## New Type Solver
1. Update resolved types for singleton unions and intersections to avoid
crashing when type checking type assertions.
2. Generalize free return type pack of a function type inferred at call
site to ensure that the free type does not leak to another module.
3. Fix crash from cyclic indexers by reducing if possible or producing
an error otherwise.
4. Fix handling of irreducible type functions to prevent type inference
from failing.
5. Fix handling of recursive metatables to avoid infinite recursion.
## New and Old Type Solver
Fix accidental capture of all exceptions in multi-threaded typechecking
by converting all typechecking exceptions to `InternalCompilerError` and
only capturing those.
## Fragment Autocomplete
1. Add a block based diff algorithm based on class index and span for
re-typechecking. This reduces the granularity of fragment autocomplete
to avoid flakiness when the fragment does not have enough type
information.
2. Fix bugs arising from incorrect scope selection for autocompletion.
## Roundtrippable AST
Store type alias location in `TypeFun` class to ensure it is accessible
for exported types as part of the public interface.
## Build System
1. Bump minimum supported CMake version to 3.10 since GitHub is phasing
out the currently supported minimum version 3.0, released 11 years ago.
2. Fix compilation when `HARDSTACKTESTS` is enabled.
## Miscellaneous
Flag removals and cleanup of unused code.
## Internal Contributors
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Ariel Weiss <aaronweiss@roblox.com>
Co-authored-by: Hunter Goldstein <hgoldstein@roblox.com>
Co-authored-by: Talha Pathan <tpathan@roblox.com>
Co-authored-by: Vighnesh Vijay <vvijay@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
## External Contributors
Thanks to [@grh-official](https://github.com/grh-official) for PR #1759
**Full Changelog**:
https://github.com/luau-lang/luau/compare/0.667...0.668
---------
Co-authored-by: Hunter Goldstein <hgoldstein@roblox.com>
Co-authored-by: Varun Saini <61795485+vrn-sn@users.noreply.github.com>
Co-authored-by: Alexander Youngblood <ayoungblood@roblox.com>
Co-authored-by: Menarul Alam <malam@roblox.com>
Co-authored-by: Vighnesh <vvijay@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Co-authored-by: Ariel Weiss <aaronweiss@roblox.com>
# General
This release introduces initial work on a Roundtrippable AST for Luau,
and numerous fixes to the new type solver, runtime, and fragment
autocomplete.
## Roundtrippable AST
To support tooling around source code transformations, we are extending
the parser to retain source information so that we can re-emit the
initial source code exactly as the author wrote it. We have made
numerous changes to the Transpiler, added new AST types such as
`AstTypeGroup`, and added source information to AST nodes such as
`AstExprInterpString`, `AstExprIfElse`, `AstTypeTable`,
`AstTypeReference`, `AstTypeSingletonString`, and `AstTypeTypeof`.
## New Type Solver
* Implement `setmetatable` and `getmetatable` type functions.
* Fix handling of nested and recursive union type functions to prevent
the solver from getting stuck.
* Free types in both old and new solver now have an upper and lower
bound to resolve mixed mode usage of the solvers in fragment
autocomplete.
* Fix infinite recursion during normalization of cyclic tables.
* Add normalization support for intersections of subclasses with negated
superclasses.
## Runtime
* Fix compilation error in Luau buffer bit operations for big-endian
machines.
## Miscellaneous
* Add test and bugfixes to fragment autocomplete.
* Fixed `clang-tidy` warnings in `Simplify.cpp`.
**Full Changelog**:
https://github.com/luau-lang/luau/compare/0.659...0.660
---
Co-authored-by: Ariel Weiss <aaronweiss@roblox.com>
Co-authored-by: Hunter Goldstein <hgoldstein@roblox.com>
Co-authored-by: Talha Pathan <tpathan@roblox.com>
Co-authored-by: Varun Saini <vsaini@roblox.com>
Co-authored-by: Vighnesh Vijay <vvijay@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
---------
Co-authored-by: Hunter Goldstein <hgoldstein@roblox.com>
Co-authored-by: Varun Saini <61795485+vrn-sn@users.noreply.github.com>
Co-authored-by: Alexander Youngblood <ayoungblood@roblox.com>
Co-authored-by: Menarul Alam <malam@roblox.com>
### What's new
* Light update this week, mostly fast flag cleanups.
### New Solver
* Rename flag to enable new solver from
`DebugLuauDeferredConstraintResolution` to `LuauSolverV2`
* Added support for magic functions for the new type checker (as opposed
to the type inference component)
* Improved handling of `string.format` with magic function improvements
* Cleaning up some of the reported errors by the new type checker
* Minor refactoring of `TypeChecker2.cpp` that happens to make the diff
very hard to read.
---
### Internal Contributors
Co-authored-by: Aaron Weiss <aaronweiss@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>
---------
Co-authored-by: Alexander McCord <amccord@roblox.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Vighnesh <vvijay@roblox.com>
Co-authored-by: Aviral Goel <agoel@roblox.com>
Co-authored-by: David Cope <dcope@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Co-authored-by: Junseo Yoo <jyoo@roblox.com>
# What's Changed?
- Code refactoring with a new clang-format
- More bug fixes / test case fixes in the new solver
## New Solver
- More precise telemetry collection of `any` types
- Simplification of two completely disjoint tables combines them into a
single table that inherits all properties / indexers
- Refining a `never & <anything>` does not produce type family types nor
constraints
- Silence "inference failed to complete" error when it is the only error
reported
---
### Internal Contributors
Co-authored-by: Aaron Weiss <aaronweiss@roblox.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Dibri Nsofor <dnsofor@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>
---------
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 <vvijay@roblox.com>
Co-authored-by: Aviral Goel <agoel@roblox.com>
Co-authored-by: David Cope <dcope@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
# 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>
---------
Co-authored-by: Alexander McCord <amccord@roblox.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Vighnesh <vvijay@roblox.com>
Co-authored-by: Aviral Goel <agoel@roblox.com>
Co-authored-by: David Cope <dcope@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
### 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
---
### Internal Contributors
Co-authored-by: Aaron Weiss <aaronweiss@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>
---------
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 <vvijay@roblox.com>
Co-authored-by: Aviral Goel <agoel@roblox.com>
Co-authored-by: David Cope <dcope@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
### 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](https://github.com/luau-lang/rfcs/pull/30)
* 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>
---------
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: David Cope <dcope@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
### 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
---
### Internal Contributors
Co-authored-by: Aaron Weiss <aaronweiss@roblox.com>
Co-authored-by: Alexander McCord <amccord@roblox.com>
Co-authored-by: James McNellis <jmcnellis@roblox.com>
Co-authored-by: Vighnesh Vijay <vvijay@roblox.com>
