lexer issue

[Oliver Kiddle <okiddle@xxxxxxxxxxx>]

Does anyone know what may be causing this:

    echo $(( ((##h << 8) + ##e) << 8)+<SPACE>
  → echo $(( ((##h << 8) +

This is with space bound to magic-space.

Also notable is that if you press <ENTER> there are TWO error messages:

zsh: parse error near `+'
zsh: parse error near `$(( ((##h << 8) + ##...'

I've not had much success in trying to understand this. The magic-space
expansion takes place in doexpandhist() but I think it has something
more to do with the errflag values and the parser, neither of which I
have much understanding of.

Oliver