Switch master to 1.38

[Mark-Simulacrum]

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[rust-highfive]

r? @alexcrichton

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[Mark-Simulacrum]

This will fail on CI because we don't have a beta yet, but the date should be accurate and we should have a beta in ~40 minutes.

[ollie27]

Suggested change

	#[cfg_attr(allfeature = "llvm-libunwind",
	#[cfg_attr(feature = "llvm-libunwind",

[Mark-Simulacrum]

2019-07-04T15:13:25.6174709Z �[0m�[1m�[38;5;9merror�[0m�[0m�[1m: use of deprecated item 'core::mem::uninitialized': use `mem::MaybeUninit` instead�[0m
2019-07-04T15:13:25.6176343Z �[0m  �[0m�[0m�[1m�[38;5;12m--> �[0m�[0msrc/libstd/io/util.rs:47:54�[0m
2019-07-04T15:13:25.6176801Z �[0m   �[0m�[0m�[1m�[38;5;12m|�[0m
2019-07-04T15:13:25.6177324Z �[0m�[1m�[38;5;12m47�[0m�[0m �[0m�[0m�[1m�[38;5;12m| �[0m�[0m        let mut buf: [u8; super::DEFAULT_BUF_SIZE] = mem::uninitialized();�[0m
2019-07-04T15:13:25.6177845Z �[0m   �[0m�[0m�[1m�[38;5;12m| �[0m�[0m                                                     �[0m�[0m�[1m�[38;5;9m^^^^^^^^^^^^^^^^^^�[0m
2019-07-04T15:13:25.6178286Z �[0m   �[0m�[0m�[1m�[38;5;12m|�[0m
2019-07-04T15:13:25.6178733Z �[0m   �[0m�[0m�[1m�[38;5;12m= �[0m�[0m�[1mnote�[0m�[0m: `-D deprecated` implied by `-D warnings`�[0m2019-07-04T15:13:25.6174709Z �[0m�[1m�[38;5;9merror�[0m�[0m�[1m: use of deprecated item 'core::mem::uninitialized': use `mem::MaybeUninit` instead�[0m
2019-07-04T15:13:25.6176343Z �[0m  �[0m�[0m�[1m�[38;5;12m--> �[0m�[0msrc/libstd/io/util.rs:47:54�[0m
2019-07-04T15:13:25.6176801Z �[0m   �[0m�[0m�[1m�[38;5;12m|�[0m
2019-07-04T15:13:25.6177324Z �[0m�[1m�[38;5;12m47�[0m�[0m �[0m�[0m�[1m�[38;5;12m| �[0m�[0m        let mut buf: [u8; super::DEFAULT_BUF_SIZE] = mem::uninitialized();�[0m
2019-07-04T15:13:25.6177845Z �[0m   �[0m�[0m�[1m�[38;5;12m| �[0m�[0m                                                     �[0m�[0m�[1m�[38;5;9m^^^^^^^^^^^^^^^^^^�[0m
2019-07-04T15:13:25.6178286Z �[0m   �[0m�[0m�[1m�[38;5;12m|�[0m
2019-07-04T15:13:25.6178733Z �[0m   �[0m�[0m�[1m�[38;5;12m= �[0m�[0m�[1mnote�[0m�[0m: `-D deprecated` implied by `-D warnings`�[0m

cc @RalfJung - I've simply allowed the warning here though I suspect this isn't the only place. It also looks like the Initializer::initialize API is not ready for MaybeUninit as taking &mut [u8] based on that documentation is UB, though I suppose it depends on whether we consider uninitialized bytes UB or not.

[RalfJung]

Yeah, while libcore and liballoc should be free of mem::uninitialized, I didn't get around to push that through libstd. Should probably open an E-mentor issue about it.

It also looks like the Initializer::initialize API is not ready for MaybeUninit as taking &mut [u8] based on that documentation is UB, though I suppose it depends on whether we consider uninitialized bytes UB or not.

Indeed. This is also related to #58363.

[RalfJung]

There's also still tons of mem::uninitialized in the platform-specific code, that will make CI fail with this PR as-is:

src/libstd/sys/cloudabi/condvar.rs
82:        let mut event: abi::event = mem::uninitialized();
83:        let mut nevents: usize = mem::uninitialized();
134:        let mut events: [abi::event; 2] = mem::uninitialized();
135:        let mut nevents: usize = mem::uninitialized();

src/libstd/sys/cloudabi/mod.rs
62:        let mut v = mem::uninitialized();

src/libstd/sys/cloudabi/time.rs
21:            let mut t = mem::uninitialized();
62:            let mut t = mem::uninitialized();

src/libstd/sys/sgx/mod.rs
143:            let mut ret: u64 = crate::mem::uninitialized();

src/libstd/sys/cloudabi/mutex.rs
56:        mem::uninitialized()
103:            let mut event: abi::event = mem::uninitialized();
104:            let mut nevents: usize = mem::uninitialized();

src/libstd/sys/cloudabi/thread.rs
75:            let mut event: abi::event = mem::uninitialized();
76:            let mut nevents: usize = mem::uninitialized();

src/libstd/sys/cloudabi/rwlock.rs
76:            let mut event: abi::event = mem::uninitialized();
77:            let mut nevents: usize = mem::uninitialized();
185:            let mut event: abi::event = mem::uninitialized();
186:            let mut nevents: usize = mem::uninitialized();

src/libstd/sys/cloudabi/abi/cloudabi.rs
1096:    let obj: auxv = core::mem::uninitialized();
1109:    let obj: auxv = core::mem::uninitialized();
1130:    let obj: ciovec = core::mem::uninitialized();
1142:    let obj: ciovec = core::mem::uninitialized();
1170:    let obj: dirent = core::mem::uninitialized();
1234:    let obj: event = core::mem::uninitialized();
1268:    let obj: fdstat = core::mem::uninitialized();
1305:    let obj: filestat = core::mem::uninitialized();
1331:    let obj: iovec = core::mem::uninitialized();
1343:    let obj: iovec = core::mem::uninitialized();
1366:    let obj: lookup = core::mem::uninitialized();
1400:    let obj: recv_in = core::mem::uninitialized();
1415:    let obj: recv_in = core::mem::uninitialized();
1444:    let obj: recv_out = core::mem::uninitialized();
1458:    let obj: recv_out = core::mem::uninitialized();
1486:    let obj: send_in = core::mem::uninitialized();
1501:    let obj: send_in = core::mem::uninitialized();
1524:    let obj: send_out = core::mem::uninitialized();
1535:    let obj: send_out = core::mem::uninitialized();
1653:    let obj: subscription = core::mem::uninitialized();
1680:    let obj: subscription = core::mem::uninitialized();
1734:    let obj: tcb = core::mem::uninitialized();
1745:    let obj: tcb = core::mem::uninitialized();
1779:    let obj: threadattr = core::mem::uninitialized();
1793:    let obj: threadattr = core::mem::uninitialized();

Probably the cloudabi and sgx modules should just get #![allow(deprecated)] for now. Does someone know who maintains those so we can Cc them?

[alexcrichton]

r=me when this is green on CI

[Mark-Simulacrum]

@bors r=alexcrichton p=50

[bors]

📌 Commit 007d87f has been approved by alexcrichton

[bors]

⌛ Testing commit 007d87f with merge baab191...

[bors]

☀️ Test successful - checks-azure, checks-travis, status-appveyor
Approved by: alexcrichton
Pushing baab191 to master...