Worked on the facebook/hermes repository to improve the reliability of type checking for arrow functions in JavaScript by stabilizing FlowChecker’s contextual typing. Addressed a bug where multi-parameter arrow callbacks previously assigned the same type to all parameters, leading to type-checking failures. The solution incremented the parameter index to ensure each parameter received the correct type from the constraint function. This change was validated through a focused test and a full Hermes build, confirming no regressions. Leveraged skills in static analysis, testing, and type checking, with work primarily involving C++ and JavaScript to enhance typing accuracy for callback patterns.