Looks like C extension doesn't work on TruffleRuby

lib/haml/attribute_builder.rb

@@ -9,8 +9,8 @@ module Haml::AttributeBuilder
                        itemscope allowfullscreen default inert sortable
                        truespeed typemustmatch download].freeze
 
-  # For JRuby and Wasm, fallback to Ruby implementation.
-  if /java|wasm/ === RUBY_PLATFORM
+  # For JRuby, TruffleRuby, and Wasm, fallback to Ruby implementation.
+  if /java|wasm/ === RUBY_PLATFORM || RUBY_ENGINE == 'truffleruby'
     class << self
       def build(escape_attrs, quote, format, boolean_attributes, object_ref, *hashes)
         hashes << Haml::ObjectRef.parse(object_ref) if object_ref

lib/haml/util.rb

@@ -14,8 +14,8 @@ module Haml
   module Util
     extend self
 
-    # For JRuby and Wasm, fallback to Ruby implementation.
-    if /java|wasm/ === RUBY_PLATFORM
+    # For JRuby, TruffleRuby, and Wasm, fallback to Ruby implementation.
+    if /java|wasm/ === RUBY_PLATFORM || RUBY_ENGINE == 'truffleruby'
       require 'cgi/escape'
 
       def self.escape_html(html)