set the current directory based on the tab's get-directory before starting the stepper.

Closes PR 11048

collects/stepper/internal-docs.txt

@@ -233,6 +233,8 @@ stepper-define-struct-hint :
   this expression came from a define-struct. The value associated with
   this label is the syntax-object representing the define-struct itself.
 
+NB: this should be renamed now that we're using it for "require" as well.
+
 stepper-test-suite-hint :
   this expression was the expression being tested in a test-suite-tool
   test.  this hint indicates to the annotator that the expression should

collects/stepper/private/annotate.rkt

@@ -1258,7 +1258,13 @@
              [(define-syntaxes (new-vars ...) e)
               exp]
              [(#%require specs ...)
-              exp]
+              #`(begin #,exp
+                    (#%plain-app #,(make-define-struct-break 
+                                    (stepper-syntax-property
+                                     exp
+                                     'stepper-define-struct-hint
+                                     ;; I hope this actually looks right, and isn't mangled by the expander:
+                                     exp))))]
              [(#%provide specs ...)
               exp]
              [(begin .  bodies)

collects/stepper/stepper-tool.rkt

@@ -234,7 +234,7 @@
   (define (stepper-tab-mixin super%)
     (class* super% (stepper-tab<%>)
       
-      (inherit get-ints get-defs get-frame)
+      (inherit get-ints get-defs get-frame get-directory)
       
       ;; a reference to a possible stepper frame.
       (define stepper-frame #f)
@@ -287,11 +287,12 @@
                [language-level-name (language-level->name language-level)])
           (if (or (stepper-works-for? language-level)
                   (is-a? language-level drracket:module-language:module-language<%>))
-              (set! stepper-frame
-                    (go this 
-                        program-expander 
-                        (+ 1 (send (get-defs) get-start-position))
-                        (+ 1 (send (get-defs) get-end-position))))
+              (parameterize ([current-directory (get-directory)])
+                (set! stepper-frame
+                      (go this 
+                          program-expander 
+                          (+ 1 (send (get-defs) get-start-position))
+                          (+ 1 (send (get-defs) get-end-position)))))
               (message-box
                (string-constant stepper-name)
                (format (string-constant stepper-language-level-message)