Auto merge of rust-lang#105041 - matthiaskrgr:rollup-7ffry90, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

 - rust-lang#104465 (Document more settings for building rustc for Fuchsia)
 - rust-lang#104951 (Simplify checking for `GeneratorKind::Async`)
 - rust-lang#104959 (Revert rust-lang#104269 (to avoid spurious hang/test failure in CI))
 - rust-lang#104978 (notify the rust-analyzer team on changes to the rust-analyzer subtree)
 - rust-lang#105010 (Fix documentation of asymptotic complexity for rustc_data_structures::SortedMap)
 - rust-lang#105016 (Add sentence when rustdoc search is running)
 - rust-lang#105020 (rustdoc: merge background-image rules in rustdoc-toggle CSS)
 - rust-lang#105024 (rustdoc: remove `fnname` CSS class that's styled exactly like `fn`)
 - rust-lang#105027 (Rustdoc-Json: Add tests for linking to foreign variants.)
 - rust-lang#105038 (Clean up pr 104954)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -514,12 +514,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             span: *span,
             ty_err: match output_ty.kind() {
                 ty::Closure(_, _) => FnMutReturnTypeErr::ReturnClosure { span: *span },
-                ty::Generator(def, ..)
-                    if matches!(
-                        self.infcx.tcx.generator_kind(def),
-                        Some(hir::GeneratorKind::Async(_))
-                    ) =>
-                {
+                ty::Generator(def, ..) if self.infcx.tcx.generator_is_async(*def) => {
                     FnMutReturnTypeErr::ReturnAsyncBlock { span: *span }
                 }
                 _ => FnMutReturnTypeErr::ReturnRef { span: *span },

compiler/rustc_data_structures/src/sorted_map.rs

@@ -10,8 +10,8 @@ mod index_map;
 pub use index_map::SortedIndexMultiMap;
 
 /// `SortedMap` is a data structure with similar characteristics as BTreeMap but
-/// slightly different trade-offs: lookup, insertion, and removal are *O*(log(*n*))
-/// and elements can be iterated in order cheaply.
+/// slightly different trade-offs: lookup is *O*(log(*n*)), insertion and removal
+/// are *O*(*n*) but elements can be iterated in order cheaply.
 ///
 /// `SortedMap` can be faster than a `BTreeMap` for small sizes (<50) since it
 /// stores data in a more compact way. It also supports accessing contiguous

compiler/rustc_lint/src/unused.rs

@@ -322,10 +322,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                 ty::Closure(..) => Some(MustUsePath::Closure(span)),
                 ty::Generator(def_id, ..) => {
                     // async fn should be treated as "implementor of `Future`"
-                    let must_use = if matches!(
-                        cx.tcx.generator_kind(def_id),
-                        Some(hir::GeneratorKind::Async(..))
-                    ) {
+                    let must_use = if cx.tcx.generator_is_async(def_id) {
                         let def_id = cx.tcx.lang_items().future_trait().unwrap();
                         is_def_must_use(cx, def_id, span)
                             .map(|inner| MustUsePath::Opaque(Box::new(inner)))

compiler/rustc_middle/src/ty/context.rs

@@ -1361,6 +1361,11 @@ impl<'tcx> TyCtxt<'tcx> {
         self.diagnostic_items(did.krate).name_to_id.get(&name) == Some(&did)
     }
 
+    /// Returns `true` if the node pointed to by `def_id` is a generator for an async construct.
+    pub fn generator_is_async(self, def_id: DefId) -> bool {
+        matches!(self.generator_kind(def_id), Some(hir::GeneratorKind::Async(_)))
+    }
+
     pub fn stability(self) -> &'tcx stability::Index {
         self.stability_index(())
     }

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -282,7 +282,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                             "you may want to use a bool value instead",
                             format!("{}", item_typo),
                         ))
-                    // FIXME(vicnenzopalazzo): make the check smarter,
+                    // FIXME(vincenzopalazzo): make the check smarter,
                     // and maybe expand with levenshtein distance checks
                     } else if item_str.as_str() == "printf" {
                         Some((

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -2544,10 +2544,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             let obligation =
                 Obligation::new(self.tcx, ObligationCause::dummy(), param_env, cleaned_pred);
 
-            // We don't use `InferCtxt::predicate_may_hold` because that
-            // will re-run predicates that overflow locally, which ends up
-            // taking a really long time to compute.
-            self.evaluate_obligation(&obligation).map_or(false, |eval| eval.may_apply())
+            self.predicate_may_hold(&obligation)
         })
     }
 

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1336,8 +1336,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     obligation.param_env,
                     trait_pred_and_suggested_ty,
                 );
-                let suggested_ty_would_satisfy_obligation =
-                    self.predicate_must_hold_modulo_regions(&new_obligation);
+                let suggested_ty_would_satisfy_obligation = self
+                    .evaluate_obligation_no_overflow(&new_obligation)
+                    .must_apply_modulo_regions();
                 if suggested_ty_would_satisfy_obligation {
                     let sp = self
                         .tcx
@@ -1988,11 +1989,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             .as_local()
             .and_then(|def_id| hir.maybe_body_owned_by(def_id))
             .map(|body_id| hir.body(body_id));
-        let is_async = self
-            .tcx
-            .generator_kind(generator_did)
-            .map(|generator_kind| matches!(generator_kind, hir::GeneratorKind::Async(..)))
-            .unwrap_or(false);
         let mut visitor = AwaitsVisitor::default();
         if let Some(body) = generator_body {
             visitor.visit_body(body);
@@ -2069,6 +2065,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
         debug!(?interior_or_upvar_span);
         if let Some(interior_or_upvar_span) = interior_or_upvar_span {
+            let is_async = self.tcx.generator_is_async(generator_did);
             let typeck_results = match generator_data {
                 GeneratorData::Local(typeck_results) => Some(typeck_results),
                 GeneratorData::Foreign(_) => None,
@@ -2641,10 +2638,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                                 if is_future
                                     && obligated_types.last().map_or(false, |ty| match ty.kind() {
                                         ty::Generator(last_def_id, ..) => {
-                                            matches!(
-                                                tcx.generator_kind(last_def_id),
-                                                Some(GeneratorKind::Async(..))
-                                            )
+                                            tcx.generator_is_async(*last_def_id)
                                         }
                                         _ => false,
                                     })

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -430,9 +430,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     ) {
         let self_ty = obligation.self_ty().skip_binder();
         if let ty::Generator(did, ..) = self_ty.kind() {
-            if let Some(rustc_hir::GeneratorKind::Async(_generator_kind)) =
-                self.tcx().generator_kind(did)
-            {
+            if self.tcx().generator_is_async(*did) {
                 debug!(?self_ty, ?obligation, "assemble_future_candidates",);
 
                 candidates.vec.push(FutureCandidate);

src/ci/docker/scripts/fuchsia-test-runner.py

@@ -189,17 +189,45 @@ Fuchsia as well. A recent version (14+) of clang should be sufficient to compile
 Rust for Fuchsia.
 
 x86-64 and AArch64 Fuchsia targets can be enabled using the following
-configuration.
-
-In `config.toml`, add:
+configuration in `config.toml`:
 
 ```toml
 [build]
 target = ["<host_platform>", "aarch64-fuchsia", "x86_64-fuchsia"]
+
+[rust]
+lld = true
+
+[target.x86_64-fuchsia]
+cc = "clang"
+cxx = "clang++"
+
+[target.aarch64-fuchsia]
+cc = "clang"
+cxx = "clang++"
+```
+
+Though not strictly required, you may also want to use `clang` for your host
+target as well:
+
+```toml
+[target.<host_platform>]
+cc = "clang"
+cxx = "clang++"
+```
+
+By default, the Rust compiler installs itself to `/usr/local` on most UNIX
+systems. You may want to install it to another location (e.g. a local `install`
+directory) by setting a custom prefix in `config.toml`:
+
+```toml
+[install]
+# Make sure to use the absolute path to your install directory
+prefix = "<RUST_SRC_PATH>/install"
 ```
 
-Additionally, the following environment variables must be configured (for
-example, using a script like `config-env.sh`):
+Next, the following environment variables must be configured. For example, using
+a script we name `config-env.sh`:
 
 ```sh
 # Configure this environment variable to be the path to the downloaded SDK
@@ -215,8 +243,11 @@ export LDFLAGS_x86_64_fuchsia="--target=x86_64-fuchsia --sysroot=${SDK_PATH}/arc
 export CARGO_TARGET_X86_64_FUCHSIA_RUSTFLAGS="-C link-arg=--sysroot=${SDK_PATH}/arch/x64/sysroot -Lnative=${SDK_PATH}/arch/x64/sysroot/lib -Lnative=${SDK_PATH}/arch/x64/lib"
 ```
 
-These can be run together in a shell environment by executing
-`(source config-env.sh && ./x.py install)`.
+Finally, the Rust compiler can be built and installed:
+
+```sh
+(source config-env.sh && ./x.py install)
+```
 
 Once `rustc` is installed, we can create a new working directory to work from,
 `hello_fuchsia` along with `hello_fuchsia/src`:
@@ -641,31 +672,38 @@ available on the [Fuchsia devsite].
 
 ### Running the compiler test suite
 
-Pre-requisites for running the Rust test suite on Fuchsia are:
-1. Checkout of Rust source.
-1. Setup of `config-env.sh` and `config.toml` from "[Targeting Fuchsia with a compiler built from source](#targeting-fuchsia-with-a-compiler-built-from-source)".
-1. Download of the Fuchsia SDK. Minimum supported SDK version is [9.20220726.1.1](https://chrome-infra-packages.appspot.com/p/fuchsia/sdk/core/linux-amd64/+/version:9.20220726.1.1)
+The commands in this section assume that they are being run from inside your
+local Rust source checkout:
+
+```sh
+cd ${RUST_SRC_PATH}
+```
+
+To run the Rust test suite on an emulated Fuchsia device, you must install the
+Rust compiler locally. See "[Targeting Fuchsia with a compiler built from source](#targeting-fuchsia-with-a-compiler-built-from-source)"
+for the steps to build locally.
 
-Interfacing with the Fuchsia emulator is handled by our test runner script located
-at `${RUST_SRC_PATH}/src/ci/docker/scripts/fuchsia-test-runner.py`.
+You'll also need to download a copy of the Fuchsia SDK. The current minimum
+supported SDK version is [9.20220726.1.1](https://chrome-infra-packages.appspot.com/p/fuchsia/sdk/core/linux-amd64/+/version:9.20220726.1.1).
 
-We start by activating our Fuchsia test environment. From a terminal:
+Fuchsia's test runner interacts with the Fuchsia emulator and is located at
+`src/ci/docker/scripts/fuchsia-test-runner.py`. We can use it to start our
+test environment with:
 
-**Issue command from ${RUST_SRC_PATH}**
 ```sh
 src/ci/docker/scripts/fuchsia-test-runner.py start
-    --rust .
+    --rust ${RUST_SRC_PATH}/install
     --sdk ${SDK_PATH}
     --target-arch {x64,arm64}
 ```
 
-Next, for ease of commands, we copy `config-env.sh` and `config.toml` into our Rust source
-code path, `${RUST_SRC_PATH}`.
+Where `${RUST_SRC_PATH}/install` is the `prefix` set in `config.toml` and
+`${SDK_PATH}` is the path to the downloaded and unzipped SDK.
 
-From there, we utilize `x.py` to run our tests, using the test runner script to
-run the tests on our emulator. To run the full `src/test/ui` test suite:
+Once our environment is started, we can run our tests using `x.py` as usual. The
+test runner script will run the compiled tests on an emulated Fuchsia device. To
+run the full `src/test/ui` test suite:
 
-**Run from ${RUST_SRC_PATH}**
 ```sh
 ( \
     source config-env.sh &&                                                   \
@@ -695,9 +733,8 @@ run the tests on our emulator. To run the full `src/test/ui` test suite:
 *Note: The test suite cannot be run in parallel at the moment, so `x.py`
 must be run with `--jobs 1` to ensure only one test runs at a time.*
 
-When finished, stop the test environment:
+When finished, the test runner can be used to stop the test environment:
 
-**Issue command from ${RUST_SRC_PATH}**
 ```sh
 src/ci/docker/scripts/fuchsia-test-runner.py stop
 ```