Rollup of 7 pull requests

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -998,6 +998,9 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                                         self.lower_const_arg(ct, FeedConstTy::No).into()
                                     }
                                 };
+                                if term.references_error() {
+                                    continue;
+                                }
                                 // FIXME(#97583): This isn't syntactically well-formed!
                                 where_bounds.push(format!(
                                     "        T: {trait}::{assoc_name} = {term}",

compiler/rustc_middle/src/ty/context.rs

@@ -585,6 +585,10 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
         self.trait_def(trait_def_id).implement_via_object
     }
 
+    fn trait_is_unsafe(self, trait_def_id: Self::DefId) -> bool {
+        self.trait_def(trait_def_id).safety == hir::Safety::Unsafe
+    }
+
     fn is_impl_trait_in_trait(self, def_id: DefId) -> bool {
         self.is_impl_trait_in_trait(def_id)
     }

compiler/rustc_middle/src/ty/sty.rs

@@ -978,6 +978,14 @@ impl<'tcx> rustc_type_ir::inherent::Ty<TyCtxt<'tcx>> for Ty<'tcx> {
     fn async_destructor_ty(self, interner: TyCtxt<'tcx>) -> Ty<'tcx> {
         self.async_destructor_ty(interner)
     }
+
+    fn has_unsafe_fields(self) -> bool {
+        if let ty::Adt(adt_def, ..) = self.kind() {
+            adt_def.all_fields().any(|x| x.safety == hir::Safety::Unsafe)
+        } else {
+            false
+        }
+    }
 }
 
 /// Type utilities

compiler/rustc_mir_build/src/thir/constant.rs

@@ -2,7 +2,7 @@ use rustc_ast as ast;
 use rustc_hir::LangItem;
 use rustc_middle::bug;
 use rustc_middle::mir::interpret::{LitToConstError, LitToConstInput};
-use rustc_middle::ty::{self, ScalarInt, TyCtxt};
+use rustc_middle::ty::{self, ScalarInt, TyCtxt, TypeVisitableExt as _};
 use tracing::trace;
 
 use crate::build::parse_float_into_scalar;
@@ -13,6 +13,10 @@ pub(crate) fn lit_to_const<'tcx>(
 ) -> Result<ty::Const<'tcx>, LitToConstError> {
     let LitToConstInput { lit, ty, neg } = lit_input;
 
+    if let Err(guar) = ty.error_reported() {
+        return Ok(ty::Const::new_error(tcx, guar));
+    }
+
     let trunc = |n| {
         let width = match tcx.layout_of(ty::TypingEnv::fully_monomorphized().as_query_input(ty)) {
             Ok(layout) => layout.size,

compiler/rustc_next_trait_solver/src/solve/trait_goals.rs

@@ -169,6 +169,14 @@ where
             return result;
         }
 
+        // Only consider auto impls of unsafe traits when there are no unsafe
+        // fields.
+        if ecx.cx().trait_is_unsafe(goal.predicate.def_id())
+            && goal.predicate.self_ty().has_unsafe_fields()
+        {
+            return Err(NoSolution);
+        }
+
         // We only look into opaque types during analysis for opaque types
         // outside of their defining scope. Doing so for opaques in the
         // defining scope may require calling `typeck` on the same item we're

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

@@ -18,6 +18,7 @@ use rustc_infer::traits::{
 use rustc_middle::ty::fast_reject::DeepRejectCtxt;
 use rustc_middle::ty::{self, ToPolyTraitRef, Ty, TypeVisitableExt, TypingMode};
 use rustc_middle::{bug, span_bug};
+use rustc_type_ir::Interner;
 use tracing::{debug, instrument, trace};
 
 use super::SelectionCandidate::*;
@@ -794,6 +795,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | ty::Never
                 | ty::Tuple(_)
                 | ty::CoroutineWitness(..) => {
+                    use rustc_type_ir::inherent::*;
+
+                    // Only consider auto impls of unsafe traits when there are
+                    // no unsafe fields.
+                    if self.tcx().trait_is_unsafe(def_id) && self_ty.has_unsafe_fields() {
+                        return;
+                    }
+
                     // Only consider auto impls if there are no manual impls for the root of `self_ty`.
                     //
                     // For example, we only consider auto candidates for `&i32: Auto` if no explicit impl

compiler/rustc_type_ir/src/inherent.rs

@@ -136,6 +136,9 @@ pub trait Ty<I: Interner<Ty = Self>>:
         matches!(self.kind(), ty::FnPtr(..))
     }
 
+    /// Checks whether this type is an ADT that has unsafe fields.
+    fn has_unsafe_fields(self) -> bool;
+
     fn fn_sig(self, interner: I) -> ty::Binder<I, ty::FnSig<I>> {
         match self.kind() {
             ty::FnPtr(sig_tys, hdr) => sig_tys.with(hdr),

compiler/rustc_type_ir/src/interner.rs

@@ -270,6 +270,9 @@ pub trait Interner:
 
     fn trait_may_be_implemented_via_object(self, trait_def_id: Self::DefId) -> bool;
 
+    /// Returns `true` if this is an `unsafe trait`.
+    fn trait_is_unsafe(self, trait_def_id: Self::DefId) -> bool;
+
     fn is_impl_trait_in_trait(self, def_id: Self::DefId) -> bool;
 
     fn delay_bug(self, msg: impl ToString) -> Self::ErrorGuaranteed;

library/core/src/iter/traits/collect.rs

@@ -492,131 +492,150 @@ impl Extend<()> for () {
     fn extend_one(&mut self, _item: ()) {}
 }
 
-#[stable(feature = "extend_for_tuple", since = "1.56.0")]
-impl<A, B, ExtendA, ExtendB> Extend<(A, B)> for (ExtendA, ExtendB)
-where
-    ExtendA: Extend<A>,
-    ExtendB: Extend<B>,
-{
-    /// Allows to `extend` a tuple of collections that also implement `Extend`.
-    ///
-    /// See also: [`Iterator::unzip`]
-    ///
-    /// # Examples
-    /// ```
-    /// let mut tuple = (vec![0], vec![1]);
-    /// tuple.extend([(2, 3), (4, 5), (6, 7)]);
-    /// assert_eq!(tuple.0, [0, 2, 4, 6]);
-    /// assert_eq!(tuple.1, [1, 3, 5, 7]);
-    ///
-    /// // also allows for arbitrarily nested tuples as elements
-    /// let mut nested_tuple = (vec![1], (vec![2], vec![3]));
-    /// nested_tuple.extend([(4, (5, 6)), (7, (8, 9))]);
-    ///
-    /// let (a, (b, c)) = nested_tuple;
-    /// assert_eq!(a, [1, 4, 7]);
-    /// assert_eq!(b, [2, 5, 8]);
-    /// assert_eq!(c, [3, 6, 9]);
-    /// ```
-    fn extend<T: IntoIterator<Item = (A, B)>>(&mut self, into_iter: T) {
-        let (a, b) = self;
-        let iter = into_iter.into_iter();
-        SpecTupleExtend::extend(iter, a, b);
-    }
+macro_rules! spec_tuple_impl {
+    ( ($ty_name:ident, $var_name:ident, $extend_ty_name: ident, $trait_name:ident, $default_fn_name:ident, $cnt:tt), ) => {
+        spec_tuple_impl!($trait_name, $default_fn_name, #[doc(fake_variadic)] #[doc = "This trait is implemented for tuples up to twelve items long. The `impl`s for 1- and 3- through 12-ary tuples were stabilized after 2-tuples, in RUSTC_CURRENT_VERSION."] => ($ty_name, $var_name, $extend_ty_name, $cnt),);
+    };
+    ( ($ty_name:ident, $var_name:ident, $extend_ty_name: ident, $trait_name:ident, $default_fn_name:ident, $cnt:tt), $(($ty_names:ident, $var_names:ident,  $extend_ty_names:ident, $trait_names:ident, $default_fn_names:ident, $cnts:tt),)*) => {
 
-    fn extend_one(&mut self, item: (A, B)) {
-        self.0.extend_one(item.0);
-        self.1.extend_one(item.1);
-    }
+        spec_tuple_impl!($(($ty_names, $var_names, $extend_ty_names, $trait_names, $default_fn_names, $cnts),)*);
+        spec_tuple_impl!($trait_name, $default_fn_name, #[doc(hidden)] => ($ty_name, $var_name, $extend_ty_name, $cnt), $(($ty_names, $var_names, $extend_ty_names, $cnts),)*);
+    };
+    ($trait_name:ident, $default_fn_name:ident, #[$meta:meta] $(#[$doctext:meta])? => $(($ty_names:ident, $var_names:ident, $extend_ty_names:ident, $cnts:tt),)*) => {
+        #[$meta]
+        $(#[$doctext])?
+        #[stable(feature = "extend_for_tuple", since = "1.56.0")]
+        impl<$($ty_names,)* $($extend_ty_names,)*> Extend<($($ty_names,)*)> for ($($extend_ty_names,)*)
+        where
+            $($extend_ty_names: Extend<$ty_names>,)*
+        {
+            /// Allows to `extend` a tuple of collections that also implement `Extend`.
+            ///
+            /// See also: [`Iterator::unzip`]
+            ///
+            /// # Examples
+            /// ```
+            /// // Example given for a 2-tuple, but 1- through 12-tuples are supported
+            /// let mut tuple = (vec![0], vec![1]);
+            /// tuple.extend([(2, 3), (4, 5), (6, 7)]);
+            /// assert_eq!(tuple.0, [0, 2, 4, 6]);
+            /// assert_eq!(tuple.1, [1, 3, 5, 7]);
+            ///
+            /// // also allows for arbitrarily nested tuples as elements
+            /// let mut nested_tuple = (vec![1], (vec![2], vec![3]));
+            /// nested_tuple.extend([(4, (5, 6)), (7, (8, 9))]);
+            ///
+            /// let (a, (b, c)) = nested_tuple;
+            /// assert_eq!(a, [1, 4, 7]);
+            /// assert_eq!(b, [2, 5, 8]);
+            /// assert_eq!(c, [3, 6, 9]);
+            /// ```
+            fn extend<T: IntoIterator<Item = ($($ty_names,)*)>>(&mut self, into_iter: T) {
+                let ($($var_names,)*) = self;
+                let iter = into_iter.into_iter();
+                $trait_name::extend(iter, $($var_names,)*);
+            }
 
-    fn extend_reserve(&mut self, additional: usize) {
-        self.0.extend_reserve(additional);
-        self.1.extend_reserve(additional);
-    }
+            fn extend_one(&mut self, item: ($($ty_names,)*)) {
+                $(self.$cnts.extend_one(item.$cnts);)*
+            }
 
-    unsafe fn extend_one_unchecked(&mut self, item: (A, B)) {
-        // SAFETY: Those are our safety preconditions, and we correctly forward `extend_reserve`.
-        unsafe {
-            self.0.extend_one_unchecked(item.0);
-            self.1.extend_one_unchecked(item.1);
-        }
-    }
-}
+            fn extend_reserve(&mut self, additional: usize) {
+                $(self.$cnts.extend_reserve(additional);)*
+            }
 
-fn default_extend_tuple<A, B, ExtendA, ExtendB>(
-    iter: impl Iterator<Item = (A, B)>,
-    a: &mut ExtendA,
-    b: &mut ExtendB,
-) where
-    ExtendA: Extend<A>,
-    ExtendB: Extend<B>,
-{
-    fn extend<'a, A, B>(
-        a: &'a mut impl Extend<A>,
-        b: &'a mut impl Extend<B>,
-    ) -> impl FnMut((), (A, B)) + 'a {
-        move |(), (t, u)| {
-            a.extend_one(t);
-            b.extend_one(u);
+            unsafe fn extend_one_unchecked(&mut self, item: ($($ty_names,)*)) {
+                // SAFETY: Those are our safety preconditions, and we correctly forward `extend_reserve`.
+                unsafe {
+                     $(self.$cnts.extend_one_unchecked(item.$cnts);)*
+                }
+            }
         }
-    }
 
-    let (lower_bound, _) = iter.size_hint();
-    if lower_bound > 0 {
-        a.extend_reserve(lower_bound);
-        b.extend_reserve(lower_bound);
-    }
+        trait $trait_name<$($ty_names),*> {
+            fn extend(self, $($var_names: &mut $ty_names,)*);
+        }
 
-    iter.fold((), extend(a, b));
-}
+        fn $default_fn_name<$($ty_names,)* $($extend_ty_names,)*>(
+            iter: impl Iterator<Item = ($($ty_names,)*)>,
+            $($var_names: &mut $extend_ty_names,)*
+        ) where
+            $($extend_ty_names: Extend<$ty_names>,)*
+        {
+            fn extend<'a, $($ty_names,)*>(
+                $($var_names: &'a mut impl Extend<$ty_names>,)*
+            ) -> impl FnMut((), ($($ty_names,)*)) + 'a {
+                #[allow(non_snake_case)]
+                move |(), ($($extend_ty_names,)*)| {
+                    $($var_names.extend_one($extend_ty_names);)*
+                }
+            }
 
-trait SpecTupleExtend<A, B> {
-    fn extend(self, a: &mut A, b: &mut B);
-}
+            let (lower_bound, _) = iter.size_hint();
+            if lower_bound > 0 {
+                $($var_names.extend_reserve(lower_bound);)*
+            }
 
-impl<A, B, ExtendA, ExtendB, Iter> SpecTupleExtend<ExtendA, ExtendB> for Iter
-where
-    ExtendA: Extend<A>,
-    ExtendB: Extend<B>,
-    Iter: Iterator<Item = (A, B)>,
-{
-    default fn extend(self, a: &mut ExtendA, b: &mut ExtendB) {
-        default_extend_tuple(self, a, b);
-    }
-}
+            iter.fold((), extend($($var_names,)*));
+        }
 
-impl<A, B, ExtendA, ExtendB, Iter> SpecTupleExtend<ExtendA, ExtendB> for Iter
-where
-    ExtendA: Extend<A>,
-    ExtendB: Extend<B>,
-    Iter: TrustedLen<Item = (A, B)>,
-{
-    fn extend(self, a: &mut ExtendA, b: &mut ExtendB) {
-        fn extend<'a, A, B>(
-            a: &'a mut impl Extend<A>,
-            b: &'a mut impl Extend<B>,
-        ) -> impl FnMut((), (A, B)) + 'a {
-            // SAFETY: We reserve enough space for the `size_hint`, and the iterator is `TrustedLen`
-            // so its `size_hint` is exact.
-            move |(), (t, u)| unsafe {
-                a.extend_one_unchecked(t);
-                b.extend_one_unchecked(u);
+        impl<$($ty_names,)* $($extend_ty_names,)* Iter> $trait_name<$($extend_ty_names),*> for Iter
+            where
+            $($extend_ty_names: Extend<$ty_names>,)*
+            Iter: Iterator<Item = ($($ty_names,)*)>,
+        {
+            default fn extend(self, $($var_names: &mut $extend_ty_names),*) {
+                $default_fn_name(self, $($var_names),*);
             }
         }
 
-        let (lower_bound, upper_bound) = self.size_hint();
+        impl<$($ty_names,)* $($extend_ty_names,)* Iter> $trait_name<$($extend_ty_names),*> for Iter
+            where
+            $($extend_ty_names: Extend<$ty_names>,)*
+            Iter: TrustedLen<Item = ($($ty_names,)*)>,
+        {
+            fn extend(self, $($var_names: &mut $extend_ty_names,)*) {
+                fn extend<'a, $($ty_names,)*>(
+                    $($var_names: &'a mut impl Extend<$ty_names>,)*
+                ) -> impl FnMut((), ($($ty_names,)*)) + 'a {
+                #[allow(non_snake_case)]
+                // SAFETY: We reserve enough space for the `size_hint`, and the iterator is `TrustedLen`
+                // so its `size_hint` is exact.
+                move |(), ($($extend_ty_names,)*)| unsafe {
+                    $($var_names.extend_one_unchecked($extend_ty_names);)*
+                }
+            }
 
-        if upper_bound.is_none() {
-            // We cannot reserve more than `usize::MAX` items, and this is likely to go out of memory anyway.
-            default_extend_tuple(self, a, b);
-            return;
-        }
+            let (lower_bound, upper_bound) = self.size_hint();
 
-        if lower_bound > 0 {
-            a.extend_reserve(lower_bound);
-            b.extend_reserve(lower_bound);
-        }
+            if upper_bound.is_none() {
+                // We cannot reserve more than `usize::MAX` items, and this is likely to go out of memory anyway.
+                $default_fn_name(self, $($var_names,)*);
+                return;
+            }
 
-        self.fold((), extend(a, b));
+            if lower_bound > 0 {
+                $($var_names.extend_reserve(lower_bound);)*
+            }
+
+            self.fold((), extend($($var_names,)*));
+        }
     }
+
+    };
 }
+
+spec_tuple_impl!(
+    (L, l, EL, TraitL, default_extend_tuple_l, 11),
+    (K, k, EK, TraitK, default_extend_tuple_k, 10),
+    (J, j, EJ, TraitJ, default_extend_tuple_j, 9),
+    (I, i, EI, TraitI, default_extend_tuple_i, 8),
+    (H, h, EH, TraitH, default_extend_tuple_h, 7),
+    (G, g, EG, TraitG, default_extend_tuple_g, 6),
+    (F, f, EF, TraitF, default_extend_tuple_f, 5),
+    (E, e, EE, TraitE, default_extend_tuple_e, 4),
+    (D, d, ED, TraitD, default_extend_tuple_d, 3),
+    (C, c, EC, TraitC, default_extend_tuple_c, 2),
+    (B, b, EB, TraitB, default_extend_tuple_b, 1),
+    (A, a, EA, TraitA, default_extend_tuple_a, 0),
+);

library/core/tests/iter/traits/iterator.rs

@@ -617,6 +617,19 @@ fn test_next_chunk() {
     assert_eq!(it.next_chunk::<0>().unwrap(), []);
 }
 
+#[test]
+fn test_collect_into_tuples() {
+    let a = vec![(1, 2, 3), (4, 5, 6), (7, 8, 9)];
+    let b = vec![1, 4, 7];
+    let c = vec![2, 5, 8];
+    let d = vec![3, 6, 9];
+    let mut e = (Vec::new(), Vec::new(), Vec::new());
+    a.iter().cloned().collect_into(&mut e);
+    assert!(e.0 == b);
+    assert!(e.1 == c);
+    assert!(e.2 == d);
+}
+
 // just tests by whether or not this compiles
 fn _empty_impl_all_auto_traits<T>() {
     use std::panic::{RefUnwindSafe, UnwindSafe};