.eslintplugin/code-no-unused-expressions.ts/isDirective
		function isDirective(node: TSESTree.Node, ancestors: TSESTree.Node[]): boolean {
			const parent = ancestors[ancestors.length - 1],
				grandparent = ancestors[ancestors.length - 2];

			return (parent.type === 'Program' || parent.type === 'BlockStatement' &&
				(/Function/u.test(grandparent.type))) &&
				directives(parent).indexOf(node) >= 0;
		}