# What's changed?
### New Type Solver
- Unification of two fresh types no longer binds them together.
- Replaced uses of raw `emplace` with `emplaceType` to catch cyclic
bound types when they are created.
- `SetIndexerConstraint` is blocked until the indexer result type is not
blocked.
- Fix a case where a blocked type got past the constraint solver.
- Searching for free types should no longer traverse into `ClassType`s.
- Fix a corner case that could result in the non-testable type `~{}`.
- Fix incorrect flagging when `any` was a parameter of some checked
function in nonstrict type checker.
- `IterableConstraint` now consider tables without `__iter` to be
iterables.
### Native Code Generation
- Improve register type info lookup by program counter.
- Generate type information for locals and upvalues
---
### 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: Vighnesh Vijay <vvijay@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
---------
Co-authored-by: Aaron Weiss <aaronweiss@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?
* Check interrupt handler inside the pattern match engine to eliminate
potential for programs to hang during string library function execution.
* Allow iteration over table properties to pass the old type solver.
### Native Code Generation
* Use in-place memory operands for math library operations on x64.
* Replace opaque bools with separate enum classes in IrDump to improve
code maintainability.
* Translate operations on inferred vectors to IR.
* Enable support for debugging native-compiled functions in Roblox
Studio.
### New Type Solver
* Rework type inference for boolean and string literals to introduce
bounded free types (bounded below by the singleton type, and above by
the primitive type) and reworked primitive type constraint to decide
which is the appropriate type for the literal.
* Introduce `FunctionCheckConstraint` to handle bidirectional
typechecking for function calls, pushing the expected parameter types
from the function onto the arguments.
* Introduce `union` and `intersect` type families to compute deferred
simplified unions and intersections to be employed by the constraint
generation logic in the new solver.
* Implement support for expanding the domain of local types in
`Unifier2`.
* Rework type inference for iteration variables bound by for in loops to
use local types.
* Change constraint blocking logic to use a set to prevent accidental
re-blocking.
* Add logic to detect missing return statements in functions.
### 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: 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 changed
- `bit32.byteswap` added
([RFC](4f543ec23b/docs/function-bit32-byteswap.md))
- Buffer library implementation
([RFC](4f543ec23b/docs/type-byte-buffer.md))
- Fixed a missing `stdint.h` include
- Fixed parser limiter for recursive type annotations being kind of
weird (fixes#645)
### Native Codegen
- Fixed a pair of issues when lowering `bit32.extract`
- Fixed a narrow edge case that could result in an infinite loop without
an interruption
- Fixed a negative array out-of-bounds access issue
- Temporarily reverted linear block predecessor value propagation
### New type solver
- We now type check assignments to annotated variables
- Fixed some test cases under local type inference
- Moved `isPending` checks for type families to improve performance
- Optimized our process for testing if a free type is sufficiently
solved
- Removed "none ptr" from lea instruction disassembly logging
### Build system & tooling
- CMake configuration now validates dependencies to maintain separation
between components
- Improvements to the fuzzer coverage
- Deduplicator for fuzzed callstacks
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Aaron Weiss <aaronweiss@roblox.com>
Co-authored-by: Vighnesh Vijay <vvijay@roblox.com>
- Improve ComparisonPrecedence lint suggestions for three-way comparisons (X < Y < Z)
- Improve type checking stability
- Improve location information for errors when parsing invalid type annotations
- Compiler now generates bytecode version 3 in all configurations
- Improve performance of comparisons against numeric constants on AArch64
- Fix autocomplete not suggesting globals defined after the cursor (fixes#622)
- Improve type checker stability
- Reduce parser C stack consumption which fixes some stack overflow crashes on deeply nested sources
- Improve performance of bit32.extract/replace when width is implied (~3% faster chess)
- Improve performance of bit32.extract when field/width are constants (~10% faster base64)
- Heap dump now annotates thread stacks with local variable/function names
