anchor.diff:              result
           else false
   
  -type Terms =
  -    Dictionary<string, Term>
  -
   type [<StructuralEquality; NoComparison>] Subquery =
       | Wildcard // matches everything
       | Eq of Term
  
positive.code: /// TODO: consider embedding hash code to make look-ups faster.
  type [<CustomEquality; NoComparison>] ArchetypeId =
      { ComponentNames : string HashSet
        Terms : Terms }
  
      static member inline Hash (hashSet : _ HashSet) =
          let mutable h = 0
  
negative.code:         end
  
  /// A collection of component stores.
  and 'w Archetype (storeTypes : Dictionary<string, Type>, terms : Dictionary<string, Term>) =
  
      let mutable freeIndex = 0
      let freeList = hashSetPlus<int> HashIdentity.Structural []
  