The language service still references a file although it got deleted from disk

In ref.ts have some class

in test.ts have some class that extends the class in ref.ts

close ref.ts from the editor.

Delete (or rename) ref.ts in the file system.

type anything in test.ts and the reference tag at the top doesn't show as error.  You can even still reference the members in the parent class.

Expected, it should show few errors in test.ts since ref.ts was gone.
