Piotr Zielinski developed a core usability feature for the dotty-staging/dotty repository, implementing inlay hints for named and by-name parameters in the Scala presentation compiler. He refactored the PcInlayHintsProvider to accurately identify and render parameter hints, enhancing code readability and reducing cognitive load during function calls. His work included updating the Parameters data model to support a variety of parameter types and function signatures, ensuring robust and context-aware inlay hints. Leveraging his expertise in compiler development, IDE features, and the Language Server Protocol, Piotr delivered a focused, well-structured enhancement that improved the overall user experience for Scala developers.