diff --git a/.rubocop.yml b/.rubocop.yml
index d8027ad5..5d58596a 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -666,6 +666,13 @@ Style/NumericLiterals:
 Style/ObjectThen:
   Enabled: true
 
+# Extensions to other Ruby libraries purposefully declare
+# multiple classes.
+Style/OneClassPerFile:
+  Exclude:
+    - lib/git/*
+    - lib/vanagon/extensions/**/*
+
 Style/OneLineConditional:
   Enabled: true
 
diff --git a/lib/vanagon/component/rules.rb b/lib/vanagon/component/rules.rb
index 68684bf2..0aa6d97f 100644
--- a/lib/vanagon/component/rules.rb
+++ b/lib/vanagon/component/rules.rb
@@ -225,7 +225,7 @@ def component_rule
       # Generate a Makefile fragment that contains all of the rules for the component.
       # @return [String]
       def format
-        rules.map(&:to_s).join("\n")
+        rules.join("\n")
       end
 
       alias to_s format
diff --git a/lib/vanagon/extensions/hashable.rb b/lib/vanagon/extensions/hashable.rb
index e59a1694..a544880f 100644
--- a/lib/vanagon/extensions/hashable.rb
+++ b/lib/vanagon/extensions/hashable.rb
@@ -7,8 +7,8 @@ module HashableAttributes
   # @return [Hash] Converts an object to a hash with keys representing
   #   each attribute (as symbols) and their corresponding values
   def to_hash
-    instance_variables.each_with_object({}) do |var, hash|
-      hash[var.to_s.delete("@")] = instance_variable_get(var)
+    instance_variables.to_h do |var|
+      [var.to_s.delete("@"), instance_variable_get(var)]
     end
   end
   alias_method :to_h, :to_hash