Clarify that you cannot make Payment Channels to yourself

content/reference-transaction-format.md

@@ -611,7 +611,7 @@ These codes indicate that the transaction was malformed, and cannot succeed acco
 | `temBAD_SIGNATURE`            | The signature to authorize this transaction is either missing, or formed in a way that is not a properly-formed signature. (See [tecNO_PERMISSION](#tec-codes) for the case where the signature is properly formed, but not authorized for this account.) |
 | `temBAD_SRC_ACCOUNT`         | The `Account` on whose behalf this transaction is being sent (the "source account") is not a properly-formed [account](concept-accounts.html) address. |
 | `temBAD_TRANSFER_RATE`       | The [`TransferRate` field of an AccountSet transaction](#transferrate) is not properly formatted or out of the acceptable range. |
-| `temDST_IS_SRC`              | The [TrustSet transaction][] improperly specified the destination of the trust line (the `issuer` field of `LimitAmount`) as the `Account` sending the transaction. You cannot extend a trust line to yourself. (In the future, this code could also apply to other cases where the destination of a transaction is not allowed to be the account sending it.) |
+| `temDST_IS_SRC`              | The improperly specified a destination address as the `Account` sending the transaction. This includes trust lines (where the destination address is the `issuer` field of `LimitAmount`) and payment channels (where the destination address is the `Destination` field). |
 | `temDST_NEEDED`               | The transaction improperly omitted a destination. This could be the `Destination` field of a [Payment](#payment) transaction, or the `issuer` sub-field of the `LimitAmount` field fo a `TrustSet` transaction. |
 | `temINVALID`                   | The transaction is otherwise invalid. For example, the transaction ID may not be the right format, the signature may not be formed properly, or something else went wrong in understanding the transaction. |
 | `temINVALID_FLAG`             | The transaction includes a [Flag](#flags) that does not exist, or includes a contradictory combination of flags. |

content/transactions/paymentchannelcreate.md

@@ -24,7 +24,7 @@ Example PaymentChannelCreate:
 | Field            | JSON Type | [Internal Type][] | Description               |
 |:-----------------|:----------|:------------------|:--------------------------|
 | `Amount`         | String    | Amount            | Amount of [XRP, in drops][Currency Amount], to deduct from the sender's balance and set aside in this channel. While the channel is open, the XRP can only go to the `Destination` address. When the channel closes, any unclaimed XRP is returned to the source address's balance. |
-| `Destination`    | String    | AccountID         | Address to receive XRP claims against this channel. This is also known as the "destination address" for the channel. |
+| `Destination`    | String    | AccountID         | Address to receive XRP claims against this channel. This is also known as the "destination address" for the channel. Cannot be the same as the sender (`Account`). |
 | `SettleDelay`    | Number    | UInt32            | Amount of time the source address must wait before closing the channel if it has unclaimed XRP. |
 | `PublicKey`      | String    | PubKey            | The public key of the key pair the source will use to sign claims against this channel, in hexadecimal. This can be any secp256k1 or Ed25519 public key. <!-- STYLE_OVERRIDE: will --> |
 | `CancelAfter`    | Number    | UInt32            | _(Optional)_ The time, in [seconds since the Ripple Epoch](reference-rippled.html#specifying-time), when this channel expires. Any transaction that would modify the channel after this time closes the channel without otherwise affecting it. This value is immutable; the channel can be closed earlier than this time but cannot remain open after this time. |