Auditing a Rebase's Conflict Resolution

You ask Claude Code to rebase your branch feature/discount-codes onto main. It reports one conflict, in pricing.ts, and resolves it by keeping "your" (the feature branch's) version of a function called applyDiscount(). The rebase completes and all existing tests pass.

1. Why can a rebase that "completes cleanly" and "passes all existing tests" still ship a wrong result? Name the specific failure mode.
2. What follow-up question should you ask Claude before trusting this resolution, and why does "all existing tests pass" not already answer it?
3. Propose one prompt you could have given before the rebase started that would have made this conflict's resolution safer by default.