This code makes opal puke during compiles -- and if..end, def..end, do..end, etc closures and obvious things in order (I went line by line)

gistfile1.txt

                                        portion_message.on(:fail) do |reply|
                                            @pending.delete(response[:thread])
                                            @buffers.delete((response[:thread])
                                            if error_handler.respond_to?(:call)
                                                error_handler.call(reply)
                                            end
                                        end
 The Error:
 
 gxg_xhr:335:45: error: unexpected token kIF
gxg_xhr:335:                                             if error_handler.respond_to?(:call)
gxg_xhr:335:                                             ^~                                 
Traceback (most recent call last):
	22: from /usr/local/bin/opal:23:in `<main>'
	21: from /usr/local/bin/opal:23:in `load'
	20: from /var/lib/gems/2.5.0/gems/opal-0.11.4/exe/opal:24:in `<top (required)>'
	19: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/cli.rb:65:in `run'
	18: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/cli.rb:87:in `builder'
	17: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/cli.rb:116:in `create_builder'
	16: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/cli.rb:156:in `evals_or_file'
	15: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/cli.rb:116:in `block in create_builder'
	14: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/builder.rb:89:in `build_str'
	13: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/builder.rb:89:in `map'
	12: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/builder.rb:89:in `block in build_str'
	11: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/builder.rb:204:in `process_require'
	10: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/builder_processors.rb:98:in `requires'
	 9: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/builder_processors.rb:88:in `compiled'
	 8: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/compiler.rb:166:in `compile'
	 7: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/compiler.rb:180:in `parse'
	 6: from /var/lib/gems/2.5.0/gems/parser-2.3.3.1/lib/parser/base.rb:209:in `tokenize'
	 5: from /var/lib/gems/2.5.0/gems/opal-0.11.4/lib/opal/parser.rb:41:in `parse'
	 4: from /var/lib/gems/2.5.0/gems/parser-2.3.3.1/lib/parser/base.rb:162:in `parse'
	 3: from /usr/lib/ruby/2.5.0/racc/parser.rb:259:in `do_parse'
	 2: from /usr/lib/ruby/2.5.0/racc/parser.rb:259:in `_racc_do_parse_c'
	 1: from /var/lib/gems/2.5.0/gems/parser-2.3.3.1/lib/parser/base.rb:263:in `on_error'
/var/lib/gems/2.5.0/gems/parser-2.3.3.1/lib/parser/diagnostic/engine.rb:71:in `process': unexpected token kIF (SyntaxError)