kacperk/ruby_koans — comment on commit d21c8fd6cb9e1a5d9846573e25fe7c568a3e1082
File: koans/about_strings.rb line 100
By kacperk:

As we talked, "<<" sign have higher precedence then "+=", and it is working in a bit different way. Using "<<" instead of "+=" can cause bugs, so is better to use "+=", unless you need use "<<" with clear purpose.