Unused Variables When Used As Typings

[JamesHenry]

This issue was initially reported here: eslint/typescript-eslint-parser#599

---

I'm still new to TypeScript so apologizes if I misunderstood this issue.

What version of TypeScript are you using?
3.2.2

What version of typescript-eslint-parser are you using?
21.0.2

What code were you trying to parse?

import * as fastify from 'fastify'
import { Server, IncomingMessage, ServerResponse } from 'http'

// Create a http server. We pass the relevant typings for our http version used.
// By passing types we get correctly typed access to the underlying http objects in routes.
// If using http2 we'd pass <http2.Http2Server, http2.Http2ServerRequest, http2.Http2ServerResponse>
const server: fastify.FastifyInstance<Server, IncomingMessage, ServerResponse> = fastify({})

const opts: fastify.RouteShorthandOptions = {
  schema: {
    response: {
      200: {
        type: 'object',
        properties: {
          pong: {
            type: 'string'
          }
        }
      }
    }
  }
}

server.get('/ping', opts, (request, reply) => {
  console.log(reply.res) // this is the http.ServerResponse with correct typings!
  reply.code(200).send({ pong: 'it worked!' })
})

From: https://github.com/fastify/fastify/blob/master/docs/TypeScript.md#example

What did you expect to happen?
No errors relating unused variables.

What happened?
It complains that Server, IncomingMessage, ServerResponse are all unused but technically they are used when defining the server variable.

[Chris911]

@JamesHenry I'm still getting this issue with v1.1.1 @typescript-eslint/no-unused-vars errors variable imported as types and only used for typing.

[armano2]

can you provide example of code?

no-unused-vars.js#L522

[Chris911]

Here's a simple repo setup to reproduce: https://gist.github.com/Chris911/69305fa1697683b90f578e9d9244fdec

In the example MongooseTypes is imported and then used in another interface but eslint errors on L1.

[armano2]

yes, that's true, this is different issue #21,
declare global uses "global" scope

[Chris911]

Ah ok. Thanks I'll follow that issue.