Assertion in debug version on return-from within a map().

[Patrick Kelley]

With master e962261

I wasn't seeing any problems in the release version of lobster, but ran the debug version to check out something unrelated, and it would fail code generation with this assertion:

Isom3/src% lobster-debug /tmp/bingus.lobster
lobster-debug: /home/pkelley/src/lobster/dev/src/lobster/codegen.h:1681: virtual void lobster::Return::Generate(lobster::CodeGen&, size_t) const: Assertion `cg.temptypestack.size() ==
cg.LoopTemps()' failed.

Here's an example that reproduces the problem:

import std

def funfun():
   return map(10) x:
      if x >= 0:
         x*x
      else:
         return [] from funfun

print(funfun())

[Wouter van Oortmerssen]

Thanks for reporting! Yes, that assert was outdated, so I just removed it.
Does look like there may be some related issues lurking, which I'll get to later.