Review fixes

programs/mango-v4/src/instructions/liq_token_bankruptcy.rs

@@ -24,9 +24,9 @@ pub struct LiqTokenBankruptcy<'info> {
     #[account(
         mut,
         has_one = group,
+        constraint = liqor.load()?.is_owner_or_delegate(liqor_owner.key()),
     )]
     pub liqor: AccountLoader<'info, MangoAccount>,
-    #[account(address = liqor.load()?.owner)]
     pub liqor_owner: Signer<'info>,
 
     #[account(
@@ -160,8 +160,9 @@ pub fn liq_token_bankruptcy(
                 liqor.tokens.deactivate(liqor_liab_raw_token_index);
             }
         } else {
-            // This happens when asset_token_index == liab_token_index: the insurance fund
-            // deposits directly into liqee, without a fee or the liqor indirection
+            // For liab_token_index == QUOTE_TOKEN_INDEX: the insurance fund deposits directly into liqee,
+            // without a fee or the liqor being involved
+            require_eq!(liab_token_index, QUOTE_TOKEN_INDEX);
             require_eq!(liab_price_adjusted, I80F48::ONE);
             require_eq!(insurance_transfer_i80f48, liab_transfer);
         }
@@ -177,8 +178,10 @@ pub fn liq_token_bankruptcy(
             indexed_total_deposits = cm!(indexed_total_deposits + bank.indexed_deposits);
         }
 
-        // TODO: what if loss is greater than entire deposits?
-        // total_indexed_deposits * (deposit_index - new_deposit_index) = remaining_liab_loss
+        // This is the solution to:
+        //   total_indexed_deposits * (deposit_index - new_deposit_index) = remaining_liab_loss
+        // AUDIT: Could it happen that remaining_liab_loss > total_indexed_deposits * deposit_index?
+        //        Probably not.
         let new_deposit_index =
             cm!(liab_deposit_index - remaining_liab_loss / indexed_total_deposits);
 

programs/mango-v4/src/instructions/liq_token_with_token.rs

@@ -15,7 +15,7 @@ pub struct LiqTokenWithToken<'info> {
     #[account(
         mut,
         has_one = group,
-        constraint = liqor.load()?.owner == liqor_owner.key() || liqor.load()?.delegate == liqor_owner.key(),
+        constraint = liqor.load()?.is_owner_or_delegate(liqor_owner.key()),
     )]
     pub liqor: AccountLoader<'info, MangoAccount>,
     pub liqor_owner: Signer<'info>,

programs/mango-v4/src/state/health.rs

@@ -518,10 +518,9 @@ impl HealthCache {
     }
 
     pub fn has_borrows(&self) -> bool {
-        let spot_borrows = self
-            .token_infos
-            .iter()
-            .any(|ti| ti.balance < -BANKRUPTCY_DUST_THRESHOLD);
+        // AUDIT: Can we really guarantee that liquidation/bankruptcy resolution always leaves
+        //        non-negative balances?
+        let spot_borrows = self.token_infos.iter().any(|ti| ti.balance.is_negative());
         let perp_borrows = self
             .perp_infos
             .iter()

programs/mango-v4/src/state/mint_info.rs

@@ -59,7 +59,10 @@ impl MintInfo {
     }
 
     pub fn verify_banks_ais(&self, all_bank_ais: &[AccountInfo]) -> Result<()> {
-        require!(all_bank_ais.iter().map(|ai| ai.key).eq(self.banks().iter()), MangoError::SomeError);
+        require!(
+            all_bank_ais.iter().map(|ai| ai.key).eq(self.banks().iter()),
+            MangoError::SomeError
+        );
         Ok(())
     }
 }

programs/mango-v4/tests/test_delegate.rs

@@ -24,7 +24,7 @@ async fn test_delegate() -> Result<(), TransportError> {
     // SETUP: Create a group, register a token (mint0), create an account
     //
 
-    let mango_setup::GroupWithTokens { group, tokens } = mango_setup::GroupWithTokensConfig {
+    let mango_setup::GroupWithTokens { group, tokens, .. } = mango_setup::GroupWithTokensConfig {
         admin,
         payer,
         mints,