In this update, we continue to improve the overall stability of the new type solver. We're also shipping some early bits of two new features, one of the language and one of the analysis API: user-defined type functions and an incremental typechecking API.

If you use the new solver and want to use all new fixes included in this release, you have to reference an additional Luau flag:

LUAU_DYNAMIC_FASTINT(LuauTypeSolverRelease)

And set its value to 645:

DFInt::LuauTypeSolverRelease.value = 645; // Or a higher value for future updates

New Solver

• Fix a crash where scopes are incorrectly accessed cross-module after they've been deallocated by appropriately zeroing out associated scope pointers for free types, generic types, table types, etc.
• Fix a crash where we were incorrectly caching results for bound types in generalization.
• Eliminated some unnecessary intermediate allocations in the constraint solver and type function infrastructure.
• Built some initial groundwork for an incremental typecheck API for use by language servers.
• Built an initial technical preview for user-defined type functions, more work still to come (including calling type functions from other type functions), but adventurous folks wanting to experiment with it can try it out by enabling FFlag::LuauUserDefinedTypeFunctionsSyntax and FFlag::LuauUserDefinedTypeFunctions in their local environment. Special thanks to @joonyoo181 who built up all the initial infrastructure for this during his internship!

Miscellaneous changes

• Fix a compilation error on Ubuntu (fixes Compilation error in TimeTrace.h when LUAU_ENABLE_TIME_TRACE enabled on ubuntu 20.04 #1437)

Internal Contributors:

Co-authored-by: Aaron Weiss [email protected]
Co-authored-by: Hunter Goldstein [email protected]
Co-authored-by: Jeremy Yoo [email protected]
Co-authored-by: Vighnesh Vijay [email protected]
Co-authored-by: Vyacheslav Egorov [email protected]