flow-invalid-exported-annotation-bug

A minimal reproduction of some errors noticed with Flow in version 0.171.0 and within VS Code (using the standard VS Code Flow extension).

Setup:

1. Ensure classic yarn (v1) is installed globally before cloning the repo
2. yarn install to fetch all dependencies, yarn flow to start the Flow server
3. Open the project in VS Code, ensure the Flow Language Support extension is installed (v1.9.2)

Steps to reproduce

1. Open Component.jsx in the text editor. Notice that four Flow errors are reported in the Problems tab below
2. Then, open helpers.js in the text editor

What is expected to happen

Errors of the form:

Cannot use property one on $ObjMap [1] in an export position. Please provide an (alternative) annotation for property
one [2]. [invalid-exported-annotation]

should appear highlighted on lines 18, 19, and 20 in helpers.js, and one prop-missing error should appear on line 14.

What happens instead

The invalid-exported-annotation errors actually disappear when the file is opened, and only reappear when the file is closed. The prop-missing error does correctly remain as expected.