This sample mono repo is set up with 2 packages: package-a and package-b where package-b depends on package-a.

package-a exports a single member interface Foo tagged as @internal. package-b exports a single member class Bar which implements Foo and is marked as @public.

Both packages packages are configured to create public and untrimmed rollups, but for the sake of this example we only really care about what package-b's rollup results.

Prerequisites:

1. This repo uses yarn, so you'll need to have that installed.

Repro steps (from the repo root):

1. Run yarn
2. Run yarn build

Observe the output under packages/package-b/dist/package-b-public.d.ts You should see something like the following:

/**
 * Bar
 *
 * @public
 */
export declare class Bar implements Foo {
	/**
	 * {@inheritDoc package-a#Foo.x}
	 */
	x: string;
}

/* Excluded from this release type: Foo */

export {};

Note that the d.ts does not include the necessary import of Foo from package-a, presumably because Foo is marked as @internal.

If we compare to the contents of packages/package-b/dist/package-b-untrimmed.d.ts, you can see that the needed import of Foo does occur as expected.