throwing exceptions is fine, but throwing exceptions during exception
handling is hard enough to do correctly that we should just forbid it
entirely out of an overabundance of caution. in cases where terminate
is the correct answer the users of Finally must call it manually now.
Change-Id: Ia51a2cb4a0638500550bfabc89cf01a6d8098983
this is supposed to act like a finally block does in other languages. a
finally block should be able to throw exceptions of its own rather than
just crashing the entire program when it throws it own exceptions. even
in the rare case of a finally throwing an unexpected exception it might
be better to report the exception from Finally instead of the original,
at least that can keep our program running instead of letting it crash.
Change-Id: Id42011e46b1df369152b4564938c0e93fa1acf32
no need for function<> with c++17 deduction. this saves allocations and virtual
calls, but has the same semantics otherwise. not going through function has the
side effect of giving compilers more insight into the cleanup code, so we need a
few local warning disables.
eldritch horrors
jade
