library /*isNonNullableByDefault*/;
import self as self;
import "dart:core" as core;
import "dart:async" as asy;

import "dart:async";

static method foo<X extends core::Object?>(self::foo::X% 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) → 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_or_exception, dynamic :stack_trace) → dynamic yielding 
    try {
      #L1:
      {
        if(x is{ForNonNullableByDefault} asy::Future<core::int>) {
          :return_value = x{self::foo::X% & asy::Future<core::int> /* '%' & '!' = '!' */};
          break #L1;
        }
        else {
          throw 42;
        }
      }
      asy::_completeOnAsyncReturn(:async_future, :return_value, :is_sync);
      return;
    }
    on dynamic catch(dynamic exception, core::StackTrace stack_trace) {
      asy::_completeOnAsyncError(:async_future, exception, stack_trace, :is_sync);
    }
  :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
  :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
  :async_op(null, null){() → dynamic};
  :is_sync = true;
  return :async_future;
}
static method main() → dynamic {}