"[developing an IDE] It's a great learning experience and at the end of the day you can learn a lot."

I could see developing a compiler (especially an optimising one or with modern optimisation techniques), I can see learning assembly, indeed if assembly is not it I can see learning C as well.
Programming an IDE though as some kind of actual learning experience beyond programming a project in general I am less sold on; I don't know how much more you would learn here than the traditional convert and merge these two data file formats into one thing we can feed our program, or that but with a GUI to allow someone to tweak it just so. Maybe once you get to the silly high end of automated error detection (more than just basic syntax forgot to close a bracket and into things where you assign a probability that it is an error, or suggest optimisations) and user assistance.

I am certainly glad you found yourself a project you can sink your teeth into, be it just an intellectual exercise for yourself or something you can use.
Mar 19, 2020