We are pleased to announce the release of Ruby 3.4.0-preview1.

## Language changes

* String literals in files without a `frozen_string_literal` comment now behave
  as if they were frozen. If they are mutated a deprecation warning is emitted.
  These warnings can be enabled with `-W:deprecated` or by setting `Warning[:deprecated] = true`.
  To disable this change, you can run Ruby with the `--disable-frozen-string-literal`
  command line argument. [[Feature #20205]]

* `it` is added to reference a block parameter. [[Feature #18980]]

* Keyword splatting `nil` when calling methods is now supported.
  `**nil` is treated similarly to `**{}`, passing no keywords,
  and not calling any conversion methods.  [[Bug #20064]]

* Block passing is no longer allowed in index.  [[Bug #19918]]

* Keyword arguments are no longer allowed in index.  [[Bug #20218]]

## Core classes updates

Note: We're only listing outstanding class updates.

* Exception

  * Exception#set_backtrace now accepts arrays of `Thread::Backtrace::Location`.
    `Kernel#raise`, `Thread#raise` and `Fiber#raise` also accept this new format. [[Feature #13557]]

* Range

  * Range#size now raises TypeError if the range is not iterable. [[Misc #18984]]



## Compatibility issues

Note: Excluding feature bug fixes.

* Error messages and backtrace displays have been changed.
  * Use a single quote instead of a backtick as a opening quote. [[Feature #16495]]
  * Display a class name before a method name (only when the class has a permanent name). [[Feature #19117]]
  * `Kernel#caller`, `Thread::Backtrace::Location`'s methods, etc. are also changed accordingly.

  ```
  Old:
  test.rb:1:in `foo': undefined method `time' for an instance of Integer
          from test.rb:2:in `<main>'

  New:
  test.rb:1:in 'Object#foo': undefined method 'time' for an instance of Integer
          from test.rb:2:in '<main>'
  ```


## C API updates

* `rb_newobj` and `rb_newobj_of` (and corresponding macros `RB_NEWOBJ`, `RB_NEWOBJ_OF`, `NEWOBJ`, `NEWOBJ_OF`) have been removed. [[Feature #20265]]
* Removed deprecated function `rb_gc_force_recycle`. [[Feature #18290]]

## Implementation improvements

* `Array#each` is rewritten in Ruby for better performance [[Feature #20182]].

## Miscellaneous changes

* Passing a block to a method which doesn't use the passed block will show
  a warning on verbose mode (`-w`).
  [[Feature #15554]]

* Redefining some core methods that are specially optimized by the interpeter
  and JIT like `String.freeze` or `Integer#+` now emits a performance class
  warning (`-W:performance` or `Warning[:performance] = true`).
  [[Feature #20429]]

See GitHub releases like [Logger](https://github.com/ruby/logger/releases) or
changelog for details of the default gems or bundled gems.

See [NEWS](https://github.com/ruby/ruby/blob/v3_4_0_preview1/NEWS.md)
or [commit logs](https://github.com/ruby/ruby/compare/v3_3_0...v3_4_0_preview1)
for more details.

With those changes, [3283 files changed, 107449 insertions(+), 115380 deletions(-)](https://github.com/ruby/ruby/compare/v3_3_0...v3_4_0_preview1#file_bucket)
since Ruby 3.3.0!


## Download

* <https://cache.ruby-lang.org/pub/ruby/3.4/ruby-3.4.0-preview1.tar.gz>

      SIZE: 22507726
      SHA1: 1619cbe06b5a8c774711b3351d18bb0f84f1d017
      SHA256: 1a3c322e90cb22e5fba0b5d257bb2be9988affa3867eba7642ed981fdde895bb
      SHA512: 29c0e32179f7b823b6708f5328e495cd333fe8dd88f7df7d9051deab47add67b14d899bba565bba1a77e1b04c9693d9708541445c112925777bb6891cb7b2b62

* <https://cache.ruby-lang.org/pub/ruby/3.4/ruby-3.4.0-preview1.tar.xz>

      SIZE: 16709536
      SHA1: 6041ad2651527d01c36106de3d3cdab680ed3132
      SHA256: 4ee4ec44366050d4b2ee1d88034cc63e0b9174a1a6650285777f3d3447213a97
      SHA512: 4ce306b9beb1e2d88c76d7f809724b66bed17e354c07a2b54aa050fc2035652e4d83deadc8dbf7a375bbdb1c816f2996334bb8e7ff5e6c24b71a858bf6b0cb7c

* <https://cache.ruby-lang.org/pub/ruby/3.4/ruby-3.4.0-preview1.zip>

      SIZE: 27731060
      SHA1: 5d79834050369ea9241d86467bf93e9e89e2ab7a
      SHA256: bd2a6c0e8396698e6f6768c00b0f155510859bb6fb92420f7b7abec610e71dbb
      SHA512: 36ea6897e6ad769141516f4c1bb18989fbde27a76f0f3abcce947f8b6b79639846ba93907e085181f7d305ab06ad73f1bbb37928049c8c951d33176ee444abbf

## What is Ruby

Ruby was first developed by Matz (Yukihiro Matsumoto) in 1993,
and is now developed as Open Source. It runs on multiple platforms
and is used all over the world especially for web development.

[Feature #13557]: https://bugs.ruby-lang.org/issues/13557
[Feature #15554]: https://bugs.ruby-lang.org/issues/15554
[Feature #16495]: https://bugs.ruby-lang.org/issues/16495
[Feature #18290]: https://bugs.ruby-lang.org/issues/18290
[Feature #18980]: https://bugs.ruby-lang.org/issues/18980
[Misc #18984]:    https://bugs.ruby-lang.org/issues/18984
[Feature #19117]: https://bugs.ruby-lang.org/issues/19117
[Bug #19918]:     https://bugs.ruby-lang.org/issues/19918
[Bug #20064]:     https://bugs.ruby-lang.org/issues/20064
[Feature #20182]: https://bugs.ruby-lang.org/issues/20182
[Feature #20205]: https://bugs.ruby-lang.org/issues/20205
[Bug #20218]:     https://bugs.ruby-lang.org/issues/20218
[Feature #20265]: https://bugs.ruby-lang.org/issues/20265
[Feature #20429]: https://bugs.ruby-lang.org/issues/20429