https://github.com/rust-lang/rfcs/pull/221
The current terminology of "task failure" often causes problems when
writing or speaking about code. You often want to talk about the
possibility of an operation that returns a Result "failing", but cannot
because of the ambiguity with task failure. Instead, you have to speak
of "the failing case" or "when the operation does not succeed" or other
circumlocutions.
Likewise, we use a "Failure" header in rustdoc to describe when
operations may fail the task, but it would often be helpful to separate
out a section describing the "Err-producing" case.
We have been steadily moving away from task failure and toward Result as
an error-handling mechanism, so we should optimize our terminology
accordingly: Result-producing functions should be easy to describe.
To update your code, rename any call to `fail!` to `panic!` instead.
Assuming you have not created your own macro named `panic!`, this
will work on UNIX based systems:
grep -lZR 'fail!' . | xargs -0 -l sed -i -e 's/fail!/panic!/g'
You can of course also do this by hand.
[breaking-change]
Replaces BTree with BTreeMap and BTreeSet, which are completely new implementations.
BTreeMap's internal Node representation is particularly inefficient at the moment to
make this first implementation easy to reason about and fairly safe. Both collections
are also currently missing some of the tooling specific to sorted collections, which
is planned as future work pending reform of these APIs. General implementation issues
are discussed with TODOs internally
Perf results on x86_64 Linux:
test treemap::bench::find_rand_100 ... bench: 76 ns/iter (+/- 4)
test treemap::bench::find_rand_10_000 ... bench: 163 ns/iter (+/- 6)
test treemap::bench::find_seq_100 ... bench: 77 ns/iter (+/- 3)
test treemap::bench::find_seq_10_000 ... bench: 115 ns/iter (+/- 1)
test treemap::bench::insert_rand_100 ... bench: 111 ns/iter (+/- 1)
test treemap::bench::insert_rand_10_000 ... bench: 996 ns/iter (+/- 18)
test treemap::bench::insert_seq_100 ... bench: 486 ns/iter (+/- 20)
test treemap::bench::insert_seq_10_000 ... bench: 800 ns/iter (+/- 15)
test btree::map::bench::find_rand_100 ... bench: 74 ns/iter (+/- 4)
test btree::map::bench::find_rand_10_000 ... bench: 153 ns/iter (+/- 5)
test btree::map::bench::find_seq_100 ... bench: 82 ns/iter (+/- 1)
test btree::map::bench::find_seq_10_000 ... bench: 108 ns/iter (+/- 0)
test btree::map::bench::insert_rand_100 ... bench: 220 ns/iter (+/- 1)
test btree::map::bench::insert_rand_10_000 ... bench: 620 ns/iter (+/- 16)
test btree::map::bench::insert_seq_100 ... bench: 411 ns/iter (+/- 12)
test btree::map::bench::insert_seq_10_000 ... bench: 534 ns/iter (+/- 14)
BTreeMap still has a lot of room for optimization, but it's already beating out TreeMap on most access patterns.
[breaking-change]
