[wpaprocki]

Well, in Python, if you duplicate a return statement, then your code will recognize only the first statement. This, for example, will return 1:

  def func():
    return 1
    return 2

If the code from the goto fail example was written in Python so as to return an object when a condition was met, and it ended up with 2 return statements, then Python would have just returned the first one in the proper scope and moved on. Of course, this still depends on implementation in the code itself.

[eyeface]

If we're talking about returns, then C/C++ would behave the same way. The second return is unreachable.

A duplicated line that isn't idempotent and that doesn't jump out of the current scope would be problematic.