Can not payback loan when dToken pool is deactivated in v3.0

[kuegi]

What happened:

trying to payback dTSLA loans on testnet right now fails with message PaybackLoanTx: Pool trading is turned off! (code 16)

What you expected to happen:

Payback must always work.

How to reproduce it (as minimally and precisely as possible):

• have a loan on testnet with dTSLA
• try to payback this loan

[defichain-bot]

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[prasannavl]

Thanks Kuegi. Will look into this.

[Jouzo]

As the TSLA-DUSD poolpair is desactivated, the payback fails when interests are being burned. See the path taken here

ain/src/masternodes/mn_checks.cpp

Line 4068 in ff03e48

res = SwapToDFIorDUSD(mnview, loanTokenId, subInterest, obj.from, consensus.burnAddress, height);

It does not handle a direct dToken burn but tries to swap it to DUSD or DFI.
This could be handled by burning dToken directly when its DUSD poolpair is desactivated.

It should be considered for a later release. Low priority as none of the mainnet dToken poolpairs are desactivated nor plan to be.