Suppose I refactor my program based on its reviews on codereview.SE. (Or someone reviews my pull request on GitHub.) Presumably, if I include the reviewer's code, they share copyright to my new program, unless their code is trivial.
But what about the following cases:
- I use the reviewer's code as a starting point and change it for my program. (I guess this depends on the changes.)
- The reviewer suggests detailed solutions in English, e.g., bug fixes or software designs. Then I translate these solutions into code.
(I'm based in the UK, if this matters.)
Note: A good concrete example is the following question (which I'm not involved in): validating-credit-card-numbers.