I see you point and I agree that what I suggest is ugly, but, as I said, for me it is better than grep, and improvement do not worth further efforts, so I'll simply continue using it by myself Really good SBCL-specific solution would be to add some sort of lispwork's dspec facility for SBCL, so that M-. would show exactly (swank/backend::definterface foo) (swank/backend::defimplementation foo) I have a patch to do things like that for asdf:defsystem and SBCL's function encapsulations (advices), so I see (ASDF/PARSE-DEFSYSTEM:DEFSYSTEM :BUDDEN-TOOLS) in my M-. for :budden-tools Code is here: https://bitbucket.org/budden/budden-tools/src/default/sbcl--find-definition-sources-by-name--patch.lisp?at=default&fileviewer=file-view-default https://bitbucket.org/budden/budden-tools/src/default/asdf-3.1.4-tools.lisp?at=default&fileviewer=file-view-default But here's not the sbcl-devel :)