Language

• Add lib functions earlier so that they are visible in top-level macros (#12848, thanks @asterite)

Standard Library

• Improve Benchmark docs (#12782, thanks @r00ster91, @straight-shoota)
• Improve documentation for Object#to_s and #inspect (#9974, thanks @straight-shoota)
• Add methods to manipulate semantic versions (#12834, thanks @gabriel-ss)
• Add types to methods with defaults (#12837, thanks @caspiano)
• examples: fix (2022-10) (#12665, thanks @maiha)
• Fix documentation for Pointer#move_to (#12677, thanks @TheEEs)
• (performance) Eliminate nil from many predicate methods (#12702, thanks @HertzDevil)
• examples: fix (2022-12) (#12870, thanks @maiha)

Collection

• Fix missed elements in Hash#select!(keys : Enumerable) (#12739, thanks @caspiano)
• Add missing docs for Indexable combinations methods (#10548, thanks @keidax)
• (performance) Optimize Range#sample(n) for integers and floats (#12535, thanks @straight-shoota)
• Add Iterable#each_cons_pair (#12726, thanks @caspiano)
• Add links to equivalent Iterator methods in Iterable (#12727, thanks @caspiano)
• (performance) Optimize Hash#select(Enumerable) and #merge!(Hash, &) (#12737, thanks @HertzDevil)
• Add Indexable#rindex! method variant (#12759, thanks @Sija)
• (performance) Use mutating collection methods (#12644, thanks @caspiano)
• Fix Enum#to_s for flag enum containing named and unnamed members (#12895, thanks @straight-shoota)

Concurrency

• Allow the EventLoop implementation to be detected at runtime (#12656, thanks @lbguilherme)
• (performance) Optimize uniqueness filter in Channel.select_impl (#12814, thanks @straight-shoota)
• Implement multithreading primitives on Windows (#11647, thanks @HertzDevil)

Crypto

• (breaking-change) Implement Digest class in Digest::CRC32 and Digest::Adler32 (#11535, thanks @BlobCodes)
• Fix OpenSSL::SSL::Context::Client#alpn_protocol= (#12724, thanks @jaclarke)
• Fix HTTP::Client certificate validation error on FQDN (host with trailing dot) (#12778, thanks @compumike)
• Enable arc4random(3) on all supported BSDs and macOS/Darwin (#12608, thanks @dmgk)

Files

• Fix: Read UInt in zip directory header (#12822, thanks @pbrumm)
• Add File.executable? for Windows (#9677, thanks @nof1000)

Macros

• Fix TypeNode#nilable? for root types (#12354, thanks @HertzDevil)
• Add argless #annotations overload (#9326, thanks @Blacksmoke16)
• Add specs for addition between ArrayLiteral and TupleLiteral (#12639, thanks @caspiano)
• Add ArrayLiteral#-(other) and TupleLiteral#-(other) (#12646, #12916 thanks @caspiano, @straight-shoota)

Networking

• (breaking-change) Add HTTP::Headers#serialize (#12765, thanks @straight-shoota)
• Ensure HTTP::Client closes response when breaking out of block (#12749, thanks @straight-shoota)
• Add HTTP::Server::Response#redirect (#12526, thanks @straight-shoota)
• (performance) Websocket: write masked data to temporary buffer before sending it (#12613, thanks @asterite)
• Validate cookie name prefixes (#10648, thanks @Blacksmoke16)
• IPAddress#loopback? should consider ::ffff:127.0.0.1/104 loopback too (#12783, thanks @carlhoerberg)

Numeric

• Support new SI prefixes in Number#humanize (#12761, thanks @HertzDevil)
• Fix BigInt#% for unsigned integers (#12773, thanks @straight-shoota)
• [WASM] Add missing __powisf2 and __powidf2 compiler-rt functions (#12569, thanks @lbguilherme)
• Add docs for Int#downto (#12468, thanks @yb66)
• Upgrade the Dragonbox algorithm (#12767, thanks @HertzDevil)
• Support scientific notation in BigDecimal#to_s (#10805, thanks @HertzDevil)
• Add #bit_reverse and #byte_swap for primitive integers (#12865, thanks @HertzDevil)
• Fix Number comparison operator docs (#12880, thanks @fdocr)

Runtime

• Exception::CallStack: avoid allocations in LibC.dl_iterate_phdr (#12625, thanks @dmgk)
• Fix explicit type conversion to u64 for GC::Stats (#12779, thanks @straight-shoota)
• Add custom message parameter to #not_nil! (#12797, thanks @straight-shoota)
• Refactor specs for Enum#to_s using assert_prints (#12882, thanks @straight-shoota)

Serialization

• (performance) Leverage GC.malloc_atomic for XML (#12692, thanks @HertzDevil)
• Refactor libXML error handling to remove global state (#12663, #12795, thanks @straight-shoota)
• Use qualified type reference YAML::Any (#12688, thanks @zw963)
• Automatically cast Int to Float for {JSON,YAML}::Any#as_f (#12835, thanks @compumike)

Specs

• Print seed info at start and end of spec output (#12755, thanks @straight-shoota)

System

• (breaking) Rename File.real_path to .realpath (#12552, thanks @straight-shoota)
• (breaking-change) Drop FreeBSD 11 compatibility code (#12612, thanks @dmgk)
• Trap when trying to raise wasm32 exceptions (#12572, thanks @lbguilherme)
• Use single helper method to pass UTF-16 strings to Windows (#12695, #12747, thanks @HertzDevil, @straight-shoota)
• Implement flock_* fiber-aware, without blocking the thread (#12861, #12728, thanks @straight-shoota)
• Implement flock_* for Win32 (#12766, thanks @straight-shoota)
• Add docs to ENV#has_key? (#12781, thanks @straight-shoota)
• Improve specs by removing absolute path references (#12776, thanks @straight-shoota)
• Update FreeBSD LibC types (#12651, thanks @dmgk)
• Organize Process specs (#12889, thanks @straight-shoota)
• Add tests for Process::Status (#12881, thanks @straight-shoota)

Text

• Raise IndexError on unmatched subpattern for MatchData#begin and #end (#12810, thanks @straight-shoota)
• Swap documentation for String#split array and block versions (#12808, thanks @hugopl)
• Add String#index/rindex! methods (#12730, thanks @Sija)
• Re-organize and enhance specs for Regex and Regex::MatchData (#12788, #12789, thanks @straight-shoota)
• Add missing positive spec for Regex#match with option (#12804, thanks @straight-shoota)
• Replace if !blank? with unless blank? (#12800, thanks @vlazar)
• Add references between String equality, comparison methods (#10531, thanks @straight-shoota)
• Extract internal Regex API for PCRE backend (#12802, thanks @straight-shoota)
• Implement Regex engine on PCRE2 (#12856, #12866, #12847, thanks @straight-shoota, thanks @HertzDevil)
• Add missing overloads for String#byte_slice (#12809, thanks @straight-shoota)

Compiler

• Improve error message when there are extra types (#12734, thanks @asterite)
• Handle triples without libc (#12594, thanks @GeopJr)
• Remove unused Program#cache_dir property (#12669, thanks @straight-shoota)
• Fix: Unwrap nested errors in error handler for Crystal::Error (#12888, thanks @straight-shoota)

Codegen

• Add missing specs for ->var.foo semantics with assignments (#9419, thanks @makenowjust)
• Use File#flock_exclusive on win32 in compiler (#12876, thanks @straight-shoota)

Generics

• Redefine defs when constant and number in generic arguments are equal (#12785, thanks @HertzDevil)
• Fix restriction of numeral generic argument against non-free variable Path (#12784, thanks @HertzDevil)

Interpreter

• Interpreter: fix class var initializer that needs an upcast (#12635, thanks @asterite)
• Reverting #12405 Compiler: don't always use Array for node dependencies and observers (#12849, thanks @beta-ziliani)
• Match Nix loader errors in compiler spec (#12852, thanks @bcardiff)
• Interpreter reply (#12738, thanks @I3oris)

Parser

• (breaking-change) Parser: Fix restrict grammar for name and supertype in type def (#12622, thanks @caspiano)
• Lexer: fix global capture vars ending with zero, e.g. $10? (#12701, thanks @FnControlOption)
• Lexer: allow regex after CRLF (#12713, thanks @FnControlOption)
• Assignment to global regex match data is not allowed (#12714, thanks @caspiano)
• Error when declaring a constant within another constant declaration (#12566, thanks @caspiano)
• Fix calls with do-end blocks within index operators (#12824, thanks @caspiano)
• Remove oct/bin floating point literals (#12687, thanks @BlobCodes)
• Parser: fix wrong/missing locations of various AST nodes (#11798, thanks @FnControlOption)
• Refactor: use helper method instead of duplicate code in lexer (#12590, thanks @straight-shoota)
• Simplify sequential character checks in Crystal lexer (#12699, thanks @caspiano)
• Lexer: delete redundant scan_ident calls (#12691, thanks @FnControlOption)
• Rename Def#yields to Def#block_arity (#12833, thanks @straight-shoota)
• Fix warning on space before colon with anonymous block arg (#12869, thanks @straight-shoota)
• Warn on missing space before colon in type declaration/restriction (#12740, thanks @straight-shoota)

Semantic

• Fix: Do not merge union types in truthy filter (#12752, thanks @straight-shoota)
• Fix crash when using sizeof, instance_sizeof, or offsetof as a type arg (#12577, thanks @keidax)
• Resolve type of free variable on block return type mismatch (#12754, thanks @caspiano)
• Order _ after any other Path when comparing overloads (#12855, thanks @HertzDevil)
• [Experimental] Compiler: try to solve string interpolation exps at compile time (#12524, thanks @asterite)
• Support @[Deprecated] on annotation (#12557, thanks @caspiano)
• Add more specific error message for uninstantiated proc type (#11219, thanks @straight-shoota)
• Add specs for system macro method (#12885, thanks @straight-shoota)

Tools

Docs-generator

• Fix range literals causing method lookups in docs generator (#12680, thanks @caspiano)
• Fix method lookup for single char class names (#12683, thanks @caspiano)

Formatter

• Formatter: document stdin filename argument (-) (#12620, thanks @caspiano)

Other

Infrastructure

• [CI] Drop Alpine libreSSL 3.1 test (#12641, thanks @straight-shoota)
• Bump version to 1.7.0-dev (#12640, thanks @straight-shoota)
• [CI] Update GHA actions (#12501, thanks @straight-shoota)
• Opt in to new overload ordering behavior in Makefile (#12703, thanks @HertzDevil)
• Merge release 1.6.2 into master (#12719, thanks @beta-ziliani)
• Configure Renovate (#12678, thanks @renovate)
• [CI] Add version pin for ilammy/msvc-dev-cmd in windows CI (#12746, thanks @straight-shoota)
• [CI] Update dependencies for windows CI (#12745, thanks @straight-shoota)
• Update GH Actions (#12742, thanks @renovate)
• [CI] Run specs in random order by default (#12541, thanks @straight-shoota)
• Update shell.nix for newer LLVM versions and aarch64-darwin (#12591, thanks @HertzDevil)
• Update previous Crystal release - 1.6.2 (#12750, thanks @straight-shoota)
• [CI] Update PCRE 8.45 for Windows CI (#12762, thanks @HertzDevil)
• Add WebAssembly specs (#12571, thanks @lbguilherme)
• Update actions/checkout action to v3 (#12805, thanks @renovate)
• Enable multithreading specs on Windows CI (#12843, thanks @HertzDevil)
• [CI] Update mwilliamson/setup-wasmtime-action action to v2 (#12864, thanks @renovate)
• [CI] Update distribution-scripts (#12891, thanks @straight-shoota)
• [CI] Update shards 0.17.2 (#12875, thanks @straight-shoota)
• Rotate breached credentials in CircleCI (#12902, thanks @matiasgarciaisaia)
• Update NOTICE.md (#12901, thanks @HertzDevil)
• Split pre-1.0 changelog (#12898, thanks @straight-shoota)

Code Improvements

• Style: Remove redundant begin blocks (#12638, thanks @caspiano)
• Lint: Fix variable name casing (#12674, thanks @Sija)
• Lint: Remove comparisons with boolean literals (#12673, thanks @Sija)
• Lint: Use Object#in? instead of multiple comparisons (#12675, thanks @Sija)
• Lint: Remove useless assignments (#12648, thanks @Sija)
• Use Object#in? in place of multiple comparisons (#12700, thanks @caspiano)
• Style: Remove explicit returns from the codebase (#12637, thanks @caspiano)
• Lint: Use Enumerable#find!/#index! variants (#12686, thanks @Sija)
• Style: Use short block notation for simple one-liners (#12676, thanks @Sija)
• Couple of ameba lint issues fixed (#12685, thanks @Sija)
• Use context-specific heredoc deliminators (#12816, thanks @straight-shoota)