global_function_in_scope

This lint rule warns when a non-local function declaration appears inside a nested scope (e.g. inside an if, for, while, do, or another function body) rather than at the top level of the file.

Why this is discouraged

A function foo() end declaration without the local keyword inside a nested scope implicitly creates or assigns to a global variable. This is almost always unintentional and can lead to:

• Accidental pollution of the global namespace, where the function leaks out of the scope in which its being defined.
• Confusing behavior, because the assignment only happens when the enclosing scope executes.
• Harder-to-debug shadowing issues when another scope references the same global name.

If the function is only needed locally, use local function instead. If it genuinely needs to be a top-level declaration, move it out of the nested scope.

Example violations

global_function_in_scope will warn on the following:

if true then
    function foo()
    end
end

local function outer()
    function inner()
    end
end

You should instead do:

if true then
    local function foo()
    end
end

local function outer()
    local function inner()
    end
end