Fixing await

_test.py

import asyncio
import sys


def run(main):
    def coro_wrapper(coro):
        if not sys._getframe(1).f_inawait:
            raise RuntimeError(
                'creating a coroutine outside of await expression')
        return coro

    c = main()

    old_wrapper = sys.get_coroutine_wrapper()
    sys.set_coroutine_wrapper(coro_wrapper)

    loop = asyncio.get_event_loop()
    try:
        loop.run_until_complete(c)
    finally:
        sys.set_coroutine_wrapper(old_wrapper)
        loop.close()


async def baz():
    print('hi')


async def bar():
    await baz()  # try removing "await"


async def foo():
    await bar()


run(foo)

noawait.out

Traceback (most recent call last):
  File "t.py", line 37, in <module>
    run(foo)
  File "t.py", line 19, in run
    loop.run_until_complete(c)
  File "/Users/yury/dev/py/cpython/Lib/asyncio/base_events.py", line 465, in run_until_complete
    return future.result()
  File "t.py", line 34, in foo
    await bar()
  File "t.py", line 30, in bar
    baz()  # try removing "await"
  File "t.py", line 9, in coro_wrapper
    'creating a coroutine outside of await expression')
RuntimeError: creating a coroutine outside of await expression