[BUG] Weird _expand & _complete behavior for $parameters in "double quotes"

[Marlon Richert <marlon.richert@xxxxxxxxx>]

Tested with 9e38ab81785c4ac755a7e78d2fe7a7db92bdf375:

  comptesteval "typeset -a bar=({$'\\0'..$'\\C-?'})"
  comptesteval 'typeset -A bat=( "$bar[@]" )'
  comptesteval 'typeset bay="$bar"'
  comptesteval 'unsetopt listambiguous'
  comptest $': "$ba"\C-B\t\t'
0: complete parameter in double quotes
>line: {: "$ba}{"}
>DESCRIPTION:{parameter}
>NO:{bar}
>NO:{bat}
>NO:{bay}
>line: {: "$bar}{"}

% make TESTNUM=Y01 check
[...]
-line: {: "$ba}{"}
+line: {: "$ba}{""}
 DESCRIPTION:{parameter}
 NO:{bar}
 NO:{bat}
 NO:{bay}
-line: {: "$bar}{"}
+line: {: \"\"\"}{}
+DESCRIPTION:{expansions}
+NO:{\"\"\"}
+DESCRIPTION:{all expansions}
+NO:{\"\"\"}
+DESCRIPTION:{original}
+NO:{"$ba""}
Test ./Y01completion.ztst failed: output differs from expected as
shown above for:
  comptesteval 'unsetopt listambiguous'
  comptest $': "$ba"\C-B\t\t'
Was testing:  complete parameter in double quotes