Dart provides the operator as to cast an expression to a specific type, and is/is! to check the assignment
compatibility with a type. These operators are used for downcasts, smart casts, and run-time type checking.
In case the as operator is used for upcasting from a subtype to a supertype, the cast is redundant as it has no effect and can never
fail. If a specific type is expected, an expression of a subtype can always be inserted without casting (Substitution Principle and Assignment
Compatibility).
Likewise, the is operator is redundant and will always return true if the type of the expression on the left side is
assignment compatible with the type on the right.
What is the potential impact?
Code redundancy
Since the operation will always succeed and has no side effects, it is pointless to use it.
Conditions with is will lead to dead code branches because they will always or never be satisfied.
