1 files changed, 2 insertions, 0 deletions

diff --git a/src/regex-emacs.c b/src/regex-emacs.c
index 23280ad3f4a..4a928861549 100644
--- a/src/regex-emacs.c
+++ b/src/regex-emacs.c
@@ -1579,6 +1579,7 @@ RE_UPDATE_SYNTAX_TABLE_FORWARD (ptrdiff_t byteoffset)
         = old_e == gl_state.b_property ? old_e_byte
           : CHARPOS_TO_BYTEOFFSET (gl_state.b_property);
       gl_state.e_byte_property = CHARPOS_TO_BYTEOFFSET (gl_state.e_property);
+      eassert (byteoffset >= gl_state.b_byte_property);
     }
 }
 
@@ -1598,6 +1599,7 @@ RE_UPDATE_SYNTAX_TABLE_BACKWARD (ptrdiff_t byteoffset)
         = old_b == gl_state.e_property ? old_b_byte
           : CHARPOS_TO_BYTEOFFSET (gl_state.e_property);
       gl_state.b_byte_property = CHARPOS_TO_BYTEOFFSET (gl_state.b_property);
+      eassert (byteoffset < gl_state.e_byte_property);
     }
 }