Would be nice to warn about omitting the "yield from" from a call

[GoogleCodeExporter]

Sometimes you write foo() instead of yield from foo().  If you use the result, 
you probably get a type error pretty quickly.  But if you don't use the result, 
you have a pretty nasty quiet failure on your hand.

Maybe we can solve this by having a __del__ method in a wrapper object that 
checks whether the generator has been consumed at all, and a similar __del__ 
method on Future.  It would have to log an error.

Similarly, it would also be useful if a Future that completed with an exception 
logged an error if it was garbage-collected before anybody looked at the error. 
 (I tried to do this once but I couldn't get it to work right; see attached 
EXCEPT.diff.)

Original issue reported on code.google.com by gvanrossum@gmail.com on 21 Mar 2013 at 2:10

Attachments:

• EXCEPT.diff