1 files changed, 4 insertions, 1 deletions

diff --git a/src/fileio.c b/src/fileio.c
index 7b3084c7aa3..eafb1e61840 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -4050,7 +4050,10 @@ actually used.")
   if (! coding_system_decided)
     {
       /* The coding system is not yet decided.  Decide it by an
-         optimized method for handling `coding:' tag.  */
+         optimized method for handling `coding:' tag.
+
+         Note that we can get here only if the buffer was empty
+         before the insertion.  */
       Lisp_Object val;
       val = Qnil;