After a break of a few weeks we're back with an episode actually recorded on March 12th (when Phil had a cold). We chat with Gor Nishanov about Coroutines, which were just adopted into the draft standard for C++20. We talk about what Coroutines are, why recent talks may have been given the wrong impression (as they focused on a library writer's perspective,) what is going into the standard (the core language features) and what is not (library support, performance guaranteed by construction) and why. We also look at Microsoft's open-sourcing of the Calculator source code - and the bugs contained therein - as well as some follow-up on contracts. Special Guest: Gor Nishanov. Links: Understanding C++ Modules: Part 1: Hello Modules, and Module Units — Vector-of-bool (Colby Pike)'s post on ModulesCode Generation with C++ Contracts — Post about how contracts affects (or may affect) code generationCounting Bugs in Windows Calculator — PVS-Studio's post looking into the Windows Calculator code for bugsGor's CppCon 2015 talk on coroutines — "C++ Coroutines - a negative overhead abstraction"Gor's CppCon 2016 talk on coroutines — "C++ Coroutines: Under the covers"Gor's CppCon 2017 talk on coroutines — "Naked coroutines live (with networking)"Gor's CppCon 2018 talk on coroutines — "Nano-coroutines to the Rescue! (Using Coroutines TS, of Course)"C++ Now 2019Core C++ (Tel Aviv)Italian C++ Conference