I experience a seemingly related issue:

type BufferStreamOrVoid<

  C extends undefined | Buffer | Stream | boolean,

  P extends undefined | Buffer,

  R extends Buffer | Stream | void = // Inline comment about void.

  // Above line comment about exclue.

  Exclude<C, false> extends never

    ? void

    : C & P extends Buffer

    ? Buffer

    : Stream

= R;

Results in:

type BufferStreamOrVoid<

  C extends undefined | Buffer | Stream | boolean,

  P extends undefined | Buffer,

  R extends Buffer | Stream | void = // Above line comment about exclue. // Inline comment about void.

  Exclude<C, false> extends never

    ? void

    : C & P extends Buffer

    ? Buffer

    : Stream

= R;

Notice how the inline comment ends up at the end of the above line comment.

Funny thing is, it even breaks max line length.

Originally posted by @tdolsen in #10260