Tracking issue for Transitioning crates to Rust 2018

[Centril]

This issue tracks the transitioning of all crates in this repo and sub-modules to Rust 2018.

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You can help by filing PRs transitioning a crate at a time to Rust 2018.
When transitioning, please apply the following to the crate root:

#![deny(rust_2018_idioms)]
#![allow(explicit_outlives_requirements)] // Remove or keep this at your option.

You can try to use cargo +nightly fix (or cargo +nightly --edition-idioms) to migrate a crate automatically; see the edition guide for details. However, due to bootstrapping, you might need to do some manual intervention here and there.

If you want to help out, please pick a crate and leave a comment here.
When you make a transitioning PR, also leave a comment here.

cc @rust-lang/compiler @rust-lang/infra

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The following crates exist in the repo or as submodules.
Checked items have been transitioned to Rust 2018.

• bootstrap
• build_helper; done in Transition build_helper to 2018 edition #58120
• liballoc; done in Transition liballoc to Rust 2018 #58081
• libarena; done in libarena => 2018 #58105
• libcore; done in libcore => 2018 #58702
• libfmt_macros; done in libfmt_macros => 2018 #58106
• libgraphviz; done in libgraphviz => 2018 #58107
• libpanic_abort; done in libpanic_abort => 2018 #58112
• libpanic_unwind; done in libpanic_unwind => 2018 #58110
• libproc_macro; done in libproc_macro => 2018 #58119
• libprofiler_builtins; done in libprofiler_builtins => 2018 #58220
• librustc; done in Move librustc to 2018 #58193
• librustc_allocator; done in librustc_allocator => 2018 #58222
• librustc_apfloat; done in librustc_apfloat => 2018 #58239
• librustc_asan; done in librustc_asan => 2018 #58219
• librustc_borrowck; done in librustc_borrowck => 2018 #58260
• librustc_codegen_llvm; done in librustc_codegen_llvm => 2018 #58546
• librustc_codegen_ssa; done in librustc_codegen_ssa => 2018 #58322
• librustc_codegen_utils; done in librustc_codegen_utils => 2018 #58259
• librustc_cratesio_shim; done in librustc_cratesio_shim => 2018 #58256
• librustc_data_structures; done in librustc_data_structures => 2018 #58312
• librustc_driver; done in librustc_driver => 2018 #58253
• librustc_errors; done librustc_errors => 2018 #58240
• librustc_fs_util; done in librustc_fs_util => 2018 #58225
• librustc_incremental; done in librustc_incremental => 2018 #58261
• librustc_interface; done in librustc_interface => 2018 #58837
• librustc_lint; done in librustc_lint => 2018 #58245
• librustc_llvm; done in librustc_llvm => 2018 #58241
• librustc_lsan; done in librustc_lsan => 2018 #58223
• librustc_metadata; done in librustc_metadata => 2018 #58255
• librustc_mir; done in librustc_mir => 2018 #58265
• librustc_msan; done in librustc_msan => 2018 #58218
• librustc_passes; done in librustc_passes => 2018 #58247
• librustc_plugin; done in librustc_plugin => 2018 #58228
• librustc_privacy; done in librustc_privacy => 2018 #58109
• librustc_resolve; done in librustc_resolve => 2018 #58236
• librustc_save_analysis; done in librustc_save_analysis => 2018 #58233
• librustc_target; done in librustc_target => 2018 #58257
• librustc_traits; done in Transition librustc_traits to 2018 edition #58251
• librustc_tsan; done in librustc_tsan => 2018 #58217
• librustc_typeck; done in librustc_typeck => 2018 #58300
• librustdoc; done in Transition librustdoc to Rust 2018 #58100
• libserialize; done in libserialize => 2018 #58318
• libstd; done in libstd => 2018 #58208
• libsyntax; done in libsyntax => 2018 #58125
• libsyntax_ext; done in libsyntax_ext => 2018 #58133
• libsyntax_pos; done in libsyntax_pos => 2018 #58124
• libterm; done in libterm => 2018 #58111
• libtest; done in Transition libtest to 2018 edition #58118
• libunwind; done in libunwind => 2018 #58128
• rustc
• stdsimd
• tools
  • build-manifest; done in Transition build-manifest to 2018 edition #58113
  • cargo - submodule: https://github.com/rust-lang/cargo/
  • cargo-test; done in Transition cargotest to Rust 2018 #58095
  • clippy - submodule: https://github.com/rust-lang/rust-clippy
    • clippy_dev
    • clippy_dummy
    • clippy_lints
    • clippy_workspace_tests; fixed in Transition leftover test libs to Rust 2018 rust-clippy#3737
    • mini-macro; fixed in Transition leftover test libs to Rust 2018 rust-clippy#3737
    • rustc_tools_util
  • compiletest; done in Transition compiletest to Rust 2018 #58091
  • error_index_generator; done in error_index_generator => 2018 #58285
  • linkchecker; done in Transition linkchecker to 2018 edition #58096
  • miri - submodule: https://github.com/solson/miri
  • remote-test-client; done in Transition remote test to Rust 2018 #58097
  • remote-test-server; done in Transition remote test to Rust 2018 #58097
  • rls - submodule: https://github.com/rust-lang/rls
  • rust-installer
  • rustbook
  • rustc-std-workspace-core; done in rustc-std-workspace-core => 2018 #58287
  • rustc-workspace-hack; done in rustc-workspace-hack => 2018 #58288
  • rustdoc; done in Transition rustdoc to 2018 edition #58115
  • rustdoc-themes; done in Transition rustdoc-theme to 2018 edition #58117
  • rustfmt - submodule: https://github.com/rust-lang/rustfmt
  • tidy; done in Transition tidy and unstable-book-gen to 2018 edition #58114
  • unstable-book-gen; done in Transition tidy and unstable-book-gen to 2018 edition #58114