library /*isNonNullableByDefault*/;
//
// Problems in library:
//
// pkg/front_end/testcases/nnbd/issue41437a.dart:14:31: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'FutureOr<bool>'.
//  - 'Future' is from 'dart:async'.
//  - 'FutureOr' is from 'dart:async'.
// Future<bool> test1() async => await getNull(); // error
//                               ^
//
// pkg/front_end/testcases/nnbd/issue41437a.dart:17:31: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'FutureOr<bool>'.
//  - 'Future' is from 'dart:async'.
//  - 'FutureOr' is from 'dart:async'.
// Future<bool> test4() async => await getFutureNull(); // error
//                               ^
//
// pkg/front_end/testcases/nnbd/issue41437a.dart:18:25: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'Future<bool>'.
//  - 'Future' is from 'dart:async'.
// Future<bool> test5() => getFutureNull(); // error
//                         ^
//
// pkg/front_end/testcases/nnbd/issue41437a.dart:23:33: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'FutureOr<bool>'.
//  - 'Future' is from 'dart:async'.
//  - 'FutureOr' is from 'dart:async'.
//   Future<bool> test1() async => await getNull(); // error
//                                 ^
//
// pkg/front_end/testcases/nnbd/issue41437a.dart:26:33: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'FutureOr<bool>'.
//  - 'Future' is from 'dart:async'.
//  - 'FutureOr' is from 'dart:async'.
//   Future<bool> test4() async => await getFutureNull(); // error
//                                 ^
//
// pkg/front_end/testcases/nnbd/issue41437a.dart:27:27: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'Future<bool>'.
//  - 'Future' is from 'dart:async'.
//   Future<bool> test5() => getFutureNull(); // error
//                           ^
//
// pkg/front_end/testcases/nnbd/issue41437a.dart:31:52: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'Future<bool>'.
//  - 'Future' is from 'dart:async'.
//   Future<bool> var1 = (() async => await getNull())(); // error
//                                                    ^
//
// pkg/front_end/testcases/nnbd/issue41437a.dart:34:58: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'Future<bool>'.
//  - 'Future' is from 'dart:async'.
//   Future<bool> var4 = (() async => await getFutureNull())(); // error
//                                                          ^
//
// pkg/front_end/testcases/nnbd/issue41437a.dart:35:46: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'Future<bool>'.
//  - 'Future' is from 'dart:async'.
//   Future<bool> var5 = (() => getFutureNull())(); // error
//                                              ^
//
import self as self;
import "dart:async" as asy;
import "dart:core" as core;

static method getNull() → dynamic
  return null;
static method getFutureNull() → asy::Future<dynamic> /* originally async */ {
  final asy::_AsyncAwaitCompleter<dynamic> :async_completer = new asy::_AsyncAwaitCompleter::•<dynamic>();
  asy::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;
  dynamic :await_ctx_var;
  function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
    try {
      #L1:
      {
        :return_value = null;
        break #L1;
      }
      asy::_completeOnAsyncReturn(:async_completer, :return_value);
      return;
    }
    on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
      :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
    }
  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
  :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
  :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
  :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
  return :async_completer.{asy::Completer::future};
}
static method getFutureBool() → asy::Future<core::bool> /* originally async */ {
  final asy::_AsyncAwaitCompleter<core::bool> :async_completer = new asy::_AsyncAwaitCompleter::•<core::bool>();
  asy::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;
  dynamic :await_ctx_var;
  function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
    try {
      #L2:
      {
        :return_value = true;
        break #L2;
      }
      asy::_completeOnAsyncReturn(:async_completer, :return_value);
      return;
    }
    on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
      :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
    }
  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
  :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
  :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
  :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
  return :async_completer.{asy::Completer::future};
}
static method test1() → asy::Future<core::bool> /* originally async */ {
  final asy::_AsyncAwaitCompleter<core::bool> :async_completer = new asy::_AsyncAwaitCompleter::•<core::bool>();
  asy::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;
  dynamic :await_ctx_var;
  dynamic :saved_try_context_var0;
  function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
    try {
      #L3:
      {
        final<BottomType> #t1 = invalid-expression "pkg/front_end/testcases/nnbd/issue41437a.dart:14:31: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'FutureOr<bool>'.
 - 'Future' is from 'dart:async'.
 - 'FutureOr' is from 'dart:async'.
Future<bool> test1() async => await getNull(); // error
                              ^";
        [yield] let dynamic #t2 = asy::_awaitHelper(self::getNull(), :async_op_then, :async_op_error, :async_op) in null;
        :return_value = :result as{TypeError,ForNonNullableByDefault} asy::FutureOr<core::bool>;
        break #L3;
      }
      asy::_completeOnAsyncReturn(:async_completer, :return_value);
      return;
    }
    on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
      :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
    }
  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
  :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
  :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
  :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
  return :async_completer.{asy::Completer::future};
}
static method test2() → asy::Future<core::bool>
  return self::getNull() as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<core::bool>;
static method test3() → core::bool
  return self::getNull() as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool;
static method test4() → asy::Future<core::bool> /* originally async */ {
  final asy::_AsyncAwaitCompleter<core::bool> :async_completer = new asy::_AsyncAwaitCompleter::•<core::bool>();
  asy::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;
  dynamic :await_ctx_var;
  dynamic :saved_try_context_var0;
  function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
    try {
      #L4:
      {
        final<BottomType> #t3 = invalid-expression "pkg/front_end/testcases/nnbd/issue41437a.dart:17:31: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'FutureOr<bool>'.
 - 'Future' is from 'dart:async'.
 - 'FutureOr' is from 'dart:async'.
Future<bool> test4() async => await getFutureNull(); // error
                              ^";
        [yield] let dynamic #t4 = asy::_awaitHelper(self::getFutureNull(), :async_op_then, :async_op_error, :async_op) in null;
        :return_value = :result as{TypeError,ForNonNullableByDefault} asy::FutureOr<core::bool>;
        break #L4;
      }
      asy::_completeOnAsyncReturn(:async_completer, :return_value);
      return;
    }
    on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
      :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
    }
  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
  :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
  :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
  :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
  return :async_completer.{asy::Completer::future};
}
static method test5() → asy::Future<core::bool>
  return let final<BottomType> #t5 = invalid-expression "pkg/front_end/testcases/nnbd/issue41437a.dart:18:25: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'Future<bool>'.
 - 'Future' is from 'dart:async'.
Future<bool> test5() => getFutureNull(); // error
                        ^" in self::getFutureNull() as{TypeError,ForNonNullableByDefault} asy::Future<core::bool>;
static method test6() → asy::Future<core::bool>
  return self::getFutureBool();
static method test7() → asy::Future<core::bool> /* originally async */ {
  final asy::_AsyncAwaitCompleter<core::bool> :async_completer = new asy::_AsyncAwaitCompleter::•<core::bool>();
  asy::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;
  dynamic :await_ctx_var;
  function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
    try {
      #L5:
      {
        :return_value = self::getFutureBool();
        break #L5;
      }
      asy::_completeOnAsyncReturn(:async_completer, :return_value);
      return;
    }
    on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
      :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
    }
  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
  :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
  :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
  :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
  return :async_completer.{asy::Completer::future};
}
static method test() → dynamic /* originally async */ {
  final asy::_AsyncAwaitCompleter<dynamic> :async_completer = new asy::_AsyncAwaitCompleter::•<dynamic>();
  asy::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;
  dynamic :await_ctx_var;
  function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
    try {
      #L6:
      {
        function test1() → asy::Future<core::bool> /* originally async */ {
          final asy::_AsyncAwaitCompleter<core::bool> :async_completer = new asy::_AsyncAwaitCompleter::•<core::bool>();
          asy::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;
          dynamic :await_ctx_var;
          dynamic :saved_try_context_var0;
          function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
            try {
              #L7:
              {
                final<BottomType> #t6 = invalid-expression "pkg/front_end/testcases/nnbd/issue41437a.dart:23:33: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'FutureOr<bool>'.
 - 'Future' is from 'dart:async'.
 - 'FutureOr' is from 'dart:async'.
  Future<bool> test1() async => await getNull(); // error
                                ^";
                [yield] let dynamic #t7 = asy::_awaitHelper(self::getNull(), :async_op_then, :async_op_error, :async_op) in null;
                :return_value = :result as{TypeError,ForNonNullableByDefault} asy::FutureOr<core::bool>;
                break #L7;
              }
              asy::_completeOnAsyncReturn(:async_completer, :return_value);
              return;
            }
            on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
              :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
            }
          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
          :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
          :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
          :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
          return :async_completer.{asy::Completer::future};
        }
        function test2() → asy::Future<core::bool>
          return self::getNull() as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<core::bool>;
        function test3() → core::bool
          return self::getNull() as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool;
        function test4() → asy::Future<core::bool> /* originally async */ {
          final asy::_AsyncAwaitCompleter<core::bool> :async_completer = new asy::_AsyncAwaitCompleter::•<core::bool>();
          asy::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;
          dynamic :await_ctx_var;
          dynamic :saved_try_context_var0;
          function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
            try {
              #L8:
              {
                final<BottomType> #t8 = invalid-expression "pkg/front_end/testcases/nnbd/issue41437a.dart:26:33: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'FutureOr<bool>'.
 - 'Future' is from 'dart:async'.
 - 'FutureOr' is from 'dart:async'.
  Future<bool> test4() async => await getFutureNull(); // error
                                ^";
                [yield] let dynamic #t9 = asy::_awaitHelper(self::getFutureNull(), :async_op_then, :async_op_error, :async_op) in null;
                :return_value = :result as{TypeError,ForNonNullableByDefault} asy::FutureOr<core::bool>;
                break #L8;
              }
              asy::_completeOnAsyncReturn(:async_completer, :return_value);
              return;
            }
            on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
              :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
            }
          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
          :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
          :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
          :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
          return :async_completer.{asy::Completer::future};
        }
        function test5() → asy::Future<core::bool>
          return let final<BottomType> #t10 = invalid-expression "pkg/front_end/testcases/nnbd/issue41437a.dart:27:27: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'Future<bool>'.
 - 'Future' is from 'dart:async'.
  Future<bool> test5() => getFutureNull(); // error
                          ^" in self::getFutureNull() as{TypeError,ForNonNullableByDefault} asy::Future<core::bool>;
        function test6() → asy::Future<core::bool>
          return self::getFutureBool();
        function test7() → asy::Future<core::bool> /* originally async */ {
          final asy::_AsyncAwaitCompleter<core::bool> :async_completer = new asy::_AsyncAwaitCompleter::•<core::bool>();
          asy::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;
          dynamic :await_ctx_var;
          function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
            try {
              #L9:
              {
                :return_value = self::getFutureBool();
                break #L9;
              }
              asy::_completeOnAsyncReturn(:async_completer, :return_value);
              return;
            }
            on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
              :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
            }
          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
          :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
          :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
          :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
          return :async_completer.{asy::Completer::future};
        }
        asy::Future<core::bool> var1 = let final<BottomType> #t11 = invalid-expression "pkg/front_end/testcases/nnbd/issue41437a.dart:31:52: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'Future<bool>'.
 - 'Future' is from 'dart:async'.
  Future<bool> var1 = (() async => await getNull())(); // error
                                                   ^" in (() → asy::Future<dynamic> /* originally async */ {
          final asy::_AsyncAwaitCompleter<dynamic> :async_completer = new asy::_AsyncAwaitCompleter::•<dynamic>();
          asy::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;
          dynamic :await_ctx_var;
          dynamic :saved_try_context_var0;
          function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
            try {
              #L10:
              {
                [yield] let dynamic #t12 = asy::_awaitHelper(self::getNull(), :async_op_then, :async_op_error, :async_op) in null;
                :return_value = :result;
                break #L10;
              }
              asy::_completeOnAsyncReturn(:async_completer, :return_value);
              return;
            }
            on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
              :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
            }
          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
          :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
          :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
          :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
          return :async_completer.{asy::Completer::future};
        }).call() as{TypeError,ForNonNullableByDefault} asy::Future<core::bool>;
        asy::Future<core::bool> var2 = (() → dynamic => self::getNull()).call() as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<core::bool>;
        core::bool var3 = (() → dynamic => self::getNull()).call() as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool;
        asy::Future<core::bool> var4 = let final<BottomType> #t13 = invalid-expression "pkg/front_end/testcases/nnbd/issue41437a.dart:34:58: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'Future<bool>'.
 - 'Future' is from 'dart:async'.
  Future<bool> var4 = (() async => await getFutureNull())(); // error
                                                         ^" in (() → asy::Future<dynamic> /* originally async */ {
          final asy::_AsyncAwaitCompleter<dynamic> :async_completer = new asy::_AsyncAwaitCompleter::•<dynamic>();
          asy::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;
          dynamic :await_ctx_var;
          dynamic :saved_try_context_var0;
          function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
            try {
              #L11:
              {
                [yield] let dynamic #t14 = asy::_awaitHelper(self::getFutureNull(), :async_op_then, :async_op_error, :async_op) in null;
                :return_value = :result;
                break #L11;
              }
              asy::_completeOnAsyncReturn(:async_completer, :return_value);
              return;
            }
            on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
              :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
            }
          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
          :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
          :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
          :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
          return :async_completer.{asy::Completer::future};
        }).call() as{TypeError,ForNonNullableByDefault} asy::Future<core::bool>;
        asy::Future<core::bool> var5 = let final<BottomType> #t15 = invalid-expression "pkg/front_end/testcases/nnbd/issue41437a.dart:35:46: Error: A value of type 'Future<dynamic>' can't be assigned to a variable of type 'Future<bool>'.
 - 'Future' is from 'dart:async'.
  Future<bool> var5 = (() => getFutureNull())(); // error
                                             ^" in (() → asy::Future<dynamic> => self::getFutureNull()).call() as{TypeError,ForNonNullableByDefault} asy::Future<core::bool>;
        asy::Future<core::bool> var6 = (() → asy::Future<core::bool> => self::getFutureBool()).call();
        asy::Future<core::bool> var7 = (() → asy::Future<core::bool> /* originally async */ {
          final asy::_AsyncAwaitCompleter<core::bool> :async_completer = new asy::_AsyncAwaitCompleter::•<core::bool>();
          asy::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;
          dynamic :await_ctx_var;
          function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
            try {
              #L12:
              {
                :return_value = self::getFutureBool();
                break #L12;
              }
              asy::_completeOnAsyncReturn(:async_completer, :return_value);
              return;
            }
            on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
              :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
            }
          :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
          :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
          :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
          :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
          return :async_completer.{asy::Completer::future};
        }).call();
      }
      asy::_completeOnAsyncReturn(:async_completer, :return_value);
      return;
    }
    on dynamic catch(dynamic :exception, core::StackTrace :stack_trace) {
      :async_completer.{asy::Completer::completeError}(:exception, :stack_trace);
    }
  :async_stack_trace = asy::_asyncStackTraceHelper(:async_op);
  :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
  :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
  :async_completer.{asy::_AsyncAwaitCompleter::start}(:async_op);
  return :async_completer.{asy::Completer::future};
}
static method main() → dynamic {}