I am interested in hearing some guidelines as to what feedback is or is not appropriate for a code review.  My team has a very unstructured review process and I am trying to suggest some ways to improve it.  I am no expert so I hope to hear from you experts out there!Should code review comments be limited to actual problems with the    code?Are criticisms about other LOC in the file appropriate even if those lines are not being modified?  i.e., criticism of pre-existing code?What about suggestions of different ways to solve the same problem?  Should I suggest a new way only when a case can be made for it being better?  How do I draw the line between contributing ideas but not sounding like a know-it-all?In matters which are purely a difference of opinion, who should get the 'final say'?  The author, the person who knows the code base the best, the person with the highest title or someone else?Any other advice for ensuring the code reviews serve their purpose without unnecessarily blocking the developer's progress?Please, if you could, provide reasoning along with any answers.  It will help this junior developer be able to really understand the best way to approach a code review.
What feedback is or is not appropriate for a code review?
code quality;code reviews