diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 6e89b8b1..f55d9335 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,23 +1,12 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2015-08-31 04:23:33 -0500 using RuboCop version 0.33.0.
+# on 2015-09-20 17:56:22 -0500 using RuboCop version 0.34.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 1
-# Configuration parameters: AllowSafeAssignment.
-Lint/AssignmentInCondition:
-  Exclude:
-    - 'lib/active_model/serializer/adapter/json_api.rb'
-
-# Offense count: 1
-Lint/EmptyEnsure:
-  Exclude:
-    - 'test/serializers/adapter_for_test.rb'
-
-# Offense count: 1
+# Offense count: 2
 Lint/HandleExceptions:
   Exclude:
     - 'Rakefile'
@@ -28,11 +17,10 @@ Lint/UnusedBlockArgument:
   Exclude:
     - 'lib/active_model/serializer/adapter/json_api/fragment_cache.rb'
 
-# Offense count: 9
+# Offense count: 7
 # Cop supports --auto-correct.
 Lint/UnusedMethodArgument:
   Exclude:
-    - 'lib/active_model/serializer/adapter.rb'
     - 'lib/active_model/serializer/adapter/null.rb'
     - 'lib/active_model/serializer/pass_through_serializer.rb'
     - 'test/fixtures/poro.rb'
@@ -43,12 +31,11 @@ Lint/UselessAccessModifier:
   Exclude:
     - 'lib/active_model/serializable_resource.rb'
 
-# Offense count: 3
+# Offense count: 2
 Lint/UselessAssignment:
   Exclude:
     - 'bench/perf.rb'
     - 'lib/active_model/serializer/adapter/json_api/fragment_cache.rb'
-    - 'test/test_helper.rb'
 
 # Offense count: 1
 # Configuration parameters: EnforcedStyle, SupportedStyles.
@@ -56,7 +43,7 @@ Rails/Date:
   Exclude:
     - 'test/fixtures/poro.rb'
 
-# Offense count: 8
+# Offense count: 4
 # Configuration parameters: EnforcedStyle, SupportedStyles.
 Rails/TimeZone:
   Exclude:
@@ -78,14 +65,13 @@ Style/AndOr:
   Exclude:
     - 'lib/active_model/serializer/lint.rb'
 
-# Offense count: 46
+# Offense count: 25
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, SupportedStyles.
 Style/BracesAroundHashParameters:
   Exclude:
     - 'test/action_controller/adapter_selector_test.rb'
     - 'test/action_controller/json_api/pagination_test.rb'
-    - 'test/action_controller/serialization_test.rb'
     - 'test/adapter/json_api/linked_test.rb'
     - 'test/adapter/json_api/pagination_links_test.rb'
     - 'test/adapter/null_test.rb'
@@ -97,9 +83,8 @@ Style/BracesAroundHashParameters:
     - 'test/serializers/attributes_test.rb'
     - 'test/serializers/fieldset_test.rb'
     - 'test/serializers/root_test.rb'
-    - 'test/serializers/urls_test.rb'
 
-# Offense count: 167
+# Offense count: 174
 # Configuration parameters: EnforcedStyle, SupportedStyles.
 Style/ClassAndModuleChildren:
   Enabled: false
@@ -120,12 +105,11 @@ Style/EachWithObject:
   Exclude:
     - 'lib/active_model/serializer/fieldset.rb'
 
-# Offense count: 3
+# Offense count: 2
 # Configuration parameters: MinBodyLength.
 Style/GuardClause:
   Exclude:
     - 'lib/active_model/serializer.rb'
-    - 'lib/active_model/serializer/adapter/json_api.rb'
     - 'test/capture_warnings.rb'
 
 # Offense count: 12
@@ -149,34 +133,12 @@ Style/IndentArray:
 Style/IndentHash:
   Enabled: false
 
-# Offense count: 1
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle, SupportedStyles.
-Style/IndentationConsistency:
-  Exclude:
-    - 'test/action_controller/serialization_scope_name_test.rb'
-
-# Offense count: 2
-# Cop supports --auto-correct.
-# Configuration parameters: Width.
-Style/IndentationWidth:
-  Exclude:
-    - 'lib/active_model/serializable_resource.rb'
-    - 'lib/active_model/serializer/fieldset.rb'
-
 # Offense count: 1
 # Cop supports --auto-correct.
 Style/Lambda:
   Exclude:
     - 'lib/active_model/serializer.rb'
 
-# Offense count: 2
-# Cop supports --auto-correct.
-Style/MethodCallParentheses:
-  Exclude:
-    - 'lib/active_model/serializer/adapter/json.rb'
-    - 'lib/active_model/serializer/adapter/json_api.rb'
-
 # Offense count: 1
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, SupportedStyles.
@@ -195,24 +157,11 @@ Style/NegatedIf:
   Exclude:
     - 'lib/action_controller/serialization.rb'
 
-# Offense count: 1
-# Configuration parameters: EnforcedStyle, MinBodyLength, SupportedStyles.
-Style/Next:
-  Exclude:
-    - 'lib/active_model/serializer/adapter/json_api.rb'
-
 # Offense count: 1
 # Cop supports --auto-correct.
 Style/NumericLiterals:
   MinDigits: 7
 
-# Offense count: 2
-# Cop supports --auto-correct.
-# Configuration parameters: PreferredDelimiters.
-Style/PercentLiteralDelimiters:
-  Exclude:
-    - 'active_model_serializers.gemspec'
-
 # Offense count: 2
 # Cop supports --auto-correct.
 Style/PerlBackrefs:
@@ -220,20 +169,17 @@ Style/PerlBackrefs:
     - 'test/fixtures/poro.rb'
     - 'test/serializers/associations_test.rb'
 
-# Offense count: 6
+# Offense count: 3
 # Configuration parameters: NamePrefix, NamePrefixBlacklist.
 Style/PredicateName:
   Exclude:
-    - 'lib/active_model/serializer/adapter.rb'
-    - 'lib/active_model/serializer/adapter/json_api.rb'
     - 'lib/active_model/serializer/associations.rb'
     - 'test/action_controller/json_api/linked_test.rb'
 
-# Offense count: 7
+# Offense count: 5
 # Cop supports --auto-correct.
 Style/RedundantSelf:
   Exclude:
-    - 'lib/active_model/serializer.rb'
     - 'lib/active_model/serializer/associations.rb'
     - 'test/fixtures/poro.rb'
 
@@ -244,13 +190,11 @@ Style/Semicolon:
   Exclude:
     - 'lib/active_model/serializer/fieldset.rb'
 
-# Offense count: 6
+# Offense count: 3
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, SupportedStyles.
 Style/SignalException:
   Exclude:
-    - 'lib/active_model/serializer.rb'
-    - 'lib/active_model/serializer/adapter.rb'
     - 'lib/active_model/serializer/fieldset.rb'
     - 'lib/active_model/serializer/pass_through_serializer.rb'
 
@@ -293,7 +237,7 @@ Style/TrailingBlankLines:
     - 'test/serializers/fieldset_test.rb'
     - 'test/support/stream_capture.rb'
 
-# Offense count: 6
+# Offense count: 5
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyleForMultiline, SupportedStyles.
 Style/TrailingComma:
diff --git a/lib/active_model/serializer/adapter/json_api.rb b/lib/active_model/serializer/adapter/json_api.rb
index 94571eaa..3637ccb7 100644
--- a/lib/active_model/serializer/adapter/json_api.rb
+++ b/lib/active_model/serializer/adapter/json_api.rb
@@ -130,11 +130,14 @@ module ActiveModel
           end
         end
 
-        def included_for(serializer)
-          included.flat_map do |inc|
-            association = serializer.associations.find { |assoc| assoc.key == inc.first }
-            _included_for(association.serializer, inc.second) if association
-          end.uniq
+        def included_resources(include_tree)
+          included = []
+
+          serializer.associations(include_tree).each do |association|
+            add_included_resources_for(association.serializer, include_tree[association.key], included)
+          end
+
+          included
         end
 
         def add_included_resources_for(serializer, include_tree, included)
diff --git a/lib/active_model/serializer/include_tree.rb b/lib/active_model/serializer/include_tree.rb
index 6d675e11..8a8f1c12 100644
--- a/lib/active_model/serializer/include_tree.rb
+++ b/lib/active_model/serializer/include_tree.rb
@@ -16,9 +16,9 @@ module ActiveModel
           when Symbol
             { included => {} }
           when Hash
-            included.each_with_object({}) { |(key, value), hash|
+            included.each_with_object({}) do |(key, value), hash|
               hash[key] = include_args_to_hash(value)
-            }
+            end
           when Array
             included.reduce({}) { |a, e| a.merge!(include_args_to_hash(e)) }
           when String