I just realized that ASDF somewhat breaks *LOAD-TRUENAME*. I had some code in a DSL that has an :INCLUDE construct, and that DSL is being interpreted at load-time. The :INCLUDE directive tries to find other lisp files relative to the current file (the source file that contained the DSL :INCLUDE expression). Now, if we were not using ASDF, I would be able to find those files by merging a name with *load-truename* (and this is how things used to work). But ASDF's relocation of the fasls breaks this. Now, of course, I could change (:INCLUDE construct "construct-source.lisp") to (:INCLUDE construct #.(asdf:system-relative-pathname "foo" "construct-source.lisp")) but: 1. This is blatantly ugly, effortful, and error-prone for the programmer. 2. It is poor software engineering, because it requires the contained thing (the DSL expression) to "know" that it is being included in a very specific ASDF system. Now if we rename the ASDF system, or shuffle files, our DSL code is broken, and that's just wrong, because it makes the abstraction upside down. I somehow assumed it would be possible to go from the FASL to the source, but I don't actually see any obvious way to do this. suggestions? thanks! r