code: function setupScope(node) {
    // by default reuse parent scope
    node.scope = (node.type === 'Program')? [] : node.parent.scope;
  
    if (node.type === 'FunctionExpression' || node.type === 'FunctionDeclaration') {
      // Functions create a new "scope" that "augments" parent scope
      node.scope = node.parent.scope.slice();
    }
  }
docs: ---