NEWS for Ruby 3.2.0

This document is a list of user-visible feature changes since the 3.1.0 release, except for bug fixes.

Note that each entry is kept to a minimum, see links for details.

Language changes

Anonymous rest and keyword rest arguments can now be passed as arguments, instead of just used in method parameters. [Feature #18351]
```
def foo(*)
  bar(*)
end
def baz(**)
  quux(**)
end
```
Constant assignment evaluation order for constants set on explicit objects has been made consistent with single attribute assignment evaluation order. With this code:
```
foo::BAR = baz
```
foo is now called before baz. Similarly, for multiple assignment to constants, left-to-right evaluation order is used. With this code:
```
  foo1::BAR1, foo2::BAR2 = baz1, baz2
```
The following evaluation order is now used:
1. foo1
2. foo2
3. baz1
4. baz2
[Bug #15928]

Command line options

Core classes updates

Note: We're only listing outstanding class updates.

Hash
- Hash#shift now always returns nil if the hash is empty, instead of returning the default value or calling the default proc. [Bug #16908]
Module
- Module.used_refinements has been added. [Feature #14332]
- Module#refinements has been added. [Feature #12737]
- Module#const_added has been added. [[Feature #17881]]
Proc
- Proc#dup returns an instance of subclass. [Bug #17545]
Refinement
- Refinement#refined_class has been added. [Feature #12737]

Stdlib updates

The following default gem are updated.
- RubyGems 3.4.0.dev
- bundler 2.4.0.dev
- etc 1.4.0
- io-console 0.5.11
- reline 0.3.1
The following bundled gems are updated.
- net-imap 0.2.3
- typeprof 0.21.2
The following default gems are now bundled gems.

Compatibility issues

Note: Excluding feature bug fixes.

Removed constants

The following deprecated constants are removed.

Random::DEFAULT [Feature #17351]
Struct::Group
Struct::Passwd

Removed methods

The following deprecated methods are removed.

Dir.exists? [Feature #17391]
File.exists? [Feature #17391]
Kernel#=~ [Feature #15231]
Kernel#taint, Kernel#untaint, Kernel#tainted? [Feature #16131]
Kernel#trust, Kernel#untrust, Kernel#untrusted? [Feature #16131]

Stdlib compatibility issues

ERB
- ERB.new no longer takes more than one positional arguments [Feature #14256]

C API updates

Removed C APIs

The following deprecated APIs are removed.

rb_cData variable.
"taintedness" and "trustedness" functions. [Feature #16131]

Implementation improvements

JIT

MJIT

YJIT: New experimental in-process JIT compiler

Static analysis

RBS

TypeProf

Debugger

error_highlight

IRB Autocomplete and Document Display

Miscellaneous changes