unresolved names result in defining a new variable, initialized to nil This is not what Lua does. All table lookups return a value corresponding to a specified

unresolved names result in defining a new variable, initialized to nil This is not what Lua does. All table lookups return a value corresponding to a specified key, if there is a correspondence. Or simply nil, doing nothing in this case. There are no global variables per se, only a table that non-local lookups end up into. In practice I find this feature means I need very thorough test coverage, or a metatable, as you've noted, or a static analyzer, as others have noted. Or a combination of all the above. You may choose a language that fits your needs rather than trying to use something that doesn’t. E.g. I think Python more or less matches your expectations here. Lua doesn’t have to please everyone, and trying to make X out of it makes no sense neither for you nor for Lua designers, if X already exists. That said, I see this as an overdramatization. Strict metatable on globals solves the issue with “automatic global variables”. But other things like static analysis and thorough testing will be required (and require your work too) in any language to achieve the “high-horse” level of guarantees.