macro-stepper: yet another local-expansion fix

svn: r17668

original commit: 6eb51f94020ddaad0e0e907d98a5f741f06012e5

collects/macro-debugger/model/reductions-engine.ss

@@ -336,10 +336,18 @@
              (k f v s ws)))]
 
     [(R** f v p s ws [#:new-local-context clause ...] . more)
-     ;; Note: pass no left-state to subclauses,
-     ;; then discard result state, restore s when return.
-     #'(RSbind (with-new-local-context v (R** f v p #f ws clause ...))
-               (lambda (f2 v2 s2 ws2) (R** f2 v2 p s ws2 . more)))]
+     ;; If vis = #t, then (clause ...) do not affect local config
+     ;; If vis = #f, then proceed normally
+     ;;   *except* must save & restore real term
+     #'(let* ([vis (visibility)]
+              [process-clauses (lambda () (R** #f (if vis #f v) _ #f ws clause ...))])
+         (RSbind (if vis
+                     (with-new-local-context v (process-clauses))
+                     (process-clauses))
+                 (lambda (f2 v2 s2 ws2)
+                   (let ([v2 (if vis v v2)]
+                         [s2 (if vis s s2)])
+                     (R** f v2 p s2 ws2 . more)))))]
 
     ;; Subterm handling
     [(R** f v p s ws [reducer hole fill] . more)

collects/macro-debugger/model/reductions.ss

@@ -360,16 +360,13 @@
      (R)]
     [(cons local rest)
      (R [#:pattern ?form]
-        [#:if (visibility)
-              ;; If macro with local-expand is transparent,
-              ;; then all local-expansions must be transparent.
-              ([#:parameterize ((macro-policy (lambda _ #t)))
-                 [#:new-local-context
-                  [LocalAction ?form local]]])
-              ([#:pass1]
-               ;; Use ?disconnected; do not modify real term
-               [LocalAction ?disconnected local]
-               [#:pass2])]
+        [#:parameterize ((macro-policy
+                          ;; If macro with local-expand is transparent,
+                          ;; then all local-expansions must be transparent.
+                          (if (visibility) (lambda _ #t) (macro-policy))))
+          [#:new-local-context
+           [#:pattern ?form]
+           [LocalAction ?form local]]]
         [LocalActions ?form rest])]))
 
 (define (LocalAction local)