Class member incorrectly stripped from .d.ts output if @internal is mentioned in unrelated comment

🔎 Search Terms

internal, .d.ts, stripInternal

🕗 Version & Regression Information

This issue appears to be present in all version of TypeScript (tested down to 3.3.3).

⏯ Playground Link

https://www.typescriptlang.org/play?stripInternal=true&ts=5.3.3#code/KYDwDg9gTgLgBAYwDYEMDOa4DEITgbwCg44B6AKnOJPLgGUALCAVyQBM4AjYONGKAJZgwwNtTi0AAgIB2MYFBkok48qWpomrNgCFgdfkJEcAvHACMAbkLVSpOABUA8gBEnALjgBbFAE9u3igA1jwwDAKY0nIKSkgA-LaUqvRa7BIyEDC0AXyCwqKq6iSaLOwAcpl6BnnGcGYATNYAvkA

💻 Code

export class Foo {
  /**
   * Should be stripped
   * @internal
   */
  shouldBeStripped = 1;

  // TODO: maybe make this @internal?
  /**
   * Should *not* be stripped
   */
  shouldNotBeStripped = 2;
}

🙁 Actual behavior

The compiler should preserve the Foo.shouldNotBeStripped property while removing Foo.shouldBeStripped.

🙂 Expected behavior

Both Foo.shouldNotBeStripped and Foo.shouldBeStripped are removed.

Additional information about the issue

If a class member has an unrelated comment mentioning @internal preceding it, TypeScript will drop that member from the .d.ts output, even though that's not the intent since there's another comment after it. Only the first comment should be checked for @internal.

Reproduce the behavior using the linked TypeScript Playground with stripInternal enabled and the provided class. Trace declaration output handling for consecutive comments, then add a regression test covering an unrelated @internal mention before a separate @internal comment. Done means only shouldBeStripped is omitted while shouldNotBeStripped remains in the .d.ts output.