[futures] add a few blanket impls to std

[tinaun]

these were defined in the futures crate, but with the core definitions moving to std these would need to move too.

[rust-highfive]

r? @KodrAus

(rust_highfive has picked a reviewer for you, use r? to override)

[cramertj]

I don't think this impl is needed anymore-- I think people should prefer to use PInBox, as it offers the same functionality in a safer way.

[cramertj]

Thanks for adding these! Are you planning to add the missing methods on Poll in a separate PR?

[cramertj]

r? @cramertj

[tinaun]

right now they exist as an extension trait in futures-core, but if there’s nothing controversial about them i can move them in

[cramertj]

@tinaun I think it's fine to move them in-- they don't seem particularly controversial to me (thinking of map, is_ready, is_pending, map_ok, and map_err).

[rust-highfive]

The job x86_64-gnu-llvm-3.9 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

[00:05:15] travis_fold:start:tidy
travis_time:start:tidy
tidy check
[00:05:15] tidy error: /checkout/src/libstd/panic.rs:330: trailing whitespace
[00:05:17] some tidy checks failed
[00:05:17] 
[00:05:17] 
[00:05:17] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/tidy" "/checkout/src" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "--no-vendor" "--quiet"
[00:05:17] 
[00:05:17] 
[00:05:17] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
[00:05:17] Build completed unsuccessfully in 0:01:50
[00:05:17] Build completed unsuccessfully in 0:01:50
[00:05:17] make: *** [tidy] Error 1
[00:05:17] Makefile:79: recipe for target 'tidy' failed

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:1964a21c
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[cramertj]

@bors r+

[bors]

📌 Commit fb507ca has been approved by cramertj

[bors]

⌛ Testing commit fb507ca with merge 1d4dbf4...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: cramertj
Pushing 1d4dbf4 to master...