0.509

Analysis changes

• Rework transaction log used for type checking which should result in more robust type checking internals with fewer bugs
• Improve refinement of complex expressions to propagate types through lookup chains like foo and foo.bar and foo.bar.baz
• Reduce the amount of memory consumed by type checker on large module graphs
• Type checker now errors on attempts to change the type of imported module fields
• The return type of newproxy is now any (#296)
• Fix error locations for type errors in string.format arguments

Runtime changes

• Make tonumber(x) ~2x faster by avoiding reparsing string arguments
• Implement new number printing algorithm (Schubfach) which makes tostring(number) produce precise (round-trippable) and short decimal output up to 10x faster
• Fix lua_Debug::linedefined to point to the line with the function definition instead of the first statement (#265)

CLI changes

• Fix minor bugs in Tab completion in Repl
• Repl now saves/restores command history in ~/.luau_history

Community contributions

• Add CodeMirror Editor for Web demo by @MathematicalDessert in #228