 +549,6 @@ static method controlFlow() → dynamic /* originally async */ {
                 final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
                 core::bool* :is_sync = false;
                 FutureOr<dynamic>* :return_value;
-                dynamic :async_stack_trace;
                 (dynamic) →* dynamic :async_op_then;
                 (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
                 core::int* :await_jump_var = 0;
@@ -582,7 +568,6 @@ static method controlFlow() → dynamic /* originally async */ {
                   on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
                     asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
                   }
-                :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
                 :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
                 :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
                 :async_op.call();
@@ -594,7 +579,6 @@ static method controlFlow() → dynamic /* originally async */ {
                 final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
                 core::bool* :is_sync = false;
                 FutureOr<dynamic>* :return_value;
-                dynamic :async_stack_trace;
                 (dynamic) →* dynamic :async_op_then;
                 (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
                 core::int* :await_jump_var = 0;
@@ -612,7 +596,6 @@ static method controlFlow() → dynamic /* originally async */ {
                   on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
                     asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
                   }
-                :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
                 :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
                 :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
                 :async_op.call();
@@ -623,7 +606,6 @@ static method controlFlow() → dynamic /* originally async */ {
               function testStream1() → asy::Stream<core::int*>* /* originally async* */ {
                 asy::_AsyncStarStreamController<core::int*>* :controller;
                 dynamic :controller_stream;
-                dynamic :async_stack_trace;
                 (dynamic) →* dynamic :async_op_then;
                 (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
                 core::int* :await_jump_var = 0;
@@ -649,7 +631,6 @@ static method controlFlow() → dynamic /* originally async */ {
                   finally {
                     :controller.{asy::_AsyncStarStreamController::close}();
                   }
-                :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
                 :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
                 :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
                 :controller = new asy::_AsyncStarStreamController::•<core::int*>(:async_op);
@@ -662,7 +643,6 @@ static method controlFlow() → dynamic /* originally async */ {
               function testStream2() → asy::Stream<core::int*>* /* originally async* */ {
                 asy::_AsyncStarStreamController<core::int*>* :controller;
                 dynamic :controller_stream;
-                dynamic :async_stack_trace;
                 (dynamic) →* dynamic :async_op_then;
                 (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
                 core::int* :await_jump_var = 0;
@@ -688,7 +668,6 @@ static method controlFlow() → dynamic /* originally async */ {
                   finally {
                     :controller.{asy::_AsyncStarStreamController::close}();
                   }
-                :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
                 :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
                 :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
                 :controller = new asy::_AsyncStarStreamController::•<core::int*>(:async_op);
@@ -708,7 +687,6 @@ static method controlFlow() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -719,7 +697,6 @@ static method future<T extends core::Object* = dynamic>(self::future::T* value)
   final asy::_Future<self::future::T*>* :async_future = new asy::_Future::•<self::future::T*>();
   core::bool* :is_sync = false;
   FutureOr<self::future::T*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -737,7 +714,6 @@ static method future<T extends core::Object* = dynamic>(self::future::T* value)
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -749,7 +725,6 @@ static method id<T extends core::Object* = dynamic>(self::id::T* value) → Futu
 static method intStream() → asy::Stream<core::int*>* /* originally async* */ {
   asy::_AsyncStarStreamController<core::int*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -774,7 +749,6 @@ static method intStream() → asy::Stream<core::int*>* /* originally async* */ {
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::int*>(:async_op);
@@ -785,7 +759,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -818,7 +791,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/await_in_cascade.dart.strong.transformed.expect

@@ -14,7 +14,6 @@ class C extends core::Object {
     final asy::_Future<core::List<core::int*>*>* :async_future = new asy::_Future::•<core::List<core::int*>*>();
     core::bool* :is_sync = false;
     FutureOr<core::List<core::int*>*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -36,7 +35,6 @@ class C extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -47,7 +45,6 @@ class C extends core::Object {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -65,7 +62,6 @@ class C extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -87,7 +83,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -106,7 +101,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/bug33196.dart.strong.transformed.expect

@@ -13,7 +13,6 @@ static method returnsString() → FutureOr<core::String*>* /* originally async *
   final asy::_Future<core::String*>* :async_future = new asy::_Future::•<core::String*>();
   core::bool* :is_sync = false;
   FutureOr<core::String*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -31,7 +30,6 @@ static method returnsString() → FutureOr<core::String*>* /* originally async *
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/bug33206.dart.strong.transformed.expect

@@ -44,7 +44,6 @@ static method f1() → asy::Future<core::List<core::Object*>*>* /* originally as
   final asy::_Future<core::List<core::Object*>*>* :async_future = new asy::_Future::•<core::List<core::Object*>*>();
   core::bool* :is_sync = false;
   FutureOr<core::List<core::Object*>*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -62,7 +61,6 @@ static method f1() → asy::Future<core::List<core::Object*>*>* /* originally as
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -75,7 +73,6 @@ static method f3() → asy::Future<core::Object*>* /* originally async */ {
   final asy::_Future<core::Object*>* :async_future = new asy::_Future::•<core::Object*>();
   core::bool* :is_sync = false;
   FutureOr<core::Object*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -93,7 +90,6 @@ static method f3() → asy::Future<core::Object*>* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -104,7 +100,6 @@ static method foo() → asy::Future<self::X*>* /* originally async */ {
   final asy::_Future<self::X*>* :async_future = new asy::_Future::•<self::X*>();
   core::bool* :is_sync = false;
   FutureOr<self::X*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -131,7 +126,6 @@ static method foo() → asy::Future<self::X*>* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -142,7 +136,6 @@ static method main() → asy::Future<void>* /* originally async */ {
   final asy::_Future<void>* :async_future = new asy::_Future::•<void>();
   core::bool* :is_sync = false;
   FutureOr<void>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -161,7 +154,6 @@ static method main() → asy::Future<void>* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/check_deferred_before_args2.dart.strong.transformed.expect

@@ -11,7 +11,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -31,7 +30,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/control_flow_collection_inference.dart.strong.transformed.expect

@@ -2342,7 +2342,6 @@ static method testForElementErrors(core::Map<core::int*, core::int*>* map, core:
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -2893,7 +2892,6 @@ static method testForElementErrors(core::Map<core::int*, core::int*>* map, core:
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/error_recovery/empty_await_for.dart.strong.transformed.expect

@@ -20,7 +20,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -67,7 +66,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/flutter_issue64155.dart.strong.transformed.expect

@@ -9,7 +9,6 @@ abstract class TestMixin<R extends core::Object* = dynamic, T extends core::Obje
     final asy::_Future<self::TestMixin::T*>* :async_future = new asy::_Future::•<self::TestMixin::T*>();
     core::bool* :is_sync = false;
     FutureOr<self::TestMixin::T*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -45,7 +44,6 @@ abstract class TestMixin<R extends core::Object* = dynamic, T extends core::Obje
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -129,7 +127,6 @@ abstract class _Class1&Object&TestMixin extends core::Object implements self::Te
     final asy::_Future<core::String*>* :async_future = new asy::_Future::•<core::String*>();
     core::bool* :is_sync = false;
     FutureOr<core::String*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -165,7 +162,6 @@ abstract class _Class1&Object&TestMixin extends core::Object implements self::Te
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -200,7 +196,6 @@ abstract class _Class2&Object&TestMixin extends core::Object implements self::Te
     final asy::_Future<core::String*>* :async_future = new asy::_Future::•<core::String*>();
     core::bool* :is_sync = false;
     FutureOr<core::String*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -236,7 +231,6 @@ abstract class _Class2&Object&TestMixin extends core::Object implements self::Te
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/general/future_or_test.dart.strong.transformed.expect

@@ -31,7 +31,6 @@ class B extends core::Object {
     final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
     core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -49,7 +48,6 @@ class B extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -76,7 +74,6 @@ class C extends core::Object {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -94,7 +91,6 @@ class C extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/general/future_return.dart.strong.transformed.expect

@@ -46,7 +46,6 @@ static method returnClass() → self::Class* /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -64,7 +63,6 @@ static method returnClass() → self::Class* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -75,7 +73,6 @@ static method returnFutureClass() → asy::Future<self::Class*>* /* originally a
   final asy::_Future<self::Class*>* :async_future = new asy::_Future::•<self::Class*>();
   core::bool* :is_sync = false;
   FutureOr<self::Class*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -93,7 +90,6 @@ static method returnFutureClass() → asy::Future<self::Class*>* /* originally a
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -104,7 +100,6 @@ static method returnFutureOrClass() → FutureOr<self::Class*>* /* originally as
   final asy::_Future<self::Class*>* :async_future = new asy::_Future::•<self::Class*>();
   core::bool* :is_sync = false;
   FutureOr<self::Class*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -122,7 +117,6 @@ static method returnFutureOrClass() → FutureOr<self::Class*>* /* originally as
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -133,7 +127,6 @@ static method returnClassFromDynamic() → self::Class* /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -151,7 +144,6 @@ static method returnClassFromDynamic() → self::Class* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -162,7 +154,6 @@ static method returnFutureClassDynamic() → asy::Future<self::Class*>* /* origi
   final asy::_Future<self::Class*>* :async_future = new asy::_Future::•<self::Class*>();
   core::bool* :is_sync = false;
   FutureOr<self::Class*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -180,7 +171,6 @@ static method returnFutureClassDynamic() → asy::Future<self::Class*>* /* origi
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -191,7 +181,6 @@ static method returnFutureOrClassDynamic() → FutureOr<self::Class*>* /* origin
   final asy::_Future<self::Class*>* :async_future = new asy::_Future::•<self::Class*>();
   core::bool* :is_sync = false;
   FutureOr<self::Class*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -209,7 +198,6 @@ static method returnFutureOrClassDynamic() → FutureOr<self::Class*>* /* origin
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -220,7 +208,6 @@ static method returnClassFromFutureClass() → self::Class* /* originally async
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -238,7 +225,6 @@ static method returnClassFromFutureClass() → self::Class* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -249,7 +235,6 @@ static method returnFutureClassFromFutureClass() → asy::Future<self::Class*>*
   final asy::_Future<self::Class*>* :async_future = new asy::_Future::•<self::Class*>();
   core::bool* :is_sync = false;
   FutureOr<self::Class*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -267,7 +252,6 @@ static method returnFutureClassFromFutureClass() → asy::Future<self::Class*>*
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -278,7 +262,6 @@ static method returnFutureOrClassFromFutureClass() → FutureOr<self::Class*>* /
   final asy::_Future<self::Class*>* :async_future = new asy::_Future::•<self::Class*>();
   core::bool* :is_sync = false;
   FutureOr<self::Class*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -296,7 +279,6 @@ static method returnFutureOrClassFromFutureClass() → FutureOr<self::Class*>* /
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -307,7 +289,6 @@ static method returnClassFromFutureOrClass() → self::Class* /* originally asyn
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -325,7 +306,6 @@ static method returnClassFromFutureOrClass() → self::Class* /* originally asyn
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -336,7 +316,6 @@ static method returnFutureClassFromFutureOrClass() → asy::Future<self::Class*>
   final asy::_Future<self::Class*>* :async_future = new asy::_Future::•<self::Class*>();
   core::bool* :is_sync = false;
   FutureOr<self::Class*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -354,7 +333,6 @@ static method returnFutureClassFromFutureOrClass() → asy::Future<self::Class*>
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -365,7 +343,6 @@ static method returnFutureOrClassFromFutureOrClass() → FutureOr<self::Class*>*
   final asy::_Future<self::Class*>* :async_future = new asy::_Future::•<self::Class*>();
   core::bool* :is_sync = false;
   FutureOr<self::Class*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -383,7 +360,6 @@ static method returnFutureOrClassFromFutureOrClass() → FutureOr<self::Class*>*
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -394,7 +370,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -435,7 +410,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/issue40662.dart.strong.transformed.expect

@@ -12,7 +12,6 @@ static method foo(core::int* x) → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -45,7 +44,6 @@ static method foo(core::int* x) → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -56,7 +54,6 @@ static method main() → void /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -76,7 +73,6 @@ static method main() → void /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -92,4 +88,4 @@ static method expect(dynamic expected, dynamic actual) → dynamic {
 Extra constant evaluation status:
 Evaluated: MethodInvocation @ org-dartlang-testcase:///issue40662.dart:8:10 -> IntConstant(-1)
 Evaluated: MethodInvocation @ org-dartlang-testcase:///issue40662.dart:9:10 -> IntConstant(-1)
-Extra constant evaluation: evaluated: 101, effectively constant: 2
+Extra constant evaluation: evaluated: 95, effectively constant: 2

pkg/front_end/testcases/general/issue42615.dart.strong.transformed.expect

@@ -27,7 +27,6 @@ static method main() → dynamic {
     final asy::_Future<core::List<dynamic>*>* :async_future = new asy::_Future::•<core::List<dynamic>*>();
     core::bool* :is_sync = false;
     FutureOr<core::List<dynamic>*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -45,7 +44,6 @@ static method main() → dynamic {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/general/no_such_method_forwarder.dart.strong.transformed.expect

@@ -12,7 +12,6 @@ class X extends core::Object {
     final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
     core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -32,7 +31,6 @@ class X extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/general/regression_flutter51828.dart.strong.transformed.expect

@@ -12,7 +12,6 @@ class A extends core::Object {
     final asy::_Future<void>* :async_future = new asy::_Future::•<void>();
     core::bool* :is_sync = false;
     FutureOr<void>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -27,7 +26,6 @@ class A extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -53,7 +51,6 @@ class B extends core::Object {
     final asy::_Future<void>* :async_future = new asy::_Future::•<void>();
     core::bool* :is_sync = false;
     FutureOr<void>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -68,7 +65,6 @@ class B extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -90,7 +86,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -116,7 +111,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general/statements.dart.strong.transformed.expect

@@ -15,7 +15,6 @@ static method foo() → dynamic {
 static method bar(dynamic d) → dynamic /* originally async* */ {
   asy::_AsyncStarStreamController<dynamic>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -69,7 +68,6 @@ static method bar(dynamic d) → dynamic /* originally async* */ {
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<dynamic>(:async_op);

pkg/front_end/testcases/general/stream_future.dart.strong.transformed.expect

@@ -38,7 +38,6 @@ static method returnFutureDynamic() → asy::Future<dynamic>* /* originally asyn
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -56,7 +55,6 @@ static method returnFutureDynamic() → asy::Future<dynamic>* /* originally asyn
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -67,7 +65,6 @@ static method returnFutureClass() → asy::Future<self::Class*>* /* originally a
   final asy::_Future<self::Class*>* :async_future = new asy::_Future::•<self::Class*>();
   core::bool* :is_sync = false;
   FutureOr<self::Class*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -85,7 +82,6 @@ static method returnFutureClass() → asy::Future<self::Class*>* /* originally a
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -95,7 +91,6 @@ static method returnFutureClass() → asy::Future<self::Class*>* /* originally a
 static method error() → asy::Stream<FutureOr<self::Class*>*>* /* originally async* */ {
   asy::_AsyncStarStreamController<FutureOr<self::Class*>*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -124,7 +119,6 @@ static method error() → asy::Stream<FutureOr<self::Class*>*>* /* originally as
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<FutureOr<self::Class*>*>(:async_op);
@@ -134,7 +128,6 @@ static method error() → asy::Stream<FutureOr<self::Class*>*>* /* originally as
 static method stream() → asy::Stream<FutureOr<self::Class*>*>* /* originally async* */ {
   asy::_AsyncStarStreamController<FutureOr<self::Class*>*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -167,7 +160,6 @@ static method stream() → asy::Stream<FutureOr<self::Class*>*>* /* originally a
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<FutureOr<self::Class*>*>(:async_op);
@@ -178,7 +170,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -221,7 +212,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/async_function.dart.weak.transformed.expect

@@ -11,7 +11,6 @@ static method asyncString() → asy::Future<core::String*>* /* originally async
   final asy::_Future<core::String*>* :async_future = new asy::_Future::•<core::String*>();
   core::bool* :is_sync = false;
   FutureOr<core::String*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -29,7 +28,6 @@ static method asyncString() → asy::Future<core::String*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -40,7 +38,6 @@ static method asyncString2() → asy::Future<core::String*>* /* originally async
   final asy::_Future<core::String*>* :async_future = new asy::_Future::•<core::String*>();
   core::bool* :is_sync = false;
   FutureOr<core::String*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -58,7 +55,6 @@ static method asyncString2() → asy::Future<core::String*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -110,7 +106,6 @@ static method syncStarString2() → core::Iterable<core::String*>* /* originally
 static method asyncStarString() → asy::Stream<core::String*>* /* originally async* */ {
   asy::_AsyncStarStreamController<core::String*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -144,7 +139,6 @@ static method asyncStarString() → asy::Stream<core::String*>* /* originally as
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::String*>(:async_op);
@@ -154,7 +148,6 @@ static method asyncStarString() → asy::Stream<core::String*>* /* originally as
 static method asyncStarString2() → asy::Stream<core::String*>* /* originally async* */ {
   asy::_AsyncStarStreamController<core::String*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -179,7 +172,6 @@ static method asyncStarString2() → asy::Stream<core::String*>* /* originally a
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::String*>(:async_op);
@@ -190,7 +182,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -209,7 +200,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/async_nested.dart.weak.transformed.expect

@@ -31,7 +31,6 @@ static method main() → void /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -69,7 +68,6 @@ static method main() → void /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/await.dart.weak.transformed.expect

@@ -8,7 +8,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -27,7 +26,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/await_complex.dart.weak.transformed.expect

@@ -60,7 +60,6 @@ static method staticMembers() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -107,7 +106,6 @@ static method staticMembers() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -118,7 +116,6 @@ static method topLevelMembers() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -160,7 +157,6 @@ static method topLevelMembers() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -171,7 +167,6 @@ static method instanceMembers() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -214,7 +209,6 @@ static method instanceMembers() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -225,7 +219,6 @@ static method others() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -268,7 +261,6 @@ static method others() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -279,7 +271,6 @@ static method conditionals() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -342,7 +333,6 @@ static method conditionals() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -353,7 +343,6 @@ static method asserts() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -417,7 +406,6 @@ static method asserts() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -428,7 +416,6 @@ static method controlFlow() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -562,7 +549,6 @@ static method controlFlow() → dynamic /* originally async */ {
                 final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
                 core::bool* :is_sync = false;
                 FutureOr<dynamic>* :return_value;
-                dynamic :async_stack_trace;
                 (dynamic) →* dynamic :async_op_then;
                 (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
                 core::int* :await_jump_var = 0;
@@ -582,7 +568,6 @@ static method controlFlow() → dynamic /* originally async */ {
                   on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
                     asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
                   }
-                :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
                 :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
                 :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
                 :async_op.call();
@@ -594,7 +579,6 @@ static method controlFlow() → dynamic /* originally async */ {
                 final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
                 core::bool* :is_sync = false;
                 FutureOr<dynamic>* :return_value;
-                dynamic :async_stack_trace;
                 (dynamic) →* dynamic :async_op_then;
                 (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
                 core::int* :await_jump_var = 0;
@@ -612,7 +596,6 @@ static method controlFlow() → dynamic /* originally async */ {
                   on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
                     asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
                   }
-                :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
                 :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
                 :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
                 :async_op.call();
@@ -623,7 +606,6 @@ static method controlFlow() → dynamic /* originally async */ {
               function testStream1() → asy::Stream<core::int*>* /* originally async* */ {
                 asy::_AsyncStarStreamController<core::int*>* :controller;
                 dynamic :controller_stream;
-                dynamic :async_stack_trace;
                 (dynamic) →* dynamic :async_op_then;
                 (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
                 core::int* :await_jump_var = 0;
@@ -649,7 +631,6 @@ static method controlFlow() → dynamic /* originally async */ {
                   finally {
                     :controller.{asy::_AsyncStarStreamController::close}();
                   }
-                :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
                 :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
                 :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
                 :controller = new asy::_AsyncStarStreamController::•<core::int*>(:async_op);
@@ -662,7 +643,6 @@ static method controlFlow() → dynamic /* originally async */ {
               function testStream2() → asy::Stream<core::int*>* /* originally async* */ {
                 asy::_AsyncStarStreamController<core::int*>* :controller;
                 dynamic :controller_stream;
-                dynamic :async_stack_trace;
                 (dynamic) →* dynamic :async_op_then;
                 (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
                 core::int* :await_jump_var = 0;
@@ -688,7 +668,6 @@ static method controlFlow() → dynamic /* originally async */ {
                   finally {
                     :controller.{asy::_AsyncStarStreamController::close}();
                   }
-                :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
                 :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
                 :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
                 :controller = new asy::_AsyncStarStreamController::•<core::int*>(:async_op);
@@ -708,7 +687,6 @@ static method controlFlow() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -719,7 +697,6 @@ static method future<T extends core::Object* = dynamic>(self::future::T* value)
   final asy::_Future<self::future::T*>* :async_future = new asy::_Future::•<self::future::T*>();
   core::bool* :is_sync = false;
   FutureOr<self::future::T*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -737,7 +714,6 @@ static method future<T extends core::Object* = dynamic>(self::future::T* value)
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -749,7 +725,6 @@ static method id<T extends core::Object* = dynamic>(self::id::T* value) → Futu
 static method intStream() → asy::Stream<core::int*>* /* originally async* */ {
   asy::_AsyncStarStreamController<core::int*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -774,7 +749,6 @@ static method intStream() → asy::Stream<core::int*>* /* originally async* */ {
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::int*>(:async_op);
@@ -785,7 +759,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -818,7 +791,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/await_in_cascade.dart.weak.transformed.expect

@@ -14,7 +14,6 @@ class C extends core::Object {
     final asy::_Future<core::List<core::int*>*>* :async_future = new asy::_Future::•<core::List<core::int*>*>();
     core::bool* :is_sync = false;
     FutureOr<core::List<core::int*>*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -36,7 +35,6 @@ class C extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -47,7 +45,6 @@ class C extends core::Object {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -65,7 +62,6 @@ class C extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -87,7 +83,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -106,7 +101,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/bug33196.dart.weak.transformed.expect

@@ -13,7 +13,6 @@ static method returnsString() → FutureOr<core::String*>* /* originally async *
   final asy::_Future<core::String*>* :async_future = new asy::_Future::•<core::String*>();
   core::bool* :is_sync = false;
   FutureOr<core::String*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -31,7 +30,6 @@ static method returnsString() → FutureOr<core::String*>* /* originally async *
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/bug33206.dart.weak.transformed.expect

@@ -44,7 +44,6 @@ static method f1() → asy::Future<core::List<core::Object*>*>* /* originally as
   final asy::_Future<core::List<core::Object*>*>* :async_future = new asy::_Future::•<core::List<core::Object*>*>();
   core::bool* :is_sync = false;
   FutureOr<core::List<core::Object*>*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -62,7 +61,6 @@ static method f1() → asy::Future<core::List<core::Object*>*>* /* originally as
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -75,7 +73,6 @@ static method f3() → asy::Future<core::Object*>* /* originally async */ {
   final asy::_Future<core::Object*>* :async_future = new asy::_Future::•<core::Object*>();
   core::bool* :is_sync = false;
   FutureOr<core::Object*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -93,7 +90,6 @@ static method f3() → asy::Future<core::Object*>* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -104,7 +100,6 @@ static method foo() → asy::Future<self::X*>* /* originally async */ {
   final asy::_Future<self::X*>* :async_future = new asy::_Future::•<self::X*>();
   core::bool* :is_sync = false;
   FutureOr<self::X*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -131,7 +126,6 @@ static method foo() → asy::Future<self::X*>* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -142,7 +136,6 @@ static method main() → asy::Future<void>* /* originally async */ {
   final asy::_Future<void>* :async_future = new asy::_Future::•<void>();
   core::bool* :is_sync = false;
   FutureOr<void>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -161,7 +154,6 @@ static method main() → asy::Future<void>* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/check_deferred_before_args2.dart.weak.transformed.expect

@@ -11,7 +11,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -31,7 +30,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/control_flow_collection_inference.dart.weak.transformed.expect

@@ -2342,7 +2342,6 @@ static method testForElementErrors(core::Map<core::int*, core::int*>* map, core:
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -2893,7 +2892,6 @@ static method testForElementErrors(core::Map<core::int*, core::int*>* map, core:
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/future_or_test.dart.weak.transformed.expect

@@ -31,7 +31,6 @@ class B extends core::Object {
     final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
     core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -49,7 +48,6 @@ class B extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -76,7 +74,6 @@ class C extends core::Object {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -94,7 +91,6 @@ class C extends core::Object {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/general_nnbd_opt_out/statements.dart.weak.transformed.expect

@@ -15,7 +15,6 @@ static method foo() → dynamic {
 static method bar(dynamic d) → dynamic /* originally async* */ {
   asy::_AsyncStarStreamController<dynamic>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -69,7 +68,6 @@ static method bar(dynamic d) → dynamic /* originally async* */ {
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<dynamic>(:async_op);

pkg/front_end/testcases/incremental_initialize_from_dill/no_outline_change_3.yaml.world.1.expect

@@ -5,7 +5,6 @@ library from "org-dartlang-test:///libA.dart" as libA {
     final dart.async::_Future<dynamic>* :async_future = new dart.async::_Future::•<dynamic>();
     dart.core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (dart.core::Object*, dart.core::StackTrace*) →* dynamic :async_op_error;
     dart.core::int* :await_jump_var = 0;
@@ -26,7 +25,6 @@ library from "org-dartlang-test:///libA.dart" as libA {
       on dynamic catch(dynamic exception, dart.core::StackTrace* stack_trace) {
         dart.async::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
     :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
     :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -59,7 +57,6 @@ library from "org-dartlang-test:///main.dart" as main {
     final dart.async::_Future<dynamic>* :async_future = new dart.async::_Future::•<dynamic>();
     dart.core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (dart.core::Object*, dart.core::StackTrace*) →* dynamic :async_op_error;
     dart.core::int* :await_jump_var = 0;
@@ -79,7 +76,6 @@ library from "org-dartlang-test:///main.dart" as main {
       on dynamic catch(dynamic exception, dart.core::StackTrace* stack_trace) {
         dart.async::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
     :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
     :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/incremental_initialize_from_dill/no_outline_change_3.yaml.world.2.expect

@@ -5,7 +5,6 @@ library from "org-dartlang-test:///libA.dart" as libA {
     final dart.async::_Future<dynamic>* :async_future = new dart.async::_Future::•<dynamic>();
     dart.core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (dart.core::Object*, dart.core::StackTrace*) →* dynamic :async_op_error;
     dart.core::int* :await_jump_var = 0;
@@ -26,7 +25,6 @@ library from "org-dartlang-test:///libA.dart" as libA {
       on dynamic catch(dynamic exception, dart.core::StackTrace* stack_trace) {
         dart.async::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
     :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
     :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -59,7 +57,6 @@ library from "org-dartlang-test:///main.dart" as main {
     final dart.async::_Future<dynamic>* :async_future = new dart.async::_Future::•<dynamic>();
     dart.core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (dart.core::Object*, dart.core::StackTrace*) →* dynamic :async_op_error;
     dart.core::int* :await_jump_var = 0;
@@ -80,7 +77,6 @@ library from "org-dartlang-test:///main.dart" as main {
       on dynamic catch(dynamic exception, dart.core::StackTrace* stack_trace) {
         dart.async::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
     :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
     :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/incremental_initialize_from_dill/no_outline_change_5.yaml.world.1.expect

@@ -23,7 +23,6 @@ library from "org-dartlang-test:///main.dart" as main {
     final dart.async::_Future<dynamic>* :async_future = new dart.async::_Future::•<dynamic>();
     dart.core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (dart.core::Object*, dart.core::StackTrace*) →* dynamic :async_op_error;
     dart.core::int* :await_jump_var = 0;
@@ -43,7 +42,6 @@ library from "org-dartlang-test:///main.dart" as main {
       on dynamic catch(dynamic exception, dart.core::StackTrace* stack_trace) {
         dart.async::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
     :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
     :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -54,7 +52,6 @@ library from "org-dartlang-test:///main.dart" as main {
     final dart.async::_Future<dynamic>* :async_future = new dart.async::_Future::•<dynamic>();
     dart.core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (dart.core::Object*, dart.core::StackTrace*) →* dynamic :async_op_error;
     dart.core::int* :await_jump_var = 0;
@@ -75,7 +72,6 @@ library from "org-dartlang-test:///main.dart" as main {
       on dynamic catch(dynamic exception, dart.core::StackTrace* stack_trace) {
         dart.async::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
     :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
     :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/incremental_initialize_from_dill/no_outline_change_5.yaml.world.2.expect

@@ -23,7 +23,6 @@ library from "org-dartlang-test:///main.dart" as main {
     final dart.async::_Future<dynamic>* :async_future = new dart.async::_Future::•<dynamic>();
     dart.core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (dart.core::Object*, dart.core::StackTrace*) →* dynamic :async_op_error;
     dart.core::int* :await_jump_var = 0;
@@ -43,7 +42,6 @@ library from "org-dartlang-test:///main.dart" as main {
       on dynamic catch(dynamic exception, dart.core::StackTrace* stack_trace) {
         dart.async::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
     :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
     :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -54,7 +52,6 @@ library from "org-dartlang-test:///main.dart" as main {
     final dart.async::_Future<dynamic>* :async_future = new dart.async::_Future::•<dynamic>();
     dart.core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (dart.core::Object*, dart.core::StackTrace*) →* dynamic :async_op_error;
     dart.core::int* :await_jump_var = 0;
@@ -75,7 +72,6 @@ library from "org-dartlang-test:///main.dart" as main {
       on dynamic catch(dynamic exception, dart.core::StackTrace* stack_trace) {
         dart.async::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
     :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
     :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/incremental_initialize_from_dill/no_outline_change_5.yaml.world.3.expect

@@ -23,7 +23,6 @@ library from "org-dartlang-test:///main.dart" as main {
     final dart.async::_Future<dynamic>* :async_future = new dart.async::_Future::•<dynamic>();
     dart.core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (dart.core::Object*, dart.core::StackTrace*) →* dynamic :async_op_error;
     dart.core::int* :await_jump_var = 0;
@@ -44,7 +43,6 @@ library from "org-dartlang-test:///main.dart" as main {
       on dynamic catch(dynamic exception, dart.core::StackTrace* stack_trace) {
         dart.async::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
     :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
     :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -55,7 +53,6 @@ library from "org-dartlang-test:///main.dart" as main {
     final dart.async::_Future<dynamic>* :async_future = new dart.async::_Future::•<dynamic>();
     dart.core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (dart.core::Object*, dart.core::StackTrace*) →* dynamic :async_op_error;
     dart.core::int* :await_jump_var = 0;
@@ -76,7 +73,6 @@ library from "org-dartlang-test:///main.dart" as main {
       on dynamic catch(dynamic exception, dart.core::StackTrace* stack_trace) {
         dart.async::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
     :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
     :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/async_await.dart.strong.transformed.expect

@@ -30,7 +30,6 @@ static method test() → void /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -54,7 +53,6 @@ static method test() → void /* originally async */ {
           final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
           core::bool* :is_sync = false;
           FutureOr<core::int*>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -72,7 +70,6 @@ static method test() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -83,7 +80,6 @@ static method test() → void /* originally async */ {
           final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
           core::bool* :is_sync = false;
           FutureOr<core::int*>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -101,7 +97,6 @@ static method test() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -112,7 +107,6 @@ static method test() → void /* originally async */ {
           final asy::_Future<asy::Future<core::int*>*>* :async_future = new asy::_Future::•<asy::Future<core::int*>*>();
           core::bool* :is_sync = false;
           FutureOr<asy::Future<core::int*>*>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -130,7 +124,6 @@ static method test() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -141,7 +134,6 @@ static method test() → void /* originally async */ {
           final asy::_Future<FutureOr<core::int*>*>* :async_future = new asy::_Future::•<FutureOr<core::int*>*>();
           core::bool* :is_sync = false;
           FutureOr<FutureOr<core::int*>*>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -159,7 +151,6 @@ static method test() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -170,7 +161,6 @@ static method test() → void /* originally async */ {
           final asy::_Future<self::MyFuture*>* :async_future = new asy::_Future::•<self::MyFuture*>();
           core::bool* :is_sync = false;
           FutureOr<self::MyFuture*>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -188,7 +178,6 @@ static method test() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -199,7 +188,6 @@ static method test() → void /* originally async */ {
           final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
           core::bool* :is_sync = false;
           FutureOr<core::int*>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -217,7 +205,6 @@ static method test() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -228,7 +215,6 @@ static method test() → void /* originally async */ {
           final asy::_Future<asy::Future<core::int*>*>* :async_future = new asy::_Future::•<asy::Future<core::int*>*>();
           core::bool* :is_sync = false;
           FutureOr<asy::Future<core::int*>*>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -246,7 +232,6 @@ static method test() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -257,7 +242,6 @@ static method test() → void /* originally async */ {
           final asy::_Future<FutureOr<core::int*>*>* :async_future = new asy::_Future::•<FutureOr<core::int*>*>();
           core::bool* :is_sync = false;
           FutureOr<FutureOr<core::int*>*>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -275,7 +259,6 @@ static method test() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -286,7 +269,6 @@ static method test() → void /* originally async */ {
           final asy::_Future<self::MyFuture*>* :async_future = new asy::_Future::•<self::MyFuture*>();
           core::bool* :is_sync = false;
           FutureOr<self::MyFuture*>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -304,7 +286,6 @@ static method test() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -315,7 +296,6 @@ static method test() → void /* originally async */ {
           final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
           core::bool* :is_sync = false;
           FutureOr<core::int*>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -333,7 +313,6 @@ static method test() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -367,7 +346,6 @@ static method test() → void /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/async_closure_return_type_flatten.dart.strong.transformed.expect

@@ -11,7 +11,6 @@ static field () →* asy::Future<core::int*>* g = () → asy::Future<core::int*>
   final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
   core::bool* :is_sync = false;
   FutureOr<core::int*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -29,7 +28,6 @@ static field () →* asy::Future<core::int*>* g = () → asy::Future<core::int*>
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/async_closure_return_type_future.dart.strong.transformed.expect

@@ -7,7 +7,6 @@ static field () →* asy::Future<core::int*>* f = () → asy::Future<core::int*>
   final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
   core::bool* :is_sync = false;
   FutureOr<core::int*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -25,7 +24,6 @@ static field () →* asy::Future<core::int*>* f = () → asy::Future<core::int*>
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/async_closure_return_type_future_or.dart.strong.transformed.expect

@@ -11,7 +11,6 @@ static field () →* asy::Future<core::int*>* g = () → asy::Future<core::int*>
   final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
   core::bool* :is_sync = false;
   FutureOr<core::int*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -29,7 +28,6 @@ static field () →* asy::Future<core::int*>* g = () → asy::Future<core::int*>
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/block_bodied_lambdas_async_all_returns_are_futures.dart.strong.transformed.expect

@@ -12,7 +12,6 @@ static method test() → dynamic {
     final asy::_Future<core::num*>* :async_future = new asy::_Future::•<core::num*>();
     core::bool* :is_sync = false;
     FutureOr<core::num*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -36,7 +35,6 @@ static method test() → dynamic {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/block_bodied_lambdas_async_all_returns_are_values.dart.strong.transformed.expect

@@ -12,7 +12,6 @@ static method test() → dynamic {
     final asy::_Future<core::num*>* :async_future = new asy::_Future::•<core::num*>();
     core::bool* :is_sync = false;
     FutureOr<core::num*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -36,7 +35,6 @@ static method test() → dynamic {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/block_bodied_lambdas_async_mix_of_values_and_futures.dart.strong.transformed.expect

@@ -12,7 +12,6 @@ static method test() → dynamic {
     final asy::_Future<core::num*>* :async_future = new asy::_Future::•<core::num*>();
     core::bool* :is_sync = false;
     FutureOr<core::num*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -36,7 +35,6 @@ static method test() → dynamic {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/block_bodied_lambdas_async_star.dart.strong.transformed.expect

@@ -9,7 +9,6 @@ static method test() → dynamic {
   () →* asy::Stream<core::num*>* f = () → asy::Stream<core::num*>* /* originally async* */ {
     asy::_AsyncStarStreamController<core::num*>* :controller;
     dynamic :controller_stream;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -39,7 +38,6 @@ static method test() → dynamic {
       finally {
         :controller.{asy::_AsyncStarStreamController::close}();
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :controller = new asy::_AsyncStarStreamController::•<core::num*>(:async_op);

pkg/front_end/testcases/inference/block_bodied_lambdas_infer_bottom_async.dart.strong.transformed.expect

@@ -10,7 +10,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -24,7 +23,6 @@ static method main() → dynamic /* originally async */ {
           final asy::_Future<Null>* :async_future = new asy::_Future::•<Null>();
           core::bool* :is_sync = false;
           FutureOr<Null>* :return_value;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -42,7 +40,6 @@ static method main() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -60,7 +57,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/block_bodied_lambdas_infer_bottom_async_star.dart.strong.transformed.expect

@@ -10,7 +10,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -23,7 +22,6 @@ static method main() → dynamic /* originally async */ {
         () →* asy::Stream<Null>* f = () → asy::Stream<Null>* /* originally async* */ {
           asy::_AsyncStarStreamController<Null>* :controller;
           dynamic :controller_stream;
-          dynamic :async_stack_trace;
           (dynamic) →* dynamic :async_op_then;
           (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
           core::int* :await_jump_var = 0;
@@ -48,7 +46,6 @@ static method main() → dynamic /* originally async */ {
             finally {
               :controller.{asy::_AsyncStarStreamController::close}();
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :controller = new asy::_AsyncStarStreamController::•<Null>(:async_op);
@@ -66,7 +63,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/downwards_inference_async_await.dart.strong.transformed.expect

@@ -10,7 +10,6 @@ static method main() → asy::Future<dynamic>* /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -32,7 +31,6 @@ static method main() → asy::Future<dynamic>* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/downwards_inference_for_each.dart.strong.transformed.expect

@@ -63,7 +63,6 @@ static method f() → asy::Future<dynamic>* /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -233,7 +232,6 @@ static method f() → asy::Future<dynamic>* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -244,7 +242,6 @@ static method main() → asy::Future<dynamic>* /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -327,7 +324,6 @@ static method main() → asy::Future<dynamic>* /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/downwards_inference_yield_yield_star.dart.strong.transformed.expect

@@ -86,7 +86,6 @@ abstract class MyStream<T extends core::Object* = dynamic> extends asy::Stream<s
 static method foo() → asy::Stream<core::List<core::int*>*>* /* originally async* */ {
   asy::_AsyncStarStreamController<core::List<core::int*>*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -131,7 +130,6 @@ static method foo() → asy::Stream<core::List<core::int*>*>* /* originally asyn
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::List<core::int*>*>(:async_op);

pkg/front_end/testcases/inference/for_each_downcast_iterable.dart.strong.transformed.expect

@@ -8,7 +8,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -90,7 +89,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/future_then.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -59,7 +58,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -70,7 +68,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -90,7 +87,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -101,7 +97,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -119,7 +114,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -130,7 +124,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -148,7 +141,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -163,7 +155,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -181,7 +172,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -192,7 +182,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -210,7 +199,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_2.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -59,7 +58,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -70,7 +68,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -90,7 +87,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -101,7 +97,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -119,7 +114,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -130,7 +124,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -148,7 +141,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -163,7 +155,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -181,7 +172,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -192,7 +182,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -210,7 +199,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_3.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -59,7 +58,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -70,7 +68,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -90,7 +87,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -101,7 +97,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -119,7 +114,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -130,7 +124,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -148,7 +141,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -163,7 +155,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -181,7 +172,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -192,7 +182,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -210,7 +199,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_4.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -59,7 +58,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -70,7 +68,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -90,7 +87,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -101,7 +97,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -119,7 +114,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -130,7 +124,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -148,7 +141,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -163,7 +155,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -181,7 +172,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -192,7 +182,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -210,7 +199,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_5.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -59,7 +58,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -70,7 +68,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -90,7 +87,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -101,7 +97,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -119,7 +114,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -130,7 +124,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -148,7 +141,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -163,7 +155,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -181,7 +172,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -192,7 +182,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -210,7 +199,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_6.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -59,7 +58,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -70,7 +68,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -90,7 +87,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -101,7 +97,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -119,7 +114,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -130,7 +124,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -148,7 +141,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -163,7 +155,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -181,7 +172,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -192,7 +182,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -210,7 +199,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_conditional.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -66,7 +65,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -77,7 +75,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -97,7 +94,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_conditional_2.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -66,7 +65,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -77,7 +75,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -97,7 +94,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_conditional_3.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -66,7 +65,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -77,7 +75,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -97,7 +94,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_conditional_4.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -66,7 +65,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -77,7 +75,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -97,7 +94,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_conditional_5.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -66,7 +65,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -77,7 +75,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -97,7 +94,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_conditional_6.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -66,7 +65,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -77,7 +75,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -97,7 +94,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_then_ifNull.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -67,7 +66,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -78,7 +76,6 @@ static method test() → void {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -98,7 +95,6 @@ static method test() → void {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/inference/future_union_async_conditional.dart.strong.transformed.expect

@@ -36,7 +36,6 @@ static method g1(core::bool* x) → asy::Future<core::int*>* /* originally async
   final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
   core::bool* :is_sync = false;
   FutureOr<core::int*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -54,7 +53,6 @@ static method g1(core::bool* x) → asy::Future<core::int*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -65,7 +63,6 @@ static method g2(core::bool* x) → asy::Future<core::int*>* /* originally async
   final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
   core::bool* :is_sync = false;
   FutureOr<core::int*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -83,7 +80,6 @@ static method g2(core::bool* x) → asy::Future<core::int*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -94,7 +90,6 @@ static method g3(core::bool* x) → asy::Future<core::int*>* /* originally async
   final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
   core::bool* :is_sync = false;
   FutureOr<core::int*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -113,7 +108,6 @@ static method g3(core::bool* x) → asy::Future<core::int*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/future_union_async_conditional_2.dart.strong.transformed.expect

@@ -36,7 +36,6 @@ static method g1(core::bool* x) → asy::Future<core::int*>* /* originally async
   final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
   core::bool* :is_sync = false;
   FutureOr<core::int*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -54,7 +53,6 @@ static method g1(core::bool* x) → asy::Future<core::int*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -65,7 +63,6 @@ static method g2(core::bool* x) → asy::Future<core::int*>* /* originally async
   final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
   core::bool* :is_sync = false;
   FutureOr<core::int*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -83,7 +80,6 @@ static method g2(core::bool* x) → asy::Future<core::int*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -94,7 +90,6 @@ static method g3(core::bool* x) → asy::Future<core::int*>* /* originally async
   final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
   core::bool* :is_sync = false;
   FutureOr<core::int*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -113,7 +108,6 @@ static method g3(core::bool* x) → asy::Future<core::int*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/future_union_downwards.dart.strong.transformed.expect

@@ -48,7 +48,6 @@ static method g2() → asy::Future<core::List<core::int*>*>* /* originally async
   final asy::_Future<core::List<core::int*>*>* :async_future = new asy::_Future::•<core::List<core::int*>*>();
   core::bool* :is_sync = false;
   FutureOr<core::List<core::int*>*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -66,7 +65,6 @@ static method g2() → asy::Future<core::List<core::int*>*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -77,7 +75,6 @@ static method g3() → asy::Future<core::List<core::int*>*>* /* originally async
   final asy::_Future<core::List<core::int*>*>* :async_future = new asy::_Future::•<core::List<core::int*>*>();
   core::bool* :is_sync = false;
   FutureOr<core::List<core::int*>*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -95,7 +92,6 @@ static method g3() → asy::Future<core::List<core::int*>*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/future_union_downwards_2.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method g2() → asy::Future<core::List<core::int*>*>* /* originally async
   final asy::_Future<core::List<core::int*>*>* :async_future = new asy::_Future::•<core::List<core::int*>*>();
   core::bool* :is_sync = false;
   FutureOr<core::List<core::int*>*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -57,7 +56,6 @@ static method g2() → asy::Future<core::List<core::int*>*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -68,7 +66,6 @@ static method g3() → asy::Future<core::List<core::int*>*>* /* originally async
   final asy::_Future<core::List<core::int*>*>* :async_future = new asy::_Future::•<core::List<core::int*>*>();
   core::bool* :is_sync = false;
   FutureOr<core::List<core::int*>*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -86,7 +83,6 @@ static method g3() → asy::Future<core::List<core::int*>*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/future_union_downwards_3.dart.strong.transformed.expect

@@ -48,7 +48,6 @@ static method g2() → asy::Future<core::List<core::int*>*>* /* originally async
   final asy::_Future<core::List<core::int*>*>* :async_future = new asy::_Future::•<core::List<core::int*>*>();
   core::bool* :is_sync = false;
   FutureOr<core::List<core::int*>*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -66,7 +65,6 @@ static method g2() → asy::Future<core::List<core::int*>*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -77,7 +75,6 @@ static method g3() → asy::Future<core::List<core::int*>*>* /* originally async
   final asy::_Future<core::List<core::int*>*>* :async_future = new asy::_Future::•<core::List<core::int*>*>();
   core::bool* :is_sync = false;
   FutureOr<core::List<core::int*>*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -95,7 +92,6 @@ static method g3() → asy::Future<core::List<core::int*>*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/future_union_downwards_4.dart.strong.transformed.expect

@@ -39,7 +39,6 @@ static method g2() → asy::Future<core::List<core::int*>*>* /* originally async
   final asy::_Future<core::List<core::int*>*>* :async_future = new asy::_Future::•<core::List<core::int*>*>();
   core::bool* :is_sync = false;
   FutureOr<core::List<core::int*>*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -57,7 +56,6 @@ static method g2() → asy::Future<core::List<core::int*>*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -68,7 +66,6 @@ static method g3() → asy::Future<core::List<core::int*>*>* /* originally async
   final asy::_Future<core::List<core::int*>*>* :async_future = new asy::_Future::•<core::List<core::int*>*>();
   core::bool* :is_sync = false;
   FutureOr<core::List<core::int*>*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -86,7 +83,6 @@ static method g3() → asy::Future<core::List<core::int*>*>* /* originally async
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/future_union_downwards_generic_method_with_future_return.dart.strong.transformed.expect

@@ -25,7 +25,6 @@ static method foo() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -46,7 +45,6 @@ static method foo() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/future_union_downwards_generic_method_with_generic_return.dart.strong.transformed.expect

@@ -12,7 +12,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -32,7 +31,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/future_union_upwards_generic_methods.dart.strong.transformed.expect

@@ -35,7 +35,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -61,7 +60,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/generator_closure.dart.strong.transformed.expect

@@ -10,7 +10,6 @@ static method main() → void {
   self::foo(() → asy::Stream<core::int*>* /* originally async* */ {
     asy::_AsyncStarStreamController<core::int*>* :controller;
     dynamic :controller_stream;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -39,7 +38,6 @@ static method main() → void {
       finally {
         :controller.{asy::_AsyncStarStreamController::close}();
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :controller = new asy::_AsyncStarStreamController::•<core::int*>(:async_op);

pkg/front_end/testcases/inference/infer_local_function_return_type.dart.strong.transformed.expect

@@ -10,7 +10,6 @@ static method test() → dynamic {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -28,7 +27,6 @@ static method test() → dynamic {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -42,7 +40,6 @@ static method test() → dynamic {
     final asy::_Future<core::int*>* :async_future = new asy::_Future::•<core::int*>();
     core::bool* :is_sync = false;
     FutureOr<core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -60,7 +57,6 @@ static method test() → dynamic {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -87,7 +83,6 @@ static method test() → dynamic {
   function f5() → asy::Stream<core::int*>* /* originally async* */ {
     asy::_AsyncStarStreamController<core::int*>* :controller;
     dynamic :controller_stream;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -112,7 +107,6 @@ static method test() → dynamic {
       finally {
         :controller.{asy::_AsyncStarStreamController::close}();
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :controller = new asy::_AsyncStarStreamController::•<core::int*>(:async_op);

pkg/front_end/testcases/inference/infer_types_on_loop_indices_for_each_loop_async.dart.strong.transformed.expect

@@ -59,7 +59,6 @@ class Bar<T extends asy::Stream<core::String*>* = asy::Stream<core::String*>*> e
     final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
     core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -104,7 +103,6 @@ class Bar<T extends asy::Stream<core::String*>* = asy::Stream<core::String*>*> e
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -130,7 +128,6 @@ class Baz<T extends core::Object* = dynamic, E extends asy::Stream<self::Baz::T*
     final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
     core::bool* :is_sync = false;
     FutureOr<dynamic>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -176,7 +173,6 @@ class Baz<T extends core::Object* = dynamic, E extends asy::Stream<self::Baz::T*
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -249,7 +245,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -451,7 +446,6 @@ Try changing the type of the variable.
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference/local_return_and_yield.dart.strong.transformed.expect

@@ -22,7 +22,6 @@ static method main() → dynamic {
     final asy::_Future<(core::int*) →* core::int*>* :async_future = new asy::_Future::•<(core::int*) →* core::int*>();
     core::bool* :is_sync = false;
     FutureOr<(core::int*) →* core::int*>* :return_value;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -43,7 +42,6 @@ static method main() → dynamic {
       on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -87,7 +85,6 @@ static method main() → dynamic {
   function e() → asy::Stream<(core::int*) →* core::int*>* /* originally async* */ {
     asy::_AsyncStarStreamController<(core::int*) →* core::int*>* :controller;
     dynamic :controller_stream;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -112,7 +109,6 @@ static method main() → dynamic {
       finally {
         :controller.{asy::_AsyncStarStreamController::close}();
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :controller = new asy::_AsyncStarStreamController::•<(core::int*) →* core::int*>(:async_op);
@@ -122,7 +118,6 @@ static method main() → dynamic {
   function f() → asy::Stream<(core::int*) →* core::int*>* /* originally async* */ {
     asy::_AsyncStarStreamController<(core::int*) →* core::int*>* :controller;
     dynamic :controller_stream;
-    dynamic :async_stack_trace;
     (dynamic) →* dynamic :async_op_then;
     (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
     core::int* :await_jump_var = 0;
@@ -147,7 +142,6 @@ static method main() → dynamic {
       finally {
         :controller.{asy::_AsyncStarStreamController::close}();
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :controller = new asy::_AsyncStarStreamController::•<(core::int*) →* core::int*>(:async_op);

pkg/front_end/testcases/inference/top_level_return_and_yield.dart.strong.transformed.expect

@@ -21,7 +21,6 @@ static method b() → asy::Future<(core::int*) →* core::int*>* /* originally a
   final asy::_Future<(core::int*) →* core::int*>* :async_future = new asy::_Future::•<(core::int*) →* core::int*>();
   core::bool* :is_sync = false;
   FutureOr<(core::int*) →* core::int*>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -42,7 +41,6 @@ static method b() → asy::Future<(core::int*) →* core::int*>* /* originally a
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -86,7 +84,6 @@ static method d() → core::Iterable<(core::int*) →* core::int*>* /* originall
 static method e() → asy::Stream<(core::int*) →* core::int*>* /* originally async* */ {
   asy::_AsyncStarStreamController<(core::int*) →* core::int*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -111,7 +108,6 @@ static method e() → asy::Stream<(core::int*) →* core::int*>* /* originally a
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<(core::int*) →* core::int*>(:async_op);
@@ -121,7 +117,6 @@ static method e() → asy::Stream<(core::int*) →* core::int*>* /* originally a
 static method f() → asy::Stream<(core::int*) →* core::int*>* /* originally async* */ {
   asy::_AsyncStarStreamController<(core::int*) →* core::int*>* :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -146,7 +141,6 @@ static method f() → asy::Stream<(core::int*) →* core::int*>* /* originally a
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<(core::int*) →* core::int*>(:async_op);

pkg/front_end/testcases/inference_new/for_each_invalid_iterable.dart.strong.transformed.expect

@@ -31,7 +31,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -129,7 +128,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/inference_new/for_each_outer_var_type.dart.strong.transformed.expect

@@ -47,7 +47,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic>* :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>* :return_value;
-  dynamic :async_stack_trace;
   (dynamic) →* dynamic :async_op_then;
   (core::Object*, core::StackTrace*) →* dynamic :async_op_error;
   core::int* :await_jump_var = 0;
@@ -208,7 +207,6 @@ Try changing the type of the variable.
     on dynamic catch(dynamic exception, core::StackTrace* stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/late_lowering/later.dart.strong.transformed.expect

@@ -140,7 +140,6 @@ static method hest() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -185,7 +184,6 @@ static method hest() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -196,7 +194,6 @@ static method fisk() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -225,7 +222,6 @@ static method fisk() → dynamic /* originally async */ {
             final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
             core::bool* :is_sync = false;
             FutureOr<dynamic>? :return_value;
-            dynamic :async_stack_trace;
             (dynamic) → dynamic :async_op_then;
             (core::Object, core::StackTrace) → dynamic :async_op_error;
             core::int :await_jump_var = 0;
@@ -245,7 +241,6 @@ static method fisk() → dynamic /* originally async */ {
               on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
                 asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
               }
-            :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
             :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
             :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
             :async_op.call();
@@ -261,7 +256,6 @@ static method fisk() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -276,4 +270,4 @@ constants  {
 
 Extra constant evaluation status:
 Evaluated: VariableGet @ org-dartlang-testcase:///later.dart:46:18 -> IntConstant(42)
-Extra constant evaluation: evaluated: 216, effectively constant: 1
+Extra constant evaluation: evaluated: 207, effectively constant: 1

pkg/front_end/testcases/late_lowering/later.dart.weak.transformed.expect

@@ -160,7 +160,6 @@ static method hest() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -205,7 +204,6 @@ static method hest() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -216,7 +214,6 @@ static method fisk() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -263,7 +260,6 @@ static method fisk() → dynamic /* originally async */ {
               final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
               core::bool* :is_sync = false;
               FutureOr<dynamic>? :return_value;
-              dynamic :async_stack_trace;
               (dynamic) → dynamic :async_op_then;
               (core::Object, core::StackTrace) → dynamic :async_op_error;
               core::int :await_jump_var = 0;
@@ -283,7 +279,6 @@ static method fisk() → dynamic /* originally async */ {
                 on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
                   asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
                 }
-              :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
               :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
               :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
               :async_op.call();
@@ -305,7 +300,6 @@ static method fisk() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/assignability_error_messages.dart.strong.transformed.expect

@@ -276,7 +276,6 @@ Try changing the type of the variable.
     final asy::_Future<self::A> :async_future = new asy::_Future::•<self::A>();
     core::bool* :is_sync = false;
     FutureOr<self::A>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -309,7 +308,6 @@ Try changing the type of the variable.
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -412,7 +410,6 @@ static method boz(Null x) → self::A {
     final asy::_Future<self::A> :async_future = new asy::_Future::•<self::A>();
     core::bool* :is_sync = false;
     FutureOr<self::A>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -443,7 +440,6 @@ static method boz(Null x) → self::A {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -470,4 +466,4 @@ Evaluated: VariableGet @ org-dartlang-testcase:///assignability_error_messages.d
 Evaluated: MethodInvocation @ org-dartlang-testcase:///assignability_error_messages.dart:77:14 -> BoolConstant(true)
 Evaluated: VariableGet @ org-dartlang-testcase:///assignability_error_messages.dart:77:14 -> NullConstant(null)
 Evaluated: VariableGet @ org-dartlang-testcase:///assignability_error_messages.dart:77:14 -> NullConstant(null)
-Extra constant evaluation: evaluated: 216, effectively constant: 12
+Extra constant evaluation: evaluated: 210, effectively constant: 12

pkg/front_end/testcases/nnbd/assignability_error_messages.dart.weak.transformed.expect

@@ -276,7 +276,6 @@ Try changing the type of the variable.
     final asy::_Future<self::A> :async_future = new asy::_Future::•<self::A>();
     core::bool* :is_sync = false;
     FutureOr<self::A>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -309,7 +308,6 @@ Try changing the type of the variable.
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -412,7 +410,6 @@ static method boz(Null x) → self::A {
     final asy::_Future<self::A> :async_future = new asy::_Future::•<self::A>();
     core::bool* :is_sync = false;
     FutureOr<self::A>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -443,7 +440,6 @@ static method boz(Null x) → self::A {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/nnbd/flutter_issue64155.dart.strong.transformed.expect

@@ -9,7 +9,6 @@ abstract class TestMixin<R extends core::Object? = dynamic, T extends core::Obje
     final asy::_Future<self::TestMixin::T%> :async_future = new asy::_Future::•<self::TestMixin::T%>();
     core::bool* :is_sync = false;
     FutureOr<self::TestMixin::T%>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -45,7 +44,6 @@ abstract class TestMixin<R extends core::Object? = dynamic, T extends core::Obje
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -79,7 +77,6 @@ abstract class _Class1&Object&TestMixin extends core::Object implements self::Te
     final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
     core::bool* :is_sync = false;
     FutureOr<core::String>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -115,7 +112,6 @@ abstract class _Class1&Object&TestMixin extends core::Object implements self::Te
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -140,7 +136,6 @@ abstract class _Class2&Object&TestMixin extends core::Object implements self::Te
     final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
     core::bool* :is_sync = false;
     FutureOr<core::String>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -176,7 +171,6 @@ abstract class _Class2&Object&TestMixin extends core::Object implements self::Te
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/nnbd/flutter_issue64155.dart.weak.transformed.expect

@@ -9,7 +9,6 @@ abstract class TestMixin<R extends core::Object? = dynamic, T extends core::Obje
     final asy::_Future<self::TestMixin::T%> :async_future = new asy::_Future::•<self::TestMixin::T%>();
     core::bool* :is_sync = false;
     FutureOr<self::TestMixin::T%>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -45,7 +44,6 @@ abstract class TestMixin<R extends core::Object? = dynamic, T extends core::Obje
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -79,7 +77,6 @@ abstract class _Class1&Object&TestMixin extends core::Object implements self::Te
     final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
     core::bool* :is_sync = false;
     FutureOr<core::String>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -115,7 +112,6 @@ abstract class _Class1&Object&TestMixin extends core::Object implements self::Te
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -140,7 +136,6 @@ abstract class _Class2&Object&TestMixin extends core::Object implements self::Te
     final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
     core::bool* :is_sync = false;
     FutureOr<core::String>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -176,7 +171,6 @@ abstract class _Class2&Object&TestMixin extends core::Object implements self::Te
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();

pkg/front_end/testcases/nnbd/issue41108.dart.strong.transformed.expect

@@ -16,7 +16,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -39,7 +38,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/issue41108.dart.weak.transformed.expect

@@ -16,7 +16,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -39,7 +38,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/issue41114.dart.strong.transformed.expect

@@ -7,7 +7,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -27,7 +26,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/issue41114.dart.weak.transformed.expect

@@ -7,7 +7,6 @@ static method main() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -27,7 +26,6 @@ static method main() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/issue41156.dart.strong.transformed.expect

@@ -59,7 +59,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -77,7 +76,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -88,7 +86,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -105,7 +102,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -116,7 +112,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -134,7 +129,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -145,7 +139,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -163,7 +156,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -174,7 +166,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -191,7 +182,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -202,7 +192,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -220,7 +209,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -232,7 +220,6 @@ static method errors() → void /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -285,7 +272,6 @@ static method errors() → void /* originally async */ {
           final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
           core::bool* :is_sync = false;
           FutureOr<core::String>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -310,7 +296,6 @@ static method errors() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -321,7 +306,6 @@ static method errors() → void /* originally async */ {
           final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
           core::bool* :is_sync = false;
           FutureOr<core::String>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -347,7 +331,6 @@ static method errors() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -358,7 +341,6 @@ static method errors() → void /* originally async */ {
           final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
           core::bool* :is_sync = false;
           FutureOr<core::String>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -383,7 +365,6 @@ static method errors() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -394,7 +375,6 @@ static method errors() → void /* originally async */ {
           final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
           core::bool* :is_sync = false;
           FutureOr<core::String>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -420,7 +400,6 @@ static method errors() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -434,7 +413,6 @@ static method errors() → void /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/issue41156.dart.weak.transformed.expect

@@ -60,7 +60,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -78,7 +77,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -89,7 +87,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -106,7 +103,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -117,7 +113,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -135,7 +130,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -146,7 +140,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -164,7 +157,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -175,7 +167,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -192,7 +183,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -203,7 +193,6 @@ static method main() → void {
     final asy::_Future<Never> :async_future = new asy::_Future::•<Never>();
     core::bool* :is_sync = false;
     FutureOr<Never>? :return_value;
-    dynamic :async_stack_trace;
     (dynamic) → dynamic :async_op_then;
     (core::Object, core::StackTrace) → dynamic :async_op_error;
     core::int :await_jump_var = 0;
@@ -221,7 +210,6 @@ static method main() → void {
       on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
         asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
       }
-    :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
     :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
     :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
     :async_op.call();
@@ -233,7 +221,6 @@ static method errors() → void /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -286,7 +273,6 @@ static method errors() → void /* originally async */ {
           final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
           core::bool* :is_sync = false;
           FutureOr<core::String>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -311,7 +297,6 @@ static method errors() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -322,7 +307,6 @@ static method errors() → void /* originally async */ {
           final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
           core::bool* :is_sync = false;
           FutureOr<core::String>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -348,7 +332,6 @@ static method errors() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -359,7 +342,6 @@ static method errors() → void /* originally async */ {
           final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
           core::bool* :is_sync = false;
           FutureOr<core::String>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -384,7 +366,6 @@ static method errors() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -395,7 +376,6 @@ static method errors() → void /* originally async */ {
           final asy::_Future<core::String> :async_future = new asy::_Future::•<core::String>();
           core::bool* :is_sync = false;
           FutureOr<core::String>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -421,7 +401,6 @@ static method errors() → void /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -435,7 +414,6 @@ static method errors() → void /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/issue41437a.dart.strong.transformed.expect

@@ -37,7 +37,6 @@ static method getFutureNull() → asy::Future<dynamic> /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -55,7 +54,6 @@ static method getFutureNull() → asy::Future<dynamic> /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -66,7 +64,6 @@ static method getFutureBool() → asy::Future<core::bool> /* originally async */
   final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
   core::bool* :is_sync = false;
   FutureOr<core::bool>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -84,7 +81,6 @@ static method getFutureBool() → asy::Future<core::bool> /* originally async */
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -95,7 +91,6 @@ static method test1() → asy::Future<core::bool> /* originally async */ {
   final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
   core::bool* :is_sync = false;
   FutureOr<core::bool>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -115,7 +110,6 @@ static method test1() → asy::Future<core::bool> /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -130,7 +124,6 @@ static method test4() → asy::Future<core::bool> /* originally async */ {
   final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
   core::bool* :is_sync = false;
   FutureOr<core::bool>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -150,7 +143,6 @@ static method test4() → asy::Future<core::bool> /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -168,7 +160,6 @@ static method test7() → asy::Future<core::bool> /* originally async */ {
   final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
   core::bool* :is_sync = false;
   FutureOr<core::bool>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -186,7 +177,6 @@ static method test7() → asy::Future<core::bool> /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -197,7 +187,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -210,7 +199,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
           core::bool* :is_sync = false;
           FutureOr<core::bool>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -230,7 +218,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -245,7 +232,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
           core::bool* :is_sync = false;
           FutureOr<core::bool>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -265,7 +251,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -283,7 +268,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
           core::bool* :is_sync = false;
           FutureOr<core::bool>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -301,7 +285,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -315,7 +298,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
           core::bool* :is_sync = false;
           FutureOr<dynamic>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -335,7 +317,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -351,7 +332,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
           core::bool* :is_sync = false;
           FutureOr<dynamic>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -371,7 +351,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -387,7 +366,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
           core::bool* :is_sync = false;
           FutureOr<core::bool>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -405,7 +383,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -419,7 +396,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/issue41437a.dart.weak.transformed.expect

@@ -37,7 +37,6 @@ static method getFutureNull() → asy::Future<dynamic> /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -55,7 +54,6 @@ static method getFutureNull() → asy::Future<dynamic> /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -66,7 +64,6 @@ static method getFutureBool() → asy::Future<core::bool> /* originally async */
   final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
   core::bool* :is_sync = false;
   FutureOr<core::bool>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -84,7 +81,6 @@ static method getFutureBool() → asy::Future<core::bool> /* originally async */
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -95,7 +91,6 @@ static method test1() → asy::Future<core::bool> /* originally async */ {
   final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
   core::bool* :is_sync = false;
   FutureOr<core::bool>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -115,7 +110,6 @@ static method test1() → asy::Future<core::bool> /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -130,7 +124,6 @@ static method test4() → asy::Future<core::bool> /* originally async */ {
   final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
   core::bool* :is_sync = false;
   FutureOr<core::bool>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -150,7 +143,6 @@ static method test4() → asy::Future<core::bool> /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -168,7 +160,6 @@ static method test7() → asy::Future<core::bool> /* originally async */ {
   final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
   core::bool* :is_sync = false;
   FutureOr<core::bool>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -186,7 +177,6 @@ static method test7() → asy::Future<core::bool> /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();
@@ -197,7 +187,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -210,7 +199,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
           core::bool* :is_sync = false;
           FutureOr<core::bool>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -230,7 +218,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -245,7 +232,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
           core::bool* :is_sync = false;
           FutureOr<core::bool>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -265,7 +251,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -283,7 +268,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
           core::bool* :is_sync = false;
           FutureOr<core::bool>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -301,7 +285,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -315,7 +298,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
           core::bool* :is_sync = false;
           FutureOr<dynamic>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -335,7 +317,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -351,7 +332,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
           core::bool* :is_sync = false;
           FutureOr<dynamic>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -371,7 +351,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -387,7 +366,6 @@ static method test() → dynamic /* originally async */ {
           final asy::_Future<core::bool> :async_future = new asy::_Future::•<core::bool>();
           core::bool* :is_sync = false;
           FutureOr<core::bool>? :return_value;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -405,7 +383,6 @@ static method test() → dynamic /* originally async */ {
             on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
               asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :async_op.call();
@@ -419,7 +396,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/issue41437b.dart.strong.transformed.expect

@@ -146,7 +146,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -291,7 +290,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/issue41437b.dart.weak.transformed.expect

@@ -146,7 +146,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -291,7 +290,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();

pkg/front_end/testcases/nnbd/issue41437c.dart.strong.transformed.expect

@@ -46,7 +46,6 @@ static method getNull() → dynamic
 static method getStreamNull() → asy::Stream<dynamic> /* originally async* */ {
   asy::_AsyncStarStreamController<dynamic>? :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -71,7 +70,6 @@ static method getStreamNull() → asy::Stream<dynamic> /* originally async* */ {
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<dynamic>(:async_op);
@@ -81,7 +79,6 @@ static method getStreamNull() → asy::Stream<dynamic> /* originally async* */ {
 static method getStreamBool() → asy::Stream<core::bool> /* originally async* */ {
   asy::_AsyncStarStreamController<core::bool>? :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -106,7 +103,6 @@ static method getStreamBool() → asy::Stream<core::bool> /* originally async* *
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::bool>(:async_op);
@@ -116,7 +112,6 @@ static method getStreamBool() → asy::Stream<core::bool> /* originally async* *
 static method test1() → asy::Stream<core::bool> /* originally async* */ {
   asy::_AsyncStarStreamController<core::bool>? :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -141,7 +136,6 @@ static method test1() → asy::Stream<core::bool> /* originally async* */ {
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::bool>(:async_op);
@@ -155,7 +149,6 @@ static method test3() → core::bool
 static method test4() → asy::Stream<core::bool> /* originally async* */ {
   asy::_AsyncStarStreamController<core::bool>? :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -183,7 +176,6 @@ static method test4() → asy::Stream<core::bool> /* originally async* */ {
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::bool>(:async_op);
@@ -200,7 +192,6 @@ static method test6() → asy::Stream<core::bool>
 static method test7() → asy::Stream<core::bool> /* originally async* */ {
   asy::_AsyncStarStreamController<core::bool>? :controller;
   dynamic :controller_stream;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -225,7 +216,6 @@ static method test7() → asy::Stream<core::bool> /* originally async* */ {
     finally {
       :controller.{asy::_AsyncStarStreamController::close}();
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :controller = new asy::_AsyncStarStreamController::•<core::bool>(:async_op);
@@ -236,7 +226,6 @@ static method test() → dynamic /* originally async */ {
   final asy::_Future<dynamic> :async_future = new asy::_Future::•<dynamic>();
   core::bool* :is_sync = false;
   FutureOr<dynamic>? :return_value;
-  dynamic :async_stack_trace;
   (dynamic) → dynamic :async_op_then;
   (core::Object, core::StackTrace) → dynamic :async_op_error;
   core::int :await_jump_var = 0;
@@ -248,7 +237,6 @@ static method test() → dynamic /* originally async */ {
         function test1() → asy::Stream<core::bool> /* originally async* */ {
           asy::_AsyncStarStreamController<core::bool>? :controller;
           dynamic :controller_stream;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -273,7 +261,6 @@ static method test() → dynamic /* originally async */ {
             finally {
               :controller.{asy::_AsyncStarStreamController::close}();
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :controller = new asy::_AsyncStarStreamController::•<core::bool>(:async_op);
@@ -287,7 +274,6 @@ static method test() → dynamic /* originally async */ {
         function test4() → asy::Stream<core::bool> /* originally async* */ {
           asy::_AsyncStarStreamController<core::bool>? :controller;
           dynamic :controller_stream;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -315,7 +301,6 @@ static method test() → dynamic /* originally async */ {
             finally {
               :controller.{asy::_AsyncStarStreamController::close}();
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :controller = new asy::_AsyncStarStreamController::•<core::bool>(:async_op);
@@ -332,7 +317,6 @@ static method test() → dynamic /* originally async */ {
         function test7() → asy::Stream<core::bool> /* originally async* */ {
           asy::_AsyncStarStreamController<core::bool>? :controller;
           dynamic :controller_stream;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -357,7 +341,6 @@ static method test() → dynamic /* originally async */ {
             finally {
               :controller.{asy::_AsyncStarStreamController::close}();
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :controller = new asy::_AsyncStarStreamController::•<core::bool>(:async_op);
@@ -370,7 +353,6 @@ static method test() → dynamic /* originally async */ {
     ^" in (() → asy::Stream<dynamic> /* originally async* */ {
           asy::_AsyncStarStreamController<dynamic>? :controller;
           dynamic :controller_stream;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -395,7 +377,6 @@ static method test() → dynamic /* originally async */ {
             finally {
               :controller.{asy::_AsyncStarStreamController::close}();
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :controller = new asy::_AsyncStarStreamController::•<dynamic>(:async_op);
@@ -410,7 +391,6 @@ static method test() → dynamic /* originally async */ {
     ^" in (() → asy::Stream<dynamic> /* originally async* */ {
           asy::_AsyncStarStreamController<dynamic>? :controller;
           dynamic :controller_stream;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -435,7 +415,6 @@ static method test() → dynamic /* originally async */ {
             finally {
               :controller.{asy::_AsyncStarStreamController::close}();
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :controller = new asy::_AsyncStarStreamController::•<dynamic>(:async_op);
@@ -450,7 +429,6 @@ static method test() → dynamic /* originally async */ {
         asy::Stream<core::bool> var7 = (() → asy::Stream<core::bool> /* originally async* */ {
           asy::_AsyncStarStreamController<core::bool>? :controller;
           dynamic :controller_stream;
-          dynamic :async_stack_trace;
           (dynamic) → dynamic :async_op_then;
           (core::Object, core::StackTrace) → dynamic :async_op_error;
           core::int :await_jump_var = 0;
@@ -475,7 +453,6 @@ static method test() → dynamic /* originally async */ {
             finally {
               :controller.{asy::_AsyncStarStreamController::close}();
             }
-          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
           :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
           :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
           :controller = new asy::_AsyncStarStreamController::•<core::bool>(:async_op);
@@ -489,7 +466,6 @@ static method test() → dynamic /* originally async */ {
     on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
       asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
     }
-  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
   :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
   :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
   :async_op.call();