https://github.com/presidentbeef/brakeman/issues/1841

brakeman still references haml 4 - which is a bit long in the tooth (Haml::Filter::Coffee class vs. module) presidentbeef#1841

lib/brakeman/parsers/haml_embedded.rb

@@ -25,20 +25,41 @@ def compile(compiler, text)
   end
 end
 
-# Fake CoffeeScript filter for Haml
-module Haml::Filters::Coffee
-  include Haml::Filters::Base
-  extend Brakeman::FakeHamlFilter
-end
+# Haml::Filters::Coffee used to be defined as a module - now it is a class
+if defined?(Haml::Filters::Coffee) && Haml::Filters::Coffee.class == Class
+  # Fake CoffeeScript filter for Haml
+  class Haml::Filters::Coffee
+    include Haml::Filters::Base
+    extend Brakeman::FakeHamlFilter
+  end
 
-# Fake Markdown filter for Haml
-module Haml::Filters::Markdown
-  include Haml::Filters::Base
-  extend Brakeman::FakeHamlFilter
-end
+  # Fake Markdown filter for Haml
+  class Haml::Filters::Markdown
+    include Haml::Filters::Base
+    extend Brakeman::FakeHamlFilter
+  end
+
+  # Fake Sass filter for Haml
+  class Haml::Filters::Sass
+    include Haml::Filters::Base
+    extend Brakeman::FakeHamlFilter
+  end
+else
+  # Fake CoffeeScript filter for Haml
+  module Haml::Filters::Coffee
+    include Haml::Filters::Base
+    extend Brakeman::FakeHamlFilter
+  end
 
-# Fake Sass filter for Haml
-module Haml::Filters::Sass
-  include Haml::Filters::Base
-  extend Brakeman::FakeHamlFilter
+  # Fake Markdown filter for Haml
+  module Haml::Filters::Markdown
+    include Haml::Filters::Base
+    extend Brakeman::FakeHamlFilter
+  end
+
+  # Fake Sass filter for Haml
+  module Haml::Filters::Sass
+    include Haml::Filters::Base
+    extend Brakeman::FakeHamlFilter
+  end
 end