Fix keyword arguments to Struct.new

spec/core/struct/new_spec.rb

@@ -79,9 +79,7 @@ def obj.to_str() "Foo" end
 
   ruby_version_is "3.2" do
     it "raises a TypeError if passed a Hash with an unknown key" do
-      NATFIXME 'it raises a TypeError if passed a Hash with an unknown key', exception: SpecFailedException do
-        -> { Struct.new(:animal, { name: 'chris' }) }.should raise_error(TypeError)
-      end
+      -> { Struct.new(:animal, { name: 'chris' }) }.should raise_error(TypeError)
     end
   end
 

src/struct.rb

@@ -5,7 +5,7 @@ class << self
     alias [] new
   end
 
-  def self.new(*attrs, &block)
+  def self.new(*attrs, keyword_init: nil, &block)
     duplicates = attrs.tally.find { |_, size| size > 1 }
     unless duplicates.nil?
       raise ArgumentError, "duplicate member: #{duplicates.first}"
@@ -17,15 +17,6 @@ def self.new(*attrs, &block)
       attrs.shift
     end
 
-    if attrs.last.is_a?(Hash)
-      options = attrs.pop
-      unknown_keys = options.keys.difference([:keyword_init])
-      if unknown_keys.any?
-        raise ArgumentError, "unknown keyword: #{unknown_keys.map(&:inspect).join(', ')}"
-      end
-    else
-      options = {}
-    end
     result = Class.new(Struct) do
       include Enumerable
 
@@ -38,7 +29,7 @@ def self.new(*attrs, &block)
       end
       alias_method :size, :length
 
-      if options[:keyword_init]
+      if keyword_init
         define_method :initialize do |args = {}|
           unless args.is_a?(Hash)
             raise ArgumentError, "wrong number of arguments (given #{args.size}, expected 0)"
@@ -61,7 +52,7 @@ def self.new(*attrs, &block)
       end
 
       self.class.define_method :keyword_init? do
-        options[:keyword_init] ? true : options[:keyword_init]
+        keyword_init ? true : keyword_init
       end
 
       define_method :each do