0.591

What's Changed

• LinterConfig.h: add missing stdint.h include by @xgqt in #1010
• Fix a use-after-free bug in the new type cloning algorithm
• Tighten up the type of coroutine.wrap. It is now <A..., R...>(f: (A...) -> R...) -> ((A...) -> R...)
• Break .luaurc out into a separate library target Luau.Config. This makes it easier for applications to reason about config files without also depending on the type inference engine.
• Move typechecking limits into FrontendOptions. This allows embedders more finely-grained control over autocomplete's internal time limits.
• Fix a stability issue with debugger debugprotectederror callback allowing break in non-yieldable contexts

New Type Solver

• Initial work toward Local Type Inference
• Introduce a new subtyping test. This will be much nicer than the old test because it is completely separate both from actual type inference and from error reporting.

Native Code Generation

• Added function to compute iterated dominance frontier
• Optimize barriers in SET_UPVALUE when tag is known
• Cache lua_State::global in a register on A64
• Optimize constant stores in A64 lowering
• Track table array size state to optimize array size checks
• Add split tag/value store into a VM register
• Check that spills can outlive the block only in specific conditions

New Contributors

• @xgqt made their first contribution in #1010

Full Changelog: 0.590...0.591

0.590

Analysis Changes

• Better indentation in multi-line type mismatch error messages
• Error message clone can no longer cause a stack overflow (when typechecking with retainFullTypeGraphs set to false); fixes #975

Runtime Changes

• string.format with %s is now ~2x faster on strings smaller than 100 characters

Other Changes

• Use const char* const* over const char** by @LoganDark in #1005
• Add luau-compile to .gitignore by @j-hui in #995

Native Codegen

• All VM side exits will block return to the native execution of the current function to preserve correctness
• Fixed executable page allocation on Apple platforms when using hardened runtime
• Added statistics for code generation (no. of functions compiler, memory used for different areas)
• Fixed issue with function entry type checks performed more that once in some functions

New Contributors

• @j-hui made their first contribution in #995

Full Changelog: 0.589...0.590

0.589

Analysis Changes

• Progress toward a diffing algorithm for types. We hope that this will be useful for writing clearer error messages.
• Add a missing recursion limiter in Unifier::tryUnifyTables. This was causing a crash in certain situations.

Runtime Changes

• Luau heap graph enumeration improvements:
  • Weak references are not reported
  • Added tag as a fallback name of non-string table links
  • Included top Luau function information in thread name to understand where thread might be suspended
• Constant folding for math.pi and math.huge at -O2
• Optimize string.format and %*
  • This change makes string interpolation 1.5x-2x faster depending on the number and type of formatted components, assuming a few are using primitive types, and reduces associated GC pressure.

Other changes

• Add dark theme by @Someon1e in #991
• Fix some EBNF cases in grammar.md by @cassanof in #999

New type checker

• Initial work toward tracking the upper and lower bounds of types accurately.

Native code generation (JIT)

• Add IrCmd::CHECK_TRUTHY for improved assert fast-calls
• Do not compute type map for modules without types
• Capture metatable+readonly state for NEW_TABLE IR instructions
• Replace JUMP_CMP_ANY with CMP_ANY and existing JUMP_EQ_INT
• Add support for exits to VM with reentry lock in VmExit

New Contributors

• @cassanof made their first contribution in #999

Full Changelog: 0.588...0.589

0.588

Analysis and Autocomplete Changes

• Luau::autocomplete no longer performs typechecking internally, make sure to run Frontend::check before performing autocomplete requests
• Autocomplete string suggestions without "" are now only suggested inside the ""
• Autocomplete suggestions now include function (anonymous autofilled) key with a full suggestion for the function expression (with arguments included) stored in AutocompleteEntry::insertText
• AutocompleteEntry::indexedWithSelf is provided for function call suggestions made with :
• Cyclic modules now see each other type exports as any to prevent memory use-after-free (similar to module return type)

Runtime Changes

• Updated inline/loop unroll cost model to better handle assignments (Fixes #978)
• math.noise speed was improved by ~30%
• table.concat speed was improved by ~5-7%
• tonumber and tostring now have fastcall paths that execute ~1.5x and ~2.5x faster respectively (Fixes #777)
• Fixed crash in luaL_typename when index refers to a non-existing value
• Fixed potential out of memory scenario when using string.sub or string.char in a loop
• Fixed behavior of some fastcall builtins when called without arguments under -O2 to match original functions
• Support for native code execution in VM is now enabled by default (note: native code still has to be generated explicitly)
• CodeGen::compile now accepts CodeGen_OnlyNativeModules flag. When set, only modules that have a --!native hot-comment at the top will be compiled to native code

Other Changes

• HATRA 23 paper by @asajeffrey in #979
• README.md: Add Gentoo Linux to listed distributions by @MagelessMayhem in #976
• docs: Document return value for table.remove by @zeux in #987
• Improve demo site by @Someon1e in #990

New Type Solver

• Generic type packs are no longer considered to be variadic during unification
• Timeout and cancellation now works in new solver
• Fixed false positive errors around 'table' and 'function' type refinements
• Table literals now use covariant unification rules. This is sound since literal has no type specified and has no aliases
• Fixed issues with blocked types escaping the constraint solver
• Fixed more places where error messages that should've been suppressed were still reported
• Fixed errors when iterating over a top table type

JIT

• 'DebugLuauAbortingChecks' flag is now supported on A64
• LOP_NEWCLOSURE has been translated to IR

New Contributors

• @MagelessMayhem made their first contribution in #976
• @Someon1e made their first contribution in #990

0.584

What's Changed

• Added support for async typechecking cancellation using a token passed through frontend options
• Added luaC_enumheap for building debug tools that need a graph of Luau heap

New Type Solver

• Errors are now suppressed when checking property lookup of error-suppressing unions

JIT

• Fixed unhandled value type in NOT_ANY lowering
• Fast-call tag checks will exit to VM on failure, instead of relying on a native fallback
• Added vector type to the type information
• Eliminated redundant direct jumps across dead blocks
• Debugger APIs are now disabled for call frames executing natively
• Implemented support for unwind registration on macOS 14

0.583

What's Changed

• Fix indexing table intersections using x["prop"] syntax by @JohnnyMorganz in #971
• Add console output codepage for windows by @imlodinu in #967
• Added Frontend::parse for a fast source graph preparation
• luau_load should check GC
• Work toward a type-diff system for nicer error messages

New Type Solver

• Correctly suppress errors in more cases
• Further improvements to typechecking of function calls and return statements
• Crash fixes
• Propagate refinements drawn from the condition of a while loop into the loop body

JIT

• Fix accidental bailout for math.frexp/modf/sign in A64
• Work toward bringing type annotation info in
• Do not propagate Luau IR constants of wrong type into load instructions
• CHECK_SAFEENV exits to VM on failure
• Implement error handling in A64 reg allocator
• Inline the string.len builtin
• Do not enter native code of a function if arguments don’t match

New Contributors

• @imlodinu made their first contribution in #967

Full Changelog: 0.582...0.583

0.582

What's Changed

• Optimized operations like instantiation and module export for very large types

New Type Solver

• Typechecking of function calls was rewritten to handle more cases correctly
• Fixed a crash that can happen after self-referential type is exported from a module
• Fixed a false positive error in string comparison
• Added handling of for...in variable type annotations and fixed issues with the iterator call inside
• Self-referential 'hasProp' and 'setProp' constraints are now handled correctly

JIT

• Added '--target' argument to luau-compile to test multiple architectures different from host architecture
• GC barrier tag check is skipped if type is already known to be GC-collectable
• Added GET_TYPE/GET_TYPEOF instructions for type/typeof fast-calls
• Improved code size of interrupt handlers on X64

0.581

What's Changed

• Build and use luau-compile in CI by @zeux in #952
• Fix Arch Linux install instructions to use AUR by @RealEthanPlayzDev in #953
• Add support for ClassType indexer in definition files by @JohnnyMorganz in #949
• Remove --compile support from the REPL. You can just use luau-compile instead.
• When an exception is thrown during parallel typechecking (usually an ICE), we now gracefully stop typechecking and drain active workers before rethrowing the exception.

New solver

• Include more source location information when we hit an internal compiler error
• Improve the logic that simplifies intersections of tables

JIT

• Save testable type annotations to bytecode
• Improve block placement for linearized blocks
• Add support for lea reg, [rip+offset] for labels
• Unify X64 and A64 codegen for RETURN
• Outline interrupt handlers for X64
• Remove global rArgN in favor of build.abi
• Change A64 INTERRUPT lowering to match X64

New Contributors

• @RealEthanPlayzDev made their first contribution in #953

Full Changelog: 0.580...0.581

0.580

What's Changed

• Update lint.md to specify language on fenced code blocks which have none by @BenMactavsin in #946
• Fix website demo's string highlighting behaviour by @BenMactavsin in #942
• Update performance.md by @zeux in #948
• Added luau-compile executable target to build/test compilation without having full REPL included.

New Type Solver

• Fixed the order in which constraints are checked to get more deterministic errors in different environments
• Fixed isNumber/isString checks to fix false positive errors in binary comparisons
• CannotCallNonFunction error is reported when calling an intersection type of non-functions

JIT

• Outlined X64 return instruction code to improve code size
• Improved performance of return instruction on A64
• Added construction of a dominator tree for future optimizations

0.579

Analysis Changes

• When type inference fails to find any matching overload for a function, we were declining to commit any changes to the type graph at all. This was resulting in confusing type errors in certain cases. Now, when a matching overload cannot be found, we always commit to the first overload we tried.

JIT

• Fix missing variadic register invalidation in FALLBACK_GETVARARGS
• Add a missing null pointer check for the result of luaT_gettm