Make pool & addresses provider immutable

[Rubilmax]

Pull Request

Issue(s) fixed

This pull request fixes nothing

[pakim249CAL]

I'm just wondering as I've never been clear on this point. Is there no way that we can do this without having to store our own rebase index? This asset should only be supplied as collateral, so it should only ever be on pool. In that case, what is stopping us from just imitating the pool logic?

[Rubilmax]

I'm just wondering as I've never been clear on this point. Is there no way that we can do this without having to store our own rebase index? This asset should only be supplied as collateral, so it should only ever be on pool. In that case, what is stopping us from just imitating the pool logic?

I agree this asset is only supposed to be supplied as collateral, because:

• Morpho cannot borrow it from the pool, hence if borrow was enabled users lending it couldn't withdraw at anytime
• Users cannot borrow it, so there's no point in storing it as supply

Then we could only store it as collateral, but we need to have a way to prevent users from supplying it for anything else than collateral.
I see 2 solutions:

1. if (configuration.isBorrowingEnabled()) revert Errors.CollateralOnly();

2. if (underlying == Constants.ST_ETH) revert Errors.CollateralOnly();

3. has the benefit of being generic, but perhaps too generic

What do you think?

[pakim249CAL]

I prefer solution 2 for now, since this is really just a very special case that the matching parts of the protocol are not built for.

[MerlinEgalite]

One thing to remember is that Aave V3 is deployed yet so the only way to test it is on an L2 where the stETH is not there.

Can we try to think about something which is more scalable? I'll reflect on this too