Don't consider unstable fields always-inhabited

[Nadrieril]

This reverts the hack in #133889 now that Pin's field is no longer public.

Fixes #143468.

r? @compiler-errors

[lqd]

Suggested change

	//! this, we temporarily made it so unstable fields are always considered uninhabited. This has now
	//! this, we temporarily made it so unstable fields are always considered inhabited. This has now

[rust-log-analyzer]

The job aarch64-gnu-llvm-19-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

To only update this specific test, also pass `--test-args uninhabited/uninhabited-unstable-field.rs`

error: 1 errors occurred comparing output.
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/uninhabited/uninhabited-unstable-field.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/uninhabited/uninhabited-unstable-field" "-A" "unused" "-A" "internal_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/uninhabited/uninhabited-unstable-field/auxiliary"
stdout: none
--- stderr -------------------------------
error: unreachable pattern
##[error]  --> /checkout/tests/ui/uninhabited/uninhabited-unstable-field.rs:24:9
   |
LL |         Foo { .. } => {} //~ ERROR unreachable
   |         ^^^^^^^^^^------
   |         |
   |         matches no values because `Foo<Void>` is uninhabited
   |         help: remove the match arm
   |
   = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
note: the lint level is defined here
  --> /checkout/tests/ui/uninhabited/uninhabited-unstable-field.rs:9:9
---
   |
LL |         _ => {} //~ ERROR unreachable
   |         ^------
   |         |
   |         matches no values because `Foo<Void>` is uninhabited
   |         help: remove the match arm
   |
   = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types

error: unreachable pattern
##[error]  --> /checkout/tests/ui/uninhabited/uninhabited-unstable-field.rs:41:9
   |
LL |         MyCoroutineState::Complete(_) => {} //~ ERROR unreachable
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^------
   |         |
   |         matches no values because `!` is uninhabited
   |         help: remove the match arm
   |