diff --git a/libethereum/BlockChain.cpp b/libethereum/BlockChain.cpp
index 195f65f1d..10256900d 100644
--- a/libethereum/BlockChain.cpp
+++ b/libethereum/BlockChain.cpp
@@ -305,7 +305,7 @@ LastHashes BlockChain::lastHashes(unsigned _n) const
 	return m_lastLastHashes;
 }
 
-tuple<h256s, h256s, bool> BlockChain::sync(BlockQueue& _bq, OverlayDB const& _stateDB, unsigned _max)
+tuple<ImportRoute, bool> BlockChain::sync(BlockQueue& _bq, OverlayDB const& _stateDB, unsigned _max)
 {
 //	_bq.tick(*this);
 
@@ -326,8 +326,8 @@ tuple<h256s, h256s, bool> BlockChain::sync(BlockQueue& _bq, OverlayDB const& _st
 				ImportRoute r;
 				DEV_TIMED_ABOVE(Block import, 500)
 					r = import(block.verified, _stateDB, ImportRequirements::Default & ~ImportRequirements::ValidNonce & ~ImportRequirements::CheckUncles);
-				fresh += r.first;
-				dead += r.second;
+				fresh += r.liveBlocks;
+				dead += r.deadBlocks;
 			}
 			catch (dev::eth::UnknownParent)
 			{
@@ -353,7 +353,7 @@ tuple<h256s, h256s, bool> BlockChain::sync(BlockQueue& _bq, OverlayDB const& _st
 				badBlocks.push_back(block.verified.info.hash());
 			}
 		}
-	return make_tuple(fresh, dead, _bq.doneDrain(badBlocks));
+	return make_tuple(ImportRoute{dead, fresh}, _bq.doneDrain(badBlocks));
 }
 
 pair<ImportResult, ImportRoute> BlockChain::attemptImport(bytes const& _block, OverlayDB const& _stateDB, ImportRequirements::value _ir) noexcept
@@ -364,21 +364,21 @@ pair<ImportResult, ImportRoute> BlockChain::attemptImport(bytes const& _block, O
 	}
 	catch (UnknownParent&)
 	{
-		return make_pair(ImportResult::UnknownParent, make_pair(h256s(), h256s()));
+		return make_pair(ImportResult::UnknownParent, ImportRoute());
 	}
 	catch (AlreadyHaveBlock&)
 	{
-		return make_pair(ImportResult::AlreadyKnown, make_pair(h256s(), h256s()));
+		return make_pair(ImportResult::AlreadyKnown, ImportRoute());
 	}
 	catch (FutureTime&)
 	{
-		return make_pair(ImportResult::FutureTime, make_pair(h256s(), h256s()));
+		return make_pair(ImportResult::FutureTime, ImportRoute());
 	}
 	catch (Exception& ex)
 	{
 		if (m_onBad)
 			m_onBad(ex);
-		return make_pair(ImportResult::Malformed, make_pair(h256s(), h256s()));
+		return make_pair(ImportResult::Malformed, ImportRoute());
 	}
 }
 
@@ -699,7 +699,7 @@ ImportRoute BlockChain::import(VerifiedBlockRef const& _block, OverlayDB const&
 			dead.push_back(h);
 		else
 			fresh.push_back(h);
-	return make_pair(fresh, dead);
+	return ImportRoute{dead, fresh};
 }
 
 void BlockChain::clearBlockBlooms(unsigned _begin, unsigned _end)
diff --git a/libethereum/BlockChain.h b/libethereum/BlockChain.h
index 534173a9a..2d3abd922 100644
--- a/libethereum/BlockChain.h
+++ b/libethereum/BlockChain.h
@@ -80,7 +80,12 @@ ldb::Slice toSlice(h256 const& _h, unsigned _sub = 0);
 using BlocksHash = std::unordered_map<h256, bytes>;
 using TransactionHashes = h256s;
 using UncleHashes = h256s;
-using ImportRoute = std::pair<h256s, h256s>;
+
+struct ImportRoute
+{
+	h256s deadBlocks;
+	h256s liveBlocks;
+};
 
 enum {
 	ExtraDetails = 0,
@@ -112,7 +117,7 @@ public:
 
 	/// Sync the chain with any incoming blocks. All blocks should, if processed in order.
 	/// @returns fresh blocks, dead blocks and true iff there are additional blocks to be processed waiting.
-	std::tuple<h256s, h256s, bool> sync(BlockQueue& _bq, OverlayDB const& _stateDB, unsigned _max);
+	std::tuple<ImportRoute, bool> sync(BlockQueue& _bq, OverlayDB const& _stateDB, unsigned _max);
 
 	/// Attempt to import the given block directly into the CanonBlockChain and sync with the state DB.
 	/// @returns the block hashes of any blocks that came into/went out of the canonical block chain.
diff --git a/libethereum/Client.cpp b/libethereum/Client.cpp
index 2f742f658..8064e7e9f 100644
--- a/libethereum/Client.cpp
+++ b/libethereum/Client.cpp
@@ -620,7 +620,7 @@ void Client::syncBlockQueue()
 	ImportRoute ir;
 	cwork << "BQ ==> CHAIN ==> STATE";
 	boost::timer t;
-	tie(ir.first, ir.second, m_syncBlockQueue) = m_bc.sync(m_bq, m_stateDB, m_syncAmount);
+	tie(ir, m_syncBlockQueue) = m_bc.sync(m_bq, m_stateDB, m_syncAmount);
 	double elapsed = t.elapsed();
 
 	cnote << m_syncAmount << "blocks imported in" << unsigned(elapsed * 1000) << "ms (" << (m_syncAmount / elapsed) << "blocks/s)";
@@ -629,7 +629,7 @@ void Client::syncBlockQueue()
 		m_syncAmount = max(c_syncMin, m_syncAmount * 9 / 10);
 	else if (elapsed < c_targetDuration * 0.9 && m_syncAmount < c_syncMax)
 		m_syncAmount = min(c_syncMax, m_syncAmount * 11 / 10 + 1);
-	if (ir.first.empty())
+	if (ir.liveBlocks.empty())
 		return;
 	onChainChanged(ir);
 }
@@ -671,7 +671,7 @@ void Client::syncTransactionQueue()
 void Client::onChainChanged(ImportRoute const& _ir)
 {
 	// insert transactions that we are declaring the dead part of the chain
-	for (auto const& h: _ir.second)
+	for (auto const& h: _ir.deadBlocks)
 	{
 		clog(ClientNote) << "Dead block:" << h;
 		for (auto const& t: m_bc.transactions(h))
@@ -682,7 +682,7 @@ void Client::onChainChanged(ImportRoute const& _ir)
 	}
 
 	// remove transactions from m_tq nicely rather than relying on out of date nonce later on.
-	for (auto const& h: _ir.first)
+	for (auto const& h: _ir.liveBlocks)
 	{
 		clog(ClientChat) << "Live block:" << h;
 		for (auto const& th: m_bc.transactionHashes(h))
@@ -696,7 +696,7 @@ void Client::onChainChanged(ImportRoute const& _ir)
 		h->noteNewBlocks();
 
 	h256Hash changeds;
-	for (auto const& h: _ir.first)
+	for (auto const& h: _ir.liveBlocks)
 		appendFromNewBlock(h, changeds);
 
 	// RESTART MINING