Allow Range#=== and Range#cover? on Range

ruby/ruby@989e07c features switching `Range#===` to use internal `r_cover_p`
instead of rubyland `include?`. This breaks expected behavior of
`ActiveSupport::CoreExt::Range` documented since at least 8b67a02.

This patch adds overrides on `Range#cover?` and `Range#===` and places all
three in a single module, `CompareWithRange`.

*Requiring core_ext/range/include_range now causes a deprecation warnning*

1 files changed, 61 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/core_ext/range/compare_range.rb b/activesupport/lib/active_support/core_ext/range/compare_range.rb
new file mode 100644
index 0000000000..704041f6de
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/range/compare_range.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module CompareWithRange #:nodoc:
+    # Extends the default Range#=== to support range comparisons.
+    #  (1..5) === (1..5) # => true
+    #  (1..5) === (2..3) # => true
+    #  (1..5) === (2..6) # => false
+    #
+    # The native Range#=== behavior is untouched.
+    #  ('a'..'f') === ('c') # => true
+    #  (5..9) === (11) # => false
+    def ===(value)
+      if value.is_a?(::Range)
+        # 1...10 includes 1..9 but it does not include 1..10.
+        operator = exclude_end? && !value.exclude_end? ? :< : :<=
+        super(value.first) && value.last.send(operator, last)
+      else
+        super
+      end
+    end
+
+    # Extends the default Range#include? to support range comparisons.
+    #  (1..5).include?(1..5) # => true
+    #  (1..5).include?(2..3) # => true
+    #  (1..5).include?(2..6) # => false
+    #
+    # The native Range#include? behavior is untouched.
+    #  ('a'..'f').include?('c') # => true
+    #  (5..9).include?(11) # => false
+    def include?(value)
+      if value.is_a?(::Range)
+        # 1...10 includes 1..9 but it does not include 1..10.
+        operator = exclude_end? && !value.exclude_end? ? :< : :<=
+        super(value.first) && value.last.send(operator, last)
+      else
+        super
+      end
+    end
+
+    # Extends the default Range#cover? to support range comparisons.
+    #  (1..5).cover?(1..5) # => true
+    #  (1..5).cover?(2..3) # => true
+    #  (1..5).cover?(2..6) # => false
+    #
+    # The native Range#cover? behavior is untouched.
+    #  ('a'..'f').cover?('c') # => true
+    #  (5..9).cover?(11) # => false
+    def cover?(value)
+      if value.is_a?(::Range)
+        # 1...10 covers 1..9 but it does not cover 1..10.
+        operator = exclude_end? && !value.exclude_end? ? :< : :<=
+        super(value.first) && value.last.send(operator, last)
+      else
+        super
+      end
+    end
+  end
+end
+
+Range.prepend(ActiveSupport::CompareWithRange)