Psalm
A static analysis tool for finding errors in PHP applications
... automatically, allowing you to improve your code without breaking a sweat. If Psalm cannot infer a type for an expression then it uses a mixed placeholder type. mixed types can sometimes mask bugs, so keeping track of them helps you avoid a number of common pitfalls. Psalm has a Language Server that’s compatible with a range of different IDEs. Psalm can fix many of the issues it finds automatically.