Tree-shaking is broken in "next" release

[benoitgrelard]

#1424

Following the above discussion, I was doing some testing around tree-shaking and it looks like the @latest is able to tree-shake a bit, but the @next isn't so we must have broken something.

I suspect perhaps it's got something to do to the parcel upgrade.

[andy-hook]

Might be worth entertaining a spike on parcel alternative if this ends up looking tricky to resolve at the tooling level (similar to #1332)

[benoitgrelard]

After some research, determined this is likely a change in Parcel2.
Opened an issue there: parcel-bundler/parcel#8216

This section of the docs seems to suggest perhaps it isn't supported: https://parceljs.org/features/scope-hoisting/#side-effects

However, if export * had been used instead, this would not be true because Parcel would not know what exports are available.

This comment also potentially hints at it: parcel-bundler/parcel#4565 (comment)