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To: zsh-workers@zsh.org
From: "Ravi (Tom) Hale" <ravi@hale.ee>
Subject: POSIX: reserved words should not expand into aliases
Message-ID: <d5990798-7ab4-746f-8f88-81b51e8551c6@hale.ee>
Date: Sun, 15 Jul 2018 19:16:00 +0700
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The [POSIX Shell Command Language section 
2.3.1](http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_03_01) 
says:

 > However, reserved words in correct grammatical context shall not be 
candidates for alias substitution.

It seems that both `{ba,z}sh` have a bug here.

How do I access a reserved word if an alias is hiding it?

Here `if` works normally:

     % if : ; then echo true; fi
     true

After aliasing `if`:

     % alias if=date
     % if : ; then echo true; fi
     zsh: parse error near `then'

Prefixing with `builtin` or `\` doesn't help:

     % builtin if : ; then echo true; fi
     zsh: parse error near `then'
     % \if : ; then echo true; fi
     zsh: parse error near `then'

How do I access a reserved word in the pathological case that it hidden 
by an alias?


Prior art: https://unix.stackexchange.com/q/456408/143394