src/vs/workbench/api/common/extHostTypes.ts/DocumentSymbol/validate
class DocumentSymbol:	static validate(candidate: DocumentSymbol): void {
		if (!candidate.name) {
			throw new Error('name must not be falsy');
		}
		if (!candidate.range.contains(candidate.selectionRange)) {
			throw new Error('selectionRange must be contained in fullRange');
		}
		if (candidate.children) {
			candidate.children.forEach(DocumentSymbol.validate);
		}
	}