Auto merge of #89037 - JohnTitor:rollup-rd9btbs, r=JohnTitor

Rollup of 10 pull requests

Successful merges:

 - #86382 (Make diagnostics clearer for `?` operators)
 - #87529 (Fix ICE in `improper_ctypes_definitions` lint with all-ZST transparent types)
 - #88339 (Add TcpListener::into_incoming and IntoIncoming)
 - #88735 (Don't lint about missing code examples in derived traits)
 - #88751 (Couple of changes to FileSearch and SearchPath)
 - #88883 (Move some tests to more reasonable directories - 7)
 - #88887 (Const Deref)
 - #88911 (Improve error message for type mismatch in generator arguments)
 - #89014 (PassWrapper: handle separate Module*SanitizerPass)
 - #89033 (Set the library path in sysroot-crates-are-unstable)

Failed merges:

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

Author: bors

Diff for: compiler/rustc_codegen_ssa/src/back/link.rs

@@ -637,7 +637,7 @@ fn link_dwarf_object<'a>(sess: &'a Session, executable_out_filename: &Path) {
     cmd.arg("-o");
     cmd.arg(&dwp_out_filename);
 
-    let mut new_path = sess.host_filesearch(PathKind::All).get_tools_search_paths(false);
+    let mut new_path = sess.get_tools_search_paths(false);
     if let Some(path) = env::var_os("PATH") {
         new_path.extend(env::split_paths(&path));
     }
@@ -2555,8 +2555,7 @@ fn add_gcc_ld_path(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
             match ld_impl {
                 LdImpl::Lld => {
                     if sess.target.lld_flavor == LldFlavor::Ld64 {
-                        let tools_path =
-                            sess.host_filesearch(PathKind::All).get_tools_search_paths(false);
+                        let tools_path = sess.get_tools_search_paths(false);
                         let ld64_exe = tools_path
                             .into_iter()
                             .map(|p| p.join("gcc-ld"))
@@ -2571,8 +2570,7 @@ fn add_gcc_ld_path(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
                             arg
                         });
                     } else {
-                        let tools_path =
-                            sess.host_filesearch(PathKind::All).get_tools_search_paths(false);
+                        let tools_path = sess.get_tools_search_paths(false);
                         let lld_path = tools_path
                             .into_iter()
                             .map(|p| p.join("gcc-ld"))

Diff for: compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -15,7 +15,6 @@ use rustc_middle::middle::dependency_format::Linkage;
 use rustc_middle::ty::TyCtxt;
 use rustc_serialize::{json, Encoder};
 use rustc_session::config::{self, CrateType, DebugInfo, LinkerPluginLto, Lto, OptLevel, Strip};
-use rustc_session::search_paths::PathKind;
 use rustc_session::Session;
 use rustc_span::symbol::Symbol;
 use rustc_target::spec::{LinkOutputKind, LinkerFlavor, LldFlavor};
@@ -101,7 +100,7 @@ pub fn get_linker<'a>(
 
     // The compiler's sysroot often has some bundled tools, so add it to the
     // PATH for the child.
-    let mut new_path = sess.host_filesearch(PathKind::All).get_tools_search_paths(self_contained);
+    let mut new_path = sess.get_tools_search_paths(self_contained);
     let mut msvc_changed_path = false;
     if sess.target.is_like_msvc {
         if let Some(ref tool) = msvc_tool {

Diff for: compiler/rustc_driver/src/lib.rs

@@ -677,10 +677,7 @@ impl RustcDefaultCalls {
                     println!("{}", targets.join("\n"));
                 }
                 Sysroot => println!("{}", sess.sysroot.display()),
-                TargetLibdir => println!(
-                    "{}",
-                    sess.target_tlib_path.as_ref().unwrap_or(&sess.host_tlib_path).dir.display()
-                ),
+                TargetLibdir => println!("{}", sess.target_tlib_path.dir.display()),
                 TargetSpec => println!("{}", sess.target.to_json().pretty()),
                 FileNames | CrateName => {
                     let input = input.unwrap_or_else(|| {

Diff for: compiler/rustc_errors/src/diagnostic.rs

@@ -74,6 +74,10 @@ impl DiagnosticStyledString {
     pub fn highlighted<S: Into<String>>(t: S) -> DiagnosticStyledString {
         DiagnosticStyledString(vec![StringPart::Highlighted(t.into())])
     }
+
+    pub fn content(&self) -> String {
+        self.0.iter().map(|x| x.content()).collect::<String>()
+    }
 }
 
 #[derive(Debug, PartialEq, Eq)]
@@ -82,6 +86,14 @@ pub enum StringPart {
     Highlighted(String),
 }
 
+impl StringPart {
+    pub fn content(&self) -> &str {
+        match self {
+            &StringPart::Normal(ref s) | &StringPart::Highlighted(ref s) => s,
+        }
+    }
+}
+
 impl Diagnostic {
     pub fn new(level: Level, message: &str) -> Self {
         Diagnostic::new_with_code(level, None, message)

Diff for: compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -1971,6 +1971,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         trace: TypeTrace<'tcx>,
         terr: &TypeError<'tcx>,
     ) -> DiagnosticBuilder<'tcx> {
+        use crate::traits::ObligationCauseCode::MatchExpressionArm;
+
         debug!("report_and_explain_type_error(trace={:?}, terr={:?})", trace, terr);
 
         let span = trace.cause.span(self.tcx);
@@ -2013,6 +2015,19 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                         _ => {}
                     }
                 }
+                if let MatchExpressionArm(box MatchExpressionArmCause { source, .. }) =
+                    trace.cause.code
+                {
+                    if let hir::MatchSource::TryDesugar = source {
+                        if let Some((expected_ty, found_ty)) = self.values_str(trace.values) {
+                            err.note(&format!(
+                                "`?` operator cannot convert from `{}` to `{}`",
+                                found_ty.content(),
+                                expected_ty.content(),
+                            ));
+                        }
+                    }
+                }
                 err
             }
             FailureCode::Error0644(failure_str) => {
@@ -2585,9 +2600,7 @@ impl<'tcx> ObligationCauseExt<'tcx> for ObligationCause<'tcx> {
             CompareImplTypeObligation { .. } => Error0308("type not compatible with trait"),
             MatchExpressionArm(box MatchExpressionArmCause { source, .. }) => {
                 Error0308(match source {
-                    hir::MatchSource::TryDesugar => {
-                        "try expression alternatives have incompatible types"
-                    }
+                    hir::MatchSource::TryDesugar => "`?` operator has incompatible types",
                     _ => "`match` arms have incompatible types",
                 })
             }

Diff for: compiler/rustc_lint/src/types.rs

@@ -851,12 +851,18 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
         use FfiResult::*;
 
         if def.repr.transparent() {
-            // Can assume that only one field is not a ZST, so only check
+            // Can assume that at most one field is not a ZST, so only check
             // that field's type for FFI-safety.
             if let Some(field) = transparent_newtype_field(self.cx.tcx, variant) {
                 self.check_field_type_for_ffi(cache, field, substs)
             } else {
-                bug!("malformed transparent type");
+                // All fields are ZSTs; this means that the type should behave
+                // like (), which is FFI-unsafe
+                FfiUnsafe {
+                    ty,
+                    reason: "this struct contains only zero-sized fields".into(),
+                    help: None,
+                }
             }
         } else {
             // We can't completely trust repr(C) markings; make sure the fields are

Diff for: compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -875,7 +875,11 @@ LLVMRustOptimizeWithNewPassManager(
 #if LLVM_VERSION_GE(11, 0)
       OptimizerLastEPCallbacks.push_back(
         [Options](ModulePassManager &MPM, OptimizationLevel Level) {
+#if LLVM_VERSION_GE(14, 0)
+          MPM.addPass(ModuleMemorySanitizerPass(Options));
+#else
           MPM.addPass(MemorySanitizerPass(Options));
+#endif
           MPM.addPass(createModuleToFunctionPassAdaptor(MemorySanitizerPass(Options)));
         }
       );
@@ -897,7 +901,11 @@ LLVMRustOptimizeWithNewPassManager(
 #if LLVM_VERSION_GE(11, 0)
       OptimizerLastEPCallbacks.push_back(
         [](ModulePassManager &MPM, OptimizationLevel Level) {
+#if LLVM_VERSION_GE(14, 0)
+          MPM.addPass(ModuleThreadSanitizerPass());
+#else
           MPM.addPass(ThreadSanitizerPass());
+#endif
           MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
         }
       );

Diff for: compiler/rustc_session/src/filesearch.rs

@@ -1,3 +1,5 @@
+//! A module for searching for libraries
+
 pub use self::FileMatch::*;
 
 use std::env;
@@ -14,8 +16,6 @@ pub enum FileMatch {
     FileDoesntMatch,
 }
 
-// A module for searching for libraries
-
 #[derive(Clone)]
 pub struct FileSearch<'a> {
     sysroot: &'a Path,
@@ -83,22 +83,10 @@ impl<'a> FileSearch<'a> {
         FileSearch { sysroot, triple, search_paths, tlib_path, kind }
     }
 
-    // Returns just the directories within the search paths.
+    /// Returns just the directories within the search paths.
     pub fn search_path_dirs(&self) -> Vec<PathBuf> {
         self.search_paths().map(|sp| sp.dir.to_path_buf()).collect()
     }
-
-    // Returns a list of directories where target-specific tool binaries are located.
-    pub fn get_tools_search_paths(&self, self_contained: bool) -> Vec<PathBuf> {
-        let rustlib_path = rustc_target::target_rustlib_path(self.sysroot, &self.triple);
-        let p = std::array::IntoIter::new([
-            Path::new(&self.sysroot),
-            Path::new(&rustlib_path),
-            Path::new("bin"),
-        ])
-        .collect::<PathBuf>();
-        if self_contained { vec![p.clone(), p.join("self-contained")] } else { vec![p] }
-    }
 }
 
 pub fn make_target_lib_path(sysroot: &Path, target_triple: &str) -> PathBuf {
@@ -107,8 +95,8 @@ pub fn make_target_lib_path(sysroot: &Path, target_triple: &str) -> PathBuf {
         .collect::<PathBuf>()
 }
 
-// This function checks if sysroot is found using env::args().next(), and if it
-// is not found, uses env::current_exe() to imply sysroot.
+/// This function checks if sysroot is found using env::args().next(), and if it
+/// is not found, uses env::current_exe() to imply sysroot.
 pub fn get_or_default_sysroot() -> PathBuf {
     // Follow symlinks.  If the resolved path is relative, make it absolute.
     fn canonicalize(path: PathBuf) -> PathBuf {

Diff for: compiler/rustc_session/src/search_paths.rs

@@ -9,17 +9,17 @@ pub struct SearchPath {
     pub files: Vec<SearchPathFile>,
 }
 
-// The obvious implementation of `SearchPath::files` is a `Vec<PathBuf>`. But
-// it is searched repeatedly by `find_library_crate`, and the searches involve
-// checking the prefix and suffix of the filename of each `PathBuf`. This is
-// doable, but very slow, because it involves calls to `file_name` and
-// `extension` that are themselves slow.
-//
-// This type augments the `PathBuf` with an `Option<String>` containing the
-// `PathBuf`'s filename. The prefix and suffix checking is much faster on the
-// `Option<String>` than the `PathBuf`. (It's an `Option` because
-// `Path::file_name` can fail; if that happens then all subsequent checking
-// will also fail, which is fine.)
+/// The obvious implementation of `SearchPath::files` is a `Vec<PathBuf>`. But
+/// it is searched repeatedly by `find_library_crate`, and the searches involve
+/// checking the prefix and suffix of the filename of each `PathBuf`. This is
+/// doable, but very slow, because it involves calls to `file_name` and
+/// `extension` that are themselves slow.
+///
+/// This type augments the `PathBuf` with an `Option<String>` containing the
+/// `PathBuf`'s filename. The prefix and suffix checking is much faster on the
+/// `Option<String>` than the `PathBuf`. (It's an `Option` because
+/// `Path::file_name` can fail; if that happens then all subsequent checking
+/// will also fail, which is fine.)
 #[derive(Clone, Debug)]
 pub struct SearchPathFile {
     pub path: PathBuf,

Diff for: compiler/rustc_session/src/session.rs

@@ -36,7 +36,7 @@ use std::fmt;
 use std::io::Write;
 use std::num::NonZeroU32;
 use std::ops::{Div, Mul};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::sync::Arc;
 use std::time::Duration;
@@ -131,9 +131,8 @@ pub struct Session {
     pub target: Target,
     pub host: Target,
     pub opts: config::Options,
-    pub host_tlib_path: SearchPath,
-    /// `None` if the host and target are the same.
-    pub target_tlib_path: Option<SearchPath>,
+    pub host_tlib_path: Lrc<SearchPath>,
+    pub target_tlib_path: Lrc<SearchPath>,
     pub parse_sess: ParseSess,
     pub sysroot: PathBuf,
     /// The name of the root source file of the crate, in the local file system.
@@ -787,8 +786,7 @@ impl Session {
             &self.sysroot,
             self.opts.target_triple.triple(),
             &self.opts.search_paths,
-            // `target_tlib_path == None` means it's the same as `host_tlib_path`.
-            self.target_tlib_path.as_ref().unwrap_or(&self.host_tlib_path),
+            &self.target_tlib_path,
             kind,
         )
     }
@@ -802,6 +800,18 @@ impl Session {
         )
     }
 
+    /// Returns a list of directories where target-specific tool binaries are located.
+    pub fn get_tools_search_paths(&self, self_contained: bool) -> Vec<PathBuf> {
+        let rustlib_path = rustc_target::target_rustlib_path(&self.sysroot, &config::host_triple());
+        let p = std::array::IntoIter::new([
+            Path::new(&self.sysroot),
+            Path::new(&rustlib_path),
+            Path::new("bin"),
+        ])
+        .collect::<PathBuf>();
+        if self_contained { vec![p.clone(), p.join("self-contained")] } else { vec![p] }
+    }
+
     pub fn init_incr_comp_session(
         &self,
         session_dir: PathBuf,
@@ -1245,11 +1255,13 @@ pub fn build_session(
 
     let host_triple = config::host_triple();
     let target_triple = sopts.target_triple.triple();
-    let host_tlib_path = SearchPath::from_sysroot_and_triple(&sysroot, host_triple);
+    let host_tlib_path = Lrc::new(SearchPath::from_sysroot_and_triple(&sysroot, host_triple));
     let target_tlib_path = if host_triple == target_triple {
-        None
+        // Use the same `SearchPath` if host and target triple are identical to avoid unnecessary
+        // rescanning of the target lib path and an unnecessary allocation.
+        host_tlib_path.clone()
     } else {
-        Some(SearchPath::from_sysroot_and_triple(&sysroot, target_triple))
+        Lrc::new(SearchPath::from_sysroot_and_triple(&sysroot, target_triple))
     };
 
     let file_path_mapping = sopts.file_path_mapping();

Diff for: compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -722,7 +722,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                 };
 
                 let found_did = match *found_trait_ty.kind() {
-                    ty::Closure(did, _) | ty::Foreign(did) | ty::FnDef(did, _) => Some(did),
+                    ty::Closure(did, _)
+                    | ty::Foreign(did)
+                    | ty::FnDef(did, _)
+                    | ty::Generator(did, ..) => Some(did),
                     ty::Adt(def, _) => Some(def.did),
                     _ => None,
                 };

Diff for: compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1256,33 +1256,40 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
             trait_ref: ty::PolyTraitRef<'tcx>,
         ) -> String {
             let inputs = trait_ref.skip_binder().substs.type_at(1);
-            let sig = if let ty::Tuple(inputs) = inputs.kind() {
-                tcx.mk_fn_sig(
-                    inputs.iter().map(|k| k.expect_ty()),
-                    tcx.mk_ty_infer(ty::TyVar(ty::TyVid::from_u32(0))),
-                    false,
-                    hir::Unsafety::Normal,
-                    abi::Abi::Rust,
-                )
-            } else {
-                tcx.mk_fn_sig(
+            let sig = match inputs.kind() {
+                ty::Tuple(inputs)
+                    if tcx.fn_trait_kind_from_lang_item(trait_ref.def_id()).is_some() =>
+                {
+                    tcx.mk_fn_sig(
+                        inputs.iter().map(|k| k.expect_ty()),
+                        tcx.mk_ty_infer(ty::TyVar(ty::TyVid::from_u32(0))),
+                        false,
+                        hir::Unsafety::Normal,
+                        abi::Abi::Rust,
+                    )
+                }
+                _ => tcx.mk_fn_sig(
                     std::iter::once(inputs),
                     tcx.mk_ty_infer(ty::TyVar(ty::TyVid::from_u32(0))),
                     false,
                     hir::Unsafety::Normal,
                     abi::Abi::Rust,
-                )
+                ),
             };
             trait_ref.rebind(sig).to_string()
         }
 
-        let argument_is_closure = expected_ref.skip_binder().substs.type_at(0).is_closure();
+        let argument_kind = match expected_ref.skip_binder().substs.type_at(0) {
+            t if t.is_closure() => "closure",
+            t if t.is_generator() => "generator",
+            _ => "function",
+        };
         let mut err = struct_span_err!(
             self.tcx.sess,
             span,
             E0631,
             "type mismatch in {} arguments",
-            if argument_is_closure { "closure" } else { "function" }
+            argument_kind
         );
 
         let found_str = format!("expected signature of `{}`", build_fn_sig_string(self.tcx, found));

Diff for: library/alloc/src/borrow.rs

@@ -330,7 +330,11 @@ impl<B: ?Sized + ToOwned> Cow<'_, B> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<B: ?Sized + ToOwned> Deref for Cow<'_, B> {
+#[rustc_const_unstable(feature = "const_deref", issue = "88955")]
+impl<B: ?Sized + ToOwned> const Deref for Cow<'_, B>
+where
+    B::Owned: ~const Borrow<B>,
+{
     type Target = B;
 
     fn deref(&self) -> &B {