=======================================
From keyword can be a variable
=======================================

var a = Assert.Range(from, to);

---

(compilation_unit
  (field_declaration
    (variable_declaration
      (implicit_type)
      (variable_declarator
        (identifier)
        (equals_value_clause
          (invocation_expression
            (member_access_expression (identifier) (identifier))
            (argument_list (argument (identifier)) (argument (identifier)))))))))