Vague error message
I would make a separate error message for return statements, one for
if-then-else and one for assignments.
Attached is an error got for a code-specification where the content is
the default content. The error message says that a return message is
allowed as the last statement, but this is not the real problem. Most
likely, the problem is that the code-specification is empty.
(from redmine: issue id 1928, created on 2014-02-13, closed on 2014-02-13)