Fix Range#step with no block and non-Numeric values

* Fixes #2824

CHANGELOG.md

@@ -57,6 +57,7 @@ Compatibility:
 * Fix arguments implicit type conversion for `Enumerable#zip` and `Array#zip` (#2788, @andrykonchin).
 * Fix `Array#unshift` to not depend on `Array#[]=` and allow overriding `#[]=` in a subclass (#2772, @andrykonchin).
 * Fix syntactic check for `void value expression` (#2821, @eregon).
+* Fix `Range#step` with no block and non-`Numeric` values (#2824, @eregon).
 
 Performance:
 

spec/ruby/core/range/step_spec.rb

@@ -474,10 +474,14 @@
         end
       end
 
+      # We use .take below to ensure the enumerator works
+      # because that's an Enumerable method and so it uses the Enumerator behavior
+      # not just a method overridden in Enumerator::ArithmeticSequence.
       describe "type" do
         context "when both begin and end are numerics" do
           it "returns an instance of Enumerator::ArithmeticSequence" do
             (1..10).step.class.should == Enumerator::ArithmeticSequence
+            (1..10).step(3).take(4).should == [1, 4, 7, 10]
           end
         end
 
@@ -490,10 +494,12 @@
         context "when range is endless" do
           it "returns an instance of Enumerator::ArithmeticSequence when begin is numeric" do
             (1..).step.class.should == Enumerator::ArithmeticSequence
+            (1..).step(2).take(3).should == [1, 3, 5]
           end
 
           it "returns an instance of Enumerator when begin is not numeric" do
             ("a"..).step.class.should == Enumerator
+            ("a"..).step(2).take(3).should == %w[a c e]
           end
         end
 
@@ -506,6 +512,7 @@
         context "when begin and end are not numerics" do
           it "returns an instance of Enumerator" do
             ("a".."z").step.class.should == Enumerator
+            ("a".."z").step(3).take(4).should == %w[a d g j]
           end
         end
       end

src/main/ruby/truffleruby/core/truffle/range_operations.rb

@@ -41,7 +41,7 @@ def self.step_no_block(range, step_size)
       if arithmetic_range?(from, to)
         Enumerator::ArithmeticSequence.new(range, :step, from, to, step_size, range.exclude_end?)
       else
-        to_enum(:step, step_size) do
+        range.to_enum(:step, step_size) do
           validated_step_args = validate_step_size(from, to, step_size)
           step_iterations_size(range, *validated_step_args)
         end