Fix {Rational,Complex}#{marshal_dump,marshal_load} to be compatible with CRuby

* Fixes #3228

Author: eregon

CHANGELOG.md

@@ -42,6 +42,7 @@ Compatibility:
 * Add `Module#const_added` (#3039,  @itarato).
 * Show the pointer size information (if available) in `FFI::Pointer#inspect` (@nirvdrum).
 * Implement performance warnings (`Warning[:performance]`) like in CRuby 3.3 (@eregon).
+* The output of `Marshal.dump` is now compatible with CRuby for `Rational` and `Complex` instances (#3228, @eregon).
 
 Performance:
 

spec/ruby/core/marshal/dump_spec.rb

@@ -271,6 +271,18 @@ def _dump(level)
     end
   end
 
+  describe "with a Rational" do
+    it "dumps a Rational" do
+      Marshal.dump(Rational(2, 3)).should == "\x04\bU:\rRational[\ai\ai\b"
+    end
+  end
+
+  describe "with a Complex" do
+    it "dumps a Complex" do
+      Marshal.dump(Complex(2, 3)).should == "\x04\bU:\fComplex[\ai\ai\b"
+    end
+  end
+
   describe "with a String" do
     it "dumps a blank String" do
       Marshal.dump("".force_encoding("binary")).should == "\004\b\"\000"
@@ -769,7 +781,6 @@ def finalizer.noop(_)
   end
 
   describe "when passed an IO" do
-
     it "writes the serialized data to the IO-Object" do
       (obj = mock('test')).should_receive(:write).at_least(1)
       Marshal.dump("test", obj)
@@ -792,8 +803,6 @@ def finalizer.noop(_)
       obj.should_receive(:binmode).at_least(1)
       Marshal.dump("test", obj)
     end
-
-
   end
 
   describe "when passed a StringIO" do

src/main/ruby/truffleruby/core/complex.rb

@@ -311,23 +311,14 @@ def fdiv(other)
     self / other
   end
 
-  def marshal_dump
-    ary = [real, imag]
-    instance_variables.each do |ivar|
-      ary.instance_variable_set(ivar, instance_variable_get(ivar))
-    end
-    ary
+  private def marshal_dump
+    [@real, @imag]
   end
-  private :marshal_dump
 
-  def marshal_load(ary)
+  private def marshal_load(ary)
     @real, @imag = ary
-    ary.instance_variables.each do |ivar|
-      instance_variable_set(ivar, ary.instance_variable_get(ivar))
-    end
     self
   end
-  private :marshal_load
 
   def <=>(other)
     if imag == 0 && Primitive.is_a?(other, Numeric)

src/main/ruby/truffleruby/core/rational.rb

@@ -406,31 +406,17 @@ def initialize(num, den)
     @denominator = den
     Primitive.freeze(self)
   end
-  private :initialize
 
-  def marshal_dump
-    ary = [@numerator, @denominator]
-
-    instance_variables.each do |ivar|
-      ary.instance_variable_set(ivar, instance_variable_get(ivar))
-    end
-
-    ary
+  private def marshal_dump
+    [@numerator, @denominator]
   end
-  private :marshal_dump
 
-  def marshal_load(ary)
+  private def marshal_load(ary)
     @numerator, @denominator = ary
-
-    ary.instance_variables.each do |ivar|
-      instance_variable_set(ivar, ary.instance_variable_get(ivar))
-    end
-
     self
   end
-  private :marshal_load
 
-  def with_precision(method, n, **kwargs)
+  private def with_precision(method, n, **kwargs)
     raise TypeError, 'not an integer' unless Primitive.is_a?(n, Integer)
 
     p = 10 ** n
@@ -445,5 +431,4 @@ def with_precision(method, n, **kwargs)
     r = Rational(wp, p)
     n < 1 ? r.to_i : r
   end
-  private :with_precision
 end