TypeError: Cannot read properties of undefined (reading 'push')

[ChristianSiegert]

I have received the following error many times now (but cannot reproduce it reliably):

error: (in promise) TypeError: Cannot read properties of undefined (reading 'push')
          () => this.#available_connections!.push(client),
                                             ^
    at PoolClient.<anonymous> ([redacted]/vendor/deno.land/x/[email protected]/pool.ts:191:46)
    at PoolClient.release ([redacted]/vendor/deno.land/x/[email protected]/client.ts:499:18)

pool.ts line 191 reads:

() => this.#available_connections!.push(client),

The exclamation mark is code smell because it suppresses a compiler warning. Without it, deno complains this.#available_connections is possibly 'undefined'. I think this case should be handled properly.