extensions/typescript-language-features/src/languageFeatures/codeLens/baseCodeLensProvider.ts/TypeScriptBaseCodeLensProvider/walkNavTree
class TypeScriptBaseCodeLensProvider:	private walkNavTree(
		document: vscode.TextDocument,
		item: Proto.NavigationTree,
		parent: Proto.NavigationTree | null,
		results: vscode.Range[]
	): void {
		if (!item) {
			return;
		}

		const range = this.extractSymbol(document, item, parent);
		if (range) {
			results.push(range);
		}

		(item.childItems || []).forEach(child => this.walkNavTree(document, child, item, results));
	}