File 2774-Don-t-eliminate-unused-erlang-make_fun3-3.patch of Package erlang

From 43758a7511214b2547ee7b5de4f7bc05a2ca78f4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Mon, 12 Oct 2020 09:16:06 +0200
Subject: [PATCH 3/3] Don't eliminate unused erlang:make_fun3/3

`erlang:make_fun3/3` is not a safe BIF. The following function should
fail:

    f() ->
         fun m:f/bad_arity,
	 ok.
---
 lib/compiler/src/erl_bifs.erl   | 10 +++++++---
 lib/compiler/test/fun_SUITE.erl |  7 +++++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/lib/compiler/src/erl_bifs.erl b/lib/compiler/src/erl_bifs.erl
index e0fa8502a1..567e7e8f42 100644
--- a/lib/compiler/src/erl_bifs.erl
+++ b/lib/compiler/src/erl_bifs.erl
@@ -188,8 +188,13 @@ is_pure(_, _, _) -> false.
 %%	and does not affect the state (although the value it returns
 %%	might depend on the state).
 %%
-%%      Note: is_function/2 and is_record/3 are NOT safe: is_function(X, foo)
-%%      and is_record(X, foo, bar) will fail.
+%%      NOTES
+%%
+%%      is_function/2 is not safe: is_function(X, foo) will fail.
+%%
+%%      is_record/3 is not safe: is_record(X, foo, bar) will fail.
+%%
+%%      erlang:make_fun/3 is safe: erlang:make_fun3(foo, bar, baz) will fail.
 
 -spec is_safe(atom(), atom(), arity()) -> boolean().
 
@@ -223,7 +228,6 @@ is_safe(erlang, is_port, 1) -> true;
 is_safe(erlang, is_reference, 1) -> true;
 is_safe(erlang, is_tuple, 1) -> true;
 is_safe(erlang, make_ref, 0) -> true;
-is_safe(erlang, make_fun, 3) -> true;
 is_safe(erlang, max, 2) -> true;
 is_safe(erlang, min, 2) -> true;
 is_safe(erlang, node, 0) -> true;
diff --git a/lib/compiler/test/fun_SUITE.erl b/lib/compiler/test/fun_SUITE.erl
index 3b8e8698de..bd8603ae81 100644
--- a/lib/compiler/test/fun_SUITE.erl
+++ b/lib/compiler/test/fun_SUITE.erl
@@ -206,11 +206,18 @@ external(Config) when is_list(Config) ->
     {'EXIT',{{badarity,_},_}} = (catch (id(fun lists:sum/1))(1, 2, 3)),
     {'EXIT',{{badarity,_},_}} = (catch apply(fun lists:sum/1, [1,2,3])),
 
+    {'EXIT',{badarg,_}} = (catch bad_external_fun()),
+
     ok.
 
 call_me(I) ->
     {ok,I}.
 
+bad_external_fun() ->
+    V0 = idea,
+    fun V0:V0/V0,                               %Should fail.
+    never_reached.
+
 eep37(Config) when is_list(Config) ->
     F = fun Fact(N) when N > 0 -> N * Fact(N - 1); Fact(0) -> 1 end,
     Add = fun _(N) -> N + 1 end,
-- 
2.26.2