I am currently a master's student in Computational Science and Engineering at the MIT Julia Lab. I have been a Julia user since 2018 and am one of the maintainers of the Julia language. Among other parts of the language, I work on Julia's front end and contribute to packages such as Cthulhu.jl, JuliaInterpreter.jl, and ArtifactUtils.jl.
Cthulhu.jl is a highly useful tool for performance engineering as well as general debugging of Julia programs. However, as the name implies, one can quickly descend into the abyss that is Julia's compilation pipeline and get lost in the vast amounts of code even modest looking Julia functions may end up generating. I present a combination of Cthulhu.jl with a step-by-step debugger, showing concrete results every step along the type lattice to make compilation more interpretable.