Improve bug message in check_ty

[phansch]

This branch was hit in Clippy and I think it would be nice to
show the thing that was unexpected in the bug message.

It's also in line with the other bug! messages in check_ty.

[rust-highfive]

r? @zackmdavis

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

[rust-highfive]

The job x86_64-gnu-llvm-6.0 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.

travis_time:end:177fae9c:start=1548830098382928281,finish=1548830099255908321,duration=872980040
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
Setting environment variables from .travis.yml
$ export IMAGE=x86_64-gnu-llvm-6.0
---
[00:14:03]    Compiling rustc_typeck v0.0.0 (/checkout/src/librustc_typeck)
[00:14:14] error[E0507]: cannot move out of borrowed content
[00:14:14]     --> src/librustc_typeck/collect.rs:1306:44
[00:14:14]      |
[00:14:14] 1306 |         Node::GenericParam(param) => match param.kind {
[00:14:14]      |                                            |
[00:14:14]      |                                            cannot move out of borrowed content
[00:14:14]      |                                            cannot move out of borrowed content
[00:14:14]      |                                            help: consider borrowing here: `&param.kind`
[00:14:14] ...
[00:14:14] 1311 |             x => bug!("unexpected non-type Node::GenericParam: {:?}", x),
[00:14:14]      |             - data moved here
[00:14:14]      |
[00:14:14] note: move occurs because `x` has type `rustc::hir::GenericParamKind`, which does not implement the `Copy` trait
[00:14:14]     --> src/librustc_typeck/collect.rs:1311:13
[00:14:14]      |
[00:14:14] 1311 |             x => bug!("unexpected non-type Node::GenericParam: {:?}", x),
[00:14:14] 
[00:14:14] error: aborting due to previous error
[00:14:14] 
[00:14:14] For more information about this error, try `rustc --explain E0507`.
---
156148 ./src/llvm-project/clang
154512 ./obj/build/bootstrap/debug/incremental
141396 ./obj/build/x86_64-unknown-linux-gnu/stage0-rustc
139748 ./obj/build/bootstrap/debug/incremental/bootstrap-2ahv8almm435e
139744 ./obj/build/bootstrap/debug/incremental/bootstrap-2ahv8almm435e/s-f90isrud82-167y8w1-211f56mf0fscc
108528 ./src/llvm-project/lldb
104288 ./obj/build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu
104284 ./obj/build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release
101784 ./obj/build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release/deps
---
travis_time:end:032694e0:start=1548831189545321365,finish=1548831189549414861,duration=4093496
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:1560be22
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|'); if [ -f "$EXE" ]; then printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE"; gdb --batch -q -c "$CORE" "$EXE" -iex 'set auto-load off' -iex 'dir src/' -iex 'set sysroot .' -ex bt -ex q; echo travis_fold":"end:crashlog; fi; done || true
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:232b8b2c
travis_time:start:232b8b2c
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/cla

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)

[zackmdavis]

Thanks! You have a borrowcheck error, but r=me after fixing that

[phansch]

@bors r=zackmdavis

[bors]

@phansch: 🔑 Insufficient privileges: Not in reviewers

[zackmdavis]

@bors r+ rollup

[bors]

📌 Commit 037fdb8 has been approved by zackmdavis