Type check TS file instead of index.d.ts in node_modules leads to build error that cannot be ignored

TypeScript Version: 4.1 RC

Search Terms: node_module check

Code

Run tsc on this PR:

https://github.com/DimensionDev/Maskbook/pull/1879

Emitting this error (I have skipLibCheck on but tsc is going to read .tssource file not.d.ts` file):

node_modules/promievent/PromiEvent.ts:28:33 - error TS2345: Argument of type '(resolve: Resolve<T>, reject: Reject) => void' is not assignable to parameter of type '(resolve: (value: T | PromiseLike<T>) => void, reject: (reason?: any) => void) => void'.
  Types of parameters 'resolve' and 'resolve' are incompatible.
    Types of parameters 'value' and 'value' are incompatible.
      Type 'T | PromiseLike<T> | undefined' is not assignable to type 'T | PromiseLike<T>'.
        Type 'undefined' is not assignable to type 'T | PromiseLike<T>'.

28      this.promise = new Promise<T>(executor)
                                      ~~~~~~~~


Found 1 error.

Reproduce the report by running tsc on DimensionDev/Maskbook PR 1879 with TypeScript 4.1 RC and skipLibCheck enabled. Start with the node_modules/promievent/PromiEvent.ts diagnostic and compare why the .ts source is checked instead of the package's index.d.ts. Done means the reported build error is no longer produced under the stated configuration, with regression coverage added if an existing compiler test location is identified.