anchor.diff:  (defun levenshtein (x y)
     "This function calculates Levenshtein distance between two given
   strings."
  -  (declare (type (simple-array character) x y)
  +  (declare (type simple-string x y)
              (inline length)
              (optimize (safety 0) (speed 3) (space 3)))
     (let* ((x-len (length x))
  
positive.code: (defun fast-find (char str str-len &optional (start 0))
    "Checks if CHAR is in STR. This function is supposed to be inlined."
    (declare (type character char)
             (type (simple-array character) str)
             (type array-index str-len start)
             (optimize (safety 0) (speed 3) (space 3)))
    (do ((i start (1+ i)))
  
negative.code: (defun overlap (x y)
    "This function calculates overlap coefficient between two given
  strings. Returned value is in range from 0 (no similarity) to 1 (exact match)."
    (declare (type simple-string x y)
             (inline string-to-set intersection-length)
             (optimize (safety 0) (speed 3) (space 3)))
    (let ((x (string-to-set x))
  