[beta] backports and bump#38377

Merged

alexcrichton merged 5 commits intorust-lang:betafrom

brson:beta-next

Dec 15, 2016

Commits on Dec 14, 2016

evaluate obligations in LIFO order during closure projection

arielb1
authored and
brson
committed
Document the question mark operator

est31
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brson
committed
Fix invalid src url

GuillaumeGomez
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brson
committed
don't double-apply variant padding to const enums

arielb1
authored and
brson
committed
Bump prereleease version
brson
committed