Find suspect symbols

find-suspect-symbols.lisp

(defun find-suspect-symbols (packages)
  "Return a list of lists of suspect symbols present in PACKAGES.

A suspect symbol is a symbol that has a name that is equal to another
symbol in another package."
  (let ((symbols-by-names (make-hash-table :test 'equal)))
    (flet ((add-package (package)
             (do-symbols (symbol package)
               (pushnew symbol (gethash (symbol-name symbol) symbols-by-names '())))))
      (dolist (package packages)
        (add-package package))
      (loop for symbols being each hash-value of symbols-by-names
            when (cdr symbols)
            collect symbols))))