Regroups assert statements as described in raiden-network#47.

raiden_contracts/contracts/TokenNetwork.sol

@@ -244,11 +244,6 @@ contract TokenNetwork is Utils {
 
         Channel storage channel = channels[channel_identifier];
 
-        // We always increase the channel counter, therefore no channel data can already exist,
-        // corresponding to this channel_identifier. This check must never fail.
-        assert(channel.settle_block_number == 0);
-        assert(channel.state == ChannelState.NonExistent);
-
         // Store channel information
         channel.settle_block_number = settle_timeout;
         channel.state = ChannelState.Opened;
@@ -259,6 +254,10 @@ contract TokenNetwork is Utils {
             participant2,
             settle_timeout
         );
+        // We always increase the channel counter, therefore no channel data can already exist,
+        // corresponding to this channel_identifier. This check must never fail.
+        assert(channel.settle_block_number == 0);
+        assert(channel.state == ChannelState.NonExistent);
 
         return channel_identifier;
     }
@@ -298,9 +297,6 @@ contract TokenNetwork is Utils {
         require(added_deposit > 0);
         // Underflow check; we use <= because added_deposit == total_deposit for the first deposit
         require(added_deposit <= total_deposit);
-        // This should never fail at this point. Added check for security, because we directly set
-        // the participant_state.deposit = total_deposit, while we transfer `added_deposit` tokens.
-        assert(participant_state.deposit + added_deposit == total_deposit);
 
         // Update the participant's channel deposit
         participant_state.deposit = total_deposit;
@@ -316,6 +312,10 @@ contract TokenNetwork is Utils {
             participant_state.deposit
         );
 
+        // This should never fail at this point. Added check for security, because we directly set
+        // the participant_state.deposit = total_deposit, while we transfer `added_deposit` tokens.
+        assert(participant_state.deposit + added_deposit == total_deposit);
+
         // Do the transfer
         require(token.transferFrom(msg.sender, address(this), added_deposit));
     }
@@ -365,9 +365,6 @@ contract TokenNetwork is Utils {
         Participant storage partner_state = channel.participants[partner];
 
         total_deposit = participant_state.deposit + partner_state.deposit;
-        // This should never happen, as we have an overflow check in setTotalDeposit
-        assert(total_deposit >= participant_state.deposit);
-        assert(total_deposit >= partner_state.deposit);
 
         // Entire withdrawn amount must not be bigger than the current channel deposit
         require(total_withdraw <= (total_deposit - partner_state.withdrawn_amount));
@@ -397,6 +394,10 @@ contract TokenNetwork is Utils {
         // Do the tokens transfer
         require(token.transfer(participant, current_withdraw));
 
+        // This should never happen, as we have an overflow check in setTotalDeposit
+        assert(total_deposit >= participant_state.deposit);
+        assert(total_deposit >= partner_state.deposit);
+
         // A withdraw should never happen if a participant already has a
         // balance proof in storage
         assert(participant_state.nonce == 0);
@@ -1191,9 +1192,6 @@ contract TokenNetwork is Utils {
         // ordered values
         require(participant2_max_transferred >= participant1_max_transferred);
 
-        assert(participant1_max_transferred >= participant1_settlement.transferred);
-        assert(participant2_max_transferred >= participant2_settlement.transferred);
-
         // This is the maximum amount that participant1 can receive at settlement time
         participant1_net_max_received = (
             participant2_max_transferred -
@@ -1212,6 +1210,10 @@ contract TokenNetwork is Utils {
             participant1_max_amount,
             participant1_settlement.withdrawn
         );
+
+        assert(participant1_max_transferred >= participant1_settlement.transferred);
+        assert(participant2_max_transferred >= participant2_settlement.transferred);
+
         return participant1_max_amount;
     }