Cannot find type definition file for ambient declaration module

TypeScript Version: 3.6 to 3.8.0-dev.20191025

Search Terms: ambient module triple slash reference path declaration

Code

// A *self-contained* demonstration of the problem follows...
[typings/somemodule/index.d.ts]
declare module "somemodule"
{
  export namespace common {
    export interface Foo {
      bar: string;
      fuzz: Number;
    }
  }
}

[src/index.ts]
/// <reference path="../typings/somemodule/index.d.ts" />

Typescript 3.5.3 works as expected, anything at or above 3.6 has the same issue..

When running tsc -d, for a manually created declaration file, the triple slash reference path file should be preserved in the output declaration file. This particular declaration file acts as a shim for an existing library whose type definitions are incomplete and is to be included as-is and without transpiler manipulation in the output declaration file. This provides accurate intellisense for package consumers and ensures build errors do not occur.

Expected behavior:
Maintain the same triple-slash reference path in the .d.ts file as was in the .ts file.

[dist/index.d.ts]
/// <reference path="../typings/somemodule/index.d.ts" />

Actual behavior:
The reference path is changed to reference types and the relative path is also broken:

[dist/index.d.ts]
/// <reference types="typings/somemodule" />

This causes consuming applications of the package to receive the following build error:
Cannot find type definition file for 'typings/somemodule'.

I have been unsuccessful in manipulating the consuming application to build correctly or provide correct intellisense with the updated directive. The original directive must be preserved.

Playground Link:

Related Issues: I believe this is where the issue was introduced: #32878

src/index.ts と typings/somemodule/index.d.ts を使用して tsc -d で問題を再現し、生成された dist/index.d.ts と期待される triple-slash reference を比較します。関連する issue #32878 を読み、パス参照の変換を引き起こしている declaration emit の動作を追跡します。元の参照パスが保持され、利用側のアプリケーションで missing type definition file が報告されなくなれば完了です。