Swift boasts a powerful language feature known as type inference, which is crucial for balancing a safe type system with ease of coding. Understanding how this essential feature is implemented can aid in writing better code. In this talk, I will explain the workings of Swift's type inference, including the fundamental algorithm that allows bidirectional propagation of type information for code, and how it's extended to accommodate language features like overloading. This will help understand why compiling code can become overly burdensome and result in errors. I will also cover interesting related topics such as overload priority, simultaneous inference in multiple statements, and the challenges of protocol compliance determination. Additionally, methods for directly observing the behavior of type inference using compiler options will be introduced, paving the way for further deepening your understanding. Speaker: omochimetaru try! Swift Tokyo Conference 2024 - try! Swift Tokyo is back! Developers from all over the world gather for tips and tricks and the latest case studies of development using Swift. Developers from all over the world will gather here. Swift and to showcase our Swift knowledge and skills, and to collaborate with each other, The event will be held for three days from March 22 - 24, 2024! Channel: https://www.youtube.com/@trySwiftConference X: https://twitter.com/tryswiftconf WebSite: https://tryswift.jp