Consider warning about misuse of query parameters with BaseModel

[nvgoldin]

I've noticed several times, especially for new users - a common mistake is to put for a in a GET request with query parameters, a BaseModel type annotation, causing the OpenAPI docs to miss the parameter entirely. Consider the following code:

from pydantic import BaseModel
from fastapi import FastAPI


class UserDetails(BaseModel):
    username: str
    full_name: str


api = FastAPI()


@api.get('/user-details')
def get_user_details(details: UserDetails):
    pass

The rendered OpenAPI documentation parameters is empty:

Is this something that would be worth solving? I think it would ease the on-boarding of new users. I can think of two solutions:

1. Printing a warning message in debug mode when that usage is detected.
2. Throwing an exception? probably too intrusive.

What do yo think? would be happy to implement the solution.