assignment from $1 drops nonprintable chars

[gmott]

Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i386' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i386-redhat-linux-gnu' 
-DCONF_VENDOR='redhat' -DSHELL -DHAVE_CONFIG_H  -D_GNU_SOURCE 
-D_FILE_OFFSET_BITS=64  -I.  -I. -I./include -I./lib -I/usr/include -O2 
-march=i386 -mcpu=i686
uname output: Linux ruby 2.4.7-10 #1 Thu Sep 6 16:46:36 EDT 2001 i686 unknown
Machine Type: i386-redhat-linux-gnu

Bash Version: 2.05
Patch Level: 8
Release Status: release

distribution:  redhat 7.2

Description:
        assignment from $a keeps the \001 character.
        assignment from $1 drops the \001 character.

Repeat-By:
        the following commands demonstrate the bug: 
          ------------------->  a=$'a\001b'
          ------------------->  set $a
          ------------------->  b=$a
          ------------------->  c=$1
          ------------------->  d="$1"
          ------------------->  echo "length(a)="${#a}, a=$a
        length(a)=3, a=ab
          ------------------->  echo "length(1)="${#1}, 1=$1
        length(1)=3, 1=ab
          ------------------->  echo "length(b)="${#b}, b=$b
        length(b)=3, b=ab
          ------------------->  echo "length(c)="${#c}, c=$c
        length(c)=2, c=ab
          ------------------->  echo "length(d)="${#d}, d=$d
        length(d)=2, d=ab