Having DisallowSpaceBeforeTokenChecker enabled for SEMICOLON is very useful to enforce the official Scala Style Guide conventions:

Type annotations should be patterned according to the following template:

value: Type

This is the style adopted by most of the Scala standard library and all of Martin Odersky’s examples. The space between value and type helps the eye in accurately parsing the syntax. The reason to place the colon at the end of the value rather than the beginning of the type is to avoid confusion in cases such as this one:

value :::

However, it breaks context bounds convention:

def f[A : ClassTag](n: Int) = new Array[A](n)