Auto merge of rust-lang#123143 - matthiaskrgr:rollup-w6e5gnl, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#121943 (Clarify atomic bit validity)
 - rust-lang#123089 (Add invariant to VecDeque::pop_* that len < cap if pop successful)
 - rust-lang#123101 (Delegation: fix ICE on wrong `Self` instantiation)
 - rust-lang#123130 (Load missing type of impl associated constant from trait definition)
 - rust-lang#123133 (chore: fix some comments)
 - rust-lang#123136 (Some wording improvement)
 - rust-lang#123139 (`num::NonZero::get` can be 1 transmute instead of 2)
 - rust-lang#123142 (Let nils know about changes to target docs)

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

Author: bors

INSTALL.md

@@ -151,8 +151,8 @@ toolchain.
    directory and uncomment the line `MSYS2_PATH_TYPE=inherit`.
 
    You could install and use MSYS2's version of git instead with `pacman`,
-   however this is not recommended as it's excrutiatingly slow, and not frequently
-   tested for compatability.
+   however this is not recommended as it's excruciatingly slow, and not frequently
+   tested for compatibility.
 
 3. Start a MINGW64 or MINGW32 shell (depending on whether you want 32-bit
    or 64-bit Rust) either from your start menu, or by running `mingw64.exe`

compiler/rustc_ast_pretty/src/pprust/state/expr.rs

@@ -75,7 +75,7 @@ pub(crate) struct FixupContext {
 }
 
 /// The default amount of fixing is minimal fixing. Fixups should be turned on
-/// in a targetted fashion where needed.
+/// in a targeted fashion where needed.
 impl Default for FixupContext {
     fn default() -> Self {
         FixupContext {

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -592,7 +592,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
             }
             self.cx.borrowck_context.constraints.outlives_constraints.push(constraint)
         }
-        // If the region is live at at least one location in the promoted MIR,
+        // If the region is live at least one location in the promoted MIR,
         // then add a liveness constraint to the main MIR for this region
         // at the location provided as an argument to this method
         //

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -409,7 +409,7 @@ fn const_validate_mplace<'mir, 'tcx>(
             }
         };
         ecx.const_validate_operand(&mplace.into(), path, &mut ref_tracking, mode)
-            // Instead of just reporting the `InterpError` via the usual machinery, we give a more targetted
+            // Instead of just reporting the `InterpError` via the usual machinery, we give a more targeted
             // error about the validation failure.
             .map_err(|error| report_validation_error(&ecx, error, alloc_id))?;
         inner = true;

compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs

@@ -11,7 +11,7 @@ use super::HirTyLowerer;
 impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
     /// Prohibit or lint against *bare* trait object types depending on the edition.
     ///
-    /// *Bare* trait object types are ones that aren't preceeded by the keyword `dyn`.
+    /// *Bare* trait object types are ones that aren't preceded by the keyword `dyn`.
     /// In edition 2021 and onward we emit a hard error for them.
     pub(super) fn prohibit_or_lint_bare_trait_object_ty(
         &self,

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -2212,6 +2212,17 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             try_emit("delegation with early bound generics");
         }
 
+        // There is no way to instantiate `Self` param for caller if
+        // 1. callee is a trait method
+        // 2. delegation item isn't an associative item
+        if let DefKind::AssocFn = self.tcx().def_kind(sig_id)
+            && let DefKind::Fn = self.tcx().def_kind(self.item_def_id())
+            && self.tcx().associated_item(sig_id).container
+                == ty::AssocItemContainer::TraitContainer
+        {
+            try_emit("delegation to a trait method from a free function");
+        }
+
         if self.tcx().asyncness(sig_id) == ty::Asyncness::Yes {
             try_emit("delegation to async functions");
         }

compiler/rustc_hir_typeck/src/lib.rs

@@ -83,20 +83,6 @@ macro_rules! type_error_struct {
     })
 }
 
-/// If this `DefId` is a "primary tables entry", returns
-/// `Some((body_id, body_ty, fn_sig))`. Otherwise, returns `None`.
-///
-/// If this function returns `Some`, then `typeck_results(def_id)` will
-/// succeed; if it returns `None`, then `typeck_results(def_id)` may or
-/// may not succeed. In some cases where this function returns `None`
-/// (notably closures), `typeck_results(def_id)` would wind up
-/// redirecting to the owning function.
-fn primary_body_of(
-    node: Node<'_>,
-) -> Option<(hir::BodyId, Option<&hir::Ty<'_>>, Option<&hir::FnSig<'_>>)> {
-    Some((node.body_id()?, node.ty(), node.fn_sig()))
-}
-
 fn has_typeck_results(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     // Closures' typeck results come from their outermost function,
     // as they are part of the same "inference environment".
@@ -106,7 +92,7 @@ fn has_typeck_results(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     }
 
     if let Some(def_id) = def_id.as_local() {
-        primary_body_of(tcx.hir_node_by_def_id(def_id)).is_some()
+        tcx.hir_node_by_def_id(def_id).body_id().is_some()
     } else {
         false
     }
@@ -163,7 +149,7 @@ fn typeck_with_fallback<'tcx>(
     let span = tcx.hir().span(id);
 
     // Figure out what primary body this item has.
-    let (body_id, body_ty, fn_sig) = primary_body_of(node).unwrap_or_else(|| {
+    let body_id = node.body_id().unwrap_or_else(|| {
         span_bug!(span, "can't type-check body of {:?}", def_id);
     });
     let body = tcx.hir().body(body_id);
@@ -176,7 +162,7 @@ fn typeck_with_fallback<'tcx>(
     }
     let mut fcx = FnCtxt::new(&root_ctxt, param_env, def_id);
 
-    if let Some(hir::FnSig { header, decl, .. }) = fn_sig {
+    if let Some(hir::FnSig { header, decl, .. }) = node.fn_sig() {
         let fn_sig = if decl.output.get_infer_ret_ty().is_some() {
             fcx.lowerer().lower_fn_ty(id, header.unsafety, header.abi, decl, None, None)
         } else {
@@ -191,42 +177,7 @@ fn typeck_with_fallback<'tcx>(
 
         check_fn(&mut fcx, fn_sig, None, decl, def_id, body, tcx.features().unsized_fn_params);
     } else {
-        let expected_type = if let Some(&hir::Ty { kind: hir::TyKind::Infer, span, .. }) = body_ty {
-            Some(fcx.next_ty_var(TypeVariableOrigin {
-                kind: TypeVariableOriginKind::TypeInference,
-                span,
-            }))
-        } else if let Node::AnonConst(_) = node {
-            match tcx.parent_hir_node(id) {
-                Node::Ty(&hir::Ty { kind: hir::TyKind::Typeof(ref anon_const), .. })
-                    if anon_const.hir_id == id =>
-                {
-                    Some(fcx.next_ty_var(TypeVariableOrigin {
-                        kind: TypeVariableOriginKind::TypeInference,
-                        span,
-                    }))
-                }
-                Node::Expr(&hir::Expr { kind: hir::ExprKind::InlineAsm(asm), .. })
-                | Node::Item(&hir::Item { kind: hir::ItemKind::GlobalAsm(asm), .. }) => {
-                    asm.operands.iter().find_map(|(op, _op_sp)| match op {
-                        hir::InlineAsmOperand::Const { anon_const } if anon_const.hir_id == id => {
-                            // Inline assembly constants must be integers.
-                            Some(fcx.next_int_var())
-                        }
-                        hir::InlineAsmOperand::SymFn { anon_const } if anon_const.hir_id == id => {
-                            Some(fcx.next_ty_var(TypeVariableOrigin {
-                                kind: TypeVariableOriginKind::MiscVariable,
-                                span,
-                            }))
-                        }
-                        _ => None,
-                    })
-                }
-                _ => None,
-            }
-        } else {
-            None
-        };
+        let expected_type = infer_type_if_missing(&fcx, node);
         let expected_type = expected_type.unwrap_or_else(fallback);
 
         let expected_type = fcx.normalize(body.value.span, expected_type);
@@ -296,6 +247,59 @@ fn typeck_with_fallback<'tcx>(
     typeck_results
 }
 
+fn infer_type_if_missing<'tcx>(fcx: &FnCtxt<'_, 'tcx>, node: Node<'tcx>) -> Option<Ty<'tcx>> {
+    let tcx = fcx.tcx;
+    let def_id = fcx.body_id;
+    let expected_type = if let Some(&hir::Ty { kind: hir::TyKind::Infer, span, .. }) = node.ty() {
+        if let Some(item) = tcx.opt_associated_item(def_id.into())
+            && let ty::AssocKind::Const = item.kind
+            && let ty::ImplContainer = item.container
+            && let Some(trait_item) = item.trait_item_def_id
+        {
+            let args =
+                tcx.impl_trait_ref(item.container_id(tcx)).unwrap().instantiate_identity().args;
+            Some(tcx.type_of(trait_item).instantiate(tcx, args))
+        } else {
+            Some(fcx.next_ty_var(TypeVariableOrigin {
+                kind: TypeVariableOriginKind::TypeInference,
+                span,
+            }))
+        }
+    } else if let Node::AnonConst(_) = node {
+        let id = tcx.local_def_id_to_hir_id(def_id);
+        match tcx.parent_hir_node(id) {
+            Node::Ty(&hir::Ty { kind: hir::TyKind::Typeof(ref anon_const), span, .. })
+                if anon_const.hir_id == id =>
+            {
+                Some(fcx.next_ty_var(TypeVariableOrigin {
+                    kind: TypeVariableOriginKind::TypeInference,
+                    span,
+                }))
+            }
+            Node::Expr(&hir::Expr { kind: hir::ExprKind::InlineAsm(asm), span, .. })
+            | Node::Item(&hir::Item { kind: hir::ItemKind::GlobalAsm(asm), span, .. }) => {
+                asm.operands.iter().find_map(|(op, _op_sp)| match op {
+                    hir::InlineAsmOperand::Const { anon_const } if anon_const.hir_id == id => {
+                        // Inline assembly constants must be integers.
+                        Some(fcx.next_int_var())
+                    }
+                    hir::InlineAsmOperand::SymFn { anon_const } if anon_const.hir_id == id => {
+                        Some(fcx.next_ty_var(TypeVariableOrigin {
+                            kind: TypeVariableOriginKind::MiscVariable,
+                            span,
+                        }))
+                    }
+                    _ => None,
+                })
+            }
+            _ => None,
+        }
+    } else {
+        None
+    };
+    expected_type
+}
+
 /// When `check_fn` is invoked on a coroutine (i.e., a body that
 /// includes yield), it returns back some information about the yield
 /// points.

compiler/rustc_parse/src/parser/expr.rs

@@ -2768,7 +2768,7 @@ impl<'a> Parser<'a> {
                 };
                 return if self.token.kind == token::CloseDelim(Delimiter::Parenthesis) {
                     // We know for sure we have seen `for ($SOMETHING in $EXPR)`, so we recover the
-                    // parser state and emit a targetted suggestion.
+                    // parser state and emit a targeted suggestion.
                     let span = vec![start_span, self.token.span];
                     let right = self.prev_token.span.between(self.look_ahead(1, |t| t.span));
                     self.bump(); // )

library/alloc/src/collections/vec_deque/mod.rs

@@ -1614,7 +1614,10 @@ impl<T, A: Allocator> VecDeque<T, A> {
             let old_head = self.head;
             self.head = self.to_physical_idx(1);
             self.len -= 1;
-            Some(unsafe { self.buffer_read(old_head) })
+            unsafe {
+                core::hint::assert_unchecked(self.len < self.capacity());
+                Some(self.buffer_read(old_head))
+            }
         }
     }
 
@@ -1638,7 +1641,10 @@ impl<T, A: Allocator> VecDeque<T, A> {
             None
         } else {
             self.len -= 1;
-            Some(unsafe { self.buffer_read(self.to_physical_idx(self.len)) })
+            unsafe {
+                core::hint::assert_unchecked(self.len < self.capacity());
+                Some(self.buffer_read(self.to_physical_idx(self.len)))
+            }
         }
     }
 

library/core/src/num/nonzero.rs

@@ -20,7 +20,15 @@ use super::{IntErrorKind, ParseIntError};
 ///
 /// # Safety
 ///
-/// Types implementing this trait must be primitves that are valid when zeroed.
+/// Types implementing this trait must be primitives that are valid when zeroed.
+///
+/// The associated `Self::NonZeroInner` type must have the same size+align as `Self`,
+/// but with a niche and bit validity making it so the following `transmutes` are sound:
+///
+/// - `Self::NonZeroInner` to `Option<Self::NonZeroInner>`
+/// - `Option<Self::NonZeroInner>` to `Self`
+///
+/// (And, consequently, `Self::NonZeroInner` to `Self`.)
 #[unstable(
     feature = "nonzero_internals",
     reason = "implementation detail which may disappear or be replaced at any time",
@@ -434,17 +442,11 @@ where
         // of some not-inlined function, LLVM don't have range metadata
         // to understand that the value cannot be zero.
         //
-        // SAFETY: `Self` is guaranteed to have the same layout as `Option<Self>`.
-        match unsafe { intrinsics::transmute_unchecked(self) } {
-            None => {
-                // SAFETY: `NonZero` is guaranteed to only contain non-zero values, so this is unreachable.
-                unsafe { intrinsics::unreachable() }
-            }
-            Some(Self(inner)) => {
-                // SAFETY: `T::NonZeroInner` is guaranteed to have the same layout as `T`.
-                unsafe { intrinsics::transmute_unchecked(inner) }
-            }
-        }
+        // For now, using the transmute `assume`s the range at runtime.
+        //
+        // SAFETY: `ZeroablePrimitive` guarantees that the size and bit validity
+        // of `.0` is such that this transmute is sound.
+        unsafe { intrinsics::transmute_unchecked(self) }
     }
 }
 

library/core/src/pin.rs

@@ -806,7 +806,7 @@
 //!
 //!     As a consequence, the struct *must not* be [`#[repr(packed)]`][packed].
 //!
-//! 3.  *Structural Notice of Destruction.* You must uphold the the
+//! 3.  *Structural Notice of Destruction.* You must uphold the
 //!     [`Drop` guarantee][drop-guarantee]: once your struct is pinned, the struct's storage cannot
 //!     be re-used without calling the structurally-pinned fields' destructors, as well.
 //!

library/core/src/sync/atomic.rs

@@ -243,7 +243,7 @@ const EMULATE_ATOMIC_BOOL: bool =
 
 /// A boolean type which can be safely shared between threads.
 ///
-/// This type has the same in-memory representation as a [`bool`].
+/// This type has the same size, alignment, and bit validity as a [`bool`].
 ///
 /// **Note**: This type is only available on platforms that support atomic
 /// loads and stores of `u8`.
@@ -272,7 +272,7 @@ unsafe impl Sync for AtomicBool {}
 
 /// A raw pointer type which can be safely shared between threads.
 ///
-/// This type has the same in-memory representation as a `*mut T`.
+/// This type has the same size and bit validity as a `*mut T`.
 ///
 /// **Note**: This type is only available on platforms that support atomic
 /// loads and stores of pointers. Its size depends on the target pointer's size.
@@ -2121,7 +2121,7 @@ macro_rules! atomic_int {
      $int_type:ident $atomic_type:ident) => {
         /// An integer type which can be safely shared between threads.
         ///
-        /// This type has the same in-memory representation as the underlying
+        /// This type has the same size and bit validity as the underlying
         /// integer type, [`
         #[doc = $s_int_type]
         /// `].

library/std/src/fs.rs

@@ -385,7 +385,7 @@ impl File {
     /// See the [`OpenOptions::open`] function for more details.
     ///
     /// See also [`std::fs::write()`][self::write] for a simple function to
-    /// create a file with a given data.
+    /// create a file with some given data.
     ///
     /// # Examples
     ///
@@ -1036,7 +1036,7 @@ impl OpenOptions {
     /// [`OpenOptions::append`] access must be used.
     ///
     /// See also [`std::fs::write()`][self::write] for a simple function to
-    /// create a file with a given data.
+    /// create a file with some given data.
     ///
     /// # Examples
     ///