PSR-12

Compound namespace depth is more than 2  

Reports the usages of compound namespaces whose depth exceeds two levels.

Else if  

Reports the usages of the else if constructs specified in two words.

Missing parameter list  

Reports missing parameter lists in a classes' instantiations.

Missing visibility  

Reports the properties, constants, and methods that are declared without visibility definition.

One-per-line trait uses  

Reports the cases of several traits being imported via a single use statement.

Order of modifiers  

Reports visibility modifiers that are specified in the incorrect order.

Short form of type keywords  

Reports usages of long form type keywords.

Usage of var  

Reports the usages of the var keyword for declaring class properties.