Update Enumerator::Lazy#{chunk_while, slice_before, slice_after, slice_when} to return instances of Enumerator::Lazy

Author: bjfish

CHANGELOG.md

@@ -15,6 +15,7 @@ Bug fixes:
 * Clear and restore errinfo on entry and normal return from methods in C extensions (#2227).
 * Fix extra whitespace in squiggly heredoc with escaped newline (#2238, @wildmaples and @norswap).
 * Fix handling of signals with `--single-threaded` (#2265).
+* Fix `Enumerator::Lazy#{chunk_while, slice_before, slice_after, slice_when}` to return instances of `Enumerator::Lazy` (#2273).
 
 Compatibility:
 

spec/ruby/core/enumerator/lazy/chunk_while_spec.rb

@@ -6,4 +6,9 @@
     s.lazy.chunk_while { |a, b| false }.first(100).should ==
       s.first(100).chunk_while { |a, b| false }.to_a
   end
+
+  it "should return a lazy enumerator" do
+    s = 0..Float::INFINITY
+    s.lazy.chunk_while { |a, b| false }.should be_kind_of(Enumerator::Lazy)
+  end
 end

spec/ruby/core/enumerator/lazy/slice_after_spec.rb

@@ -6,4 +6,9 @@
     s.lazy.slice_after { |n| true }.first(100).should ==
       s.first(100).slice_after { |n| true }.to_a
   end
+
+  it "should return a lazy enumerator" do
+    s = 0..Float::INFINITY
+    s.lazy.slice_after { |n| true }.should be_kind_of(Enumerator::Lazy)
+  end
 end

spec/ruby/core/enumerator/lazy/slice_before_spec.rb

@@ -6,4 +6,9 @@
     s.lazy.slice_before { |n| true }.first(100).should ==
       s.first(100).slice_before { |n| true }.to_a
   end
+
+  it "should return a lazy enumerator" do
+    s = 0..Float::INFINITY
+    s.lazy.slice_before { |n| true }.should be_kind_of(Enumerator::Lazy)
+  end
 end

spec/ruby/core/enumerator/lazy/slice_when_spec.rb

@@ -6,4 +6,9 @@
     s.lazy.slice_when { |a, b| true }.first(100).should ==
       s.first(100).slice_when { |a, b| true }.to_a
   end
+
+  it "should return a lazy enumerator" do
+    s = 0..Float::INFINITY
+    s.lazy.slice_when { |a, b| true }.should be_kind_of(Enumerator::Lazy)
+  end
 end

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

@@ -523,11 +523,21 @@ def chunk(&block)
       super(&block).lazy
     end
 
-    # clone these methods from the superclass
-    alias_method :chunk_while, :chunk_while
-    alias_method :slice_after, :slice_after
-    alias_method :slice_before, :slice_before
-    alias_method :slice_when, :slice_when
+    def chunk_while(&block)
+      super(&block).lazy
+    end
+
+    def slice_after(&block)
+      super(&block).lazy
+    end
+
+    def slice_before(&block)
+      super(&block).lazy
+    end
+
+    def slice_when(&block)
+      super(&block).lazy
+    end
 
     def uniq
       if block_given?