infinite loop with aliases

[Zefram <zefram@xxxxxxxxxxxxxxxxx>]

% foo<
zsh: parse error near `\n'
% alias foo='a=b foo'
% foo<

zsh goes into an infinite loop and can't be interrupted.  It seems to
be looping in the lexer or the parser; I'm not familiar with that code
so I can't easily diagnose it.

One other oddity:

% zsh -fc 'foo<'
zsh: parse error near `<'
% zsh -f
% foo<
zsh: parse error near `\n'

Why the difference in error messages?

-zefram