diff --git a/lib/jekyll/drops/drop.rb b/lib/jekyll/drops/drop.rb
index 98eb864a..23237a08 100644
--- a/lib/jekyll/drops/drop.rb
+++ b/lib/jekyll/drops/drop.rb
@@ -83,6 +83,19 @@ module Jekyll
         end
       end
 
+      # Check if key exists in Drop
+      #
+      # key - the string key whose value to fetch
+      #
+      # Returns true if the given key is present
+      def key?(key)
+        if self.class.mutable && @mutations.key?(key)
+          true
+        else
+          respond_to?(key) || fallback_data.key?(key)
+        end
+      end
+
       # Generates a list of keys with user content as their values.
       # This gathers up the Drop methods and keys of the mutations and
       # underlying data hashes and performs a set union to ensure a list
diff --git a/lib/jekyll/frontmatter_defaults.rb b/lib/jekyll/frontmatter_defaults.rb
index 673d9a99..edf70969 100644
--- a/lib/jekyll/frontmatter_defaults.rb
+++ b/lib/jekyll/frontmatter_defaults.rb
@@ -90,7 +90,7 @@ module Jekyll
     end
 
     def applies_path?(scope, path)
-      return true if !scope.has_key?('path') || scope['path'].empty?
+      return true if !scope.key?('path') || scope['path'].empty?
 
       scope_path = Pathname.new(scope['path'])
       Pathname.new(sanitize_path(path)).ascend do |path|
@@ -150,7 +150,7 @@ module Jekyll
     # Returns an array of hashes
     def matching_sets(path, type)
       valid_sets.select do |set|
-        !set.has_key?('scope') || applies?(set['scope'], path, type)
+        !set.key?('scope') || applies?(set['scope'], path, type)
       end
     end
 
diff --git a/lib/jekyll/regenerator.rb b/lib/jekyll/regenerator.rb
index c7d47c59..52ff5178 100644
--- a/lib/jekyll/regenerator.rb
+++ b/lib/jekyll/regenerator.rb
@@ -90,7 +90,7 @@ module Jekyll
       return true if path.nil?
 
       # Check for path in cache
-      if cache.has_key? path
+      if cache.key? path
         return cache[path]
       end
 
diff --git a/lib/jekyll/tags/include.rb b/lib/jekyll/tags/include.rb
index e3bee115..4152e7ef 100644
--- a/lib/jekyll/tags/include.rb
+++ b/lib/jekyll/tags/include.rb
@@ -115,7 +115,7 @@ eos
         validate_path(path, dir, site.safe)
 
         # Add include to dependency tree
-        if context.registers[:page] && context.registers[:page].has_key?("path")
+        if context.registers[:page] && context.registers[:page].key?("path")
           site.regenerator.add_dependency(
             site.in_source_dir(context.registers[:page]["path"]),
             path
@@ -138,7 +138,7 @@ eos
         context.registers[:cached_partials] ||= {}
         cached_partial = context.registers[:cached_partials]
 
-        if cached_partial.has_key?(path)
+        if cached_partial.key?(path)
           cached_partial[path]
         else
           cached_partial[path] = context.registers[:site].liquid_renderer.file(path).parse(read_file(path, context))