Copy NEWS.md to doc/NEWS-3.0.0.md and update for 3.1.0

2 files changed, 822 insertions, 781 deletions

diff --git a/NEWS.md b/NEWS.md
index 2dcfacb6e2..ccbf60ca60 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,7 +1,7 @@
-# NEWS for Ruby 3.0.0
+# NEWS for Ruby 3.1.0
 
 This document is a list of user visible feature changes
-since the **2.7.0** release, except for bug fixes.
+since the **3.0.0** release, except for bug fixes.
 
 Note that each entry is kept so brief that no reason behind or reference
 information is supplied with.  For a full list of changes with all
@@ -10,811 +10,32 @@ sufficient information, see the ChangeLog file or Redmine
 
 ## Language changes
 
-* Keyword arguments are now separated from positional arguments.
-  Code that resulted in deprecation warnings in Ruby 2.7 will now
-  result in ArgumentError or different behavior. [[Feature #14183]]
-
-* Procs accepting a single rest argument and keywords are no longer
-  subject to autosplatting.  This now matches the behavior of Procs
-  accepting a single rest argument and no keywords.
-  [[Feature #16166]]
-
-    ```ruby
-    pr = proc{|*a, **kw| [a, kw]}
-
-    pr.call([1])
-    # 2.7 => [[1], {}]
-    # 3.0 => [[[1]], {}]
-
-    pr.call([1, {a: 1}])
-    # 2.7 => [[1], {:a=>1}] # and deprecation warning
-    # 3.0 => [[[1, {:a=>1}]], {}]
-    ```
-
-* Arguments forwarding (`...`) now supports leading arguments.
-  [[Feature #16378]]
-
-    ```ruby
-    def method_missing(meth, ...)
-      send(:"do_#{meth}", ...)
-    end
-    ```
-
-* Pattern matching (`case/in`) is no longer experimental. [[Feature #17260]]
-
-* One-line pattern matching is redesigned.  [EXPERIMENTAL]
-
-    * `=>` is added. It can be used like a rightward assignment.
-      [[Feature #17260]]
-
-        ```ruby
-        0 => a
-        p a #=> 0
-
-        {b: 0, c: 1} => {b:}
-        p b #=> 0
-        ```
-
-    * `in` is changed to return `true` or `false`. [[Feature #17371]]
-
-        ```ruby
-        # version 3.0
-        0 in 1 #=> false
-
-        # version 2.7
-        0 in 1 #=> raise NoMatchingPatternError
-        ```
-
-* Find-pattern is added.  [EXPERIMENTAL]
-  [[Feature #16828]]
-
-    ```ruby
-    case ["a", 1, "b", "c", 2, "d", "e", "f", 3]
-    in [*pre, String => x, String => y, *post]
-      p pre  #=> ["a", 1]
-      p x    #=> "b"
-      p y    #=> "c"
-      p post #=> [2, "d", "e", "f", 3]
-    end
-    ```
-
-* Endless method definition is added.  [EXPERIMENTAL]
-  [[Feature #16746]]
-
-    ```ruby
-    def square(x) = x * x
-    ```
-
-* Interpolated String literals are no longer frozen when
-  `# frozen-string-literal: true` is used. [[Feature #17104]]
-
-* Magic comment `shareable_constant_value` added to freeze constants.
-  See {Magic Comments}[rdoc-ref:doc/syntax/comments.rdoc@Magic+Comments] for more details.
-  [[Feature #17273]]
-
-* A {static analysis}[rdoc-label:label-Static+analysis] foundation is
-  introduced.
-    * {RBS}[rdoc-label:label-RBS] is introduced. It is a type definition
-      language for Ruby programs.
-    * {TypeProf}[rdoc-label:label-TypeProf] is experimentally bundled. It is a
-      type analysis tool for Ruby programs.
-
-* Deprecation warnings are no longer shown by default (since Ruby 2.7.2).
-  Turn them on with `-W:deprecated` (or with `-w` to show other warnings too).
-  [[Feature #16345]]
-
-* $SAFE and $KCODE are now normal global variables with no special behavior.
-  C-API methods related to $SAFE have been removed.
-  [[Feature #16131]] [[Feature #17136]]
-
-* yield in singleton class definitions in methods is now a SyntaxError
-  instead of a warning. yield in a class definition outside of a method
-  is now a SyntaxError instead of a LocalJumpError.  [[Feature #15575]]
-
-* When a class variable is overtaken by the same definition in an
-  ancestor class/module, a RuntimeError is now raised (previously,
-  it only issued a warning in verbose mode).  Additionally, accessing a
-  class variable from the toplevel scope is now a RuntimeError.
-  [[Bug #14541]]
-
-* Assigning to a numbered parameter is now a SyntaxError instead of
-  a warning.
-
 ## Command line options
 
-### `--help` option
-
-When the environment variable `RUBY_PAGER` or `PAGER` is present and has
-a non-empty value, and the standard input and output are tty, the `--help`
-option shows the help message via the pager designated by the value.
-[[Feature #16754]]
-
-### `--backtrace-limit` option
-
-The `--backtrace-limit` option limits the maximum length of a backtrace.
-[[Feature #8661]]
-
 ## Core classes updates
 
 Outstanding ones only.
 
-* Array
-
-    * The following methods now return Array instances instead of
-      subclass instances when called on subclass instances:
-      [[Bug #6087]]
-
-        * Array#drop
-        * Array#drop_while
-        * Array#flatten
-        * Array#slice!
-        * Array#slice / Array#[]
-        * Array#take
-        * Array#take_while
-        * Array#uniq
-        * Array#*
-
-    * Can be sliced with Enumerator::ArithmeticSequence
-
-        ```ruby
-        dirty_data = ['--', 'data1', '--', 'data2', '--', 'data3']
-        dirty_data[(1..).step(2)] # take each second element
-        # => ["data1", "data2", "data3"]
-        ```
-
-* Binding
-
-    * Binding#eval when called with one argument will use "(eval)"
-      for `__FILE__` and 1 for `__LINE__` in the evaluated code.
-      [[Bug #4352]] [[Bug #17419]]
-
-* ConditionVariable
-
-    * ConditionVariable#wait may now invoke the `block`/`unblock` scheduler
-      hooks in a non-blocking context. [[Feature #16786]]
-
-* Dir
-
-    * Dir.glob and Dir.[] now sort the results by default, and
-      accept the `sort:` keyword option.  [[Feature #8709]]
-
-* ENV
-
-    * ENV.except has been added, which returns a hash excluding the
-      given keys and their values.  [[Feature #15822]]
-
-    * Windows: Read ENV names and values as UTF-8 encoded Strings
-      [[Feature #12650]]
-
-* Encoding
-
-    * Added new encoding IBM720.  [[Feature #16233]]
-
-    * Changed default for Encoding.default_external to UTF-8 on Windows
-      [[Feature #16604]]
-
-* Fiber
-
-    * Fiber.new(blocking: true/false) allows you to create non-blocking
-      execution contexts. [[Feature #16786]]
-
-    * Fiber#blocking? tells whether the fiber is non-blocking. [[Feature #16786]]
-
-    * Fiber#backtrace and Fiber#backtrace_locations provide per-fiber backtrace.
-      [[Feature #16815]]
-
-    * The limitation of Fiber#transfer is relaxed. [[Bug #17221]]
-
-* GC
-
-    * GC.auto_compact= and GC.auto_compact have been added to control
-      when compaction runs.  Setting `auto_compact=` to true will cause
-      compaction to occur during major collections.  At the moment,
-      compaction adds significant overhead to major collections, so please
-      test first!  [[Feature #17176]]
-
-* Hash
-
-    * Hash#transform_keys and Hash#transform_keys! now accept a hash that maps
-      keys to new keys.  [[Feature #16274]]
-
-    * Hash#except has been added, which returns a hash excluding the
-      given keys and their values.  [[Feature #15822]]
-
-* IO
-
-    * IO#nonblock? now defaults to `true`. [[Feature #16786]]
-
-    * IO#wait_readable, IO#wait_writable, IO#read, IO#write and other
-      related methods (e.g. IO#puts, IO#gets) may invoke the scheduler hook
-      `#io_wait(io, events, timeout)` in a non-blocking execution context.
-      [[Feature #16786]]
-
-* Kernel
-
-    * Kernel#clone when called with the `freeze: false` keyword will call
-      `#initialize_clone` with the `freeze: false` keyword.
-      [[Bug #14266]]
-
-    * Kernel#clone when called with the `freeze: true` keyword will call
-      `#initialize_clone` with the `freeze: true` keyword, and will
-      return a frozen copy even if the receiver is unfrozen.
-      [[Feature #16175]]
-
-    * Kernel#eval when called with two arguments will use "(eval)"
-      for `__FILE__` and 1 for `__LINE__` in the evaluated code.
-      [[Bug #4352]]
-
-    * Kernel#lambda now warns if called without a literal block.
-      [[Feature #15973]]
-
-    * Kernel.sleep invokes the scheduler hook `#kernel_sleep(...)` in a
-      non-blocking execution context. [[Feature #16786]]
-
-* Module
-
-    * Module#include and Module#prepend now affect classes and modules
-      that have already included or prepended the receiver, mirroring the
-      behavior if the arguments were included in the receiver before
-      the other modules and classes included or prepended the receiver.
-      [[Feature #9573]]
-
-        ```ruby
-        class C; end
-        module M1; end
-        module M2; end
-        C.include M1
-        M1.include M2
-        p C.ancestors #=> [C, M1, M2, Object, Kernel, BasicObject]
-        ```
-
-    * Module#public, Module#protected, Module#private, Module#public_class_method,
-      Module#private_class_method, toplevel "private" and "public" methods
-      now accept single array argument with a list of method names. [[Feature #17314]]
-
-    * Module#attr_accessor, Module#attr_reader, Module#attr_writer and Module#attr
-      methods now return an array of defined method names as symbols.
-      [[Feature #17314]]
-
-    * Module#alias_method now returns the defined alias as a symbol.
-      [[Feature #17314]]
-
-* Mutex
-
-    * `Mutex` is now acquired per-`Fiber` instead of per-`Thread`. This change
-      should be compatible for essentially all usages and avoids blocking when
-      using a scheduler. [[Feature #16792]]
-
-* Proc
-
-    * Proc#== and Proc#eql? are now defined and will return true for
-      separate Proc instances if the procs were created from the same block.
-      [[Feature #14267]]
-
-* Queue / SizedQueue
-
-    * Queue#pop, SizedQueue#push and related methods may now invoke the
-      `block`/`unblock` scheduler hooks in a non-blocking context.
-      [[Feature #16786]]
-
-* Ractor
-
-    * New class added to enable parallel execution. See rdoc-ref:ractor.md for
-      more details.
-
-* Random
-
-    * `Random::DEFAULT` now refers to the `Random` class instead of being a `Random` instance,
-      so it can work with `Ractor`.
-      [[Feature #17322]]
-
-    * `Random::DEFAULT` is deprecated since its value is now confusing and it is no longer global,
-      use `Kernel.rand`/`Random.rand` directly, or create a `Random` instance with `Random.new` instead.
-      [[Feature #17351]]
-
-
-* String
-
-    * The following methods now return or yield String instances
-      instead of subclass instances when called on subclass instances:
-      [[Bug #10845]]
-
-        * String#*
-        * String#capitalize
-        * String#center
-        * String#chomp
-        * String#chop
-        * String#delete
-        * String#delete_prefix
-        * String#delete_suffix
-        * String#downcase
-        * String#dump
-        * String#each_char
-        * String#each_grapheme_cluster
-        * String#each_line
-        * String#gsub
-        * String#ljust
-        * String#lstrip
-        * String#partition
-        * String#reverse
-        * String#rjust
-        * String#rpartition
-        * String#rstrip
-        * String#scrub
-        * String#slice!
-        * String#slice / String#[]
-        * String#split
-        * String#squeeze
-        * String#strip
-        * String#sub
-        * String#succ / String#next
-        * String#swapcase
-        * String#tr
-        * String#tr_s
-        * String#upcase
-
-* Symbol
-
-    * Symbol#to_proc now returns a lambda Proc.  [[Feature #16260]]
-
-    * Symbol#name has been added, which returns the name of the symbol
-      if it is named.  The returned string is frozen.  [[Feature #16150]]
-
-* Fiber
-
-    * Introduce Fiber.set_scheduler for intercepting blocking operations and
-      Fiber.scheduler for accessing the current scheduler. See
-      rdoc-ref:fiber.md for more details about what operations are supported and
-      how to implement the scheduler hooks. [[Feature #16786]]
-
-    * Fiber.blocking? tells whether the current execution context is
-      blocking. [[Feature #16786]]
-
-    * Thread#join invokes the scheduler hooks `block`/`unblock` in a
-      non-blocking execution context. [[Feature #16786]]
-
-* Thread
-
-    * Thread.ignore_deadlock accessor has been added for disabling the
-      default deadlock detection, allowing the use of signal handlers to
-      break deadlock. [[Bug #13768]]
-
-* Warning
-
-    * Warning#warn now supports a category keyword argument.
-      [[Feature #17122]]
-
 ## Stdlib updates
 
 Outstanding ones only.
 
-* BigDecimal
-
-    * Update to BigDecimal 3.0.0
-
-    * This version is Ractor compatible.
-
-* Bundler
-
-    * Update to Bundler 2.2.3
-
-* CGI
-
-    * Update to 0.2.0
-
-    * This version is Ractor compatible.
-
-* CSV
-
-    * Update to CSV 3.1.9
-
-* Date
-
-    * Update to Date 3.1.1
-
-    * This version is Ractor compatible.
-
-* Digest
-
-    * Update to Digest 3.0.0
-
-    * This version is Ractor compatible.
-
-* Etc
-
-    * Update to Etc 1.2.0
-
-    * This version is Ractor compatible.
-
-* Fiddle
-
-    * Update to Fiddle 1.0.5
-
-* IRB
-
-    * Update to IRB 1.2.6
-
-* JSON
-
-    * Update to JSON 2.5.0
-
-    * This version is Ractor compatible.
-
-* Set
-
-    * Update to set 1.0.0
-
-    * SortedSet has been removed for dependency and performance reasons.
-
-    * Set#join is added as a shorthand for `.to_a.join`.
-
-    * Set#<=> is added.
-
-* Socket
-
-    * Add :connect_timeout to TCPSocket.new [[Feature #17187]]
-
-* Net::HTTP
-
-    * Net::HTTP#verify_hostname= and Net::HTTP#verify_hostname have been
-      added to skip hostname verification.  [[Feature #16555]]
-
-    * Net::HTTP.get, Net::HTTP.get_response, and Net::HTTP.get_print
-      can take the request headers as a Hash in the second argument when the
-      first argument is a URI.  [[Feature #16686]]
-
-* Net::SMTP
-
-    * Add SNI support.
-
-    * Net::SMTP.start arguments are keyword arguments.
-
-    * TLS should not check the host name by default.
-
-* OpenStruct
-
-    * Initialization is no longer lazy. [[Bug #12136]]
-
-    * Builtin methods can now be overridden safely. [[Bug #15409]]
-
-    * Implementation uses only methods ending with `!`.
-
-    * Ractor compatible.
-
-    * Improved support for YAML. [[Bug #8382]]
-
-    * Use officially discouraged. Read OpenStruct@Caveats section.
-
-* Pathname
-
-    * Ractor compatible.
-
-* Psych
-
-    * Update to Psych 3.3.0
-
-    * This version is Ractor compatible.
-
-* Reline
-
-    * Update to Reline 0.1.5
-
-* RubyGems
-
-    * Update to RubyGems 3.2.3
-
-* StringIO
-
-    * Update to StringIO 3.0.0
-
-    * This version is Ractor compatible.
-
-* StringScanner
-
-    * Update to StringScanner 3.0.0
-
-    * This version is Ractor compatible.
-
 ## Compatibility issues
 
 Excluding feature bug fixes.
 
-* Regexp literals and all Range objects are frozen. [[Feature #8948]] [[Feature #16377]] [[Feature #15504]]
-
-    ```ruby
-    /foo/.frozen? #=> true
-    (42...).frozen? # => true
-    ```
-
-* EXPERIMENTAL: Hash#each consistently yields a 2-element array. [[Bug #12706]]
-
-    * Now `{ a: 1 }.each(&->(k, v) { })` raises an ArgumentError
-      due to lambda's arity check.
-
-* When writing to STDOUT redirected to a closed pipe, no broken pipe
-  error message will be shown now.  [[Feature #14413]]
-
-* `TRUE`/`FALSE`/`NIL` constants are no longer defined.
-
-* Integer#zero? overrides Numeric#zero? for optimization.  [[Misc #16961]]
-
-* Enumerable#grep and Enumerable#grep_v when passed a Regexp and no block no longer modify
-  Regexp.last_match. [[Bug #17030]]
-
-* Requiring 'open-uri' no longer redefines `Kernel#open`.
-  Call `URI.open` directly or `use URI#open` instead. [[Misc #15893]]
-
-* SortedSet has been removed for dependency and performance reasons.
-
 ## Stdlib compatibility issues
 
-* Default gems
-
-    * The following libraries are promoted to default gems from stdlib.
-
-        * English
-        * abbrev
-        * base64
-        * drb
-        * debug
-        * erb
-        * find
-        * net-ftp
-        * net-http
-        * net-imap
-        * net-protocol
-        * open-uri
-        * optparse
-        * pp
-        * prettyprint
-        * resolv-replace
-        * resolv
-        * rinda
-        * set
-        * securerandom
-        * shellwords
-        * tempfile
-        * tmpdir
-        * time
-        * tsort
-        * un
-        * weakref
-
-    * The following extensions are promoted to default gems from stdlib.
-
-        * digest
-        * io-nonblock
-        * io-wait
-        * nkf
-        * pathname
-        * syslog
-        * win32ole
-
-* Bundled gems
-
-    * net-telnet and xmlrpc have been removed from the bundled gems.
-      If you are interested in maintaining them, please comment on
-      your plan to https://github.com/ruby/xmlrpc
-      or https://github.com/ruby/net-telnet.
-
-* SDBM has been removed from the Ruby standard library. [[Bug #8446]]
-
-    * The issues of sdbm will be handled at https://github.com/ruby/sdbm
-
-* WEBrick has been removed from the Ruby standard library. [[Feature #17303]]
-
-    * The issues of WEBrick will be handled at https://github.com/ruby/webrick
-
 ## C API updates
 
-* C API functions related to $SAFE have been removed.
-  [[Feature #16131]]
-
-* C API header file `ruby/ruby.h` was split. [[GH-2991]]
-
-    This should have no impact on extension libraries,
-    but users might experience slow compilations.
-
-* Memory view interface [EXPERIMENTAL]
-
-    * The memory view interface is a C-API set to exchange a raw memory area,
-      such as a numeric array or a bitmap image, between extension libraries.
-      The extension libraries can share also the metadata of the memory area
-      that consists of the shape, the element format, and so on.
-      Using these kinds of metadata, the extension libraries can share even
-      a multidimensional array appropriately.
-      This feature is designed by referring to Python's buffer protocol.
-      [[Feature #13767]] [[Feature #14722]]
-
-* Ractor related C APIs are introduced (experimental) in "include/ruby/ractor.h".
-
 ## Implementation improvements
 
-* New method cache mechanism for Ractor. [[Feature #16614]]
-
-    * Inline method caches pointed from ISeq can be accessed by multiple Ractors
-      in parallel and synchronization is needed even for method caches. However,
-      such synchronization can be overhead so introducing new inline method cache
-      mechanisms, (1) Disposable inline method cache (2) per-Class method cache
-      and (3) new invalidation mechanism. (1) can avoid per-method call
-      synchronization because it only uses atomic operations.
-      See the ticket for more details.
-
-* The number of hashes allocated when using a keyword splat in
-  a method call has been reduced to a maximum of 1, and passing
-  a keyword splat to a method that accepts specific keywords
-  does not allocate a hash.
-
-* `super` is optimized when the same type of method is called in the previous call
-  if it's not refinements or an attr reader or writer.
-
 ### JIT
 
-* Performance improvements of JIT-ed code
-
-    * Microarchitectural optimizations
-
-        * Native functions shared by multiple methods are deduplicated on JIT compaction.
-
-        * Decrease code size of hot paths by some optimizations and partitioning cold paths.
-
-    * Instance variables
-
-        * Eliminate some redundant checks.
-
-        * Skip checking a class and a object multiple times in a method when possible.
-
-        * Optimize accesses in some core classes like Hash and their subclasses.
-
-    * Method inlining support for some C methods
-
-        * `Kernel`: `#class`, `#frozen?`
-
-        * `Integer`: `#-@`, `#~`, `#abs`, `#bit_length`, `#even?`, `#integer?`, `#magnitude`,
-          `#odd?`, `#ord`, `#to_i`, `#to_int`, `#zero?`
-
-        * `Struct`: reader methods for 10th or later members
-
-    * Constant references are inlined.
-
-    * Always generate appropriate code for `==`, `nil?`, and `!` calls depending on
-      a receiver class.
-
-    * Reduce the number of PC accesses on branches and method returns.
-
-    * Optimize C method calls a little.
-
-* Compilation process improvements
-
-    * It does not keep temporary files in /tmp anymore.
-
-    * Throttle GC and compaction of JIT-ed code.
-
-    * Avoid GC-ing JIT-ed code when not necessary.
-
-    * GC-ing JIT-ed code is executed in a background thread.
-
-    * Reduce the number of locks between Ruby and JIT threads.
-
 ## Static analysis
 
 ### RBS
 
-* RBS is a new language for type definition of Ruby programs.
-  It allows writing types of classes and modules with advanced
-  types including union types, overloading, generics, and
-  _interface types_ for duck typing.
-
-* Ruby ships with type definitions for core/stdlib classes.
-
-* `rbs` gem is bundled to load and process RBS files.
-
 ### TypeProf
 
-* TypeProf is a type analysis tool for Ruby code based on abstract interpretation.
-
-    * It reads non-annotated Ruby code, tries inferring its type signature, and prints
-      the analysis result in RBS format.
-
-    * Though it supports only a subset of the Ruby language yet, we will continuously
-      improve the coverage of language features, analysis performance, and usability.
-
-```ruby
-# test.rb
-def foo(x)
-  if x > 10
-    x.to_s
-  else
-    nil
-  end
-end
-
-foo(42)
-```
-
-```
-$ typeprof test.rb
-# Classes
-class Object
-  def foo : (Integer) -> String?
-end
-```
-
 ## Miscellaneous changes
-
-* Methods using `ruby2_keywords` will no longer keep empty keyword
-  splats, those are now removed just as they are for methods not
-  using `ruby2_keywords`.
-
-* When an exception is caught in the default handler, the error
-  message and backtrace are printed in order from the innermost.
-  [[Feature #8661]]
-
-* Accessing an uninitialized instance variable no longer emits a
-  warning in verbose mode. [[Feature #17055]]
-
-[Bug #4352]:      https://bugs.ruby-lang.org/issues/4352
-[Bug #6087]:      https://bugs.ruby-lang.org/issues/6087
-[Bug #8382]:      https://bugs.ruby-lang.org/issues/8382
-[Bug #8446]:      https://bugs.ruby-lang.org/issues/8446
-[Feature #8661]:  https://bugs.ruby-lang.org/issues/8661
-[Feature #8709]:  https://bugs.ruby-lang.org/issues/8709
-[Feature #8948]:  https://bugs.ruby-lang.org/issues/8948
-[Feature #9573]:  https://bugs.ruby-lang.org/issues/9573
-[Bug #10845]:     https://bugs.ruby-lang.org/issues/10845
-[Bug #12136]:     https://bugs.ruby-lang.org/issues/12136
-[Feature #12650]: https://bugs.ruby-lang.org/issues/12650
-[Bug #12706]:     https://bugs.ruby-lang.org/issues/12706
-[Feature #13767]: https://bugs.ruby-lang.org/issues/13767
-[Bug #13768]:     https://bugs.ruby-lang.org/issues/13768
-[Feature #14183]: https://bugs.ruby-lang.org/issues/14183
-[Bug #14266]:     https://bugs.ruby-lang.org/issues/14266
-[Feature #14267]: https://bugs.ruby-lang.org/issues/14267
-[Feature #14413]: https://bugs.ruby-lang.org/issues/14413
-[Bug #14541]:     https://bugs.ruby-lang.org/issues/14541
-[Feature #14722]: https://bugs.ruby-lang.org/issues/14722
-[Bug #15409]:     https://bugs.ruby-lang.org/issues/15409
-[Feature #15504]: https://bugs.ruby-lang.org/issues/15504
-[Feature #15575]: https://bugs.ruby-lang.org/issues/15575
-[Feature #15822]: https://bugs.ruby-lang.org/issues/15822
-[Misc #15893]:    https://bugs.ruby-lang.org/issues/15893
-[Feature #15921]: https://bugs.ruby-lang.org/issues/15921
-[Feature #15973]: https://bugs.ruby-lang.org/issues/15973
-[Feature #16131]: https://bugs.ruby-lang.org/issues/16131
-[Feature #16150]: https://bugs.ruby-lang.org/issues/16150
-[Feature #16166]: https://bugs.ruby-lang.org/issues/16166
-[Feature #16175]: https://bugs.ruby-lang.org/issues/16175
-[Feature #16233]: https://bugs.ruby-lang.org/issues/16233
-[Feature #16260]: https://bugs.ruby-lang.org/issues/16260
-[Feature #16274]: https://bugs.ruby-lang.org/issues/16274
-[Feature #16345]: https://bugs.ruby-lang.org/issues/16345
-[Feature #16377]: https://bugs.ruby-lang.org/issues/16377
-[Feature #16378]: https://bugs.ruby-lang.org/issues/16378
-[Feature #16555]: https://bugs.ruby-lang.org/issues/16555
-[Feature #16604]: https://bugs.ruby-lang.org/issues/16604
-[Feature #16614]: https://bugs.ruby-lang.org/issues/16614
-[Feature #16686]: https://bugs.ruby-lang.org/issues/16686
-[Feature #16746]: https://bugs.ruby-lang.org/issues/16746
-[Feature #16754]: https://bugs.ruby-lang.org/issues/16754
-[Feature #16786]: https://bugs.ruby-lang.org/issues/16786
-[Feature #16792]: https://bugs.ruby-lang.org/issues/16792
-[Feature #16815]: https://bugs.ruby-lang.org/issues/16815
-[Feature #16828]: https://bugs.ruby-lang.org/issues/16828
-[Misc #16961]:    https://bugs.ruby-lang.org/issues/16961
-[Bug #17030]:     https://bugs.ruby-lang.org/issues/17030
-[Feature #17055]: https://bugs.ruby-lang.org/issues/17055
-[Feature #17104]: https://bugs.ruby-lang.org/issues/17104
-[Feature #17122]: https://bugs.ruby-lang.org/issues/17122
-[Feature #17136]: https://bugs.ruby-lang.org/issues/17136
-[Feature #17176]: https://bugs.ruby-lang.org/issues/17176
-[Feature #17187]: https://bugs.ruby-lang.org/issues/17187
-[Bug #17221]:     https://bugs.ruby-lang.org/issues/17221
-[Feature #17260]: https://bugs.ruby-lang.org/issues/17260
-[Feature #17273]: https://bugs.ruby-lang.org/issues/17273
-[Feature #17303]: https://bugs.ruby-lang.org/issues/17303
-[Feature #17314]: https://bugs.ruby-lang.org/issues/17314
-[Feature #17322]: https://bugs.ruby-lang.org/issues/17322
-[Feature #17351]: https://bugs.ruby-lang.org/issues/17351
-[Feature #17371]: https://bugs.ruby-lang.org/issues/17371
-[Bug #17419]:     https://bugs.ruby-lang.org/issues/17419
-[GH-2991]:        https://github.com/ruby/ruby/pull/2991
diff --git a/doc/NEWS-3.0.0.md b/doc/NEWS-3.0.0.md
new file mode 100644
index 0000000000..2dcfacb6e2
--- /dev/null
+++ b/doc/NEWS-3.0.0.md
@@ -0,0 +1,820 @@
+# NEWS for Ruby 3.0.0
+
+This document is a list of user visible feature changes
+since the **2.7.0** release, except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or reference
+information is supplied with.  For a full list of changes with all
+sufficient information, see the ChangeLog file or Redmine
+(e.g. `https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER`).
+
+## Language changes
+
+* Keyword arguments are now separated from positional arguments.
+  Code that resulted in deprecation warnings in Ruby 2.7 will now
+  result in ArgumentError or different behavior. [[Feature #14183]]
+
+* Procs accepting a single rest argument and keywords are no longer
+  subject to autosplatting.  This now matches the behavior of Procs
+  accepting a single rest argument and no keywords.
+  [[Feature #16166]]
+
+    ```ruby
+    pr = proc{|*a, **kw| [a, kw]}
+
+    pr.call([1])
+    # 2.7 => [[1], {}]
+    # 3.0 => [[[1]], {}]
+
+    pr.call([1, {a: 1}])
+    # 2.7 => [[1], {:a=>1}] # and deprecation warning
+    # 3.0 => [[[1, {:a=>1}]], {}]
+    ```
+
+* Arguments forwarding (`...`) now supports leading arguments.
+  [[Feature #16378]]
+
+    ```ruby
+    def method_missing(meth, ...)
+      send(:"do_#{meth}", ...)
+    end
+    ```
+
+* Pattern matching (`case/in`) is no longer experimental. [[Feature #17260]]
+
+* One-line pattern matching is redesigned.  [EXPERIMENTAL]
+
+    * `=>` is added. It can be used like a rightward assignment.
+      [[Feature #17260]]
+
+        ```ruby
+        0 => a
+        p a #=> 0
+
+        {b: 0, c: 1} => {b:}
+        p b #=> 0
+        ```
+
+    * `in` is changed to return `true` or `false`. [[Feature #17371]]
+
+        ```ruby
+        # version 3.0
+        0 in 1 #=> false
+
+        # version 2.7
+        0 in 1 #=> raise NoMatchingPatternError
+        ```
+
+* Find-pattern is added.  [EXPERIMENTAL]
+  [[Feature #16828]]
+
+    ```ruby
+    case ["a", 1, "b", "c", 2, "d", "e", "f", 3]
+    in [*pre, String => x, String => y, *post]
+      p pre  #=> ["a", 1]
+      p x    #=> "b"
+      p y    #=> "c"
+      p post #=> [2, "d", "e", "f", 3]
+    end
+    ```
+
+* Endless method definition is added.  [EXPERIMENTAL]
+  [[Feature #16746]]
+
+    ```ruby
+    def square(x) = x * x
+    ```
+
+* Interpolated String literals are no longer frozen when
+  `# frozen-string-literal: true` is used. [[Feature #17104]]
+
+* Magic comment `shareable_constant_value` added to freeze constants.
+  See {Magic Comments}[rdoc-ref:doc/syntax/comments.rdoc@Magic+Comments] for more details.
+  [[Feature #17273]]
+
+* A {static analysis}[rdoc-label:label-Static+analysis] foundation is
+  introduced.
+    * {RBS}[rdoc-label:label-RBS] is introduced. It is a type definition
+      language for Ruby programs.
+    * {TypeProf}[rdoc-label:label-TypeProf] is experimentally bundled. It is a
+      type analysis tool for Ruby programs.
+
+* Deprecation warnings are no longer shown by default (since Ruby 2.7.2).
+  Turn them on with `-W:deprecated` (or with `-w` to show other warnings too).
+  [[Feature #16345]]
+
+* $SAFE and $KCODE are now normal global variables with no special behavior.
+  C-API methods related to $SAFE have been removed.
+  [[Feature #16131]] [[Feature #17136]]
+
+* yield in singleton class definitions in methods is now a SyntaxError
+  instead of a warning. yield in a class definition outside of a method
+  is now a SyntaxError instead of a LocalJumpError.  [[Feature #15575]]
+
+* When a class variable is overtaken by the same definition in an
+  ancestor class/module, a RuntimeError is now raised (previously,
+  it only issued a warning in verbose mode).  Additionally, accessing a
+  class variable from the toplevel scope is now a RuntimeError.
+  [[Bug #14541]]
+
+* Assigning to a numbered parameter is now a SyntaxError instead of
+  a warning.
+
+## Command line options
+
+### `--help` option
+
+When the environment variable `RUBY_PAGER` or `PAGER` is present and has
+a non-empty value, and the standard input and output are tty, the `--help`
+option shows the help message via the pager designated by the value.
+[[Feature #16754]]
+
+### `--backtrace-limit` option
+
+The `--backtrace-limit` option limits the maximum length of a backtrace.
+[[Feature #8661]]
+
+## Core classes updates
+
+Outstanding ones only.
+
+* Array
+
+    * The following methods now return Array instances instead of
+      subclass instances when called on subclass instances:
+      [[Bug #6087]]
+
+        * Array#drop
+        * Array#drop_while
+        * Array#flatten
+        * Array#slice!
+        * Array#slice / Array#[]
+        * Array#take
+        * Array#take_while
+        * Array#uniq
+        * Array#*
+
+    * Can be sliced with Enumerator::ArithmeticSequence
+
+        ```ruby
+        dirty_data = ['--', 'data1', '--', 'data2', '--', 'data3']
+        dirty_data[(1..).step(2)] # take each second element
+        # => ["data1", "data2", "data3"]
+        ```
+
+* Binding
+
+    * Binding#eval when called with one argument will use "(eval)"
+      for `__FILE__` and 1 for `__LINE__` in the evaluated code.
+      [[Bug #4352]] [[Bug #17419]]
+
+* ConditionVariable
+
+    * ConditionVariable#wait may now invoke the `block`/`unblock` scheduler
+      hooks in a non-blocking context. [[Feature #16786]]
+
+* Dir
+
+    * Dir.glob and Dir.[] now sort the results by default, and
+      accept the `sort:` keyword option.  [[Feature #8709]]
+
+* ENV
+
+    * ENV.except has been added, which returns a hash excluding the
+      given keys and their values.  [[Feature #15822]]
+
+    * Windows: Read ENV names and values as UTF-8 encoded Strings
+      [[Feature #12650]]
+
+* Encoding
+
+    * Added new encoding IBM720.  [[Feature #16233]]
+
+    * Changed default for Encoding.default_external to UTF-8 on Windows
+      [[Feature #16604]]
+
+* Fiber
+
+    * Fiber.new(blocking: true/false) allows you to create non-blocking
+      execution contexts. [[Feature #16786]]
+
+    * Fiber#blocking? tells whether the fiber is non-blocking. [[Feature #16786]]
+
+    * Fiber#backtrace and Fiber#backtrace_locations provide per-fiber backtrace.
+      [[Feature #16815]]
+
+    * The limitation of Fiber#transfer is relaxed. [[Bug #17221]]
+
+* GC
+
+    * GC.auto_compact= and GC.auto_compact have been added to control
+      when compaction runs.  Setting `auto_compact=` to true will cause
+      compaction to occur during major collections.  At the moment,
+      compaction adds significant overhead to major collections, so please
+      test first!  [[Feature #17176]]
+
+* Hash
+
+    * Hash#transform_keys and Hash#transform_keys! now accept a hash that maps
+      keys to new keys.  [[Feature #16274]]
+
+    * Hash#except has been added, which returns a hash excluding the
+      given keys and their values.  [[Feature #15822]]
+
+* IO
+
+    * IO#nonblock? now defaults to `true`. [[Feature #16786]]
+
+    * IO#wait_readable, IO#wait_writable, IO#read, IO#write and other
+      related methods (e.g. IO#puts, IO#gets) may invoke the scheduler hook
+      `#io_wait(io, events, timeout)` in a non-blocking execution context.
+      [[Feature #16786]]
+
+* Kernel
+
+    * Kernel#clone when called with the `freeze: false` keyword will call
+      `#initialize_clone` with the `freeze: false` keyword.
+      [[Bug #14266]]
+
+    * Kernel#clone when called with the `freeze: true` keyword will call
+      `#initialize_clone` with the `freeze: true` keyword, and will
+      return a frozen copy even if the receiver is unfrozen.
+      [[Feature #16175]]
+
+    * Kernel#eval when called with two arguments will use "(eval)"
+      for `__FILE__` and 1 for `__LINE__` in the evaluated code.
+      [[Bug #4352]]
+
+    * Kernel#lambda now warns if called without a literal block.
+      [[Feature #15973]]
+
+    * Kernel.sleep invokes the scheduler hook `#kernel_sleep(...)` in a
+      non-blocking execution context. [[Feature #16786]]
+
+* Module
+
+    * Module#include and Module#prepend now affect classes and modules
+      that have already included or prepended the receiver, mirroring the
+      behavior if the arguments were included in the receiver before
+      the other modules and classes included or prepended the receiver.
+      [[Feature #9573]]
+
+        ```ruby
+        class C; end
+        module M1; end
+        module M2; end
+        C.include M1
+        M1.include M2
+        p C.ancestors #=> [C, M1, M2, Object, Kernel, BasicObject]
+        ```
+
+    * Module#public, Module#protected, Module#private, Module#public_class_method,
+      Module#private_class_method, toplevel "private" and "public" methods
+      now accept single array argument with a list of method names. [[Feature #17314]]
+
+    * Module#attr_accessor, Module#attr_reader, Module#attr_writer and Module#attr
+      methods now return an array of defined method names as symbols.
+      [[Feature #17314]]
+
+    * Module#alias_method now returns the defined alias as a symbol.
+      [[Feature #17314]]
+
+* Mutex
+
+    * `Mutex` is now acquired per-`Fiber` instead of per-`Thread`. This change
+      should be compatible for essentially all usages and avoids blocking when
+      using a scheduler. [[Feature #16792]]
+
+* Proc
+
+    * Proc#== and Proc#eql? are now defined and will return true for
+      separate Proc instances if the procs were created from the same block.
+      [[Feature #14267]]
+
+* Queue / SizedQueue
+
+    * Queue#pop, SizedQueue#push and related methods may now invoke the
+      `block`/`unblock` scheduler hooks in a non-blocking context.
+      [[Feature #16786]]
+
+* Ractor
+
+    * New class added to enable parallel execution. See rdoc-ref:ractor.md for
+      more details.
+
+* Random
+
+    * `Random::DEFAULT` now refers to the `Random` class instead of being a `Random` instance,
+      so it can work with `Ractor`.
+      [[Feature #17322]]
+
+    * `Random::DEFAULT` is deprecated since its value is now confusing and it is no longer global,
+      use `Kernel.rand`/`Random.rand` directly, or create a `Random` instance with `Random.new` instead.
+      [[Feature #17351]]
+
+
+* String
+
+    * The following methods now return or yield String instances
+      instead of subclass instances when called on subclass instances:
+      [[Bug #10845]]
+
+        * String#*
+        * String#capitalize
+        * String#center
+        * String#chomp
+        * String#chop
+        * String#delete
+        * String#delete_prefix
+        * String#delete_suffix
+        * String#downcase
+        * String#dump
+        * String#each_char
+        * String#each_grapheme_cluster
+        * String#each_line
+        * String#gsub
+        * String#ljust
+        * String#lstrip
+        * String#partition
+        * String#reverse
+        * String#rjust
+        * String#rpartition
+        * String#rstrip
+        * String#scrub
+        * String#slice!
+        * String#slice / String#[]
+        * String#split
+        * String#squeeze
+        * String#strip
+        * String#sub
+        * String#succ / String#next
+        * String#swapcase
+        * String#tr
+        * String#tr_s
+        * String#upcase
+
+* Symbol
+
+    * Symbol#to_proc now returns a lambda Proc.  [[Feature #16260]]
+
+    * Symbol#name has been added, which returns the name of the symbol
+      if it is named.  The returned string is frozen.  [[Feature #16150]]
+
+* Fiber
+
+    * Introduce Fiber.set_scheduler for intercepting blocking operations and
+      Fiber.scheduler for accessing the current scheduler. See
+      rdoc-ref:fiber.md for more details about what operations are supported and
+      how to implement the scheduler hooks. [[Feature #16786]]
+
+    * Fiber.blocking? tells whether the current execution context is
+      blocking. [[Feature #16786]]
+
+    * Thread#join invokes the scheduler hooks `block`/`unblock` in a
+      non-blocking execution context. [[Feature #16786]]
+
+* Thread
+
+    * Thread.ignore_deadlock accessor has been added for disabling the
+      default deadlock detection, allowing the use of signal handlers to
+      break deadlock. [[Bug #13768]]
+
+* Warning
+
+    * Warning#warn now supports a category keyword argument.
+      [[Feature #17122]]
+
+## Stdlib updates
+
+Outstanding ones only.
+
+* BigDecimal
+
+    * Update to BigDecimal 3.0.0
+
+    * This version is Ractor compatible.
+
+* Bundler
+
+    * Update to Bundler 2.2.3
+
+* CGI
+
+    * Update to 0.2.0
+
+    * This version is Ractor compatible.
+
+* CSV
+
+    * Update to CSV 3.1.9
+
+* Date
+
+    * Update to Date 3.1.1
+
+    * This version is Ractor compatible.
+
+* Digest
+
+    * Update to Digest 3.0.0
+
+    * This version is Ractor compatible.
+
+* Etc
+
+    * Update to Etc 1.2.0
+
+    * This version is Ractor compatible.
+
+* Fiddle
+
+    * Update to Fiddle 1.0.5
+
+* IRB
+
+    * Update to IRB 1.2.6
+
+* JSON
+
+    * Update to JSON 2.5.0
+
+    * This version is Ractor compatible.
+
+* Set
+
+    * Update to set 1.0.0
+
+    * SortedSet has been removed for dependency and performance reasons.
+
+    * Set#join is added as a shorthand for `.to_a.join`.
+
+    * Set#<=> is added.
+
+* Socket
+
+    * Add :connect_timeout to TCPSocket.new [[Feature #17187]]
+
+* Net::HTTP
+
+    * Net::HTTP#verify_hostname= and Net::HTTP#verify_hostname have been
+      added to skip hostname verification.  [[Feature #16555]]
+
+    * Net::HTTP.get, Net::HTTP.get_response, and Net::HTTP.get_print
+      can take the request headers as a Hash in the second argument when the
+      first argument is a URI.  [[Feature #16686]]
+
+* Net::SMTP
+
+    * Add SNI support.
+
+    * Net::SMTP.start arguments are keyword arguments.
+
+    * TLS should not check the host name by default.
+
+* OpenStruct
+
+    * Initialization is no longer lazy. [[Bug #12136]]
+
+    * Builtin methods can now be overridden safely. [[Bug #15409]]
+
+    * Implementation uses only methods ending with `!`.
+
+    * Ractor compatible.
+
+    * Improved support for YAML. [[Bug #8382]]
+
+    * Use officially discouraged. Read OpenStruct@Caveats section.
+
+* Pathname
+
+    * Ractor compatible.
+
+* Psych
+
+    * Update to Psych 3.3.0
+
+    * This version is Ractor compatible.
+
+* Reline
+
+    * Update to Reline 0.1.5
+
+* RubyGems
+
+    * Update to RubyGems 3.2.3
+
+* StringIO
+
+    * Update to StringIO 3.0.0
+
+    * This version is Ractor compatible.
+
+* StringScanner
+
+    * Update to StringScanner 3.0.0
+
+    * This version is Ractor compatible.
+
+## Compatibility issues
+
+Excluding feature bug fixes.
+
+* Regexp literals and all Range objects are frozen. [[Feature #8948]] [[Feature #16377]] [[Feature #15504]]
+
+    ```ruby
+    /foo/.frozen? #=> true
+    (42...).frozen? # => true
+    ```
+
+* EXPERIMENTAL: Hash#each consistently yields a 2-element array. [[Bug #12706]]
+
+    * Now `{ a: 1 }.each(&->(k, v) { })` raises an ArgumentError
+      due to lambda's arity check.
+
+* When writing to STDOUT redirected to a closed pipe, no broken pipe
+  error message will be shown now.  [[Feature #14413]]
+
+* `TRUE`/`FALSE`/`NIL` constants are no longer defined.
+
+* Integer#zero? overrides Numeric#zero? for optimization.  [[Misc #16961]]
+
+* Enumerable#grep and Enumerable#grep_v when passed a Regexp and no block no longer modify
+  Regexp.last_match. [[Bug #17030]]
+
+* Requiring 'open-uri' no longer redefines `Kernel#open`.
+  Call `URI.open` directly or `use URI#open` instead. [[Misc #15893]]
+
+* SortedSet has been removed for dependency and performance reasons.
+
+## Stdlib compatibility issues
+
+* Default gems
+
+    * The following libraries are promoted to default gems from stdlib.
+
+        * English
+        * abbrev
+        * base64
+        * drb
+        * debug
+        * erb
+        * find
+        * net-ftp
+        * net-http
+        * net-imap
+        * net-protocol
+        * open-uri
+        * optparse
+        * pp
+        * prettyprint
+        * resolv-replace
+        * resolv
+        * rinda
+        * set
+        * securerandom
+        * shellwords
+        * tempfile
+        * tmpdir
+        * time
+        * tsort
+        * un
+        * weakref
+
+    * The following extensions are promoted to default gems from stdlib.
+
+        * digest
+        * io-nonblock
+        * io-wait
+        * nkf
+        * pathname
+        * syslog
+        * win32ole
+
+* Bundled gems
+
+    * net-telnet and xmlrpc have been removed from the bundled gems.
+      If you are interested in maintaining them, please comment on
+      your plan to https://github.com/ruby/xmlrpc
+      or https://github.com/ruby/net-telnet.
+
+* SDBM has been removed from the Ruby standard library. [[Bug #8446]]
+
+    * The issues of sdbm will be handled at https://github.com/ruby/sdbm
+
+* WEBrick has been removed from the Ruby standard library. [[Feature #17303]]
+
+    * The issues of WEBrick will be handled at https://github.com/ruby/webrick
+
+## C API updates
+
+* C API functions related to $SAFE have been removed.
+  [[Feature #16131]]
+
+* C API header file `ruby/ruby.h` was split. [[GH-2991]]
+
+    This should have no impact on extension libraries,
+    but users might experience slow compilations.
+
+* Memory view interface [EXPERIMENTAL]
+
+    * The memory view interface is a C-API set to exchange a raw memory area,
+      such as a numeric array or a bitmap image, between extension libraries.
+      The extension libraries can share also the metadata of the memory area
+      that consists of the shape, the element format, and so on.
+      Using these kinds of metadata, the extension libraries can share even
+      a multidimensional array appropriately.
+      This feature is designed by referring to Python's buffer protocol.
+      [[Feature #13767]] [[Feature #14722]]
+
+* Ractor related C APIs are introduced (experimental) in "include/ruby/ractor.h".
+
+## Implementation improvements
+
+* New method cache mechanism for Ractor. [[Feature #16614]]
+
+    * Inline method caches pointed from ISeq can be accessed by multiple Ractors
+      in parallel and synchronization is needed even for method caches. However,
+      such synchronization can be overhead so introducing new inline method cache
+      mechanisms, (1) Disposable inline method cache (2) per-Class method cache
+      and (3) new invalidation mechanism. (1) can avoid per-method call
+      synchronization because it only uses atomic operations.
+      See the ticket for more details.
+
+* The number of hashes allocated when using a keyword splat in
+  a method call has been reduced to a maximum of 1, and passing
+  a keyword splat to a method that accepts specific keywords
+  does not allocate a hash.
+
+* `super` is optimized when the same type of method is called in the previous call
+  if it's not refinements or an attr reader or writer.
+
+### JIT
+
+* Performance improvements of JIT-ed code
+
+    * Microarchitectural optimizations
+
+        * Native functions shared by multiple methods are deduplicated on JIT compaction.
+
+        * Decrease code size of hot paths by some optimizations and partitioning cold paths.
+
+    * Instance variables
+
+        * Eliminate some redundant checks.
+
+        * Skip checking a class and a object multiple times in a method when possible.
+
+        * Optimize accesses in some core classes like Hash and their subclasses.
+
+    * Method inlining support for some C methods
+
+        * `Kernel`: `#class`, `#frozen?`
+
+        * `Integer`: `#-@`, `#~`, `#abs`, `#bit_length`, `#even?`, `#integer?`, `#magnitude`,
+          `#odd?`, `#ord`, `#to_i`, `#to_int`, `#zero?`
+
+        * `Struct`: reader methods for 10th or later members
+
+    * Constant references are inlined.
+
+    * Always generate appropriate code for `==`, `nil?`, and `!` calls depending on
+      a receiver class.
+
+    * Reduce the number of PC accesses on branches and method returns.
+
+    * Optimize C method calls a little.
+
+* Compilation process improvements
+
+    * It does not keep temporary files in /tmp anymore.
+
+    * Throttle GC and compaction of JIT-ed code.
+
+    * Avoid GC-ing JIT-ed code when not necessary.
+
+    * GC-ing JIT-ed code is executed in a background thread.
+
+    * Reduce the number of locks between Ruby and JIT threads.
+
+## Static analysis
+
+### RBS
+
+* RBS is a new language for type definition of Ruby programs.
+  It allows writing types of classes and modules with advanced
+  types including union types, overloading, generics, and
+  _interface types_ for duck typing.
+
+* Ruby ships with type definitions for core/stdlib classes.
+
+* `rbs` gem is bundled to load and process RBS files.
+
+### TypeProf
+
+* TypeProf is a type analysis tool for Ruby code based on abstract interpretation.
+
+    * It reads non-annotated Ruby code, tries inferring its type signature, and prints
+      the analysis result in RBS format.
+
+    * Though it supports only a subset of the Ruby language yet, we will continuously
+      improve the coverage of language features, analysis performance, and usability.
+
+```ruby
+# test.rb
+def foo(x)
+  if x > 10
+    x.to_s
+  else
+    nil
+  end
+end
+
+foo(42)
+```
+
+```
+$ typeprof test.rb
+# Classes
+class Object
+  def foo : (Integer) -> String?
+end
+```
+
+## Miscellaneous changes
+
+* Methods using `ruby2_keywords` will no longer keep empty keyword
+  splats, those are now removed just as they are for methods not
+  using `ruby2_keywords`.
+
+* When an exception is caught in the default handler, the error
+  message and backtrace are printed in order from the innermost.
+  [[Feature #8661]]
+
+* Accessing an uninitialized instance variable no longer emits a
+  warning in verbose mode. [[Feature #17055]]
+
+[Bug #4352]:      https://bugs.ruby-lang.org/issues/4352
+[Bug #6087]:      https://bugs.ruby-lang.org/issues/6087
+[Bug #8382]:      https://bugs.ruby-lang.org/issues/8382
+[Bug #8446]:      https://bugs.ruby-lang.org/issues/8446
+[Feature #8661]:  https://bugs.ruby-lang.org/issues/8661
+[Feature #8709]:  https://bugs.ruby-lang.org/issues/8709
+[Feature #8948]:  https://bugs.ruby-lang.org/issues/8948
+[Feature #9573]:  https://bugs.ruby-lang.org/issues/9573
+[Bug #10845]:     https://bugs.ruby-lang.org/issues/10845
+[Bug #12136]:     https://bugs.ruby-lang.org/issues/12136
+[Feature #12650]: https://bugs.ruby-lang.org/issues/12650
+[Bug #12706]:     https://bugs.ruby-lang.org/issues/12706
+[Feature #13767]: https://bugs.ruby-lang.org/issues/13767
+[Bug #13768]:     https://bugs.ruby-lang.org/issues/13768
+[Feature #14183]: https://bugs.ruby-lang.org/issues/14183
+[Bug #14266]:     https://bugs.ruby-lang.org/issues/14266
+[Feature #14267]: https://bugs.ruby-lang.org/issues/14267
+[Feature #14413]: https://bugs.ruby-lang.org/issues/14413
+[Bug #14541]:     https://bugs.ruby-lang.org/issues/14541
+[Feature #14722]: https://bugs.ruby-lang.org/issues/14722
+[Bug #15409]:     https://bugs.ruby-lang.org/issues/15409
+[Feature #15504]: https://bugs.ruby-lang.org/issues/15504
+[Feature #15575]: https://bugs.ruby-lang.org/issues/15575
+[Feature #15822]: https://bugs.ruby-lang.org/issues/15822
+[Misc #15893]:    https://bugs.ruby-lang.org/issues/15893
+[Feature #15921]: https://bugs.ruby-lang.org/issues/15921
+[Feature #15973]: https://bugs.ruby-lang.org/issues/15973
+[Feature #16131]: https://bugs.ruby-lang.org/issues/16131
+[Feature #16150]: https://bugs.ruby-lang.org/issues/16150
+[Feature #16166]: https://bugs.ruby-lang.org/issues/16166
+[Feature #16175]: https://bugs.ruby-lang.org/issues/16175
+[Feature #16233]: https://bugs.ruby-lang.org/issues/16233
+[Feature #16260]: https://bugs.ruby-lang.org/issues/16260
+[Feature #16274]: https://bugs.ruby-lang.org/issues/16274
+[Feature #16345]: https://bugs.ruby-lang.org/issues/16345
+[Feature #16377]: https://bugs.ruby-lang.org/issues/16377
+[Feature #16378]: https://bugs.ruby-lang.org/issues/16378
+[Feature #16555]: https://bugs.ruby-lang.org/issues/16555
+[Feature #16604]: https://bugs.ruby-lang.org/issues/16604
+[Feature #16614]: https://bugs.ruby-lang.org/issues/16614
+[Feature #16686]: https://bugs.ruby-lang.org/issues/16686
+[Feature #16746]: https://bugs.ruby-lang.org/issues/16746
+[Feature #16754]: https://bugs.ruby-lang.org/issues/16754
+[Feature #16786]: https://bugs.ruby-lang.org/issues/16786
+[Feature #16792]: https://bugs.ruby-lang.org/issues/16792
+[Feature #16815]: https://bugs.ruby-lang.org/issues/16815
+[Feature #16828]: https://bugs.ruby-lang.org/issues/16828
+[Misc #16961]:    https://bugs.ruby-lang.org/issues/16961
+[Bug #17030]:     https://bugs.ruby-lang.org/issues/17030
+[Feature #17055]: https://bugs.ruby-lang.org/issues/17055
+[Feature #17104]: https://bugs.ruby-lang.org/issues/17104
+[Feature #17122]: https://bugs.ruby-lang.org/issues/17122
+[Feature #17136]: https://bugs.ruby-lang.org/issues/17136
+[Feature #17176]: https://bugs.ruby-lang.org/issues/17176
+[Feature #17187]: https://bugs.ruby-lang.org/issues/17187
+[Bug #17221]:     https://bugs.ruby-lang.org/issues/17221
+[Feature #17260]: https://bugs.ruby-lang.org/issues/17260
+[Feature #17273]: https://bugs.ruby-lang.org/issues/17273
+[Feature #17303]: https://bugs.ruby-lang.org/issues/17303
+[Feature #17314]: https://bugs.ruby-lang.org/issues/17314
+[Feature #17322]: https://bugs.ruby-lang.org/issues/17322
+[Feature #17351]: https://bugs.ruby-lang.org/issues/17351
+[Feature #17371]: https://bugs.ruby-lang.org/issues/17371
+[Bug #17419]:     https://bugs.ruby-lang.org/issues/17419
+[GH-2991]:        https://github.com/ruby/ruby/pull/2991