Auto merge of rust-lang#122803 - jhpratt:rollup-nmgs79k, r=jhpratt

Rollup of 8 pull requests

Successful merges:

 - rust-lang#122545 (Ignore paths from expansion in `unused_qualifications`)
 - rust-lang#122729 (Relax SeqCst ordering in standard library.)
 - rust-lang#122740 (use more accurate terminology)
 - rust-lang#122749 (make `type_flags(ReError) & HAS_ERROR`)
 - rust-lang#122764 (coverage: Remove incorrect assertions from counter allocation)
 - rust-lang#122765 (Add `usize::MAX` arg tests for Vec)
 - rust-lang#122776 (Rename `hir::Let` into `hir::LetExpr`)
 - rust-lang#122786 (compiletest: Introduce `remove_and_create_dir_all()` helper)

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

Author: bors

Diff for: compiler/rustc_ast_lowering/src/expr.rs

@@ -157,7 +157,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     hir::ExprKind::AddrOf(*k, *m, ohs)
                 }
                 ExprKind::Let(pat, scrutinee, span, is_recovered) => {
-                    hir::ExprKind::Let(self.arena.alloc(hir::Let {
+                    hir::ExprKind::Let(self.arena.alloc(hir::LetExpr {
                         span: self.lower_span(*span),
                         pat: self.lower_pat(pat),
                         ty: None,

Diff for: compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -434,10 +434,6 @@ fn check_opaque_type_parameter_valid(
     // Only check the parent generics, which will ignore any of the
     // duplicated lifetime args that come from reifying late-bounds.
     for (i, arg) in opaque_type_key.args.iter().take(parent_generics.count()).enumerate() {
-        if let Err(guar) = arg.error_reported() {
-            return Err(guar);
-        }
-
         let arg_is_param = match arg.unpack() {
             GenericArgKind::Type(ty) => matches!(ty.kind(), ty::Param(_)),
             GenericArgKind::Lifetime(lt) if is_ty_alias => {

Diff for: compiler/rustc_hir/src/hir.rs

@@ -1259,7 +1259,7 @@ pub struct Arm<'hir> {
 /// In an `if let`, imagine it as `if (let <pat> = <expr>) { ... }`; in a let-else, it is part of
 /// the desugaring to if-let. Only let-else supports the type annotation at present.
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
-pub struct Let<'hir> {
+pub struct LetExpr<'hir> {
     pub span: Span,
     pub pat: &'hir Pat<'hir>,
     pub ty: Option<&'hir Ty<'hir>>,
@@ -1852,7 +1852,7 @@ pub enum ExprKind<'hir> {
     ///
     /// These are not `Local` and only occur as expressions.
     /// The `let Some(x) = foo()` in `if let Some(x) = foo()` is an example of `Let(..)`.
-    Let(&'hir Let<'hir>),
+    Let(&'hir LetExpr<'hir>),
     /// An `if` block, with an optional else block.
     ///
     /// I.e., `if <expr> { <expr> } else { <expr> }`.

Diff for: compiler/rustc_hir/src/intravisit.rs

@@ -753,7 +753,7 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
         ExprKind::DropTemps(ref subexpression) => {
             try_visit!(visitor.visit_expr(subexpression));
         }
-        ExprKind::Let(Let { span: _, pat, ty, init, is_recovered: _ }) => {
+        ExprKind::Let(LetExpr { span: _, pat, ty, init, is_recovered: _ }) => {
             // match the visit order in walk_local
             try_visit!(visitor.visit_expr(init));
             try_visit!(visitor.visit_pat(pat));

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

@@ -1387,7 +1387,7 @@ impl<'a> State<'a> {
                 // Print `}`:
                 self.bclose_maybe_open(expr.span, true);
             }
-            hir::ExprKind::Let(&hir::Let { pat, ty, init, .. }) => {
+            hir::ExprKind::Let(&hir::LetExpr { pat, ty, init, .. }) => {
                 self.print_let(pat, ty, init);
             }
             hir::ExprKind::If(test, blk, elseopt) => {

Diff for: compiler/rustc_hir_typeck/src/_match.rs

@@ -317,7 +317,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         err.note("`if` expressions without `else` evaluate to `()`");
         err.help("consider adding an `else` block that evaluates to the expected type");
         *error = true;
-        if let ExprKind::Let(hir::Let { span, pat, init, .. }) = cond_expr.kind
+        if let ExprKind::Let(hir::LetExpr { span, pat, init, .. }) = cond_expr.kind
             && let ExprKind::Block(block, _) = then_expr.kind
             // Refutability checks occur on the MIR, so we approximate it here by checking
             // if we have an enum with a single variant or a struct in the pattern.

Diff for: compiler/rustc_hir_typeck/src/expr.rs

@@ -1261,7 +1261,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    pub(super) fn check_expr_let(&self, let_expr: &'tcx hir::Let<'tcx>, hir_id: HirId) -> Ty<'tcx> {
+    pub(super) fn check_expr_let(
+        &self,
+        let_expr: &'tcx hir::LetExpr<'tcx>,
+        hir_id: HirId,
+    ) -> Ty<'tcx> {
         // for let statements, this is done in check_stmt
         let init = let_expr.init;
         self.warn_if_unreachable(init.hir_id, init.span, "block in `let` expression");

Diff for: compiler/rustc_hir_typeck/src/expr_use_visitor.rs

@@ -245,7 +245,7 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
                 }
             }
 
-            hir::ExprKind::Let(hir::Let { pat, init, .. }) => {
+            hir::ExprKind::Let(hir::LetExpr { pat, init, .. }) => {
                 self.walk_local(init, pat, None, |t| t.borrow_expr(init, ty::ImmBorrow))
             }
 

Diff for: compiler/rustc_hir_typeck/src/gather_locals.rs

@@ -29,7 +29,7 @@ impl<'a> DeclOrigin<'a> {
     }
 }
 
-/// A declaration is an abstraction of [hir::Local] and [hir::Let].
+/// A declaration is an abstraction of [hir::Local] and [hir::LetExpr].
 ///
 /// It must have a hir_id, as this is how we connect gather_locals to the check functions.
 pub(super) struct Declaration<'a> {
@@ -48,9 +48,9 @@ impl<'a> From<&'a hir::Local<'a>> for Declaration<'a> {
     }
 }
 
-impl<'a> From<(&'a hir::Let<'a>, hir::HirId)> for Declaration<'a> {
-    fn from((let_expr, hir_id): (&'a hir::Let<'a>, hir::HirId)) -> Self {
-        let hir::Let { pat, ty, span, init, is_recovered: _ } = *let_expr;
+impl<'a> From<(&'a hir::LetExpr<'a>, hir::HirId)> for Declaration<'a> {
+    fn from((let_expr, hir_id): (&'a hir::LetExpr<'a>, hir::HirId)) -> Self {
+        let hir::LetExpr { pat, ty, span, init, is_recovered: _ } = *let_expr;
         Declaration { hir_id, pat, ty, span, init: Some(init), origin: DeclOrigin::LetExpr }
     }
 }

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

@@ -94,9 +94,6 @@ impl<'tcx> InferCtxt<'tcx> {
         cause: &ObligationCause<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
     ) -> InferResult<'tcx, ()> {
-        if a.references_error() || b.references_error() {
-            return Ok(InferOk { value: (), obligations: vec![] });
-        }
         let process = |a: Ty<'tcx>, b: Ty<'tcx>| match *a.kind() {
             ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) if def_id.is_local() => {
                 let def_id = def_id.expect_local();

Diff for: compiler/rustc_middle/src/ty/region.rs

@@ -251,6 +251,7 @@ impl<'tcx> Region<'tcx> {
             }
             ty::ReError(_) => {
                 flags = flags | TypeFlags::HAS_FREE_REGIONS;
+                flags = flags | TypeFlags::HAS_ERROR;
             }
         }
 

Diff for: compiler/rustc_mir_transform/src/coverage/counters.rs

@@ -1,13 +1,12 @@
+use std::fmt::{self, Debug};
+
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::graph::WithNumNodes;
-use rustc_index::bit_set::BitSet;
 use rustc_index::IndexVec;
-use rustc_middle::mir::coverage::*;
+use rustc_middle::mir::coverage::{CounterId, CovTerm, Expression, ExpressionId, Op};
 
-use super::graph::{BasicCoverageBlock, CoverageGraph, TraverseCoverageGraphWithLoops};
-
-use std::fmt::{self, Debug};
+use crate::coverage::graph::{BasicCoverageBlock, CoverageGraph, TraverseCoverageGraphWithLoops};
 
 /// The coverage counter or counter expression associated with a particular
 /// BCB node or BCB edge.
@@ -18,10 +17,6 @@ pub(super) enum BcbCounter {
 }
 
 impl BcbCounter {
-    fn is_expression(&self) -> bool {
-        matches!(self, Self::Expression { .. })
-    }
-
     pub(super) fn as_term(&self) -> CovTerm {
         match *self {
             BcbCounter::Counter { id, .. } => CovTerm::Counter(id),
@@ -60,10 +55,6 @@ pub(super) struct CoverageCounters {
     /// We currently don't iterate over this map, but if we do in the future,
     /// switch it back to `FxIndexMap` to avoid query stability hazards.
     bcb_edge_counters: FxHashMap<(BasicCoverageBlock, BasicCoverageBlock), BcbCounter>,
-    /// Tracks which BCBs have a counter associated with some incoming edge.
-    /// Only used by assertions, to verify that BCBs with incoming edge
-    /// counters do not have their own physical counters (expressions are allowed).
-    bcb_has_incoming_edge_counters: BitSet<BasicCoverageBlock>,
     /// Table of expression data, associating each expression ID with its
     /// corresponding operator (+ or -) and its LHS/RHS operands.
     expressions: IndexVec<ExpressionId, Expression>,
@@ -83,7 +74,6 @@ impl CoverageCounters {
             counter_increment_sites: IndexVec::new(),
             bcb_counters: IndexVec::from_elem_n(None, num_bcbs),
             bcb_edge_counters: FxHashMap::default(),
-            bcb_has_incoming_edge_counters: BitSet::new_empty(num_bcbs),
             expressions: IndexVec::new(),
         };
 
@@ -122,14 +112,6 @@ impl CoverageCounters {
     }
 
     fn set_bcb_counter(&mut self, bcb: BasicCoverageBlock, counter_kind: BcbCounter) -> BcbCounter {
-        assert!(
-            // If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also
-            // have an expression (to be injected into an existing `BasicBlock` represented by this
-            // `BasicCoverageBlock`).
-            counter_kind.is_expression() || !self.bcb_has_incoming_edge_counters.contains(bcb),
-            "attempt to add a `Counter` to a BCB target with existing incoming edge counters"
-        );
-
         if let Some(replaced) = self.bcb_counters[bcb].replace(counter_kind) {
             bug!(
                 "attempt to set a BasicCoverageBlock coverage counter more than once; \
@@ -146,19 +128,6 @@ impl CoverageCounters {
         to_bcb: BasicCoverageBlock,
         counter_kind: BcbCounter,
     ) -> BcbCounter {
-        // If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also
-        // have an expression (to be injected into an existing `BasicBlock` represented by this
-        // `BasicCoverageBlock`).
-        if let Some(node_counter) = self.bcb_counter(to_bcb)
-            && !node_counter.is_expression()
-        {
-            bug!(
-                "attempt to add an incoming edge counter from {from_bcb:?} \
-                when the target BCB already has {node_counter:?}"
-            );
-        }
-
-        self.bcb_has_incoming_edge_counters.insert(to_bcb);
         if let Some(replaced) = self.bcb_edge_counters.insert((from_bcb, to_bcb), counter_kind) {
             bug!(
                 "attempt to set an edge counter more than once; from_bcb: \

Diff for: compiler/rustc_resolve/src/late.rs

@@ -4672,7 +4672,9 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
             return;
         }
 
-        if path.iter().any(|seg| seg.ident.span.from_expansion()) {
+        if finalize.path_span.from_expansion()
+            || path.iter().any(|seg| seg.ident.span.from_expansion())
+        {
             return;
         }
 

Diff for: compiler/rustc_type_ir/src/flags.rs

@@ -85,7 +85,7 @@ bitflags! {
                                           | TypeFlags::HAS_TY_INHERENT.bits()
                                           | TypeFlags::HAS_CT_PROJECTION.bits();
 
-        /// Is an error type/const reachable?
+        /// Is an error type/lifetime/const reachable?
         const HAS_ERROR                   = 1 << 15;
 
         /// Does this have any region that "appears free" in the type?

Diff for: config.example.toml

@@ -915,6 +915,6 @@
 # Available options: fast, balanced, best
 #compression-profile = "fast"
 
-# Copy the linker, DLLs, and various libraries from MinGW into the rustc toolchain.
+# Copy the linker, DLLs, and various libraries from MinGW into the Rust toolchain.
 # Only applies when the host or target is pc-windows-gnu.
 #include-mingw-linker = true

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

@@ -233,7 +233,7 @@ macro_rules! acquire {
 ///     let val = Arc::clone(&val);
 ///
 ///     thread::spawn(move || {
-///         let v = val.fetch_add(1, Ordering::SeqCst);
+///         let v = val.fetch_add(1, Ordering::Relaxed);
 ///         println!("{v:?}");
 ///     });
 /// }

Diff for: library/alloc/tests/vec.rs

@@ -2643,3 +2643,44 @@ fn test_vec_from_array_ref() {
 fn test_vec_from_array_mut_ref() {
     assert_eq!(Vec::from(&mut [1, 2, 3]), vec![1, 2, 3]);
 }
+
+/// This assortment of tests, in combination with miri, verifies we handle UB on fishy arguments
+/// in the stdlib. Draining and extending the allocation are fairly well-tested earlier, but
+/// `vec.insert(usize::MAX, val)` once slipped by!
+///
+/// All code that manipulates the collection types should be tested with "trivially wrong" args.
+#[test]
+fn max_dont_panic() {
+    let mut v = vec![0];
+    let _ = v.get(usize::MAX);
+    v.shrink_to(usize::MAX);
+    v.truncate(usize::MAX);
+}
+
+#[test]
+#[should_panic]
+fn max_insert() {
+    let mut v = vec![0];
+    v.insert(usize::MAX, 1);
+}
+
+#[test]
+#[should_panic]
+fn max_remove() {
+    let mut v = vec![0];
+    v.remove(usize::MAX);
+}
+
+#[test]
+#[should_panic]
+fn max_splice() {
+    let mut v = vec![0];
+    v.splice(usize::MAX.., core::iter::once(1));
+}
+
+#[test]
+#[should_panic]
+fn max_swap_remove() {
+    let mut v = vec![0];
+    v.swap_remove(usize::MAX);
+}

Diff for: library/core/src/alloc/global.rs

@@ -24,10 +24,7 @@ use crate::ptr;
 /// use std::alloc::{GlobalAlloc, Layout};
 /// use std::cell::UnsafeCell;
 /// use std::ptr::null_mut;
-/// use std::sync::atomic::{
-///     AtomicUsize,
-///     Ordering::{Acquire, SeqCst},
-/// };
+/// use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
 ///
 /// const ARENA_SIZE: usize = 128 * 1024;
 /// const MAX_SUPPORTED_ALIGN: usize = 4096;
@@ -61,7 +58,7 @@ use crate::ptr;
 ///         let mut allocated = 0;
 ///         if self
 ///             .remaining
-///             .fetch_update(SeqCst, SeqCst, |mut remaining| {
+///             .fetch_update(Relaxed, Relaxed, |mut remaining| {
 ///                 if size > remaining {
 ///                     return None;
 ///                 }
@@ -81,7 +78,7 @@ use crate::ptr;
 ///
 /// fn main() {
 ///     let _s = format!("allocating a string!");
-///     let currently = ALLOCATOR.remaining.load(Acquire);
+///     let currently = ALLOCATOR.remaining.load(Relaxed);
 ///     println!("allocated so far: {}", ARENA_SIZE - currently);
 /// }
 /// ```

Diff for: library/panic_unwind/src/emcc.rs

@@ -84,7 +84,7 @@ pub unsafe fn cleanup(ptr: *mut u8) -> Box<dyn Any + Send> {
         super::__rust_foreign_exception();
     }
 
-    let was_caught = (*adjusted_ptr).caught.swap(true, Ordering::SeqCst);
+    let was_caught = (*adjusted_ptr).caught.swap(true, Ordering::Relaxed);
     if was_caught {
         // Since cleanup() isn't allowed to panic, we just abort instead.
         intrinsics::abort();

Diff for: library/proc_macro/src/bridge/handle.rs

@@ -21,15 +21,15 @@ impl<T> OwnedStore<T> {
     pub(super) fn new(counter: &'static AtomicU32) -> Self {
         // Ensure the handle counter isn't 0, which would panic later,
         // when `NonZero::new` (aka `Handle::new`) is called in `alloc`.
-        assert_ne!(counter.load(Ordering::SeqCst), 0);
+        assert_ne!(counter.load(Ordering::Relaxed), 0);
 
         OwnedStore { counter, data: BTreeMap::new() }
     }
 }
 
 impl<T> OwnedStore<T> {
     pub(super) fn alloc(&mut self, x: T) -> Handle {
-        let counter = self.counter.fetch_add(1, Ordering::SeqCst);
+        let counter = self.counter.fetch_add(1, Ordering::Relaxed);
         let handle = Handle::new(counter).expect("`proc_macro` handle counter overflowed");
         assert!(self.data.insert(handle, x).is_none());
         handle

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

@@ -329,7 +329,7 @@ static HOOK: AtomicPtr<()> = AtomicPtr::new(ptr::null_mut());
 /// ```
 #[unstable(feature = "alloc_error_hook", issue = "51245")]
 pub fn set_alloc_error_hook(hook: fn(Layout)) {
-    HOOK.store(hook as *mut (), Ordering::SeqCst);
+    HOOK.store(hook as *mut (), Ordering::Release);
 }
 
 /// Unregisters the current allocation error hook, returning it.
@@ -339,7 +339,7 @@ pub fn set_alloc_error_hook(hook: fn(Layout)) {
 /// If no custom hook is registered, the default hook will be returned.
 #[unstable(feature = "alloc_error_hook", issue = "51245")]
 pub fn take_alloc_error_hook() -> fn(Layout) {
-    let hook = HOOK.swap(ptr::null_mut(), Ordering::SeqCst);
+    let hook = HOOK.swap(ptr::null_mut(), Ordering::Acquire);
     if hook.is_null() { default_alloc_error_hook } else { unsafe { mem::transmute(hook) } }
 }
 
@@ -362,7 +362,7 @@ fn default_alloc_error_hook(layout: Layout) {
 #[alloc_error_handler]
 #[unstable(feature = "alloc_internals", issue = "none")]
 pub fn rust_oom(layout: Layout) -> ! {
-    let hook = HOOK.load(Ordering::SeqCst);
+    let hook = HOOK.load(Ordering::Acquire);
     let hook: fn(Layout) =
         if hook.is_null() { default_alloc_error_hook } else { unsafe { mem::transmute(hook) } };
     hook(layout);

Diff for: library/std/src/net/test.rs

@@ -7,12 +7,12 @@ use crate::sync::atomic::{AtomicUsize, Ordering};
 static PORT: AtomicUsize = AtomicUsize::new(0);
 
 pub fn next_test_ip4() -> SocketAddr {
-    let port = PORT.fetch_add(1, Ordering::SeqCst) as u16 + base_port();
+    let port = PORT.fetch_add(1, Ordering::Relaxed) as u16 + base_port();
     SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), port))
 }
 
 pub fn next_test_ip6() -> SocketAddr {
-    let port = PORT.fetch_add(1, Ordering::SeqCst) as u16 + base_port();
+    let port = PORT.fetch_add(1, Ordering::Relaxed) as u16 + base_port();
     SocketAddr::V6(SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), port, 0, 0))
 }
 

Diff for: library/std/src/panicking.rs

@@ -272,7 +272,7 @@ fn default_hook(info: &PanicInfo<'_>) {
                 drop(backtrace::print(err, crate::backtrace_rs::PrintFmt::Full))
             }
             Some(BacktraceStyle::Off) => {
-                if FIRST_PANIC.swap(false, Ordering::SeqCst) {
+                if FIRST_PANIC.swap(false, Ordering::Relaxed) {
                     let _ = writeln!(
                         err,
                         "note: run with `RUST_BACKTRACE=1` environment variable to display a \