quotes invade positional parameters

[jidanni]

WITNESS for yourselves as the quotes invade the parameters, absconding
with the ones at the edges, when close enough.

$ cat 201012contract
#!/bin/sh -eux
set a b c d e f
: ''$@''
: '  '$@'  '
: '    '$*'    '
: '    ' $* '    '
: " "$* " "
$ ./201012contract
+ set a b c d e f
+ : a b c d e f
+ : '  a' b c d e 'f  '
+ : '    a' b c d e 'f    '
+ : '    ' a b c d e f '    '
+ : ' a' b c d e f ' '
$ apt-show-versions bash
bash/unstable uptodate 4.1-3

OK, the problem may only be -x deep, affecting the -x reporting output,
but not the actual functionality, thank G.O.D.