# General
* Expose an optional `get_alias` API as an alternative to `get_config`
in Luau.Require and Luau.RequireNavigator.
* Improve the Luau CLI's virtual filesystem implementation to fix bugs
related to `init.luau`. Fixes
https://github.com/luau-lang/luau/issues/1816
# New Type Solver
* Avoid double reporting errors when erroneous arguments are provided to
type functions.
* Fix some instances of unresovable cyclic type functions in loops by
only considering the first loop cycles. This results in some type
inference inaccuracies when the type of a variable in loop through
multiple iterations. Fixes
https://github.com/luau-lang/luau/issues/1413.
* Better generalize free types that have meaningful lower and upper
bounds, especially for table indexers.
* Report more specific errors when assigning or returning table literal
types, instead of citing the *entire* table type.
* Inference for functions with generic type packs is greatly improved.
* Fix some internal compiler exceptions when using type-stating
functions like `table.freeze` in `if _ then _ else _` expressions and
short circuiting binary operations.
* More consistently simplify unions of primitive types, especially in
array-like and dictionary-like tables.
* Fix a crash when type checking an erroneous type alias containing
`typeof` with a type assertion expression, as in:
```
type MyTable = {}
-- This will error at type checking time as it's a duplicate
type MyTable = typeof(setmetatable(SomeTable :: {}, SomeMetaTable));
```
* Fix a crash when inferring the type of an index expression where the
indexee is invalid (e.g. `nil`).
# Runtime
* Avoid throwing an exception from `luau_load` if we run out of memory.
* Type functions are no longer compiled and included in bytecode. Fixes
#1817.
* Fix some instances of Luau C API functions reading invalid debug
information (generally when the first or last instruction of a block was
being inspected). Fixes#1369.
* Avoid potential signed integer overflow when doing bounds checks on
tables.
* Support 16 byte aligned userdata objects when system allocation
alignment is also 16 bytes.
* Fix memory leaks in `Luau.Require` when using VM build with no
exceptions. Fixes#1827.
---------
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: James McNellis <jmcnellis@roblox.com>
Co-authored-by: Sora Kanosue <skanosue@roblox.com>
Co-authored-by: Talha Pathan <tpathan@roblox.com>
Co-authored-by: Varun Saini <vsaini@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
# General Changes
* Remove a `static_assert` that prevented Luau from building on 32-bit
targets.
* Fix `proxyrequire` (see https://github.com/luau-lang/luau/pull/1804)
* Replace contents API with new `loadname` API in Luau.Require
* Store the positions of `:` symbols in the CST.
* Fix a minor bug in the new incremental autocomplete engine: Properly
suggest `else` and `elseif` if the cursor is currently within an `if`
block.
# New Type Solver
* Allow generics to be substituted for negation types when performing
subtype tests
* Crash fixes
* Surface subtyping errors more consistently.
* Avoid creating double-negation types (like `~~(false?)`) when
generating constraints.
# Internal Contributors
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Ariel Weiss <aaronweiss@roblox.com>
Co-authored-by: Aviral Goel <agoel@roblox.com>
Co-authored-by: Hunter Goldstein <hgoldstein@roblox.com>
Co-authored-by: Sora Kanosue <skanosue@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>
Co-authored-by: Aviral Goel <agoel@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>
We have lots of new changes for you!
# What's Changed
## General
- We updated Luau's license year to 2025!
- We fixed a bug where large amounts of errors were being printed when
deep intersections of unions error.
## Require-by-String
This release introduces the `Luau.Require` library, which exposes the
runtime semantics of require-by-string, including support for the new
`@self` alias described in [this
RFC](https://github.com/luau-lang/rfcs/pull/109).
The library operates on a virtualized filesystem, allowing consumers to
specify navigation rules without assuming a filesystem context.
Documentation in `Require.h` explains how to enable the library, and the
`setupState` function in Repl.cpp demonstrates how we've integrated it
into the luau CLI tool. Note that the interface in `Require.h` is
written in C, which enables any application written in a language with a
C foreign-function interface to link against this library and enable
require-by-string. This makes it straightforward for any application
embedding Luau to support require-by-string, provided that it defines or
operates within an environment resembling a virtual filesystem.
The core navigation semantics of require-by-string have additionally
been pulled into the `Luau.RequireNavigator` library. While
`Luau.Require` internally depends on `Luau.RequireNavigator`, the latter
does not depend on the Luau VM. This library provides an interface for
inspecting require-by-string's navigation behavior and therefore serves
as a useful dependency for static tooling. Documentation for
`Luau.RequireNavigator` is available in `RequireNavigator.h`.
## Autocomplete
- We fixed a memory leak in fragment autocomplete!
## New Solver And Old Solver
- We've found a infinite iteration error over a type pack. We added a
way to detect this error and throw an `InternalCompileError` instead.
- We fix `table.freeze` not accounting for the first argument not
getting type stated. We fall back to regular inference instead.
- We fix a crash in the old solver with `length_error`.
- We fix a crash in the new solver stemming from generalization
reentrancy. Now we correctly generalize interior free types that do not
appear in a function signature.
- We fix a nil refinement. (Fixes
https://github.com/luau-lang/luau/issues/1687 and
https://github.com/luau-lang/luau/issues/1451)
### Internal Contributors
Co-authored-by: Andy Friesen <afriesen@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>
Full Changelog: https://github.com/luau-lang/luau/compare/0.668...0.669
---------
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: Aviral Goel <agoel@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>
