Stabilize Formatter alignment

[GuillaumeGomez]

Fixes #27726.

cc @SimonSapin

[rust-highfive]

r? @cramertj

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[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.

[00:02:56]    Compiling core v0.0.0 (file:///checkout/src/libcore)
[00:02:56]    Compiling unwind v0.0.0 (file:///checkout/src/libunwind)
[00:02:56]    Compiling build_helper v0.1.0 (file:///checkout/src/build_helper)
[00:02:59]    Compiling std v0.0.0 (file:///checkout/src/libstd)
[00:02:59] error[E0541]: unknown meta item 'version'
[00:02:59]     --> libcore/fmt/mod.rs:1387:43
[00:02:59]      |
[00:02:59] 1387 |     #[stable(feature = "fmt_flags_align", version = "1.28.0")]
[00:02:59] 
[00:03:03]    Compiling compiler_builtins v0.0.0 (file:///checkout/src/rustc/compiler_builtins_shim)
[00:03:03]    Compiling cmake v0.1.30
[00:03:03]    Compiling alloc_jemalloc v0.0.0 (file:///checkout/src/liballoc_jemalloc)
---
[00:03:10] Caused by:
[00:03:10]   process didn't exit successfully: `/checkout/obj/build/bootstrap/debug/rustc --crate-name core libcore/lib.rs --color always --error-format json --crate-type lib --emit=dep-info,link -C opt-level=3 -C metadata=0d1ebef792b1d9ca -C extra-filename=-0d1ebef792b1d9ca --out-dir /checkout/obj/build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps --target x86_64-unknown-linux-gnu -L dependency=/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps -L dependency=/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-std/release/deps` (exit code: 101)
[00:03:10] warning: build failed, waiting for other jobs to finish...
[00:03:21] error: build failed
[00:03:21] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "build" "--target" "x86_64-unknown-linux-gnu" "-j" "4" "--release" "--locked" "--color" "always" "--features" "panic-unwind jemalloc backtrace" "--manifest-path" "/checkout/src/libstd/Cargo.toml" "--message-format" "json"
[00:03:21] expected success, got: exit code: 101
[00:03:21] thread 'main' panicked at 'cargo must succeed', bootstrap/compile.rs:1091:9
[00:03:21] travis_fold:end:stage0-std

[00:03:21] travis_time:end:stage0-std:start=1527325845822004388,finish=1527325871017376103,duration=25195371715


[00:03:21] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
[00:03:21] Build completed unsuccessfully in 0:00:26
[00:03:21] Makefile:79: recipe for target 'tidy' failed
[00:03:21] make: *** [tidy] Error 1

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:0af8454a
$ 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)

[SimonSapin]

r=me with the attribute fixed

[bors]

☔ The latest upstream changes (presumably #51082) made this pull request unmergeable. Please resolve the merge conflicts.

[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.

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)

[GuillaumeGomez]

@bors: r=SimonSapin

[bors]

📌 Commit fb447f1 has been approved by SimonSapin

[bors]

⌛ Testing commit fb447f1 with merge dcb4056...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: SimonSapin
Pushing dcb4056 to master...

[tmccombs]

Shouldn't core::fmt::Alignment be re-exported as std::fmt::Alignment?

[GuillaumeGomez]

That's a good point. I'll do it as well.