Re: [PATCH] * etc/NEWS: Document incompatibilities introduced by record types.

[Sam Steingold <sds@gnu.org>]

> * Stefan Monnier <zbaavre@veb.hzbagerny.pn> [2017-12-12 17:20:29 -0500]:
>
>> If programmers are not supposed to do it, let's detect it and report
>> an error when they try.  That way, they will know it's an error as
>> soon as they try, rather than needing to debug it to find out it's an error.
>
> When was the last time you saw a user try to redefine the
> "integer" type?
> [ I'll be happy to hear about cases in other languages than Elisp,
>   since otherwise it's going to be depressingly silent I'm afraid.  ]

What's so special about "integer"?
How many other built-in types does Emacs Lisp have?
Can you list them all by heart? Can everyone?
What about many different packages which may redefine each other's
types?  Especially since Emacs Lisp does not have the Common Lisp-style
package system, and it does not enforce the prefix conventions.

It seems to me that warning on redefining a type (or defining a type
with a name which already names a type) is a very good idea.
Emacs Lisp already warns on redefining functions with a different
signature.  Why not warn about types?

Thanks.

-- 
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