Which scope rules apply to variables defined within nested Pug mixins?

Pug allows the creation of reusable components through mixins, which can be nested to build complex component hierarchies. While arguments passed to a mixin are locally scoped to that specific block, the behavior of variables declared inside a nested mixin relative to its parent mixin requires clarification.

The goal is to determine if a variable initialized within a child mixin can be accessed by the parent mixin after the child call completes, or if the local scope is strictly destroyed upon the child mixin's termination.

• Does a variable declared inside a nested mixin leak into the parent mixin's scope?
• What is the precise behavior of variable shadowing when a parent and child mixin use the same variable name?