File 0575-erl_bifs-Add-a-note-to-the-comment-for-is_pure-3.patch of Package erlang
From 02de9d7de92298e807a0eef4816b36eab825e63a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <firstname.lastname@example.org>
Date: Wed, 20 Feb 2019 14:43:41 +0100
Subject: [PATCH 6/6] erl_bifs: Add a note to the comment for is_pure/3
lib/compiler/src/erl_bifs.erl | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/lib/compiler/src/erl_bifs.erl b/lib/compiler/src/erl_bifs.erl
index d925decce6..94a5dfe012 100644
@@ -32,6 +32,22 @@
%% Returns `true' if the function `Module:Name/Arity' does not
%% affect the state, nor depend on the state, although its
%% evaluation is not guaranteed to complete normally for all input.
+%% NOTE: There is no need to include every new pure BIF
+%% here. Including it here means that the value of the function
+%% will be evaluated at compile-time if the arguments are
+%% constant. If that optimization is not useful/desired, there is
+%% no need to include the new BIF here.
+%% Functions whose return value could conceivably change in a
+%% future version of the runtime system must NOT be included here.
+%% Here are some example of functions that should not be
+%% included: `term_to_binary/1', hashing functions, non-trivial
+%% encode/decode functions.
+%% When unsure whether a new BIF should be included here, the
+%% conservative safe choice is NOT to include it.
-spec is_pure(atom(), atom(), arity()) -> boolean().