Fix an ICE when matching over const slices

[varkor]

Fixes #51655. I'm not super familiar with this code, so tell me if this is the wrong approach 😅

r? @oli-obk

[oli-obk]

Makes total sense, thx

@bors r+

[bors]

📌 Commit e14e48b has been approved by oli-obk

[bors]

⌛ Testing commit e14e48b with merge f00e8ef3095e49851f0cacbef1f92e03db215ae0...

[bors]

💔 Test failed - status-travis

[rust-highfive]

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.

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[rust-highfive]

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.

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[kennytm]

@bors retry #43283

[bors]

⌛ Testing commit e14e48b with merge 870d2b4fc93727f201e19210a202dc8ee24b7e86...

[bors]

💔 Test failed - status-travis

[rust-highfive]

The job x86_64-gnu-debug 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.

[00:02:27]  Downloading petgraph v0.4.12
[00:02:33]  Downloading num_cpus v1.8.0
[00:02:37]  Downloading itoa v0.4.1
[00:02:37]  Downloading dtoa v0.4.2
[00:02:48] warning: spurious network error (2 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/dtoa/0.4.2/download`, got 500
[00:02:48]  Downloading cfg-if v0.1.2
[00:02:59]  Downloading syn v0.13.1
[00:02:59]  Downloading quote v0.5.1
[00:03:02]  Downloading serde_derive_internals v0.23.1
---
[00:03:52]     Finished dev [unoptimized] target(s) in 2m 51.63s
[00:03:52]  Downloading rayon-core v1.4.0
[00:04:04] warning: spurious network error (2 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/rayon-core/1.4.0/download`, got 500
[00:04:04]  Downloading either v1.5.0
[00:04:17] warning: spurious network error (2 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/either/1.5.0/download`, got 500
[00:04:17]  Downloading curl v0.4.12
[00:04:17]  Downloading log v0.4.1
[00:04:32] warning: spurious network error (2 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/log/0.4.1/download`, got 500
[00:04:49] warning: spurious network error (1 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/log/0.4.1/download`, got 500
[00:04:49] warning: spurious network error (1 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/log/0.4.1/download`, got 500
[00:05:05] thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: HttpNot200 { code: 500, url: "https://crates.io/api/v1/crates/log/0.4.1/download" }
[00:05:05] unable to get packages from source', libcore/result.rs:945:5
[00:05:05] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[00:05:05] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[00:05:05] thread 'main' panicked at 'command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "metadata" "--format-version" "1" "--features" "panic-unwind jemalloc backtrace" "--manifest-path" "/checkout/src/libstd/Cargo.toml"
[00:05:05] expected success, got: exit code: 101', build_helper/lib.rs:122:9
[00:05:05] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap check
[00:05:05] Build completed unsuccessfully in 0:04:22
travis_time:end:1181279c:start=1529826034504923079,finish=1529826340508325166,duration=306003402087

---
travis_time:end:1689c5c3:start=1529826340796160409,finish=1529826340804432813,duration=8272404
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:1a5dc466
$ head -30 ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
head: cannot open ‘./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers’ for reading: No such file or directory
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:15dd9676
$ dmesg | grep -i kill

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)

[rust-highfive]

The job x86_64-gnu-debug 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.

[00:02:27]  Downloading petgraph v0.4.12
[00:02:33]  Downloading num_cpus v1.8.0
[00:02:37]  Downloading itoa v0.4.1
[00:02:37]  Downloading dtoa v0.4.2
[00:02:48] warning: spurious network error (2 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/dtoa/0.4.2/download`, got 500
[00:02:48]  Downloading cfg-if v0.1.2
[00:02:59]  Downloading syn v0.13.1
[00:02:59]  Downloading quote v0.5.1
[00:03:02]  Downloading serde_derive_internals v0.23.1
---
[00:03:52]     Finished dev [unoptimized] target(s) in 2m 51.63s
[00:03:52]  Downloading rayon-core v1.4.0
[00:04:04] warning: spurious network error (2 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/rayon-core/1.4.0/download`, got 500
[00:04:04]  Downloading either v1.5.0
[00:04:17] warning: spurious network error (2 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/either/1.5.0/download`, got 500
[00:04:17]  Downloading curl v0.4.12
[00:04:17]  Downloading log v0.4.1
[00:04:32] warning: spurious network error (2 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/log/0.4.1/download`, got 500
[00:04:49] warning: spurious network error (1 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/log/0.4.1/download`, got 500
[00:04:49] warning: spurious network error (1 tries remaining): failed to get 200 response from `https://crates.io/api/v1/crates/log/0.4.1/download`, got 500
[00:05:05] thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: HttpNot200 { code: 500, url: "https://crates.io/api/v1/crates/log/0.4.1/download" }
[00:05:05] unable to get packages from source', libcore/result.rs:945:5
[00:05:05] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[00:05:05] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[00:05:05] thread 'main' panicked at 'command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "metadata" "--format-version" "1" "--features" "panic-unwind jemalloc backtrace" "--manifest-path" "/checkout/src/libstd/Cargo.toml"
[00:05:05] expected success, got: exit code: 101', build_helper/lib.rs:122:9
[00:05:05] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap check
[00:05:05] Build completed unsuccessfully in 0:04:22
travis_time:end:1181279c:start=1529826034504923079,finish=1529826340508325166,duration=306003402087

---
travis_time:end:1689c5c3:start=1529826340796160409,finish=1529826340804432813,duration=8272404
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:1a5dc466
$ head -30 ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
head: cannot open ‘./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers’ for reading: No such file or directory
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:15dd9676
$ dmesg | grep -i kill

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)

[pietroalbini]

@bors retry (crates.io outage)

[bors]

⌛ Testing commit e14e48b with merge 987f7ddffefcb9780a7c67ddadbfae11f24fb5f2...

[bors]

💔 Test failed - status-travis

[rust-highfive]

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)

[rust-highfive]

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)

[kennytm]

@bors retry

Segfault in libstd test?

[bors]

⌛ Testing commit e14e48b with merge ecfe370...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: oli-obk
Pushing ecfe370 to master...