From 58481c7119ff3e74932cfe9d3e5bde26919af18b Mon Sep 17 00:00:00 2001
From: Michael Sproul <michael@sigmaprime.io>
Date: Mon, 20 May 2019 15:04:55 +1000
Subject: [PATCH] spec v0.6.1: verify proposer slashing

---
 .../src/per_block_processing/errors.rs               |  6 ++----
 .../per_block_processing/verify_proposer_slashing.rs | 12 +++++-------
 2 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/eth2/state_processing/src/per_block_processing/errors.rs b/eth2/state_processing/src/per_block_processing/errors.rs
index 902d525027..a922b01518 100644
--- a/eth2/state_processing/src/per_block_processing/errors.rs
+++ b/eth2/state_processing/src/per_block_processing/errors.rs
@@ -281,10 +281,8 @@ pub enum ProposerSlashingInvalid {
     ProposalEpochMismatch(Slot, Slot),
     /// The proposals are identical and therefore not slashable.
     ProposalsIdentical,
-    /// The specified proposer has already been slashed.
-    ProposerAlreadySlashed,
-    /// The specified proposer has already been withdrawn.
-    ProposerAlreadyWithdrawn(u64),
+    /// The specified proposer cannot be slashed because they are already slashed, or not active.
+    ProposerNotSlashable(u64),
     /// The first proposal signature was invalid.
     BadProposal1Signature,
     /// The second proposal signature was invalid.
diff --git a/eth2/state_processing/src/per_block_processing/verify_proposer_slashing.rs b/eth2/state_processing/src/per_block_processing/verify_proposer_slashing.rs
index 0c66a9b15a..98a9a248cc 100644
--- a/eth2/state_processing/src/per_block_processing/verify_proposer_slashing.rs
+++ b/eth2/state_processing/src/per_block_processing/verify_proposer_slashing.rs
@@ -7,7 +7,7 @@ use types::*;
 ///
 /// Returns `Ok(())` if the `ProposerSlashing` is valid, otherwise indicates the reason for invalidity.
 ///
-/// Spec v0.5.1
+/// Spec v0.6.1
 pub fn verify_proposer_slashing<T: EthSpec>(
     proposer_slashing: &ProposerSlashing,
     state: &BeaconState<T>,
@@ -34,11 +34,9 @@ pub fn verify_proposer_slashing<T: EthSpec>(
         Invalid::ProposalsIdentical
     );
 
-    verify!(!proposer.slashed, Invalid::ProposerAlreadySlashed);
-
     verify!(
-        proposer.withdrawable_epoch > state.slot.epoch(spec.slots_per_epoch),
-        Invalid::ProposerAlreadyWithdrawn(proposer_slashing.proposer_index)
+        proposer.is_slashable_at(state.current_epoch()),
+        Invalid::ProposerNotSlashable(proposer_slashing.proposer_index)
     );
 
     verify!(
@@ -67,7 +65,7 @@ pub fn verify_proposer_slashing<T: EthSpec>(
 ///
 /// Returns `true` if the signature is valid.
 ///
-/// Spec v0.5.1
+/// Spec v0.6.1
 fn verify_header_signature(
     header: &BeaconBlockHeader,
     pubkey: &PublicKey,
@@ -77,7 +75,7 @@ fn verify_header_signature(
     let message = header.signed_root();
     let domain = spec.get_domain(
         header.slot.epoch(spec.slots_per_epoch),
-        Domain::BeaconBlock,
+        Domain::BeaconProposer,
         fork,
     );
     header.signature.verify(&message[..], domain, pubkey)