Close WSOL into itself

[hrls]

token/program/src/processor.rs

Lines 677 to 679 in 90b8f5c

	if Self::cmp_pubkeys(source_account_info.key, destination_account_info.key) {
	return Err(ProgramError::InvalidAccountData);
	}

Why we can't close account pointing itself as target for lamports?

[joncinque]

That's a good question. Conceptually I don't see a reason why not, but I imagine it was to simplify the implementation of the instruction. Any ideas @febo ?

[febo]

Maybe was to prevent locking sol on an account without a keypair (e.g., PDA) or because closing pointing to itself does not actually close the account?

I guess that with the addition of unwrap_lamports, it somewhat covers a bit the use-case for a self-close, unless the intention is to actually reuse the token account as a "normal" account.

[hrls]

prevent locking sol on an account without a keypair (e.g., PDA)

But we can still use any other account as the destination_account, whether it's a PDA or not.
I'm not sure if using the ATA program is source of problem here as well. For example closing the account into itself, then create and closing again. I assume it should work, since non-zero lamports shouldn't prevent the ATA from initializing the account.