5 files changed, 34 insertions, 4 deletions
diff --git a/activemodel/CHANGELOG.md b/activemodel/CHANGELOG.md
index 8a3578229a..b28c83e4ed 100644
--- a/activemodel/CHANGELOG.md
+++ b/activemodel/CHANGELOG.md
@@ -1,9 +1,5 @@
 ## Rails 6.0.0.alpha (Unreleased) ##
 
-*   Do not lose all multiple `:includes` with options in serialization.
-
-    *Mike Mangino*
-
 *   Rails 6 requires Ruby 2.4.1 or newer.
 
     *Jeremy Daer*
diff --git a/activemodel/lib/active_model/attribute_assignment.rb b/activemodel/lib/active_model/attribute_assignment.rb
index aa931119ff..217bf1ac01 100644
--- a/activemodel/lib/active_model/attribute_assignment.rb
+++ b/activemodel/lib/active_model/attribute_assignment.rb
@@ -35,6 +35,8 @@ module ActiveModel
       _assign_attributes(sanitize_for_mass_assignment(attributes))
     end
 
+    alias attributes= assign_attributes
+
     private
 
       def _assign_attributes(attributes)
diff --git a/activemodel/lib/active_model/attributes.rb b/activemodel/lib/active_model/attributes.rb
index 046ae67ad7..4083bf827b 100644
--- a/activemodel/lib/active_model/attributes.rb
+++ b/activemodel/lib/active_model/attributes.rb
@@ -66,6 +66,10 @@ module ActiveModel
       super
     end
 
+    def attributes
+      @attributes.to_hash
+    end
+
     private
 
       def write_attribute(attr_name, value)
diff --git a/activemodel/test/cases/attribute_assignment_test.rb b/activemodel/test/cases/attribute_assignment_test.rb
index 448f8587fd..b06291f1b4 100644
--- a/activemodel/test/cases/attribute_assignment_test.rb
+++ b/activemodel/test/cases/attribute_assignment_test.rb
@@ -68,6 +68,14 @@ class AttributeAssignmentTest < ActiveModel::TestCase
     assert_equal "world", model.description
   end
 
+  test "simple assignment alias" do
+    model = Model.new
+
+    model.attributes = { name: "hello", description: "world" }
+    assert_equal "hello", model.name
+    assert_equal "world", model.description
+  end
+
   test "assign non-existing attribute" do
     model = Model.new
     error = assert_raises(ActiveModel::UnknownAttributeError) do
diff --git a/activemodel/test/cases/attributes_test.rb b/activemodel/test/cases/attributes_test.rb
index 7c1d813ce0..5483fb101d 100644
--- a/activemodel/test/cases/attributes_test.rb
+++ b/activemodel/test/cases/attributes_test.rb
@@ -47,6 +47,26 @@ module ActiveModel
       assert_equal true, data.boolean_field
     end
 
+    test "reading attributes" do
+      data = ModelForAttributesTest.new(
+        integer_field: 1.1,
+        string_field: 1.1,
+        decimal_field: 1.1,
+        boolean_field: 1.1
+      )
+
+      expected_attributes = {
+        integer_field: 1,
+        string_field: "1.1",
+        decimal_field: BigDecimal("1.1"),
+        string_with_default: "default string",
+        date_field: Date.new(2016, 1, 1),
+        boolean_field: true
+      }.stringify_keys
+
+      assert_equal expected_attributes, data.attributes
+    end
+
     test "nonexistent attribute" do
       assert_raise ActiveModel::UnknownAttributeError do
         ModelForAttributesTest.new(nonexistent: "nonexistent")