1 files changed, 4 insertions, 0 deletions

diff --git a/src/lread.c b/src/lread.c
index 44d071e97e2..1f4a8c5e093 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -1512,6 +1512,10 @@ read1 (readcharfun, pch, first_in_list)
               val = Fmake_bool_vector (length, Qnil);
               bcopy (XSTRING (tmp)->data, XBOOL_VECTOR (val)->data,
                      size_in_chars);
+              /* Clear the extraneous bits in the last byte.  */
+              if (XINT (length) != size_in_chars * BITS_PER_CHAR)
+                XBOOL_VECTOR (val)->data[size_in_chars - 1]
+                  &= (1 << (XINT (length) % BITS_PER_CHAR)) - 1;
               return val;
             }
           Fsignal (Qinvalid_read_syntax, Fcons (make_string ("#&...", 5),