Sure, but this only lets me to getParameterTypes(), and then Type does not have a getDescriptor() or similar. Notice how I need not the FQNs of parameters, but the proper descriptors

Not that I am aware of but if you want to implement something like that you may have a look into the AsmUtil class where the transformation from descriptor to Type happens. You can implement an AbstractTypeVisitor to do the "reverse transformation" for each Type. We will be happy to incorporate a contribution :)

You can implement an AbstractTypeVisitor to do the "reverse transformation" for each Type.

I am attempting to do work with AbstractTypeVisitor myself to achive a form of descriptor for a method, and am wondering how I would properly implement a reversal for array types - since it does not give access to the base type or dimensions from the ArrayType instance.

To get around this I had to explictly pass the Type instance into my implementation of AbstractTypeVisitor and then extract the data from the passed instance manually.

Is this perhaps an oversight with the underlying caseArrayType? Since caseClassType gets passed a ClassType, wouldn't it make sense to pass the ArrayType to caseArrayType?

yes your suggestion makes sense! We'd love to merge a PR for it :)

We'd love to merge a PR for it :)

I've made a PR here - my IntelliJ had a dodgy time indexing the codebase, so hopefully I didn't miss anything. 😄