Propagate Bug#14412 fix to backtrace_eval_unrewind

* src/eval.c (unbind_to): Redo so that the FALLTHROUGH!! comment
becomes accurate again. This shouldn’t affect behavior.
(backtrace_eval_unrewind): Apply the recent unbind_to fix here, too.

1 files changed, 9 insertions, 12 deletions

diff --git a/src/eval.c b/src/eval.c
index 571681c318f..bd0cf68369c 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -3196,15 +3196,12 @@ unbind_to (ptrdiff_t count, Lisp_Object value)
           { /* If variable has a trivial value (no forwarding), we can
                just set it.  No need to check for constant symbols here,
                since that was already done by specbind.  */
-            Lisp_Object symbol = specpdl_symbol (specpdl_ptr);
-            if (SYMBOLP (symbol))
+            Lisp_Object sym = specpdl_symbol (specpdl_ptr);
+            if (SYMBOLP (sym) && XSYMBOL (sym)->redirect == SYMBOL_PLAINVAL)
               {
-                struct Lisp_Symbol *sym = XSYMBOL (symbol);
-                if (sym->redirect == SYMBOL_PLAINVAL)
-                  {
-                    SET_SYMBOL_VAL (sym, specpdl_old_value (specpdl_ptr));
-                    break;
-                  }
+                SET_SYMBOL_VAL (XSYMBOL (sym),
+                                specpdl_old_value (specpdl_ptr));
+                break;
               }
             else
               { /* FALLTHROUGH!!
@@ -3412,12 +3409,12 @@ backtrace_eval_unrewind (int distance)
           { /* If variable has a trivial value (no forwarding), we can
                just set it.  No need to check for constant symbols here,
                since that was already done by specbind.  */
-            struct Lisp_Symbol *sym = XSYMBOL (specpdl_symbol (tmp));
-            if (sym->redirect == SYMBOL_PLAINVAL)
+            Lisp_Object sym = specpdl_symbol (tmp);
+            if (SYMBOLP (sym) && XSYMBOL (sym)->redirect == SYMBOL_PLAINVAL)
               {
                 Lisp_Object old_value = specpdl_old_value (tmp);
-                set_specpdl_old_value (tmp, SYMBOL_VAL (sym));
-                SET_SYMBOL_VAL (sym, old_value);
+                set_specpdl_old_value (tmp, SYMBOL_VAL (XSYMBOL (sym)));
+                SET_SYMBOL_VAL (XSYMBOL (sym), old_value);
                 break;
               }
             else