0.635

What's Changed?

• Bugfixes in the new solver
• Store definitionLocation in ClassType by @JohnnyMorganz in #1313
• Optimizations for UnionFind by @birds3345 in #1334

New Solver

• Equality graphs(E-Graphs) data structures were added
• Refactored even more instances of "type family" with "type function"
• table.insert no longer spuriously warns while selecting an overload for reasonable arguments.
• Add time tracing for the new solver
• Miscellaneous fixes to unit tests

---

Internal Contributors

Co-authored-by: Aaron Weiss aaronweiss@roblox.com
Co-authored-by: Alexander McCord amccord@roblox.com
Co-authored-by: Jeremy Yoo jyoo@roblox.com
Co-authored-by: Vighnesh Vijay vvijay@roblox.com
Co-authored-by: Vyacheslav Egorov vegorov@roblox.com

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Full Changelog: 0.634...0.635

0.634

What's Changed?

• Performance improvement in the old solver
• Bugfixes in the new solver
• Keep commentLocations on SourceModule for definition files by @JohnnyMorganz in #1314
• Fix incorrect comment in Bytecode.h by @mttsner in #1315

Old Solver

• Mark types that do not need instantiation when being exported to
  prevent unnecessary work from being done

New Solver

• Index-out-of-bounds bug fix in the resolution resolver
• Subtyping reasonings are merged only if all failed

---

Internal Contributors

Co-authored-by: Aaron Weiss aaronweiss@roblox.com
Co-authored-by: Vighnesh Vijay vvijay@roblox.com
Co-authored-by: Vyacheslav Egorov vegorov@roblox.com

New Contributors

• @mttsner made their first contribution in #1315

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Full Changelog: 0.633...0.634

0.633

What's Changed?

• Mostly stability and bugfixes with the new solver.

New Solver

• Typechecking with the new solver should respect the no-check hot comment.
• Record type alias locations and property locations of table assignments
• Maintain location information for exported table types
• Stability fixes for normalization
• Report internal constraint solver errors.

---

Internal Contributors

Co-authored-by: Aaron Weiss aaronweiss@roblox.com
Co-authored-by: Alexander McCord amccord@roblox.com
Co-authored-by: Andy Friesen afriesen@roblox.com
Co-authored-by: Vighnesh Vijay vvijay@roblox.com
Co-authored-by: Vyacheslav Egorov vegorov@roblox.com

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Full Changelog: 0.632...0.633

0.632

What's Changed?

• Fix #1137 by appropriately retaining additional metadata from definition files throughout the type system.
• Improve Frontend for LSPs by appropriately allowing the cancellation of typechecking while running its destructor.

New Solver

• Added support for the rawget type function.
• Reduced overall static memory usage of builtin type functions.
• Fixed a crash where visitors could mutate a union or intersection type and fail to invalidate iteration over them in doing so.
• Revised autocomplete functionality to not rely on a separate run of the type solver when using the new solver.
• Implemented a more relaxed semantic rule for casting.
• Fixed some smaller crashes in the new solver.

Native Code Generation

• Add additional codegen specialization for math.sign
• Cleaned up a large number of outstanding fflags in the code.

Internal Contributors

Co-authored-by: Aaron Weiss aaronweiss@roblox.com
Co-authored-by: Alexander McCord amccord@roblox.com
Co-authored-by: Andy Friesen afriesen@roblox.com
Co-authored-by: James McNellis jmcnellis@roblox.com
Co-authored-by: Jeremy Yoo jyoo@roblox.com
Co-authored-by: Vighnesh Vijay vvijay@roblox.com
Co-authored-by: Vyacheslav Egorov vegorov@roblox.com

---

Full Changelog: 0.631...0.632

0.631

What's new

• Added lint warning for using redundant @native attributes on functions inside a --!native module
• Improved typechecking speed in old solver for modules with large types

New Solver

• Fixed the length type function sealing the table prematurely
• Fixed crashes caused by general table indexing expressions

VM

• Added support for a specialized 3-argument fast-call instruction to improve performance of vector constructor, buffer writes and a few bit32 methods

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Full Changelog: 0.630...0.631

0.630

What's new

• A bug in exception handling in GCC(11/12/13) on MacOS prevents our test suite from running.
• Parser now supports leading | or & when declaring Union and Intersection types (#1286)
• We now support parsing of attributes on functions as described in the rfc
  • With this change, expressions such as local x = @native function(x) return x+1 end and f(@native function(x) return x+1 end) are now
    valid.
• Added support for @native attribute - we can now force native compilation of individual functions if the @native attribute is specified before the function keyword (works for lambdas too).

New Solver

• Many fixes in the new solver for crashes and instability
• Refinements now use simplification and not normalization in a specific case of two tables
• Assume that compound assignments do not change the type of the left-side operand
• Fix error that prevented Class Methods from being overloaded

VM

• Updated description of Garbage Collector invariant

---

Internal Contributors

Co-authored-by: Aaron Weiss aaronweiss@roblox.com
Co-authored-by: Alexander McCord amccord@roblox.com
Co-authored-by: Andy Friesen afriesen@roblox.com
Co-authored-by: Aviral Goel agoel@roblox.com
Co-authored-by: Vighnesh Vijay vvijay@roblox.com
Co-authored-by: Vyacheslav Egorov vegorov@roblox.com

---

Full Changelog: 0.629...0.630

0.629

What's Changed

• Fix edge case in 'findBindingAtPosition' when looking up global binding at start of file by @JohnnyMorganz in #1254
• implement leading bar and ampersand in types by @jackdotink in #1286
• Fix incorrect comment in lgc.h by @zeux in #1288
• tests: Adjust conformance tests to account for array invariant by @zeux in #1289
• Implemented parsing logic for attributes
• Added lua_setuserdatametatable and lua_getuserdatametatable C API methods for a faster userdata metatable fetch compared to luaL_getmetatable. Note that metatable reference has to still be pinned in memory!

New Solver

• Further improvement to the assignment inference logic
• Fix many bugs surrounding constraint dispatch order

Native Codegen

• Add IR lowering hooks for custom host userdata types
• Add IR to create new tagged userdata objects
• Remove outdated NativeState

---

Internal Contributors

Co-authored-by: Aaron Weiss aaronweiss@roblox.com
Co-authored-by: Alexander McCord amccord@roblox.com
Co-authored-by: Andy Friesen afriesen@roblox.com
Co-authored-by: Aviral Goel agoel@roblox.com
Co-authored-by: Vighnesh Vijay vvijay@roblox.com
Co-authored-by: Vyacheslav Egorov vegorov@roblox.com

New Contributors

• @jackdotink made their first contribution in #1286

Full Changelog: 0.628...0.629

0.628

What's new?

• Remove a case of unsound table.move optimization
• Add Luau stack slot reservations that were missing in REPL (fixes #1273)

New Type Solver

• Assignments have been completely reworked to fix a case of cyclic constraint dependency
• When indexing, if the fresh type's upper bound already contains a compatible indexer, do not add another upper bound
• Distribute type arguments over all type families sans eq, keyof, rawkeyof, and other internal type families
• Fix a case where buffers component weren't read in two places (fixes #1267)
• Fix a case where things that constitutes a strong ref were slightly incorrect
• Fix a case where constraint dependencies weren't setup wrt for ... in statement

Native Codegen

• Fix an optimization that splits TValue store only when its value and its tag are compatible
• Implement a system to plug additional type information for custom host userdata types

---

Internal Contributors

Co-authored-by: Aaron Weiss aaronweiss@roblox.com
Co-authored-by: Alexander McCord amccord@roblox.com
Co-authored-by: Andy Friesen afriesen@roblox.com
Co-authored-by: Vighnesh Vijay vvijay@roblox.com
Co-authored-by: Vyacheslav Egorov vegorov@roblox.com

---

Full Changelog: 0.627...0.628

0.627

What's new?

• Fix typo in a comment by @birds3345 in #1255
• add cmake folder to .gitignore by @birds3345 in #1246

New Type Solver

• Improved error messages for type families to describe what's wrong in more detail, and ideally without using the term type family at all.
• Change boolean and string singletons in type checking to report errors to the user when they've gotten an impossible type (indicating a type error from their context).
• Split debugging flags for type family reduction (DebugLuauLogTypeFamilies) from general solver logging (DebugLuauLogSolver).
• Improve type simplification to support patterns like (number | string) | (string | number) becoming number | string.

Native Code Generation

• Use templated luaV_doarith to speedup vector operation fallbacks.
• Various small changes to better support arm64 on Windows.

Internal Contributors

Co-authored-by: Aaron Weiss aaronweiss@roblox.com
Co-authored-by: Andy Friesen afriesen@roblox.com
Co-authored-by: James McNellis jmcnellis@roblox.com
Co-authored-by: Vighnesh Vijay vvijay@roblox.com
Co-authored-by: Vyacheslav Egorov vegorov@roblox.com

---

Full Changelog: 0.626...0.627

0.626

What's changed?

New Type Solver

• Fixed crash in numeric binary operation type families
• Results of an indexing operation are now comparable to nil without a false positive error
• Fixed a crash when a type that failed normalization was accessed
• Iterating on a free value now implies that it is iterable

Full Changelog: 0.625...0.626