Lua and Typesafety = Sol
github.com
github.com
The lead author gave a good presentation at Lua Workshop 2017 in SF: https://www.lua.org/wshop17/Maidl.pdf
Both Sol and Typed Lua are no longer maintained. The Typed Lua author is working on a statically compiled cousin to Lua: https://github.com/titan-lang/titan
I haven't used Sol or Typed Lua (too lazy), but I use the Typed Lua syntax for my recent API documentation as it reads well and allows me to minimally document an API before I get around to adding proper descriptions.