Auto merge of rust-lang#120441 - matthiaskrgr:rollup-s06vd7k, r=matth…

…iaskrgr

Rollup of 6 pull requests

Successful merges:

 - rust-lang#116677 (References refer to allocated objects)
 - rust-lang#118533 (Suppress unhelpful diagnostics for unresolved top level attributes)
 - rust-lang#120232 (Add support for custom JSON targets when using build-std.)
 - rust-lang#120238 (Always check the result of `pthread_mutex_lock`)
 - rust-lang#120266 (Improve documentation for [A]Rc::into_inner)
 - rust-lang#120373 (Adjust Behaviour of `read_dir` and `ReadDir` in Windows Implementation: Check Whether Path to Search In Exists)

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

compiler/rustc_errors/src/lib.rs

@@ -509,6 +509,7 @@ pub enum StashKey {
     MaybeForgetReturn,
     /// Query cycle detected, stashing in favor of a better error.
     Cycle,
+    UndeterminedMacroResolution,
 }
 
 fn default_track_diagnostic(diag: Diagnostic, f: &mut dyn FnMut(Diagnostic)) {

compiler/rustc_passes/src/check_attr.rs

@@ -5,8 +5,10 @@
 //! item.
 
 use crate::{errors, fluent_generated as fluent};
-use rustc_ast::{ast, AttrStyle, Attribute, LitKind, MetaItemKind, MetaItemLit, NestedMetaItem};
+use rustc_ast::{ast, AttrKind, AttrStyle, Attribute, LitKind};
+use rustc_ast::{MetaItemKind, MetaItemLit, NestedMetaItem};
 use rustc_data_structures::fx::FxHashMap;
+use rustc_errors::StashKey;
 use rustc_errors::{Applicability, DiagCtxt, IntoDiagnosticArg, MultiSpan};
 use rustc_feature::{AttributeDuplicates, AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
 use rustc_hir as hir;
@@ -2530,6 +2532,14 @@ fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
         if attr.style == AttrStyle::Inner {
             for attr_to_check in ATTRS_TO_CHECK {
                 if attr.has_name(*attr_to_check) {
+                    if let AttrKind::Normal(ref p) = attr.kind
+                        && let Some(diag) = tcx.dcx().steal_diagnostic(
+                            p.item.path.span,
+                            StashKey::UndeterminedMacroResolution,
+                        )
+                    {
+                        diag.cancel();
+                    }
                     let item = tcx
                         .hir()
                         .items()

compiler/rustc_resolve/src/macros.rs

@@ -1,10 +1,9 @@
 //! A bunch of methods and structures more or less related to resolving macros and
 //! interface provided by `Resolver` to macro expander.
 
-use crate::errors::{
-    self, AddAsNonDerive, CannotDetermineMacroResolution, CannotFindIdentInThisScope,
-    MacroExpectedFound, RemoveSurroundingDerive,
-};
+use crate::errors::CannotDetermineMacroResolution;
+use crate::errors::{self, AddAsNonDerive, CannotFindIdentInThisScope};
+use crate::errors::{MacroExpectedFound, RemoveSurroundingDerive};
 use crate::Namespace::*;
 use crate::{BuiltinMacroState, Determinacy, MacroData};
 use crate::{DeriveData, Finalize, ParentScope, ResolutionError, Resolver, ScopeSet};
@@ -15,6 +14,7 @@ use rustc_ast_pretty::pprust;
 use rustc_attr::StabilityLevel;
 use rustc_data_structures::intern::Interned;
 use rustc_data_structures::sync::Lrc;
+use rustc_errors::StashKey;
 use rustc_errors::{struct_span_code_err, Applicability};
 use rustc_expand::base::{Annotatable, DeriveResolutions, Indeterminate, ResolverExpand};
 use rustc_expand::base::{SyntaxExtension, SyntaxExtensionKind};
@@ -25,9 +25,8 @@ use rustc_hir::def_id::{CrateNum, DefId, LocalDefId};
 use rustc_middle::middle::stability;
 use rustc_middle::ty::RegisteredTools;
 use rustc_middle::ty::{TyCtxt, Visibility};
-use rustc_session::lint::builtin::{
-    LEGACY_DERIVE_HELPERS, SOFT_UNSTABLE, UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
-};
+use rustc_session::lint::builtin::UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES;
+use rustc_session::lint::builtin::{LEGACY_DERIVE_HELPERS, SOFT_UNSTABLE};
 use rustc_session::lint::builtin::{UNUSED_MACROS, UNUSED_MACRO_RULES};
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_session::parse::feature_err;
@@ -703,21 +702,21 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                     // situations should be reported as errors, so this is a bug.
                     this.dcx().span_delayed_bug(span, "inconsistent resolution for a macro");
                 }
-            } else {
+            } else if this.tcx.dcx().has_errors().is_none() && this.privacy_errors.is_empty() {
                 // It's possible that the macro was unresolved (indeterminate) and silently
                 // expanded into a dummy fragment for recovery during expansion.
                 // Now, post-expansion, the resolution may succeed, but we can't change the
                 // past and need to report an error.
                 // However, non-speculative `resolve_path` can successfully return private items
                 // even if speculative `resolve_path` returned nothing previously, so we skip this
-                // less informative error if the privacy error is reported elsewhere.
-                if this.privacy_errors.is_empty() {
-                    this.dcx().emit_err(CannotDetermineMacroResolution {
-                        span,
-                        kind: kind.descr(),
-                        path: Segment::names_to_string(path),
-                    });
-                }
+                // less informative error if no other error is reported elsewhere.
+
+                let err = this.dcx().create_err(CannotDetermineMacroResolution {
+                    span,
+                    kind: kind.descr(),
+                    path: Segment::names_to_string(path),
+                });
+                err.stash(span, StashKey::UndeterminedMacroResolution);
             }
         };
 

library/alloc/src/rc.rs

@@ -939,8 +939,11 @@ impl<T, A: Allocator> Rc<T, A> {
     /// it is guaranteed that exactly one of the calls returns the inner value.
     /// This means in particular that the inner value is not dropped.
     ///
-    /// This is equivalent to `Rc::try_unwrap(this).ok()`. (Note that these are not equivalent for
-    /// [`Arc`](crate::sync::Arc), due to race conditions that do not apply to `Rc`.)
+    /// [`Rc::try_unwrap`] is conceptually similar to `Rc::into_inner`.
+    /// And while they are meant for different use-cases, `Rc::into_inner(this)`
+    /// is in fact equivalent to <code>[Rc::try_unwrap]\(this).[ok][Result::ok]()</code>.
+    /// (Note that the same kind of equivalence does **not** hold true for
+    /// [`Arc`](crate::sync::Arc), due to race conditions that do not apply to `Rc`!)
     #[inline]
     #[stable(feature = "rc_into_inner", since = "1.70.0")]
     pub fn into_inner(this: Self) -> Option<T> {

library/alloc/src/sync.rs

@@ -983,9 +983,13 @@ impl<T, A: Allocator> Arc<T, A> {
     /// it is guaranteed that exactly one of the calls returns the inner value.
     /// This means in particular that the inner value is not dropped.
     ///
-    /// The similar expression `Arc::try_unwrap(this).ok()` does not
-    /// offer such a guarantee. See the last example below
-    /// and the documentation of [`Arc::try_unwrap`].
+    /// [`Arc::try_unwrap`] is conceptually similar to `Arc::into_inner`, but it
+    /// is meant for different use-cases. If used as a direct replacement
+    /// for `Arc::into_inner` anyway, such as with the expression
+    /// <code>[Arc::try_unwrap]\(this).[ok][Result::ok]()</code>, then it does
+    /// **not** give the same guarantee as described in the previous paragraph.
+    /// For more information, see the examples below and read the documentation
+    /// of [`Arc::try_unwrap`].
     ///
     /// # Examples
     ///

library/core/src/primitive_docs.rs

@@ -1384,6 +1384,30 @@ mod prim_usize {}
 /// work on references as well as they do on owned values! The implementations described here are
 /// meant for generic contexts, where the final type `T` is a type parameter or otherwise not
 /// locally known.
+///
+/// # Safety
+///
+/// For all types, `T: ?Sized`, and for all `t: &T` or `t: &mut T`, when such values cross an API
+/// boundary, the following invariants must generally be upheld:
+///
+/// * `t` is aligned to `align_of_val(t)`
+/// * `t` is dereferenceable for `size_of_val(t)` many bytes
+///
+/// If `t` points at address `a`, being "dereferenceable" for N bytes means that the memory range
+/// `[a, a + N)` is all contained within a single [allocated object].
+///
+/// For instance, this means that unsafe code in a safe function may assume these invariants are
+/// ensured of arguments passed by the caller, and it may assume that these invariants are ensured
+/// of return values from any safe functions it calls. In most cases, the inverse is also true:
+/// unsafe code must not violate these invariants when passing arguments to safe functions or
+/// returning values from safe functions; such violations may result in undefined behavior. Where
+/// exceptions to this latter requirement exist, they will be called out explicitly in documentation.
+///
+/// It is not decided yet whether unsafe code may violate these invariants temporarily on internal
+/// data. As a consequence, unsafe code which violates these invariants temporarily on internal data
+/// may become unsound in future versions of Rust depending on how this question is decided.
+///
+/// [allocated object]: ptr#allocated-object
 #[stable(feature = "rust1", since = "1.0.0")]
 mod prim_ref {}
 

library/profiler_builtins/build.rs

@@ -12,7 +12,8 @@ fn main() {
         return;
     }
 
-    let target = env::var("TARGET").expect("TARGET was not set");
+    let target_os = env::var("CARGO_CFG_TARGET_OS").expect("CARGO_CFG_TARGET_OS was not set");
+    let target_env = env::var("CARGO_CFG_TARGET_ENV").expect("CARGO_CFG_TARGET_ENV was not set");
     let cfg = &mut cc::Build::new();
 
     // FIXME: `rerun-if-changed` directives are not currently emitted and the build script
@@ -40,7 +41,7 @@ fn main() {
         "InstrProfilingBiasVar.c",
     ];
 
-    if target.contains("msvc") {
+    if target_env == "msvc" {
         // Don't pull in extra libraries on MSVC
         cfg.flag("/Zl");
         profile_sources.push("WindowsMMap.c");
@@ -55,7 +56,7 @@ fn main() {
         cfg.flag("-fno-builtin");
         cfg.flag("-fomit-frame-pointer");
         cfg.define("VISIBILITY_HIDDEN", None);
-        if !target.contains("windows") {
+        if target_os != "windows" {
             cfg.flag("-fvisibility=hidden");
             cfg.define("COMPILER_RT_HAS_UNAME", Some("1"));
         } else {

library/std/build.rs

@@ -2,41 +2,46 @@ use std::env;
 
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
-    let target = env::var("TARGET").expect("TARGET was not set");
-    if target.contains("linux")
-        || target.contains("netbsd")
-        || target.contains("dragonfly")
-        || target.contains("openbsd")
-        || target.contains("freebsd")
-        || target.contains("solaris")
-        || target.contains("illumos")
-        || target.contains("apple-darwin")
-        || target.contains("apple-ios")
-        || target.contains("apple-tvos")
-        || target.contains("apple-watchos")
-        || target.contains("uwp")
-        || target.contains("windows")
-        || target.contains("fuchsia")
-        || (target.contains("sgx") && target.contains("fortanix"))
-        || target.contains("hermit")
-        || target.contains("l4re")
-        || target.contains("redox")
-        || target.contains("haiku")
-        || target.contains("vxworks")
-        || target.contains("wasm32")
-        || target.contains("wasm64")
-        || target.contains("espidf")
-        || target.contains("solid")
-        || target.contains("nintendo-3ds")
-        || target.contains("vita")
-        || target.contains("aix")
-        || target.contains("nto")
-        || target.contains("xous")
-        || target.contains("hurd")
-        || target.contains("uefi")
-        || target.contains("teeos")
-        || target.contains("zkvm")
-        // See src/bootstrap/synthetic_targets.rs
+    let target_arch = env::var("CARGO_CFG_TARGET_ARCH").expect("CARGO_CFG_TARGET_ARCH was not set");
+    let target_os = env::var("CARGO_CFG_TARGET_OS").expect("CARGO_CFG_TARGET_OS was not set");
+    let target_vendor =
+        env::var("CARGO_CFG_TARGET_VENDOR").expect("CARGO_CFG_TARGET_VENDOR was not set");
+    let target_env = env::var("CARGO_CFG_TARGET_ENV").expect("CARGO_CFG_TARGET_ENV was not set");
+
+    if target_os == "linux"
+        || target_os == "netbsd"
+        || target_os == "dragonfly"
+        || target_os == "openbsd"
+        || target_os == "freebsd"
+        || target_os == "solaris"
+        || target_os == "illumos"
+        || target_os == "macos"
+        || target_os == "ios"
+        || target_os == "tvos"
+        || target_os == "watchos"
+        || target_os == "windows"
+        || target_os == "fuchsia"
+        || (target_vendor == "fortranix" && target_env == "sgx")
+        || target_os == "hermit"
+        || target_os == "l4re"
+        || target_os == "redox"
+        || target_os == "haiku"
+        || target_os == "vxworks"
+        || target_arch == "wasm32"
+        || target_arch == "wasm64"
+        || target_os == "espidf"
+        || target_os.starts_with("solid")
+        || (target_vendor == "nintendo" && target_env == "newlib")
+        || target_os == "vita"
+        || target_os == "aix"
+        || target_os == "nto"
+        || target_os == "xous"
+        || target_os == "hurd"
+        || target_os == "uefi"
+        || target_os == "teeos"
+        || target_os == "zkvm"
+
+        // See src/bootstrap/src/core/build_steps/synthetic_targets.rs
         || env::var("RUSTC_BOOTSTRAP_SYNTHETIC_TARGET").is_ok()
     {
         // These platforms don't have any special requirements.
@@ -48,7 +53,7 @@ fn main() {
         // - mipsel-sony-psp
         // - nvptx64-nvidia-cuda
         // - arch=avr
-        // - JSON targets
+        // - JSON targets not describing an excluded target above.
         // - Any new targets that have not been explicitly added above.
         println!("cargo:rustc-cfg=feature=\"restricted-std\"");
     }

library/std/src/sys/pal/unix/locks/pthread_mutex.rs

@@ -1,4 +1,5 @@
 use crate::cell::UnsafeCell;
+use crate::io::Error;
 use crate::mem::{forget, MaybeUninit};
 use crate::sys::cvt_nz;
 use crate::sys_common::lazy_box::{LazyBox, LazyInit};
@@ -103,8 +104,24 @@ impl Mutex {
 
     #[inline]
     pub unsafe fn lock(&self) {
+        #[cold]
+        #[inline(never)]
+        fn fail() -> ! {
+            let error = Error::last_os_error();
+            panic!("failed to lock mutex: {error}");
+        }
+
         let r = libc::pthread_mutex_lock(raw(self));
-        debug_assert_eq!(r, 0);
+        // As we set the mutex type to `PTHREAD_MUTEX_NORMAL` above, we expect
+        // the lock call to never fail. Unfortunately however, some platforms
+        // (Solaris) do not conform to the standard, and instead always provide
+        // deadlock detection. How kind of them! Unfortunately that means that
+        // we need to check the error code here. To save us from UB on other
+        // less well-behaved platforms in the future, we do it even on "good"
+        // platforms like macOS. See #120147 for more context.
+        if r != 0 {
+            fail()
+        }
     }
 
     #[inline]

library/std/src/sys/pal/windows/fs.rs

@@ -112,6 +112,13 @@ impl fmt::Debug for ReadDir {
 impl Iterator for ReadDir {
     type Item = io::Result<DirEntry>;
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
+        if self.handle.0 == c::INVALID_HANDLE_VALUE {
+            // This iterator was initialized with an `INVALID_HANDLE_VALUE` as its handle.
+            // Simply return `None` because this is only the case when `FindFirstFileW` in
+            // the construction of this iterator returns `ERROR_FILE_NOT_FOUND` which means
+            // no matchhing files can be found.
+            return None;
+        }
         if let Some(first) = self.first.take() {
             if let Some(e) = DirEntry::new(&self.root, &first) {
                 return Some(Ok(e));
@@ -1068,14 +1075,39 @@ pub fn readdir(p: &Path) -> io::Result<ReadDir> {
     unsafe {
         let mut wfd = mem::zeroed();
         let find_handle = c::FindFirstFileW(path.as_ptr(), &mut wfd);
+
         if find_handle != c::INVALID_HANDLE_VALUE {
             Ok(ReadDir {
                 handle: FindNextFileHandle(find_handle),
                 root: Arc::new(root),
                 first: Some(wfd),
             })
         } else {
-            Err(Error::last_os_error())
+            // The status `ERROR_FILE_NOT_FOUND` is returned by the `FindFirstFileW` function
+            // if no matching files can be found, but not necessarily that the path to find the
+            // files in does not exist.
+            //
+            // Hence, a check for whether the path to search in exists is added when the last
+            // os error returned by Windows is `ERROR_FILE_NOT_FOUND` to handle this scenario.
+            // If that is the case, an empty `ReadDir` iterator is returned as it returns `None`
+            // in the initial `.next()` invocation because `ERROR_NO_MORE_FILES` would have been
+            // returned by the `FindNextFileW` function.
+            //
+            // See issue #120040: https://github.com/rust-lang/rust/issues/120040.
+            let last_error = api::get_last_error();
+            if last_error.code == c::ERROR_FILE_NOT_FOUND {
+                return Ok(ReadDir {
+                    handle: FindNextFileHandle(find_handle),
+                    root: Arc::new(root),
+                    first: None,
+                });
+            }
+
+            // Just return the error constructed from the raw OS error if the above is not the case.
+            //
+            // Note: `ERROR_PATH_NOT_FOUND` would have been returned by the `FindFirstFileW` function
+            // when the path to search in does not exist in the first place.
+            Err(Error::from_raw_os_error(last_error.code as i32))
         }
     }
 }

tests/ui/derives/issue-36617.rs

@@ -1,16 +1,16 @@
-#![derive(Copy)] //~ ERROR cannot determine resolution for the attribute macro `derive`
+#![derive(Copy)]
 //~^ ERROR `derive` attribute cannot be used at crate level
 
-#![test]//~ ERROR cannot determine resolution for the attribute macro `test`
+#![test]
 //~^ ERROR `test` attribute cannot be used at crate level
 
-#![test_case]//~ ERROR cannot determine resolution for the attribute macro `test_case`
+#![test_case]
 //~^ ERROR `test_case` attribute cannot be used at crate level
 
-#![bench]//~ ERROR cannot determine resolution for the attribute macro `bench`
+#![bench]
 //~^ ERROR `bench` attribute cannot be used at crate level
 
-#![global_allocator]//~ ERROR cannot determine resolution for the attribute macro `global_allocator`
+#![global_allocator]
 //~^ ERROR `global_allocator` attribute cannot be used at crate level
 
 fn main() {}