Inconsistent auto trait impls in standard library

Following the recent PRs implementing Send for TcpStream/File on uefi targets, I wanted to audit (at least) auto trait impls across other targets for types in the standard library. I wrote some tooling to do this via rustdoc-json-types output.

This is on tier 2+ targets with the exception of wasm32-wasip2, wasm32-unknown-emscripten, x86_64-unknown-uefi, i686-unknown-uefi, wasm32-wasip1, wasm32-wasip1-threads, and aarch64-unknown-uefi which I failed to build docs for locally (haven't dug into why, bunch of types aren't defined though).

Filing this as a first step, I think the next step is going to be digging in on why the impls are missing/present and whether that's just oversight or if there's something actually platform-specific about it. I suspect the long-term outcome is that we ought to have assertions in sys/ on auto trait impls for exposed types (e.g., sys::Mutex) and/or tests on each public module type for the auto traits it implements. But that's fairly annoying to stamp out across all of the public API so we could try to move the ad-hoc tooling I wrote in-tree and run it in CI.

impl core::panic::unwind_safe::UnwindSafe for

• std::thread::thread::Thread missing on [sparcv9-sun-solaris, x86_64-fortanix-unknown-sgx, x86_64-pc-solaris, x86_64-unknown-illumos, x86_64-unknown-netbsd, x86_64-unknown-redox]
• std::sync::nonpoison::condvar::Condvar missing on [aarch64-apple-darwin, aarch64-apple-ios, aarch64-apple-ios-macabi, aarch64-apple-ios-sim, aarch64-apple-tvos, aarch64-apple-tvos-sim, aarch64-apple-visionos, aarch64-apple-visionos-sim, aarch64-apple-watchos, aarch64-apple-watchos-sim, sparcv9-sun-solaris, x86_64-apple-darwin, x86_64-apple-ios, x86_64-apple-ios-macabi, x86_64-fortanix-unknown-sgx, x86_64-pc-solaris, x86_64-unknown-illumos, x86_64-unknown-netbsd, x86_64-unknown-redox]
• std::sync::nonpoison::rwlock::RwLockReadGuard missing on [wasm32-unknown-unknown]
• std::sync::nonpoison::mutex::Mutex missing on [aarch64-apple-darwin, aarch64-apple-ios, aarch64-apple-ios-macabi, aarch64-apple-ios-sim, aarch64-apple-tvos, aarch64-apple-tvos-sim, aarch64-apple-visionos, aarch64-apple-visionos-sim, aarch64-apple-watchos, aarch64-apple-watchos-sim, sparcv9-sun-solaris, x86_64-apple-darwin, x86_64-apple-ios, x86_64-apple-ios-macabi, x86_64-fortanix-unknown-sgx, x86_64-pc-solaris, x86_64-unknown-illumos, x86_64-unknown-netbsd, x86_64-unknown-redox]
• std::sync::barrier::Barrier missing on [aarch64-apple-darwin, aarch64-apple-ios, aarch64-apple-ios-macabi, aarch64-apple-ios-sim, aarch64-apple-tvos, aarch64-apple-tvos-sim, aarch64-apple-visionos, aarch64-apple-visionos-sim, aarch64-apple-watchos, aarch64-apple-watchos-sim, sparcv9-sun-solaris, x86_64-apple-darwin, x86_64-apple-ios, x86_64-apple-ios-macabi, x86_64-fortanix-unknown-sgx, x86_64-pc-solaris, x86_64-unknown-illumos, x86_64-unknown-netbsd, x86_64-unknown-redox]
• std::process::Command only present on [aarch64-pc-windows-gnullvm, aarch64-pc-windows-msvc, aarch64-unknown-none, aarch64-unknown-none-softfloat, arm64ec-pc-windows-msvc, armv7a-none-eabi, armv7a-none-eabihf, armv7r-none-eabi, armv7r-none-eabihf, armv8r-none-eabihf, i686-pc-windows-gnu, i686-pc-windows-gnullvm, i686-pc-windows-msvc, loongarch64-unknown-none, loongarch64-unknown-none-softfloat, nvptx64-nvidia-cuda, riscv32i-unknown-none-elf, riscv32im-unknown-none-elf, riscv32imac-unknown-none-elf, riscv32imafc-unknown-none-elf, riscv32imc-unknown-none-elf, riscv64gc-unknown-none-elf, riscv64imac-unknown-none-elf, s390x-unknown-none-softfloat, thumbv6m-none-eabi, thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7a-uwp-windows-msvc, thumbv7em-none-eabi, thumbv7em-none-eabihf, thumbv7m-none-eabi, thumbv7r-none-eabi, thumbv7r-none-eabihf, thumbv8m.base-none-eabi, thumbv8m.main-none-eabi, thumbv8m.main-none-eabihf, thumbv8r-none-eabihf, wasm32-unknown-unknown, wasm32v1-none, x86_64-fortanix-unknown-sgx, x86_64-pc-windows-gnu, x86_64-pc-windows-gnullvm, x86_64-pc-windows-msvc, x86_64-unknown-none]
• std::sync::poison::rwlock::MappedRwLockReadGuard missing on [wasm32-unknown-unknown]
• std::sync::nonpoison::rwlock::MappedRwLockReadGuard missing on [wasm32-unknown-unknown]
• std::sync::poison::rwlock::RwLockReadGuard missing on [wasm32-unknown-unknown]

impl core::panic::unwind_safe::RefUnwindSafe for

• std::thread::thread::Thread missing on [sparcv9-sun-solaris, x86_64-fortanix-unknown-sgx, x86_64-pc-solaris, x86_64-unknown-illumos, x86_64-unknown-netbsd, x86_64-unknown-redox]
• std::sync::nonpoison::rwlock::RwLockReadGuard missing on [wasm32-unknown-unknown]
• std::sync::nonpoison::rwlock::MappedRwLockWriteGuard missing on [wasm32-unknown-unknown]
• std::sync::nonpoison::mutex::MappedMutexGuard missing on [wasm32-unknown-unknown]
• std::process::Command only present on [aarch64-pc-windows-gnullvm, aarch64-pc-windows-msvc, aarch64-unknown-none, aarch64-unknown-none-softfloat, arm64ec-pc-windows-msvc, armv7a-none-eabi, armv7a-none-eabihf, armv7r-none-eabi, armv7r-none-eabihf, armv8r-none-eabihf, i686-pc-windows-gnu, i686-pc-windows-gnullvm, i686-pc-windows-msvc, loongarch64-unknown-none, loongarch64-unknown-none-softfloat, nvptx64-nvidia-cuda, riscv32i-unknown-none-elf, riscv32im-unknown-none-elf, riscv32imac-unknown-none-elf, riscv32imafc-unknown-none-elf, riscv32imc-unknown-none-elf, riscv64gc-unknown-none-elf, riscv64imac-unknown-none-elf, s390x-unknown-none-softfloat, thumbv6m-none-eabi, thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7a-uwp-windows-msvc, thumbv7em-none-eabi, thumbv7em-none-eabihf, thumbv7m-none-eabi, thumbv7r-none-eabi, thumbv7r-none-eabihf, thumbv8m.base-none-eabi, thumbv8m.main-none-eabi, thumbv8m.main-none-eabihf, thumbv8r-none-eabihf, wasm32-unknown-unknown, wasm32v1-none, x86_64-fortanix-unknown-sgx, x86_64-pc-windows-gnu, x86_64-pc-windows-gnullvm, x86_64-pc-windows-msvc, x86_64-unknown-none]
• std::sync::poison::rwlock::MappedRwLockReadGuard missing on [wasm32-unknown-unknown]
• std::sync::poison::mutex::MappedMutexGuard missing on [wasm32-unknown-unknown]
• std::sync::poison::rwlock::MappedRwLockWriteGuard missing on [wasm32-unknown-unknown]
• std::thread::scoped::Scope missing on [sparcv9-sun-solaris, x86_64-fortanix-unknown-sgx, x86_64-pc-solaris, x86_64-unknown-illumos, x86_64-unknown-netbsd, x86_64-unknown-redox]
• std::sync::nonpoison::rwlock::MappedRwLockReadGuard missing on [wasm32-unknown-unknown]
• std::sync::poison::rwlock::RwLockReadGuard missing on [wasm32-unknown-unknown]

impl core::marker::Send for

• std::env::Vars only present on [aarch64-unknown-none, aarch64-unknown-none-softfloat, armv7a-none-eabi, armv7a-none-eabihf, armv7r-none-eabi, armv7r-none-eabihf, armv8r-none-eabihf, loongarch64-unknown-none, loongarch64-unknown-none-softfloat, nvptx64-nvidia-cuda, riscv32i-unknown-none-elf, riscv32im-unknown-none-elf, riscv32imac-unknown-none-elf, riscv32imafc-unknown-none-elf, riscv32imc-unknown-none-elf, riscv64gc-unknown-none-elf, riscv64imac-unknown-none-elf, s390x-unknown-none-softfloat, thumbv6m-none-eabi, thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7em-none-eabi, thumbv7em-none-eabihf, thumbv7m-none-eabi, thumbv7r-none-eabi, thumbv7r-none-eabihf, thumbv8m.base-none-eabi, thumbv8m.main-none-eabi, thumbv8m.main-none-eabihf, thumbv8r-none-eabihf, wasm32-unknown-unknown, wasm32v1-none, x86_64-unknown-none]
• std::env::VarsOs only present on [aarch64-unknown-none, aarch64-unknown-none-softfloat, armv7a-none-eabi, armv7a-none-eabihf, armv7r-none-eabi, armv7r-none-eabihf, armv8r-none-eabihf, loongarch64-unknown-none, loongarch64-unknown-none-softfloat, nvptx64-nvidia-cuda, riscv32i-unknown-none-elf, riscv32im-unknown-none-elf, riscv32imac-unknown-none-elf, riscv32imafc-unknown-none-elf, riscv32imc-unknown-none-elf, riscv64gc-unknown-none-elf, riscv64imac-unknown-none-elf, s390x-unknown-none-softfloat, thumbv6m-none-eabi, thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7em-none-eabi, thumbv7em-none-eabihf, thumbv7m-none-eabi, thumbv7r-none-eabi, thumbv7r-none-eabihf, thumbv8m.base-none-eabi, thumbv8m.main-none-eabi, thumbv8m.main-none-eabihf, thumbv8r-none-eabihf, wasm32-unknown-unknown, wasm32v1-none, x86_64-unknown-none]
• std::sync::once::OnceState missing on [aarch64-apple-darwin, aarch64-apple-ios, aarch64-apple-ios-macabi, aarch64-apple-ios-sim, aarch64-apple-tvos, aarch64-apple-tvos-sim, aarch64-apple-visionos, aarch64-apple-visionos-sim, aarch64-apple-watchos, aarch64-apple-watchos-sim, sparcv9-sun-solaris, x86_64-apple-darwin, x86_64-apple-ios, x86_64-apple-ios-macabi, x86_64-fortanix-unknown-sgx, x86_64-pc-solaris, x86_64-unknown-illumos, x86_64-unknown-netbsd, x86_64-unknown-redox]
• std::process::CommandArgs only present on [aarch64-pc-windows-gnullvm, aarch64-pc-windows-msvc, aarch64-unknown-none, aarch64-unknown-none-softfloat, arm64ec-pc-windows-msvc, armv7a-none-eabi, armv7a-none-eabihf, armv7r-none-eabi, armv7r-none-eabihf, armv8r-none-eabihf, i686-pc-windows-gnu, i686-pc-windows-gnullvm, i686-pc-windows-msvc, loongarch64-unknown-none, loongarch64-unknown-none-softfloat, nvptx64-nvidia-cuda, riscv32i-unknown-none-elf, riscv32im-unknown-none-elf, riscv32imac-unknown-none-elf, riscv32imafc-unknown-none-elf, riscv32imc-unknown-none-elf, riscv64gc-unknown-none-elf, riscv64imac-unknown-none-elf, s390x-unknown-none-softfloat, thumbv6m-none-eabi, thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7a-uwp-windows-msvc, thumbv7em-none-eabi, thumbv7em-none-eabihf, thumbv7m-none-eabi, thumbv7r-none-eabi, thumbv7r-none-eabihf, thumbv8m.base-none-eabi, thumbv8m.main-none-eabi, thumbv8m.main-none-eabihf, thumbv8r-none-eabihf, wasm32-unknown-unknown, wasm32v1-none, x86_64-fortanix-unknown-sgx, x86_64-pc-windows-gnu, x86_64-pc-windows-gnullvm, x86_64-pc-windows-msvc, x86_64-unknown-none]

impl core::marker::Freeze for

• std::sync::poison::condvar::Condvar only present on [aarch64-unknown-none, aarch64-unknown-none-softfloat, armv7a-none-eabi, armv7a-none-eabihf, armv7r-none-eabi, armv7r-none-eabihf, armv8r-none-eabihf, loongarch64-unknown-none, loongarch64-unknown-none-softfloat, nvptx64-nvidia-cuda, riscv32i-unknown-none-elf, riscv32im-unknown-none-elf, riscv32imac-unknown-none-elf, riscv32imafc-unknown-none-elf, riscv32imc-unknown-none-elf, riscv64gc-unknown-none-elf, riscv64imac-unknown-none-elf, s390x-unknown-none-softfloat, thumbv6m-none-eabi, thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7em-none-eabi, thumbv7em-none-eabihf, thumbv7m-none-eabi, thumbv7r-none-eabi, thumbv7r-none-eabihf, thumbv8m.base-none-eabi, thumbv8m.main-none-eabi, thumbv8m.main-none-eabihf, thumbv8r-none-eabihf, wasm32-unknown-unknown, wasm32v1-none, x86_64-unknown-none]
• std::sync::nonpoison::condvar::Condvar only present on [aarch64-unknown-none, aarch64-unknown-none-softfloat, armv7a-none-eabi, armv7a-none-eabihf, armv7r-none-eabi, armv7r-none-eabihf, armv8r-none-eabihf, loongarch64-unknown-none, loongarch64-unknown-none-softfloat, nvptx64-nvidia-cuda, riscv32i-unknown-none-elf, riscv32im-unknown-none-elf, riscv32imac-unknown-none-elf, riscv32imafc-unknown-none-elf, riscv32imc-unknown-none-elf, riscv64gc-unknown-none-elf, riscv64imac-unknown-none-elf, s390x-unknown-none-softfloat, thumbv6m-none-eabi, thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7em-none-eabi, thumbv7em-none-eabihf, thumbv7m-none-eabi, thumbv7r-none-eabi, thumbv7r-none-eabihf, thumbv8m.base-none-eabi, thumbv8m.main-none-eabi, thumbv8m.main-none-eabihf, thumbv8r-none-eabihf, wasm32-unknown-unknown, wasm32v1-none, x86_64-unknown-none]

impl core::marker::Sync for

• std::env::Vars only present on [aarch64-unknown-none, aarch64-unknown-none-softfloat, armv7a-none-eabi, armv7a-none-eabihf, armv7r-none-eabi, armv7r-none-eabihf, armv8r-none-eabihf, loongarch64-unknown-none, loongarch64-unknown-none-softfloat, nvptx64-nvidia-cuda, riscv32i-unknown-none-elf, riscv32im-unknown-none-elf, riscv32imac-unknown-none-elf, riscv32imafc-unknown-none-elf, riscv32imc-unknown-none-elf, riscv64gc-unknown-none-elf, riscv64imac-unknown-none-elf, s390x-unknown-none-softfloat, thumbv6m-none-eabi, thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7em-none-eabi, thumbv7em-none-eabihf, thumbv7m-none-eabi, thumbv7r-none-eabi, thumbv7r-none-eabihf, thumbv8m.base-none-eabi, thumbv8m.main-none-eabi, thumbv8m.main-none-eabihf, thumbv8r-none-eabihf, wasm32-unknown-unknown, wasm32v1-none, x86_64-unknown-none]
• std::env::VarsOs only present on [aarch64-unknown-none, aarch64-unknown-none-softfloat, armv7a-none-eabi, armv7a-none-eabihf, armv7r-none-eabi, armv7r-none-eabihf, armv8r-none-eabihf, loongarch64-unknown-none, loongarch64-unknown-none-softfloat, nvptx64-nvidia-cuda, riscv32i-unknown-none-elf, riscv32im-unknown-none-elf, riscv32imac-unknown-none-elf, riscv32imafc-unknown-none-elf, riscv32imc-unknown-none-elf, riscv64gc-unknown-none-elf, riscv64imac-unknown-none-elf, s390x-unknown-none-softfloat, thumbv6m-none-eabi, thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7em-none-eabi, thumbv7em-none-eabihf, thumbv7m-none-eabi, thumbv7r-none-eabi, thumbv7r-none-eabihf, thumbv8m.base-none-eabi, thumbv8m.main-none-eabi, thumbv8m.main-none-eabihf, thumbv8r-none-eabihf, wasm32-unknown-unknown, wasm32v1-none, x86_64-unknown-none]
• std::process::CommandArgs only present on [aarch64-pc-windows-gnullvm, aarch64-pc-windows-msvc, aarch64-unknown-none, aarch64-unknown-none-softfloat, arm64ec-pc-windows-msvc, armv7a-none-eabi, armv7a-none-eabihf, armv7r-none-eabi, armv7r-none-eabihf, armv8r-none-eabihf, i686-pc-windows-gnu, i686-pc-windows-gnullvm, i686-pc-windows-msvc, loongarch64-unknown-none, loongarch64-unknown-none-softfloat, nvptx64-nvidia-cuda, riscv32i-unknown-none-elf, riscv32im-unknown-none-elf, riscv32imac-unknown-none-elf, riscv32imafc-unknown-none-elf, riscv32imc-unknown-none-elf, riscv64gc-unknown-none-elf, riscv64imac-unknown-none-elf, s390x-unknown-none-softfloat, thumbv6m-none-eabi, thumbv7a-none-eabi, thumbv7a-none-eabihf, thumbv7a-uwp-windows-msvc, thumbv7em-none-eabi, thumbv7em-none-eabihf, thumbv7m-none-eabi, thumbv7r-none-eabi, thumbv7r-none-eabihf, thumbv8m.base-none-eabi, thumbv8m.main-none-eabi, thumbv8m.main-none-eabihf, thumbv8r-none-eabihf, wasm32-unknown-unknown, wasm32v1-none, x86_64-fortanix-unknown-sgx, x86_64-pc-windows-gnu, x86_64-pc-windows-gnullvm, x86_64-pc-windows-msvc, x86_64-unknown-none]