diff --git a/activerecord/lib/active_record/associations/join_dependency.rb b/activerecord/lib/active_record/associations/join_dependency.rb
index b852656c854c6..871ca1c91db84 100644
--- a/activerecord/lib/active_record/associations/join_dependency.rb
+++ b/activerecord/lib/active_record/associations/join_dependency.rb
@@ -69,7 +69,7 @@ def graft(*associations)
         join_assocs = join_associations
 
         associations.reject { |association|
-          join_assocs.detect { |a| association == a }
+          join_assocs.detect { |a| node_cmp association, a }
         }.each { |association|
           join_node = find_parent_node(association.parent) || @join_root
           type      = association.join_type
@@ -122,14 +122,19 @@ def instantiate(result_set)
       private
 
       def find_parent_node(parent)
-        @join_root.find { |join_part|
-          case parent
-          when JoinBase
-            parent.base_klass == join_part.base_klass
-          else
-            parent == join_part
-          end
-        }
+        @join_root.find { |join_part| node_cmp parent, join_part }
+      end
+
+      def node_cmp(parent, join_part)
+        return unless parent.class == join_part.class
+
+        case parent
+        when JoinBase
+          parent.base_klass == join_part.base_klass
+        else
+          parent.reflection == join_part.reflection &&
+            node_cmp(parent.parent, join_part.parent)
+        end
       end
 
       def join_base
@@ -182,7 +187,7 @@ def find_or_build_scalar(reflection, parent, join_type)
 
       def find_join_association(reflection, parent)
         join_associations.detect { |j|
-          j.reflection == reflection && j.parent == parent
+          j.reflection == reflection && node_cmp(j.parent, parent)
         }
       end
 
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
index e2ac892e71e9d..3f9afa8992959 100644
--- a/activerecord/lib/active_record/associations/join_dependency/join_association.rb
+++ b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
@@ -33,12 +33,6 @@ def initialize(reflection, index, parent, join_type, alias_tracker)
         def parent_table_name; parent.table_name; end
         alias :alias_suffix :parent_table_name
 
-        def ==(other)
-          other.class == self.class &&
-            other.reflection == reflection &&
-            other.parent == parent
-        end
-
         def join_constraints
           joins         = []
           tables        = @tables.dup
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_base.rb b/activerecord/lib/active_record/associations/join_dependency/join_base.rb
index c90ae80e4a3ff..d3bc3dd1ad7a0 100644
--- a/activerecord/lib/active_record/associations/join_dependency/join_base.rb
+++ b/activerecord/lib/active_record/associations/join_dependency/join_base.rb
@@ -8,11 +8,6 @@ def initialize(klass)
           super(klass, nil)
         end
 
-        def ==(other)
-          other.class == self.class &&
-            other.base_klass == base_klass
-        end
-
         def aliased_prefix
           "t0"
         end
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_part.rb b/activerecord/lib/active_record/associations/join_dependency/join_part.rb
index 3e9bdbfbab5e5..b8ce8ff46d6a9 100644
--- a/activerecord/lib/active_record/associations/join_dependency/join_part.rb
+++ b/activerecord/lib/active_record/associations/join_dependency/join_part.rb
@@ -48,10 +48,6 @@ def aliased_table
           Arel::Nodes::TableAlias.new table, aliased_table_name
         end
 
-        def ==(other)
-          raise NotImplementedError
-        end
-
         # An Arel::Table for the active_record
         def table
           raise NotImplementedError