1 files changed, 8 insertions, 5 deletions

diff --git a/src/coding.c b/src/coding.c
index fa079a749cb..6d2e6d9c454 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -4800,11 +4800,14 @@ code_convert_region (from, from_byte, to, to_byte, coding, encodep, replace)
         {
           detect_coding (coding, BYTE_POS_ADDR (from_byte), len_byte);
           if (coding->type == coding_type_undecided)
-            /* It seems that the text contains only ASCII, but we
-               should not left it undecided because the deeper
-               decoding routine (decode_coding) tries to detect the
-               encodings again in vain.  */
-            coding->type = coding_type_emacs_mule;
+            {
+              /* It seems that the text contains only ASCII, but we
+                 should not left it undecided because the deeper
+                 decoding routine (decode_coding) tries to detect the
+                 encodings again in vain.  */
+              coding->type = coding_type_emacs_mule;
+              coding->category_idx = CODING_CATEGORY_IDX_EMACS_MULE;
+            }
         }
       if (coding->eol_type == CODING_EOL_UNDECIDED
           && coding->type != coding_type_ccl)