Implement Enumerator::Lazy#eager

(cherry picked from commit f8b3866)

Author: bjfish

CHANGELOG.md

@@ -34,6 +34,7 @@ Compatibility:
 * `**kwargs` now accept non-Symbol keys like Ruby 2.7.
 * Updated the Unicode Emoji version (#2173, @wildmaples).
 * Added `Enumerator::Yielder#to_proc`.
+* Implemented `Enumerator::Lazy#eager`.
 
 Performance:
 

spec/tags/core/enumerator/lazy/eager_tags.txt

@@ -310,6 +310,10 @@ def lazy
       self
     end
 
+    def eager
+      Enumerator.instance_method(:enum_for).bind(self).call(:each) { size }
+    end
+
     # TODO: rewind and/or to_a/force behave improperly on outputs of take, drop, uniq, possibly more
 
     alias_method :force, :to_a

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

@@ -9,3 +9,6 @@
 exclude :test_zip_nested, "needs investigation"
 exclude :test_initialize, "needs investigation"
 exclude :test_take_rewound, "needs investigation"
+exclude :test_with_index, "needs investigation"
+exclude :test_lazy_to_enum_lazy_methods, "needs investigation"
+exclude :test_filter_map, "needs investigation"

test/mri/excludes/TestLazyEnumerator.rb

@@ -167,7 +167,6 @@ ruby/test_env.rb # TestEnv#test_aset = core:/core/rubinius/bootstrap/time.rb:28:
 ruby/test_file.rb
 ruby/test_iseq.rb
 ruby/test_iterator.rb # /Users/chrisseaton/Documents/ruby/jruby/test/mri/lib/minitest/unit.rb:1417:in `sort': internal implementation error - NullPointerException null org.truffleruby.runtime.subsystems.TraceManager$4.probeTaggedAs(TraceManager.java:117) (RuntimeError)
-ruby/test_lazy_enumerator.rb
 ruby/test_m17n_comb.rb # cannot load such file -- etc
 ruby/test_marshal.rb # including this causes error in test_objectspace.rb
 ruby/test_pipe.rb # tests not excluding