anchor.diff:  
   [NOTE]
   ====
  -We may decided to remove support for implicit downcasts
  +Consider removing support for implicit downcasts?
   ====
   
   Regardless of whether the downcast was implicit or explicit, the AttributeBindingSource needs to understand the set of
  
positive.code: Discuss design of SQM model.
  
  At a high level, SQM defines:
  . a domain model metamodel (org.hibernate.sqm.domain) which represents access to information about
  the application's domain model
  . a semantic query model that represents a query against that domain model.
  
  
  The first thing SQM needs to interpret the meaning of a query is some knowledge of the domain
  model being queried.  This is the purpose of the `org.hibernate.sqm.domain` package
  
  == FromClause
  
  The FromClause defines the parts of the domain model available to the query.  A FromClause
  is made up of one or more FromElementSpaces.  A FromElementSpace is defined by a "query root"
  
negative.code: Now we have 2 Bindings declared (`Person p` and `Person pm`) for the same Bindable (`Person`).
  
  
  === Downcasts
  
  FromElements (others) act as a source of attribute bindings/references.  For example, given a query defining `Person` as a
  root we can now refer to any of the attributes defined on `Person` and its superclasses in the query.
  