[erlang-questions] Erlang/OTP 20.0, atoms and function names with Unicode

[derek]

I found this feature from some of the merged PRs of Erlang/OTP 20

https://github.com/erlang/otp/blob/master/lib/stdlib/doc/src/unicode_usage.xml#L66-L71
https://github.com/erlang/otp/pulls?q=unicode

> Erlang/OTP 20.0, atoms and function can contain Unicode characters

so I built the binary from git checked out source code (from revision
efcb91bce) and play with it: it seems in escript interpreting mode it
works, but compiling mode still has errors:

➸ cat ./hello.erl
#!/usr/bin/env escript
%% -*- coding: utf-8 -*-
%%! +pc unicode

-module(hello).
%-mode(compile).
-export([main/1, 'hello_юникод_世界'/0]).

main(_) ->
  % io:format("~p~n", [{io:printable_range(), io:getopts()}]),
  % 'hello_'(),
  io:setopts([{encoding,unicode}]),
  % io:format("~p~n", [{io:printable_range(), io:getopts()}]),
  'hello_юникод_世界'(),
  io:format("~tp~n", [{"Hello, 世界, юникод"}]).

'hello_юникод_世界'() ->
  io:format("~tp~n", [{'hello_юникод', <<"Hello, 世界; юникод"/utf8>>,
"Hello, 世界; юникод"}]).

➸ erlang20 ./hello.erl
{'hello_юникод',<<"Hello, 世界; юникод"/utf8>>,"Hello, 世界; юникод"}
{"Hello, 世界, юникод"}

If I uncomment the "-mode(compile)." line, it just runs into compilation
error (same as below shell compilation errors)

Or in the Erlang shell, trying to compile it just failed: (I have to remove
(or comment out) the first "#!/usr/bin/env escript" line)

➸ erlang20
Erlang/OTP 20 [DEVELOPMENT] [erts-9.0] [source-efcb91bce] [64-bit]
[smp:8:8] [ds:8:8:10] [async-threads:10] [hipe] [kernel-poll:false]

Eshell V9.0  (abort with ^G)
1> c(hello).
hello.erl: internal error in beam_asm;
crash reason: badarg

  in function  list_to_binary/1
     called as list_to_binary([[5,104,101,108,108,111],
  [4,109,97,105,110],
  [2,105,111],
  [7,115,101,116,111,112,116,115],
  [6,102,111,114,109,97,116],
  [15,104,101,108,108,111,95,1102,1085,1080,1082,1086,1076,95,19990,30028],
  "\vmodule_info",
  [6,101,114,108,97,110,103],
  [15,103,101,116,95,109,111,100,117,108,101,95,105,110,102,111]])
  in call from beam_asm:chunk/3 (beam_asm.erl, line 213)
  in call from beam_asm:build_file/8 (beam_asm.erl, line 97)
  in call from beam_asm:module/4 (beam_asm.erl, line 31)
  in call from compile:beam_asm/1 (compile.erl, line 1370)
  in call from compile:'-internal_comp/4-anonymous-1-'/2 (compile.erl, line
329)
  in call from compile:fold_comp/3 (compile.erl, line 355)
  in call from compile:internal_comp/4 (compile.erl, line 339)
error
2>

I have looked up in many of the commit messages, still not seeing a good
example of how to use unicode in function names? Could some developer
behind this feature give more examples?
https://github.com/erlang/otp/blame/master/lib/stdlib/doc/src/unicode_usage.xml#L66-L71
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