VSCode cannot import Rascal modules of the same project

I have a Rascal/Flybytes project in VSCode. When I define two modules, even if they are in the same folder, they cannot import each other. Consider the files A.rsc and B.rsc in the same folder:

module A

int a() = 2;

module B

import A; //line 3

int b() {
    return a(); //line 6
}

Then I get 3 errors in module B:

For line 3:

Reference to name A cannot be resolved

Undefined module A

And for line 6:

Undefined a

When simply opening a shell and importing B, everything works fine. The issue also only happens for local modules; importing a Flybytes module, for example, works flawlessly.

What is the problem here? What can I do to make VScode see local modules?

In case it matters, I'm on a Mac with Apple Silicon. I have noticed that the ARM port of VSCode is a bit buggy sometimes.

Seems like the folder was not properly opened in the VScode Explorer. Opening the folder there fixed the problem. I never knew this was necessary, but apparently it is not possible to just open a single Rascal file in VScode without having it spit tons of errors.

VScode is a bit weird in opening files as well - sometimes opening a file/folder just doesn't work and a restart is needed to fix this. But that is a VScode bug and not related to this issue.