- // Insert does insert before, and lower bound gives the one before.
- ElementIter = Elements.insert(++ElementIter, Element);
+ // We may have hit the beginning of our SparseBitVector, in which case,
+ // we may need to insert right after this element, which requires moving
+ // the current iterator forward one, because insert does insert before.
+ if (ElementIter != Elements.end() &&
+ ElementIter->index() < ElementIndex)
+ ElementIter = Elements.insert(++ElementIter, Element);
+ else
+ ElementIter = Elements.insert(ElementIter, Element);