> **Note**: Class types are used to describe values that are instances of a class---these are the most commonly used types. To instead learn about types for class objects themselves, see [T.class_of](/docs/class-of).| sorbet.org
Sorbet implements a **control flow-sensitive** type system. It models control| sorbet.org
| sorbet.org
Sorbet provides the most value when it has a wealth of programmer-supplied| sorbet.org
RBI files are "Ruby Interface" files. Sorbet uses RBI files to learn about| sorbet.org