File 2747-Correct-wording-about-filters-in-comprehen... of Package erlang

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File 2747-Correct-wording-about-filters-in-comprehensions.patch of Package erlang

From bd5a14e074efccab87b65ffb7f52f1599d82aaea Mon Sep 17 00:00:00 2001
From: ilya-klyuchnikov <ilya.klyuchnikov@gmail.com>
Date: Thu, 2 Dec 2021 08:26:14 +0000
Subject: [PATCH] Correct wording about filters in comprehensions

The previous wording may result into false impression that the compiler performs checks to ensure that a filter is "well-formed", while the filter is checked at runtime.

Fixes #5470.
---
 system/doc/reference_manual/expressions.xml | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/system/doc/reference_manual/expressions.xml b/system/doc/reference_manual/expressions.xml
index 0b0b6e3652..956775d7e8 100644
--- a/system/doc/reference_manual/expressions.xml
+++ b/system/doc/reference_manual/expressions.xml
@@ -1575,7 +1575,11 @@ end</pre>
 <c>BitStringExpr</c> must be an expression, which evaluates to a
 bitstring.</item>
 <item>A filter is an expression, which evaluates to
- <c>true</c> or <c>false</c>.</item>
+ <c>true</c> or <c>false</c>, or a
+ <seeguide marker="#guard_expressions">guard expression</seeguide>.
+ If the filter is not a guard expression and evaluates
+ to a non-Boolean value <c>Val</c>, an exception
+ <c>{bad_filter, Val}</c> is triggered at runtime.</item>
 </list>
 The variables in the generator patterns shadow previously bound variables,
 including variables bound in a previous generator pattern.
@@ -1626,8 +1630,12 @@ end</pre>
 &nbsp;&nbsp;<c><![CDATA[BitstringPattern <= BitStringExpr]]></c>. 
 <c>BitStringExpr</c> must be an expression that evaluates to a
 bitstring.</item>
- <item>A filter is an expression that evaluates to
- <c>true</c> or <c>false</c>.</item>
+ <item>A filter is an expression, which evaluates to
+ <c>true</c> or <c>false</c>, or a
+ <seeguide marker="#guard_expressions">guard expression</seeguide>.
+ If the filter is not a guard expression and evaluates
+ to a non-Boolean value <c>Val</c>, an exception
+ <c>{bad_filter, Val}</c> is triggered at runtime.</item>
 </list>
 The variables in the generator patterns shadow previously bound variables,
 including variables bound in a previous generator pattern.
-- 
2.31.1

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File 2747-Correct-wording-about-filters-in-comprehensions.patch of Package erlang

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