src/vs/editor/contrib/snippet/snippetParser.ts/Marker/snippet
class Marker:	get snippet(): TextmateSnippet | undefined {
		let candidate: Marker = this;
		while (true) {
			if (!candidate) {
				return undefined;
			}
			if (candidate instanceof TextmateSnippet) {
				return candidate;
			}
			candidate = candidate.parent;
		}
	}