split DELEGATION_RESERVED_METHOD_NAMES in half

actionview/lib/action_view/template.rb

@@ -326,7 +326,7 @@ module ActionView
       def locals_code #:nodoc:
         # Only locals with valid variable names get set directly. Others will
         # still be available in local_assigns.
-        locals = @locals.to_set - Module::DELEGATION_RESERVED_METHOD_NAMES.dup.delete("block")
+        locals = @locals - Module::RUBY_RESERVED_KEYWORDS
         locals = locals.grep(/\A(?![A-Z0-9])(?:[[:alnum:]_]|[^\0-\177])+\z/)
 
         # Double assign to suppress the dreaded 'assigned but unused variable' warning

actionview/test/fixtures/test/test_template_with_block_variable.erb

@@ -1 +0,0 @@
-<%= block %>

actionview/test/fixtures/test/test_template_with_delegation_reserved_keywords.erb

@@ -0,0 +1 @@
+<%= _ %> <%= arg %> <%= args %> <%= block %>

actionview/test/template/compiled_templates_test.rb

@@ -14,10 +14,6 @@ class CompiledTemplatesTest < ActiveSupport::TestCase
       render(file: "test/render_file_with_ruby_keyword_locals", locals: { class: "foo" })
   end
 
-  def test_template_with_block_variable
-    assert_equal "foo", render(file: "test/test_template_with_block_variable", locals: { block: "foo" })
-  end
-
   def test_template_with_invalid_identifier_locals
     locals = {
       foo: "bar",
@@ -28,6 +24,16 @@ class CompiledTemplatesTest < ActiveSupport::TestCase
     assert_equal locals.inspect, render(file: "test/render_file_inspect_local_assigns", locals: locals)
   end
 
+  def test_template_with_delegation_reserved_keywords
+    locals = {
+      _: "one",
+      arg: "two",
+      args: "three",
+      block: "four",
+    }
+    assert_equal "one two three four", render(file: "test/test_template_with_delegation_reserved_keywords", locals: locals)
+  end
+
   def test_template_with_unicode_identifier
     assert_equal "🎂", render(file: "test/render_file_unicode_local", locals: { 🎃: "🎂" })
   end

activesupport/lib/active_support/core_ext/module/delegation.rb

@@ -6,11 +6,12 @@ class Module
   # option is not used.
   class DelegationError < NoMethodError; end
 
+  RUBY_RESERVED_KEYWORDS = %w(alias and BEGIN begin break case class def defined? do
+  else elsif END end ensure false for if in module next nil not or redo rescue retry
+  return self super then true undef unless until when while yield)
+  DELEGATION_RESERVED_KEYWORDS = %w(_ arg args block)
   DELEGATION_RESERVED_METHOD_NAMES = Set.new(
-    %w(_ arg args alias and BEGIN begin block break case class def defined? do
-       else elsif END end ensure false for if in module next nil not or redo
-       rescue retry return self super then true undef unless until when while
-       yield)
+    RUBY_RESERVED_KEYWORDS + DELEGATION_RESERVED_KEYWORDS
   ).freeze
 
   # Provides a +delegate+ class method to easily expose contained objects'