From: "k0kubun (Takashi Kokubun) via ruby-core" <ruby-core@...>
Date: 2023-07-22T01:02:21+00:00
Subject: [ruby-core:114252] [Ruby master Feature#19780] Remove tailcall_optimization support

Issue #19780 has been reported by k0kubun (Takashi Kokubun).



----------------------------------------

Feature #19780: Remove tailcall_optimization support

https://bugs.ruby-lang.org/issues/19780



* Author: k0kubun (Takashi Kokubun)

* Status: Open

* Priority: Normal

----------------------------------------

## Proposal

Remove `tailcall_optimization` flag from `RubyVM::InstructionSequence`



## Motivation

The consensus at [Feature #6602] seems to be that we're not going to enable tailcall optimization by default until we introduce syntax for it. Until this syntax is introduced, this feature is useless. Can we remove this flag until we do support that future syntax?



## Background

This script doesn't work with `--yjit-call-threshold=1` on any YJIT-enabled build.



```rb

src = <<-EOS

  def apply_one_and_two(&block)

    [1, p(1)]

  end

���

  def add_one_and_two

    apply_one_and_two(&:+)

  end

EOS

���

RubyVM::InstructionSequence.new(

  "proc {|_|_.class_eval {#{src}}}",

  __FILE__, __FILE__, 1,

  tailcall_optimization: true,

  trace_instruction: false,

).eval[self.singleton_class]

���

def entry

  add_one_and_two

end

���

entry

```



I already wasted a lot of time just for noticing it's already broken. I don't want to waste time for users that do not exist yet.







-- 

https://bugs.ruby-lang.org/

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