From: Juanma Barranquero <lekktu@gmail.com>
To: "Mattias Engdegård" <mattias.engdegard@gmail.com>
Cc: emacs-devel <emacs-devel@gnu.org>
Subject: Re: Warn about comparing quoted lists (etc) using `eq`
Date: Thu, 15 Dec 2022 05:17:13 +0100 [thread overview]
Message-ID: <CAAeL0SRGszwv5gmS7+M8onPmuZip5SdUH6bsOPS-2hz9FRRErw@mail.gmail.com> (raw)
In-Reply-To: <8D624413-5A6C-46D7-A4EB-53C23F7CC4D3@gmail.com>
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Note that your patch has a false positive with the empty string, which is
optimized to be always the same object (well, ISTR there are two, a unibyte
one and a multibyte one).
(byte-compile '(let ((x "")) (eq x ""))) => Warning: `eq' called with
literal string that may never match (arg 2)
(let ((x "")) (eq x "")) => t
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next prev parent reply other threads:[~2022-12-15 4:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-14 18:17 Warn about comparing quoted lists (etc) using `eq` Mattias Engdegård
2022-12-14 18:29 ` Eli Zaretskii
2022-12-14 20:57 ` Mattias Engdegård
2022-12-14 18:57 ` [External] : " Drew Adams
2022-12-15 4:17 ` Juanma Barranquero [this message]
2022-12-15 6:34 ` Dr. Arne Babenhauserheide
2022-12-15 7:00 ` Juanma Barranquero
2022-12-15 9:36 ` Mattias Engdegård
2022-12-15 10:06 ` Juanma Barranquero
2022-12-15 10:50 ` Ihor Radchenko
2022-12-15 13:58 ` Mattias Engdegård
2022-12-15 16:13 ` [External] : " Drew Adams
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