bug#75498: 31.0.50; cl-block is not lexically scoped

bug#75498: 31.0.50; cl-block is not lexically scoped

[Ihor Radchenko]

According to the docstring, `cl-block' should be lexically scoped:

    Code inside the BODY forms can call cl-return-from
    to jump prematurely out of the block.  This differs from catch and throw
    in two respects:  First, the NAME is an unevaluated symbol rather than a
    quoted symbol or other form; and second, NAME is lexically rather than
    dynamically scoped:  Only references to it within BODY will work.  These
    references may appear inside macro expansions, but not inside functions
    called from BODY.

But try the following reproducer:

1. create file test.el

;; -*- lexical-binding: t; -*-

(defun return-from-x ()
  (cl-return-from x 'dynamic))

(defun x-block ()
  (cl-block x
    (return-from-x)
    (cl-return-from x 'lexical)))

2. (load "/path/to/test.el)
3. M-: (x-block)

Expected: 'lexical is returned.
Observed: 'dynamic is returned.

In GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
 3.24.42, cairo version 1.18.2) of 2025-01-10 built on localhost
Repository revision: e8deac66adef279a15c806d7547a7610b0189795
Repository branch: scratch/igc
Windowing system distributor 'The X.Org Foundation', version 11.0.12101014
System Description: Gentoo Linux

Configured using:
 'configure --with-mps=yes --with-native-compilation 'CFLAGS=-g3
 -I/opt/mps/include -L/opt/mps/lib'
 JAVAC=/etc/java-config-2/current-system-vm/bin/javac
 PKG_CONFIG_PATH=/usr/share/guile-data/3.0/pkgconfig'

-- 
Ihor Radchenko // yantar92,
Org mode maintainer,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>

bug#75498: 31.0.50; cl-block is not lexically scoped

[Eli Zaretskii]

> From: Ihor Radchenko <yantar92@posteo.net>
> Date: Sat, 11 Jan 2025 16:10:39 +0000
> 
> 
> According to the docstring, `cl-block' should be lexically scoped:
> 
>     Code inside the BODY forms can call cl-return-from
>     to jump prematurely out of the block.  This differs from catch and throw
>     in two respects:  First, the NAME is an unevaluated symbol rather than a
>     quoted symbol or other form; and second, NAME is lexically rather than
>     dynamically scoped:  Only references to it within BODY will work.  These
>     references may appear inside macro expansions, but not inside functions
>     called from BODY.
> 
> But try the following reproducer:
> 
> 1. create file test.el
> 
> ;; -*- lexical-binding: t; -*-
> 
> (defun return-from-x ()
>   (cl-return-from x 'dynamic))
> 
> (defun x-block ()
>   (cl-block x
>     (return-from-x)
>     (cl-return-from x 'lexical)))
> 
> 2. (load "/path/to/test.el)
> 3. M-: (x-block)
> 
> Expected: 'lexical is returned.
> Observed: 'dynamic is returned.

Adding Stefan.