Subject: 30.0.50; mutate-constant warning with pure function

From: Basil Contovounesios <[email-masked]>
Date: Sat, 17 Jun 2023 12:32:02 +0100

Given a file foo.el that defines a pure function foo:

and another file bar.el that mutates the result of foo:

byte-compiling bar.el emits a mutate-constant warning, even though the
result of foo is a fresh list:

$ for f in foo bar; do emacs -Q -batch -L . -f batch-byte-compile $f.el; done

In toplevel form:
bar.el:3:2: Warning: ‘setcar’ on constant list (arg 1)

Am I missing something?

Thanks,

-- 
Basil

In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.16.0, Xaw3d scroll bars) of 2023-06-17 built on blc
Repository revision: c279369a7a9e373bb4b88feff0a05f56f3c0fa3b
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: Ubuntu 22.04.2 LTS

Configured using:
 'configure CC=gcc-12 'CFLAGS=-Og -ggdb3' --prefix=/home/bic/.local
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