Rollup lost an entire piece of code

[arguiot]

• Rollup Version: v2.7.3
• Operating System (or Browser): macOS Catalina 10.15.5 on Safari
• Link to reproduction (IMPORTANT, read below):

Here is the REPL link.

I didn't past all my code as it's private, but this roughly what happened. Here are screenshots of the result I'm getting:

I managed to find a workaround by not having a list constant:

Expected Behavior

Rollup should always keep the code when not certain if it's accessible or not. So it doesn't lose any important code

Actual Behavior

Inside a class, Rollup lost an entire piece of code for no reason. Maybe Rollup thought that the code wasn't accessible.

If you ever need the real code to fix the issue, please tell me here, so I can share the code by email.

[lukastaegert]

If code is missing, then Rollup did not find a side-effect. The important part would be to see the original code of the monitor function without your fix so that I can understand what side-effect was overlooked.

[arguiot]

Concerning the original code of the monitor function, here it is:

monitor() {
  const persons = [this.bob, this.alice, this.charlie, this.david]
  const list = persons.filter(person => person.isPark)
  list.forEach(p => {
            list.forEach(pp => {
                if (p == pp) {
                    return
                }
                const diffX = p.x - pp.x;
                const diffY = p.y - pp.y;

                const dist = Math.sqrt(diffX * diffX + diffY * diffY);
                if (dist <= 40) {
                    this.contact(p, pp)
                }
            })
        })
}

[lukastaegert]

Thanks, I was able to reduce it to a minimal reproduction:

https://rollupjs.org/repl/?version=2.7.6&shareable=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

[lukastaegert]

Thanks again, pending fix at #3539