Worked on core compiler infrastructure for the Julia language, focusing on both observability and correctness. Enhanced the MilesCranmer/julia repository by extending trace-dispatch logging to cover the full-cache path after associative-cache misses, improving visibility into method dispatch and enabling more effective debugging and performance tuning. In the JuliaLang/julia repository, addressed a bug in function specialization involving complex union types such as Union{Function, Nothing}, preventing incorrect code generation and misoptimizations. The work demonstrated expertise in compiler internals, low-level programming, and type systems, using C and Julia to incrementally improve both the reliability and transparency of the Julia compiler.