0.547

Analysis changes

• Type aliases can no longer override primitive types; attempts to do that will result in a type error
• Fix misleading type error messages for mismatches in expression list length during assignment
• Fix incorrect type name display in certain cases

Runtime changes

• setmetatable/getmetatable are now ~2x faster
• tools/perfstat.py can be used to display statistics about profiles captured via --profile switch

Community contributions

None this week; PRs are always welcome!

0.546

Runtime changes

• Add lua_rawiter for faster table iteration from C (~2x faster than lua_next, results in the same iteration order if the table isn't modified during traversal)

Community contributions

• Add lua_cleartable by @petrihakkinen in #678

0.545

Analysis changes

• Improve type error messages for argument count mismatch in certain cases
• Fix type checking variadic returns when the type is incompatible which type checked in certain cases

Runtime changes

• Reduce size of upvalue objects by 8 bytes on 64-bit platforms
• Reduce I$ footprint of interpreter by 1.5 KB by removing support for bytecode v2
• Reduce GC pause during atomic stage for programs with a lot of threads

Community contributions

• Add lua_rawsetfield by @petrihakkinen in #671

0.544

Analysis changes

• Remove type definitions of utf8.nfcnormalize/nfdnormalize/graphemes that aren't supported by standalone Luau library

Runtime changes

• Add lua_costatus to retrieve extended thread status (similar to coroutine.status)
• Improve GC sweeping performance (2-10% improvement on allocation-heavy benchmarks)

Community contributions

None this week; PRs are always welcome!

0.543

Analysis changes

• Improve type checking stability
• Improve ComparisonPrecedence lint suggestions for three-way comparisons (X < Y < Z)
• Improve location information for errors when parsing invalid type annotations

Runtime changes

• Compiler can no longer be configured to generate bytecode version 2; runtime support for version 2 will be removed in a future release
• Improve performance of comparisons against numeric constants on AArch64

Community contributions

• Fix overloaded metamethod in class definitions by @JohnnyMorganz in #653

0.542

Analysis changes

• Fix DeprecatedGlobal warning text in cases when the global is deprecated without a suggested alternative
• Fix an off-by-one error in type error text for incorrect use of string.format
• Reduce stack consumption further during parsing, hopefully eliminating stack overflows during parsing/compilation

Runtime changes

• Simplify garbage collection treatment of upvalues, reducing cache misses during sweeping stage and reducing the cost of upvalue assignment (SETUPVAL)
• Simplify garbage collection treatment of sleeping and alive threads, reducing cache misses during sweeping stage
• Simplify management of string buffers, removing redundant linked list operations

Community contributions

• Pass environment scope to autocomplete typechecker by @JohnnyMorganz in #610
• String interpolation by @Kampfkarren in #614

Note on interpolated strings

Support for interpolated strings is marked as experimental in this release as the syntax is being validated for compatibility with editors and future proposals; to use it in command-line tools, pass --fflags=LuauInterpolatedStringBaseSupport to enable it early.

0.541

Analysis changes

• Fix autocomplete not suggesting globals defined after the cursor (fixes #622)
• Improve type checker stability

Runtime changes

• 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

Community contributions

• Fix lint.md formatting by @Mactavsin in #637
• Prevent overflow in lua_newuserdatadtor by @XmiliaH in #639

0.540

Analysis changes

• Add ComparisonPrecedence lint to warn about erroneous use of not with comparisons, e.g not a == b where a ~= b was intended
• Several stability and performance improvements in the type checker

Runtime changes

• Bytecode compiler now emits optimized instruction sequences for multiple assignments, accelerating some benchmarks by 10%
• Fix reachability analysis for weak keys/values in heapgraph.py
• Fix CodeGen test failures on big endian architectures

Community contributions

• Add autocomplete context to result by @JohnnyMorganz in #611

0.539

Analysis changes

• Introduce IntegerParsing lint that warns on uses of integer literals that exceed 2^64 (fixes #518)
• Fix minor inconsistencies in synthesized names for types with metatables

Runtime changes

• Comparisons with constants are now significantly faster when using clang as a compiler (10-50% gains on internal benchmarks)
• Luau compiler now emits bytecode with version 3; version 2 is still supported but will be removed in about a month
• When calling non-existent methods on tables or strings, foo:bar now produces a more precise error message (fixes #255)

Community contributions

• Add Ctrl-C handling to the REPL by @jaykru in #537
• Add %* format specifier by @Kampfkarren in #619

0.538

Analysis changes

• Improve autocomplete behavior in certain cases for : calls

Runtime changes

• Fix warnings on Xcode 14 beta due to use of sprintf
• Improve debug.traceback performance by 1.15-1.75x depending on the platform
• Fix a corner case with table assignment semantics when key didn't exist in the table and __newindex was defined: we now use Lua 5.2 semantics and call __newindex, which results in less wasted space, support for NaN keys in __newindex path and correct support for frozen tables (see #380, #565)

Community contributions

• Store AstExprFunction in astTypes for stats by @JohnnyMorganz in #612