0.507

Analysis changes

• Type ascription (::) now permits casts between related types in both directions, allowing to refine or loosen the type (RFC #56)
• Fix type definition for tonumber to return number? since the input string isn't guaranteed to contain a valid number
• Fix type refinements for field access via []
• Many stability fixes for type checker
• Provide extra information in error messages for type mismatches in more cases
• Improve performance of type checking for large unions when union members are string literals

Runtime changes

• Fix some C APIs like lua_equal or lua_getfield triggering GC assertions in presence of metatables
• Add lua_getcoverage API for code coverage collection
• Improve performance of truthiness checks in some cases, particularly on Apple M1, resulting in 10-25% perf gains on qsort benchmark depending on the CPU/compiler
• Fix support for little-endian systems; IBM s390x here we go!

CLI changes

• Add coverage reporting support to Repl (--coverage command line argument)
• Add shebang support by @Rerumu in #149
• Work around code signing issues during Makefile builds on macOS

Community contributions

• Fix Json Encoding for AstArray by @xgladius in #279
• Add Grammar documentation by @JohnnyMorganz in #266