1 files changed, 15 insertions, 0 deletions

diff --git a/src/eval.c b/src/eval.c
index 8d8b9b14d42..41085cdef5c 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2899,16 +2899,31 @@ specbind (symbol, value)
           || BUFFER_OBJFWDP (XSYMBOL (symbol)->value))
         {
           Lisp_Object current_buffer, binding_buffer;
+          
           /* For a local variable, record both the symbol and which
              buffer's value we are saving.  */
           current_buffer = Fcurrent_buffer ();
           binding_buffer = current_buffer;
+          
           /* If the variable is not local in this buffer,
              we are saving the global value, so restore that.  */
           if (NILP (Flocal_variable_p (symbol, binding_buffer)))
             binding_buffer = Qnil;
           specpdl_ptr->symbol
             = Fcons (symbol, Fcons (binding_buffer, current_buffer));
+
+          /* If SYMBOL is a per-buffer variable which doesn't have a
+             buffer-local value here, make the `let' change the global
+             value by changing the value of SYMBOL in all buffers not
+             having their own value.  This is consistent with what
+             happens with other buffer-local variables.  */
+          if (NILP (binding_buffer)
+              && BUFFER_OBJFWDP (XSYMBOL (symbol)->value))
+            {
+              ++specpdl_ptr;
+              Fset_default (symbol, value);
+              return;
+            }
         }
       else
         specpdl_ptr->symbol = symbol;