diff --git a/extra/fuel/fuel.factor b/extra/fuel/fuel.factor
index 7f6af22df8..c1d90ebbcc 100644
--- a/extra/fuel/fuel.factor
+++ b/extra/fuel/fuel.factor
@@ -17,13 +17,13 @@ SYMBOL: fuel-status-stack
 V{ } clone fuel-status-stack set-global
 
 SYMBOL: fuel-eval-result
-f clone fuel-eval-result set-global
+f fuel-eval-result set-global
 
 SYMBOL: fuel-eval-output
-f clone fuel-eval-result set-global
+f fuel-eval-result set-global
 
 SYMBOL: fuel-eval-res-flag
-t clone fuel-eval-res-flag set-global
+t fuel-eval-res-flag set-global
 
 : fuel-eval-restartable? ( -- ? )
     fuel-eval-res-flag get-global ; inline
@@ -105,12 +105,11 @@ M: source-file fuel-pprint path>> fuel-pprint ;
 : fuel-forget-error ( -- ) f error set-global ; inline
 : fuel-forget-result ( -- ) f fuel-eval-result set-global ; inline
 : fuel-forget-output ( -- ) f fuel-eval-output set-global ; inline
+: fuel-forget-status ( -- )
+    fuel-forget-error fuel-forget-result fuel-forget-output ; inline
 
 : (fuel-begin-eval) ( -- )
-    fuel-push-status
-    fuel-forget-error
-    fuel-forget-result
-    fuel-forget-output ;
+    fuel-push-status fuel-forget-status ; inline
 
 : (fuel-end-eval) ( output -- )
     fuel-eval-output set-global fuel-retort fuel-pop-status ; inline
@@ -136,14 +135,17 @@ M: source-file fuel-pprint path>> fuel-pprint ;
 
 ! Loading files
 
-: fuel-run-file ( path -- ) run-file ; inline
+SYMBOL: :uses
+
+: fuel-set-use-hook ( -- )
+    [ amended-use get clone :uses prefix fuel-eval-set-result ]
+    print-use-hook set ;
+
+: fuel-run-file ( path -- )
+    [ fuel-set-use-hook run-file ] curry with-scope ; inline
 
 : fuel-with-autouse ( quot -- )
-    [
-        auto-use? on
-        [ amended-use get clone fuel-eval-set-result ] print-use-hook set
-        call
-    ] curry with-scope ;
+    [ auto-use? on fuel-set-use-hook call ] curry with-scope ;
 
 : (fuel-get-uses) ( lines -- )
     [ parse-fresh drop ] curry with-compilation-unit ; inline
diff --git a/misc/fuel/fuel-autodoc.el b/misc/fuel/fuel-autodoc.el
index a1c1d19b98..151631eea1 100644
--- a/misc/fuel/fuel-autodoc.el
+++ b/misc/fuel/fuel-autodoc.el
@@ -31,8 +31,9 @@
   :group 'fuel-autodoc
   :type 'boolean)
 
+
 
-;;; Autodoc mode:
+;;; Highlighting for autodoc messages:
 
 (defvar fuel-autodoc--font-lock-buffer
   (let ((buffer (get-buffer-create " *fuel help minibuffer messages*")))
@@ -48,6 +49,11 @@
   (let ((font-lock-verbose nil)) (font-lock-fontify-buffer))
   (buffer-string))
 
+
+;;; Eldoc function:
+
+(defvar fuel-autodoc--timeout 200)
+
 (defun fuel-autodoc--word-synopsis (&optional word)
   (let ((word (or word (fuel-syntax-symbol-at-point)))
         (fuel-log--inhibit-p t))
@@ -55,7 +61,7 @@
       (let* ((cmd (if (fuel-syntax--in-using)
                       `(:fuel* (,word fuel-vocab-summary) :in t)
                     `(:fuel* (((:quote ,word) synopsis :get)) :in)))
-             (ret (fuel-eval--send/wait cmd 20))
+             (ret (fuel-eval--send/wait cmd fuel-autodoc--timeout))
              (res (fuel-eval--retort-result ret)))
         (when (and ret (not (fuel-eval--retort-error ret)) (stringp res))
           (if fuel-autodoc-minibuffer-font-lock
@@ -70,6 +76,9 @@
            (funcall fuel-autodoc--fallback-function))
       (fuel-autodoc--word-synopsis)))
 
+
+;;; Autodoc mode:
+
 (make-variable-buffer-local
  (defvar fuel-autodoc-mode-string " A"
    "Modeline indicator for fuel-autodoc-mode"))
diff --git a/misc/fuel/fuel-debug-uses.el b/misc/fuel/fuel-debug-uses.el
index 127e11d23e..7b90093c21 100644
--- a/misc/fuel/fuel-debug-uses.el
+++ b/misc/fuel/fuel-debug-uses.el
@@ -23,12 +23,6 @@
 
 ;;; Customization:
 
-(fuel-font-lock--defface fuel-font-lock-debug-missing-vocab
-  'font-lock-warning-face fuel-debug "missing vocabulary names")
-
-(fuel-font-lock--defface fuel-font-lock-debug-unneeded-vocab
-  'font-lock-warning-face fuel-debug "unneeded vocabulary names")
-
 (fuel-font-lock--defface fuel-font-lock-debug-uses-header
   'bold fuel-debug "headers in Uses buffers")
 
@@ -53,26 +47,6 @@
             (forward-line))
           (reverse lines))))))
 
-(defun fuel-debug--highlight-names (names ref face)
-  (dolist (n names)
-    (when (not (member n ref))
-      (put-text-property 0 (length n) 'font-lock-face face n))))
-
-(defun fuel-debug--uses-new-uses (file uses)
-  (pop-to-buffer (find-file-noselect file))
-  (goto-char (point-min))
-  (if (re-search-forward "^USING: " nil t)
-      (let ((begin (point))
-            (end (or (and (re-search-forward "\\_<;\\_>") (point)) (point))))
-        (kill-region begin end))
-    (re-search-forward "^IN: " nil t)
-    (beginning-of-line)
-    (open-line 2)
-    (insert "USING: "))
-  (let ((start (point)))
-    (insert (mapconcat 'substring-no-properties uses " ") " ;")
-    (fill-region start (point) nil)))
-
 (defun fuel-debug--uses-filter (restarts)
   (let ((result) (i 1) (rn 0))
     (dolist (r restarts (reverse result))
@@ -87,9 +61,6 @@
 (fuel-popup--define fuel-debug--uses-buffer
   "*fuel uses*" 'fuel-debug-uses-mode)
 
-(make-variable-buffer-local
- (defvar fuel-debug--uses nil))
-
 (make-variable-buffer-local
  (defvar fuel-debug--uses-file nil))
 
@@ -122,27 +93,15 @@
     (fuel-popup--display (fuel-debug--uses-buffer))))
 
 (defun fuel-debug--uses-cont (retort)
-  (let ((uses (fuel-eval--retort-result retort))
+  (let ((uses (fuel-debug--uses retort))
         (err (fuel-eval--retort-error retort)))
     (if uses (fuel-debug--uses-display uses)
       (fuel-debug--uses-display-err retort))))
 
-(defun fuel-debug--insert-vlist (title vlist)
-  (goto-char (point-max))
-  (insert title "\n\n  ")
-  (let ((i 0) (step 5))
-    (dolist (v vlist)
-      (setq i (1+ i))
-      (insert v)
-      (insert (if (zerop (mod i step)) "\n  " " ")))
-    (unless (zerop (mod i step)) (newline))
-    (newline)))
-
 (defun fuel-debug--uses-display (uses)
   (let* ((inhibit-read-only t)
          (old (with-current-buffer (find-file-noselect fuel-debug--uses-file)
-                (fuel-syntax--usings)))
-         (old (sort old 'string<))
+                (sort (fuel-syntax--find-usings t) 'string<)))
          (new (sort uses 'string<)))
     (erase-buffer)
     (fuel-debug--uses-insert-title)
@@ -177,14 +136,15 @@
 
 (defun fuel-debug--uses-update-usings ()
   (interactive)
-  (let ((inhibit-read-only t))
-    (when (and fuel-debug--uses-file fuel-debug--uses)
-      (fuel-debug--uses-new-uses fuel-debug--uses-file fuel-debug--uses)
-      (message "USING: updated!")
-      (with-current-buffer (fuel-debug--uses-buffer)
-        (insert "\nDone!")
-        (fuel-debug--uses-clean)
-        (bury-buffer)))))
+  (let ((inhibit-read-only t)
+        (file fuel-debug--uses-file)
+        (uses fuel-debug--uses))
+    (when (and uses file)
+      (insert "\nDone!")
+      (fuel-debug--uses-clean)
+      (fuel-popup--quit)
+      (fuel-debug--replace-usings file uses)
+      (message "USING: updated!"))))
 
 (defun fuel-debug--uses-restart (n)
   (when (and (> n 0) (<= n (length fuel-debug--uses-restarts)))
@@ -210,11 +170,11 @@
 
 (defconst fuel-debug--uses-header-regex
   (format "^%s.*$" (regexp-opt '("Infering USING: stanza for "
-                              "Current USING: is already fine!"
-                              "Current vocabulary list:"
-                              "Correct vocabulary list:"
-                              "Sorry, couldn't infer the vocabulary list."
-                              "Done!"))))
+                                 "Current USING: is already fine!"
+                                 "Current vocabulary list:"
+                                 "Correct vocabulary list:"
+                                 "Sorry, couldn't infer the vocabulary list."
+                                 "Done!"))))
 
 (defconst fuel-debug--uses-prompt-regex
   (format "^%s" (regexp-opt '("Asking Factor. Please, wait ..."
diff --git a/misc/fuel/fuel-debug.el b/misc/fuel/fuel-debug.el
index f376bde1c9..4d84ad5141 100644
--- a/misc/fuel/fuel-debug.el
+++ b/misc/fuel/fuel-debug.el
@@ -31,6 +31,12 @@
   :group 'fuel-debug
   :type 'hook)
 
+(defcustom fuel-debug-confirm-restarts-p t
+  "Whether to ask for confimation before executing a restart in
+the debugger."
+  :group 'fuel-debug
+  :type 'boolean)
+
 (defcustom fuel-debug-show-short-help t
   "Whether to show short help on available keys in debugger."
   :group 'fuel-debug
@@ -43,7 +49,9 @@
   (column variable-name "column numbers in errors/warnings")
   (info comment "information headers")
   (restart-number warning "restart numbers")
-  (restart-name function-name "restart names")))
+  (restart-name function-name "restart names")
+  (missing-vocab warning"missing vocabulary names")
+  (unneeded-vocab warning "unneeded vocabulary names")))
 
 
 ;;; Font lock and other pattern matching:
@@ -92,6 +100,9 @@
 (make-variable-buffer-local
  (defvar fuel-debug--file nil))
 
+(make-variable-buffer-local
+ (defvar fuel-debug--uses nil))
+
 (defun fuel-debug--prepare-compilation (file msg)
   (let ((inhibit-read-only t))
     (with-current-buffer (fuel-debug--buffer)
@@ -114,6 +125,7 @@
         (fuel-debug--display-restarts err)
         (delete-blank-lines)
         (newline))
+      (fuel-debug--display-uses ret)
       (let ((hstr (fuel-debug--help-string err fuel-debug--file)))
         (if fuel-debug-show-short-help
             (insert "-----------\n" hstr "\n")
@@ -124,6 +136,46 @@
       (when (and err (not no-pop)) (fuel-popup--display))
       (not err))))
 
+(defun fuel-debug--uses (ret)
+  (let ((uses (fuel-eval--retort-result ret)))
+    (and (eq :uses (car uses))
+         (cdr uses))))
+
+(defun fuel-debug--insert-vlist (title vlist)
+  (goto-char (point-max))
+  (insert title "\n\n  ")
+  (let ((i 0) (step 5))
+    (dolist (v vlist)
+      (setq i (1+ i))
+      (insert v)
+      (insert (if (zerop (mod i step)) "\n  " " ")))
+    (unless (zerop (mod i step)) (newline))
+    (newline)))
+
+(defun fuel-debug--highlight-names (names ref face)
+  (dolist (n names)
+    (when (not (member n ref))
+      (put-text-property 0 (length n) 'font-lock-face face n))))
+
+(defun fuel-debug--insert-uses (uses)
+  (let* ((file (or file fuel-debug--file))
+         (old (with-current-buffer (find-file-noselect file)
+                (sort (fuel-syntax--find-usings t) 'string<)))
+         (new (sort uses 'string<)))
+    (when (not (equalp old new))
+      (fuel-debug--highlight-names old new 'fuel-font-lock-debug-unneeded-vocab)
+      (newline)
+      (fuel-debug--insert-vlist "Correct vocabulary list:" new)
+      new)))
+
+(defun fuel-debug--display-uses (ret)
+  (when (setq fuel-debug--uses (fuel-debug--uses ret))
+    (newline)
+    (fuel-debug--highlight-names fuel-debug--uses
+                                 nil 'fuel-font-lock-debug-missing-vocab)
+    (fuel-debug--insert-vlist "Missing vocabularies:" fuel-debug--uses)
+    (newline)))
+
 (defun fuel-debug--display-output (ret)
   (let* ((last (fuel-eval--retort-output fuel-debug--last-ret))
          (current (fuel-eval--retort-output ret))
@@ -149,7 +201,7 @@
       (newline))))
 
 (defun fuel-debug--help-string (err &optional file)
-  (format "Press %s%s%sq bury buffer"
+  (format "Press %s%s%s%sq bury buffer"
           (if (or file (fuel-eval--error-file err)) "g go to file, " "")
           (let ((rsn (length (fuel-eval--error-restarts err))))
             (cond ((zerop rsn) "")
@@ -160,7 +212,8 @@
               (save-excursion
                 (goto-char (point-min))
                 (when (search-forward (car ci) nil t)
-                  (setq str (format "%c %s, %s" (cdr ci) (car ci) str))))))))
+                  (setq str (format "%c %s, %s" (cdr ci) (car ci) str))))))
+          (if (and (not err) fuel-debug--uses) "u to update USING:, " "")))
 
 (defun fuel-debug--buffer-file ()
   (with-current-buffer (fuel-debug--buffer)
@@ -229,6 +282,31 @@
              (fuel-eval--send/wait `(:fuel ((:factor ,info)))) "")
       (error "Sorry, no %s info available" info))))
 
+(defun fuel-debug--replace-usings (file uses)
+  (pop-to-buffer (find-file-noselect file))
+  (goto-char (point-min))
+  (if (re-search-forward "^USING: " nil t)
+      (let ((begin (point))
+            (end (or (and (re-search-forward "\\_<;\\_>") (point)) (point))))
+        (kill-region begin end))
+    (re-search-forward "^IN: " nil t)
+    (beginning-of-line)
+    (open-line 2)
+    (insert "USING: "))
+  (let ((start (point)))
+    (insert (mapconcat 'substring-no-properties uses " ") " ;")
+    (fill-region start (point) nil)))
+
+(defun fuel-debug-update-usings ()
+  (interactive)
+  (when (and fuel-debug--file fuel-debug--uses)
+    (let* ((file fuel-debug--file)
+           (old (with-current-buffer (find-file-noselect file)
+                  (fuel-syntax--find-usings t)))
+           (uses (sort (append fuel-debug--uses old) 'string<)))
+      (fuel-popup--quit)
+      (fuel-debug--replace-usings file uses))))
+
 
 ;;; Fuel Debug mode:
 
@@ -239,9 +317,11 @@
     (define-key map "\C-c\C-c" 'fuel-debug-goto-error)
     (define-key map "n" 'next-line)
     (define-key map "p" 'previous-line)
+    (define-key map "u" 'fuel-debug-update-usings)
     (dotimes (n 9)
       (define-key map (vector (+ ?1 n))
-        `(lambda () (interactive) (fuel-debug-exec-restart ,(1+ n) t))))
+        `(lambda () (interactive)
+           (fuel-debug-exec-restart ,(1+ n) fuel-debug-confirm-restarts-p))))
     (dolist (ci fuel-debug--compiler-info-alist)
       (define-key map (vector (cdr ci))
         `(lambda () (interactive) (fuel-debug-show--compiler-info ,(car ci)))))
diff --git a/misc/fuel/fuel-help.el b/misc/fuel/fuel-help.el
index 9216a9fd02..325e2971be 100644
--- a/misc/fuel/fuel-help.el
+++ b/misc/fuel/fuel-help.el
@@ -140,6 +140,7 @@
                 "Notes"
                 "Parent topics:"
                 "See also"
+                "Side effects"
                 "Syntax"
                 "Variable description"
                 "Variable value"
diff --git a/misc/fuel/fuel-syntax.el b/misc/fuel/fuel-syntax.el
index 8234f9fcc8..036ac7cbd0 100644
--- a/misc/fuel/fuel-syntax.el
+++ b/misc/fuel/fuel-syntax.el
@@ -301,21 +301,9 @@
   (funcall fuel-syntax--current-vocab-function))
 
 (defun fuel-syntax--find-in ()
-  (let* ((vocab)
-         (ip
-          (save-excursion
-            (when (re-search-backward fuel-syntax--current-vocab-regex nil t)
-              (setq vocab (match-string-no-properties 1))
-              (point)))))
-    (when ip
-      (let ((pp (save-excursion
-                  (when (re-search-backward fuel-syntax--sub-vocab-regex ip t)
-                    (point)))))
-        (when (and pp (> pp ip))
-          (let ((sub (match-string-no-properties 1)))
-            (unless (save-excursion (search-backward (format "%s>" sub) pp t))
-              (setq vocab (format "%s.%s" vocab (downcase sub))))))))
-    vocab))
+  (save-excursion
+    (when (re-search-backward fuel-syntax--current-vocab-regex nil t)
+      (match-string-no-properties 1))))
 
 (make-variable-buffer-local
  (defvar fuel-syntax--usings-function 'fuel-syntax--find-usings))
@@ -323,13 +311,19 @@
 (defsubst fuel-syntax--usings ()
   (funcall fuel-syntax--usings-function))
 
-(defun fuel-syntax--find-usings ()
+(defun fuel-syntax--find-usings (&optional no-private)
   (save-excursion
     (let ((usings))
       (goto-char (point-max))
       (while (re-search-backward fuel-syntax--using-lines-regex nil t)
         (dolist (u (split-string (match-string-no-properties 1) nil t))
           (push u usings)))
+      (goto-char (point-min))
+      (when (and (not no-private)
+                 (re-search-forward "\\_<<PRIVATE\\_>" nil t)
+                 (re-search-forward "\\_<PRIVATE>\\_>" nil t))
+        (goto-char (point-max))
+        (push (concat (fuel-syntax--find-in) ".private") usings))
       usings)))