Do syntax copy of an array of Statement's.
Determine if an enclosed break would apply to this statement, such as if it is a loop or switch statement.
Determine if an enclosed continue would apply to this statement, such as if it is a loop statement.
If this statement has code that needs to run in a finally clause at the end of the current scope, return that code in the form of a Statement.
Flatten out the scope by presenting the statement as an array of statements.
Find last statement in a sequence of statements.
Support Visitor Pattern
Does this statement end with a return statement?
A cheaper method of doing downcasting of Statements.
https://dlang.org/spec/statement.html#do-statement