diff --git a/lib/graphql/compatibility/schema_parser_specification.rb b/lib/graphql/compatibility/schema_parser_specification.rb
index bfe86fd8af..5d1c754e67 100644
--- a/lib/graphql/compatibility/schema_parser_specification.rb
+++ b/lib/graphql/compatibility/schema_parser_specification.rb
@@ -595,31 +595,27 @@ def test_it_parses_whole_definition_with_descriptions
 
             assert_equal 6, document.definitions.size
 
-            schema_definition = document.definitions.shift
+            schema_definition, directive_definition, enum_type_definition, object_type_definition, input_object_type_definition, interface_type_definition = document.definitions
+
             assert_equal GraphQL::Language::Nodes::SchemaDefinition, schema_definition.class
 
-            directive_definition = document.definitions.shift
             assert_equal GraphQL::Language::Nodes::DirectiveDefinition, directive_definition.class
             assert_equal 'This is a directive', directive_definition.description
 
-            enum_type_definition = document.definitions.shift
             assert_equal GraphQL::Language::Nodes::EnumTypeDefinition, enum_type_definition.class
             assert_equal "Multiline comment\n\nWith an enum", enum_type_definition.description
 
             assert_nil enum_type_definition.values[0].description
             assert_equal 'Not a creative color', enum_type_definition.values[1].description
 
-            object_type_definition = document.definitions.shift
             assert_equal GraphQL::Language::Nodes::ObjectTypeDefinition, object_type_definition.class
             assert_equal 'Comment without preceding space', object_type_definition.description
             assert_equal 'And a field to boot', object_type_definition.fields[0].description
 
-            input_object_type_definition = document.definitions.shift
             assert_equal GraphQL::Language::Nodes::InputObjectTypeDefinition, input_object_type_definition.class
             assert_equal 'Comment for input object types', input_object_type_definition.description
             assert_equal 'Color of the car', input_object_type_definition.fields[0].description
 
-            interface_type_definition = document.definitions.shift
             assert_equal GraphQL::Language::Nodes::InterfaceTypeDefinition, interface_type_definition.class
             assert_equal 'Comment for interface definitions', interface_type_definition.description
             assert_equal 'Amount of wheels', interface_type_definition.fields[0].description
diff --git a/lib/graphql/language/document_from_schema_definition.rb b/lib/graphql/language/document_from_schema_definition.rb
index 78dc153a75..6d43166955 100644
--- a/lib/graphql/language/document_from_schema_definition.rb
+++ b/lib/graphql/language/document_from_schema_definition.rb
@@ -65,7 +65,7 @@ def build_field_node(field)
         )
 
         if field.deprecation_reason
-          field_node.directives << GraphQL::Language::Nodes::Directive.new(
+          field_node = field_node.merge_directive(
             name: GraphQL::Directive::DeprecatedDirective.name,
             arguments: [GraphQL::Language::Nodes::Argument.new(name: "reason", value: field.deprecation_reason)]
           )
@@ -107,7 +107,7 @@ def build_enum_value_node(enum_value)
         )
 
         if enum_value.deprecation_reason
-          enum_value_node.directives << GraphQL::Language::Nodes::Directive.new(
+          enum_value_node = enum_value_node.merge_directive(
             name: GraphQL::Directive::DeprecatedDirective.name,
             arguments: [GraphQL::Language::Nodes::Argument.new(name: "reason", value: enum_value.deprecation_reason)]
           )
diff --git a/lib/graphql/language/nodes.rb b/lib/graphql/language/nodes.rb
index 3e39c6e44e..d6e62b2038 100644
--- a/lib/graphql/language/nodes.rb
+++ b/lib/graphql/language/nodes.rb
@@ -168,7 +168,7 @@ def merge_#{method_name.to_s.sub(/s$/, "")}(node_opts)
               else
                 module_eval <<-RUBY, __FILE__, __LINE__
                   def children
-                    @children ||= #{children_of_type.keys.map { |k| "@#{k}" }.join(" + ")}
+                    @children ||= (#{children_of_type.keys.map { |k| "@#{k}" }.join(" + ")}).freeze
                   end
                 RUBY
               end
@@ -200,7 +200,7 @@ def scalar_methods(*method_names)
                 attr_reader #{method_names.map { |m| ":#{m}"}.join(", ")}
 
                 def scalars
-                  @scalars ||= [#{method_names.map { |k| "@#{k}" }.join(", ")}]
+                  @scalars ||= [#{method_names.map { |k| "@#{k}" }.join(", ")}].freeze
                 end
               RUBY
             end
@@ -224,7 +224,9 @@ def generate_initialize_node
               arguments = scalar_method_names.map { |m| "#{m}: nil"} +
                 @children_methods.keys.map { |m| "#{m}: []" }
 
-              assignments = all_method_names.map { |m| "@#{m} = #{m}"}
+              assignments = scalar_method_names.map { |m| "@#{m} = #{m}"} +
+                @children_methods.keys.map { |m| "@#{m} = #{m}.freeze" }
+
               module_eval <<-RUBY, __FILE__, __LINE__
                 def initialize_node #{arguments.join(", ")}
                   #{assignments.join("\n")}