Statically-annotated types have been shown to aid developers in a number of programming tasks, and this benefit holds true even when static type checking is not used. It is hypothesized that this is because developers use type annotations as in-code documentation. In this study, we aim to provide evidence that developers use type annotations as in-code documentation. Understanding this hypothesized use will help to understand how, and in what contexts, developers use type information; additionally, it may help to design better development tools and inform educational decisions. To provide this evidence, we conduct an eye tracking study with 26 undergraduate students to determine if they read type annotations during code comprehension and bug localization in the TypeScript language. We found that developers do not look directly at lines containing type annotations or type declarations more often when they are present, in either code summarization or bug localization tasks. The results have implications for tool builders to improve the availability of type information, the development community to build good standards for use of type annotations, and education to enforce deliberate teaching of reading patterns.

Modern software engineering research often relies on mining open-source software repositories, to either provide motivation for their research problems and/or evaluation of the proposed approach. Mining ultra-large-scale software repositories is still a difficult task, requiring substantial expertise and access to significant hardware. Tools such as Boa can help researchers easily mine large numbers of open-source repositories. There has also recently been more of a push toward open science, with an emphasis on making replication packages available. Building such replication packages incurs additional workload for researchers. In this tutorial, we teach how to use the Boa infrastructure for mining software repository data. We leverage Boa’s VS Code IDE extension to help write and submit Boa queries, and also leverage Boa’s study template to show how researchers can more easily analyze the output from Boa and automatically produce a suitable replication package that is published on Zenodo.