Lost generic type argument from import() statements

[Innei]

Bug report

Hi, guys, I ran into two problems.

1. generator can't bundle generic types correctly when I not import generic type before.
2. path alias replace not working in import(...).

I don't know how to describe him, please see the following code.

Input code

The following examples are composed of three files, I will comment the file names. And I used path alias in tsconfig.json. e.g. ~/ redirect to src/

// interface/request.ts
// this file is shared for all case
export type RequestProxyResult<
  T,
  R = { data: T; [key: string]: any },
> = Promise<ResponseProxyExtraRaw<T, R>>

export type ResponseProxyExtraRaw<T, R = any> = T & {
  $raw: R
}

// utils/index.ts
// this file is shared for all case
import { RequestProxyResult } from '~/interfaces/request'

export const foo = (): RequestProxyResult<{}> => {
  // not care this, just force asserting a type
  return {} as any
}

case 1:

If the implicit type definition is not imported manually.

// index.case1.ts
import { foo } from '~/utils'
export const case1 = foo() // case1 type is RequestProxyResult<{}, {  [key: string]: any; data: {};}>, this type automatically inferred from ts

And run generator. It say build/index.d.ts(10,25): error TS2707: Generic type 'RequestProxyResult' requires between 1 and 2 type arguments. Lost generic type. The generated files are as follows

// Generated by dts-bundle-generator v6.1.0

export declare type RequestProxyResult<T, R = {
	data: T;
	[key: string]: any;
}> = Promise<ResponseProxyExtraRaw<T, R>>;
export declare type ResponseProxyExtraRaw<T, R = any> = T & {
	$raw: R;
};
export declare const case1: RequestProxyResult; // <------------- expected: RequestProxyResult<{}, {  [key: string]: any; data: {};}>

export {};

case 2:

// index.case2.ts
import { foo } from '~/utils'
import { ResponseProxyExtraRaw } from '~/interfaces/request' // <-------- Just import the type file, but not import required implicit type
export const case2 = foo()

dts Output:

// Generated by dts-bundle-generator v6.1.0

export declare type RequestProxyResult<T, R = {
	data: T;
	[key: string]: any;
}> = Promise<ResponseProxyExtraRaw<T, R>>;
export declare type ResponseProxyExtraRaw<T, R = any> = T & {
	$raw: R;
};
export declare const case2: import("~/interfaces/request").RequestProxyResult<{}, {             // <--------- import("~/") path alias not replace.
	[key: string]: any;
	data: {};
}>;

export {};

case 3:

This case is worked. Also the expected output.

// index.case3.ts

import { foo } from '~/utils'
import { RequestProxyResult } from '~/interfaces/request' //  <--------  import the type file, and import required implicit type, aka`RequestProxyResult`
export const case3 = foo() // aka: RequestProxyResult<...>

Output:

// Generated by dts-bundle-generator v6.1.0

export declare type RequestProxyResult<T, R = {
	data: T;
	[key: string]: any;
}> = Promise<ResponseProxyExtraRaw<T, R>>;
export declare type ResponseProxyExtraRaw<T, R = any> = T & {
	$raw: R;
};
export declare const case3: RequestProxyResult<{}, {  // <---------- worked.
	[key: string]: any;
	data: {};
}>;

export {};

Expected output

See above

Actual output

See above

Reproduce Repository

https://github.com/Innei/dts-reproduction

Additional context

• TypeScript 4.4.4

Thanks.

[timocov]

Hi there, sorry for late reply.

case 1:

This is a bug, I'll fix it.

case 2:

I'm afraid this is a bug of typescript compiler since it generates incorrect d.ts output. This statement import("~/interfaces/request") cannot work without your tsconfig so most likely this shouldn't be like that (it should be resolved to ./interfaces/request for example like in the case 1). Thus please create an issue in https://github.com/microsoft/TypeScript for this case.

[timocov]

The fix for case 1 was just released in v6.2.0. Thanks for you report!