fix: signIn infer provider type

[ArthurPedroti]

The "P" type it's not passed in any props, so the result type doesn't understand and returns the "false type" always, Adding the "P" at provider type props.

My local test implementation:

// next-auth.d.ts
import 'next-auth'
import {
  BuiltInProviderType,
  RedirectableProviderType
} from 'next-auth/providers'
import {
  LiteralUnion,
  SignInAuthorizationParams,
  SignInOptions,
  SignInResponse
} from 'next-auth/react'

declare module 'next-auth/react' {
  export * from 'next-auth/react'

  export declare function signIn<
    P extends RedirectableProviderType | undefined = undefined
  >(
    provider?: LiteralUnion<P | BuiltInProviderType>,
    options?: SignInOptions,
    authorizationParams?: SignInAuthorizationParams
  ): Promise<
    P extends RedirectableProviderType ? SignInResponse | undefined : undefined
  >
}

before:

after:

🧢 Checklist

• Documentation
• Tests
• Ready to be merged

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1 Ignored Deployment

Name	Status	Preview	Updated
next-auth	⬜️ Ignored (Inspect)		May 26, 2022 at 1:39PM (UTC)

[balazsorban44]

Thanks! Do you this fixes the issue #4513?

[balazsorban44]

@ArthurPedroti this, unfortunately, broke tests: https://github.com/nextauthjs/next-auth/runs/6674906912?check_suite_focus=true so I have to revert it. Feel free to have another look.