Remove ActiveRecord::Model

In the end I think the pain of implementing this seamlessly was not
worth the gain provided.

The intention was that it would allow plain ruby objects that might not
live in your main application to be subclassed and have persistence
mixed in. But I've decided that the benefit of doing that is not worth
the amount of complexity that the implementation introduced.

2 files changed, 4 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 84aaa39fed..99c2f45bc8 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -159,7 +159,7 @@ module ActiveRecord
     #   Person.exists?(false)
     #   Person.exists?
     def exists?(conditions = :none)
-      conditions = conditions.id if ActiveRecord::Model === conditions
+      conditions = conditions.id if Base === conditions
       return false if !conditions
 
       join_dependency = construct_join_dependency_for_association_find
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
index 71030cb5d7..bd7aeb0c4e 100644
--- a/activerecord/lib/active_record/relation/predicate_builder.rb
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -40,7 +40,7 @@ module ActiveRecord
       #
       # For polymorphic relationships, find the foreign key and type:
       # PriceEstimate.where(:estimate_of => treasure)
-      if klass && value.class < ActiveRecord::Tag && reflection = klass.reflect_on_association(column.to_sym)
+      if klass && value.class < Base && reflection = klass.reflect_on_association(column.to_sym)
         if reflection.polymorphic?
           queries << build(table[reflection.foreign_type], value.class.base_class)
         end
@@ -67,7 +67,7 @@ module ActiveRecord
       def self.build(attribute, value)
         case value
         when Array, ActiveRecord::Associations::CollectionProxy
-          values = value.to_a.map {|x| x.is_a?(ActiveRecord::Model) ? x.id : x}
+          values = value.to_a.map {|x| x.is_a?(Base) ? x.id : x}
           ranges, values = values.partition {|v| v.is_a?(Range)}
 
           values_predicate = if values.include?(nil)
@@ -93,7 +93,7 @@ module ActiveRecord
           attribute.in(value.arel.ast)
         when Range
           attribute.in(value)
-        when ActiveRecord::Model
+        when ActiveRecord::Base
           attribute.eq(value.id)
         when Class
           # FIXME: I think we need to deprecate this behavior