Because with-compilation-unit is keyed of *load-recursive*, when compilation is happening in the context of a load (a top-level form in a loaded file calls compile-file or compile-update file) warnings are deferred until the end of the load. That might never occur if the load doesn't complete, because, say, the image quits for some reason. If the following is the content of a file which is loaded: (compile-file "foo") (exit 0) then warnings during the compilation are not issued when compile-file terminates, and will never be issued because of the termination due to the exit call. * share/txr/stdlib/compiler.tl (*in-compilation-unit*): New special variable. (with-compilation-unit): Use *in-compilation-unit* to determinw when a compilation unit has ended, and dump all the deferred warnings then. We will bind *load-recursive* because that is required for deferring warnings.