Resume firstGeq search from within tree

ConflictSet.cpp

@@ -628,9 +628,6 @@ struct FirstGeqStepwise {
           }
         }
       }
-      [[fallthrough]];
-    case Init:
-      phase = Search;
       if (n->partialKeyLen > 0) {
         int commonLen = std::min<int>(n->partialKeyLen, remaining.size());
         for (int i = 0; i < commonLen; ++i) {
@@ -655,6 +652,9 @@ struct FirstGeqStepwise {
           return downLeftSpine();
         }
       }
+      [[fallthrough]];
+    case Init:
+      phase = Search;
       if (remaining.size() == 0 && n->entryPresent) {
         cmp = 0;
         return true;
@@ -954,7 +954,16 @@ bool checkRangeRead(Node *n, const std::span<const uint8_t> begin,
              begin.subspan(0, lcp - search.remaining.size()) ==
          0);
 
-  auto left = firstGeq(n, begin);
+  // Check that we can start FirstGeq where Search left off
+  int consumed = lcp - search.remaining.size();
+  assert(consumed >= 0);
+  auto left =
+      firstGeq(search.n, begin.subspan(consumed, int(begin.size()) - consumed));
+#ifndef NDEBUG
+  auto iter = firstGeq(n, begin);
+  assert(left.cmp == iter.cmp);
+  assert(left.n == iter.n);
+#endif
 
 #if DEBUG_VERBOSE && !defined(NDEBUG)
   fprintf(stderr, "firstGeq for `%s' got `%s'\n", printable(begin).c_str(),