diff --git a/src/land/engine/ArcanistLandEngine.php b/src/land/engine/ArcanistLandEngine.php
--- a/src/land/engine/ArcanistLandEngine.php
+++ b/src/land/engine/ArcanistLandEngine.php
@@ -1257,53 +1257,55 @@
             $should_push = $is_last;
           }
 
-          if ($should_push) {
-            try {
-              $this->pushChange($into_commit);
-              $this->setHasUnpushedChanges(false);
-            } catch (ArcanistLandPushFailureException $ex) {
-
-              // TODO: If the push fails, fetch and retry if the remote ref
-              // has moved ahead of us.
-
-              if ($this->getIntoLocal()) {
-                $can_retry = false;
-              } else if ($this->getIntoEmpty()) {
-                $can_retry = false;
-              } else if ($this->getIntoRemote() !== $this->getOntoRemote()) {
-                $can_retry = false;
-              } else {
-                $can_retry = false;
-              }
-
-              if ($can_retry) {
-                // New commit state here
-                $into_commit = '..';
-                continue;
-              }
-
-              throw new PhutilArgumentUsageException(
-                $ex->getMessage());
+          if ($should_push === false) {
+            break;
+          }
+
+          try {
+            $this->pushChange($into_commit);
+            $this->setHasUnpushedChanges(false);
+          } catch (ArcanistLandPushFailureException $ex) {
+
+            // TODO: If the push fails, fetch and retry if the remote ref
+            // has moved ahead of us.
+
+            if ($this->getIntoLocal()) {
+              $can_retry = false;
+            } else if ($this->getIntoEmpty()) {
+              $can_retry = false;
+            } else if ($this->getIntoRemote() !== $this->getOntoRemote()) {
+              $can_retry = false;
+            } else {
+              $can_retry = false;
+            }
+
+            if ($can_retry) {
+              // New commit state here
+              $into_commit = '..';
+              continue;
             }
 
-            if ($need_cascade) {
+            throw new PhutilArgumentUsageException(
+              $ex->getMessage());
+          }
 
-              // NOTE: We cascade each set we've pushed, but we're going to
-              // cascade them from most recent to least recent. This way,
-              // branches which descend from more recent changes only cascade
-              // once, directly in to the correct state.
+          if ($need_cascade) {
 
-              $need_cascade = array_reverse($need_cascade);
-              foreach ($need_cascade as $cascade_set) {
-                $this->cascadeState($set, $into_commit);
-              }
-              $need_cascade = array();
-            }
+            // NOTE: We cascade each set we've pushed, but we're going to
+            // cascade them from most recent to least recent. This way,
+            // branches which descend from more recent changes only cascade
+            // once, directly in to the correct state.
 
-            if (!$is_keep) {
-              $this->pruneBranches($need_prune);
-              $need_prune = array();
+            $need_cascade = array_reverse($need_cascade);
+            foreach ($need_cascade as $cascade_set) {
+              $this->cascadeState($cascade_set, $into_commit);
             }
+            $need_cascade = array();
+          }
+
+          if (!$is_keep) {
+            $this->pruneBranches($need_prune);
+            $need_prune = array();
           }
 
           break;
diff --git a/src/land/engine/ArcanistMercurialLandEngine.php b/src/land/engine/ArcanistMercurialLandEngine.php
--- a/src/land/engine/ArcanistMercurialLandEngine.php
+++ b/src/land/engine/ArcanistMercurialLandEngine.php
@@ -6,6 +6,7 @@
   private $ontoBranchMarker;
   private $ontoMarkers;
 
+  private $rebasedCommitMap = array();
   private $rebasedActiveCommit;
 
   protected function getDefaultSymbols() {
@@ -771,8 +772,12 @@
 
   protected function executeMerge(ArcanistLandCommitSet $set, $into_commit) {
     $api = $this->getRepositoryAPI();
+    $log = $this->getLogEngine();
 
     if ($this->getStrategy() !== 'squash') {
+      $log->writeError(
+        pht('TODO'),
+        pht('Merge strategy is not yet supported on Mercurial repositories.'));
       throw new Exception(pht('TODO: Support merge strategies'));
     }
 
@@ -783,10 +788,7 @@
     // we continue.
 
     $bookmark_refs = $api->newMarkerRefQuery()
-      ->withMarkerTypes(
-        array(
-          ArcanistMarkerRef::TYPE_BOOKMARK,
-        ))
+      ->withMarkerTypes(array(ArcanistMarkerRef::TYPE_BOOKMARK))
       ->execute();
 
     // TODO: Add a Mercurial version check requiring 2.1.1 or newer.
@@ -842,6 +844,14 @@
       $future->resolvex();
 
     } catch (CommandException $ex) {
+      $log->writeError(
+        pht('REBASE CONFLICT'),
+        pht(
+          'Commits for %s do not rebase cleanly onto %s. Manually rebase and '.
+          'resolve conflicts before landing again.',
+          $revision_ref->getRefDisplayName(),
+          $api->getDisplayHash($into_commit)));
+
       // Aborting the rebase should restore the same state prior to running the
       // rebase command.
       $api->execManualLocalWithExtension(
@@ -875,6 +885,10 @@
     list($stdout) = $api->execxLocal('log --rev tip --template %s', '{node}');
     $new_cursor = trim($stdout);
 
+    foreach ($set->getCommits() as $commit) {
+      $this->rebasedCommitMap[$commit->getHash()] = $new_cursor;
+    }
+
     // If any of the commits that were rebased was the active commit before the
     // workflow started, track the new commit so it can be used as the working
     // directory after the land has succeeded.
@@ -1053,6 +1067,12 @@
 
     $old_commit = last($set->getCommits())->getHash();
     $new_commit = $into_commit;
+    // Rebase the child commits onto the commit which $old_commit was rebased
+    // into. The $into_commit will be the last set's final rebased commit but
+    // this set may be an intermediate set that was landed.
+    if (isset($this->rebasedCommitMap[$old_commit])) {
+      $new_commit = $this->rebasedCommitMap[$old_commit];
+    }
 
     list($output) = $api->execxLocal(
       'log --rev %s --template %s',
@@ -1065,8 +1085,11 @@
         continue;
       }
 
-      // TODO: If the only heads which are descendants of this child will
-      // be deleted, we can skip this rebase?
+      // If this child was rebased as part of landing then it shouldn't be
+      // rebased now. Doing so will result in rebase conflicts.
+      if (isset($this->rebasedCommitMap[$child_hash])) {
+        continue;
+      }
 
       try {
         $api->execxLocalWithExtension(
@@ -1075,6 +1098,14 @@
           $child_hash,
           $new_commit);
       } catch (CommandException $ex) {
+        $log->writeError(
+          pht('REBASE CONFLICT'),
+          pht(
+            'Failed to rebase %s cleanly onto %s. Manually rebase and '.
+            'resolve conflicts.',
+            $api->getDisplayHash($child_hash),
+            $api->getDisplayHash($new_commit)));
+
         // Aborting the rebase should restore the same state prior to running
         // the rebase command.
         $api->execManualLocalWithExtension(