The respond_to_missing function in lib/ostruct.rb is causing issues when using versions of Ruby < 2.3.0
def respond_to_missing?(mid, include_private = false) # :nodoc:
mname = mid.to_s.chomp("=").to_sym
@table&.key?(mname) || super
end
Line 196 uses the &. (Safe Navigation Operator) which was introduced in Ruby 2.3.0.
If you want to use the Safe Navigation Operator then please specify the required_ruby_version property in the ostruct.gemspec file