Auto merge of rust-lang#91093 - matthiaskrgr:rollup-kovzwx0, r=matthi…

…askrgr

Rollup of 6 pull requests

Successful merges:

 - rust-lang#89741 (Mark `Arc::from_inner` / `Rc::from_inner` as unsafe)
 - rust-lang#90927 (Fix float ICE)
 - rust-lang#90994 (Fix ICE `rust-lang#90993`: add missing call to cancel)
 - rust-lang#91018 (Adopt let_else in more places in rustc_mir_build)
 - rust-lang#91022 (Suggest `await` in more situations where infer types are involved)
 - rust-lang#91088 (Revert "require full validity when determining the discriminant of a value")

Failed merges:

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

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -265,12 +265,6 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             }
             sym::discriminant_value => {
                 let place = self.deref_operand(&args[0])?;
-                if M::enforce_validity(self) {
-                    // This is 'using' the value, so make sure the validity invariant is satisfied.
-                    // (Also see https://github.com/rust-lang/rust/pull/89764.)
-                    self.validate_operand(&place.into())?;
-                }
-
                 let discr_val = self.read_discriminant(&place.into())?.0;
                 self.write_scalar(discr_val, dest)?;
             }

compiler/rustc_const_eval/src/interpret/step.rs

@@ -304,12 +304,6 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
             Discriminant(place) => {
                 let op = self.eval_place_to_op(place, None)?;
-                if M::enforce_validity(self) {
-                    // This is 'using' the value, so make sure the validity invariant is satisfied.
-                    // (Also see https://github.com/rust-lang/rust/pull/89764.)
-                    self.validate_operand(&op)?;
-                }
-
                 let discr_val = self.read_discriminant(&op)?.0;
                 self.write_scalar(discr_val, &dest)?;
             }

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -310,6 +310,34 @@ pub fn unexpected_hidden_region_diagnostic(
     err
 }
 
+/// Structurally compares two types, modulo any inference variables.
+///
+/// Returns `true` if two types are equal, or if one type is an inference variable compatible
+/// with the other type. A TyVar inference type is compatible with any type, and an IntVar or
+/// FloatVar inference type are compatible with themselves or their concrete types (Int and
+/// Float types, respectively). When comparing two ADTs, these rules apply recursively.
+pub fn same_type_modulo_infer(a: Ty<'tcx>, b: Ty<'ctx>) -> bool {
+    match (&a.kind(), &b.kind()) {
+        (&ty::Adt(did_a, substs_a), &ty::Adt(did_b, substs_b)) => {
+            if did_a != did_b {
+                return false;
+            }
+
+            substs_a.types().zip(substs_b.types()).all(|(a, b)| same_type_modulo_infer(a, b))
+        }
+        (&ty::Int(_), &ty::Infer(ty::InferTy::IntVar(_)))
+        | (&ty::Infer(ty::InferTy::IntVar(_)), &ty::Int(_) | &ty::Infer(ty::InferTy::IntVar(_)))
+        | (&ty::Float(_), &ty::Infer(ty::InferTy::FloatVar(_)))
+        | (
+            &ty::Infer(ty::InferTy::FloatVar(_)),
+            &ty::Float(_) | &ty::Infer(ty::InferTy::FloatVar(_)),
+        )
+        | (&ty::Infer(ty::InferTy::TyVar(_)), _)
+        | (_, &ty::Infer(ty::InferTy::TyVar(_))) => true,
+        _ => a == b,
+    }
+}
+
 impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn report_region_errors(&self, errors: &Vec<RegionResolutionError<'tcx>>) {
         debug!("report_region_errors(): {} errors to start", errors.len());
@@ -1761,7 +1789,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             self.get_impl_future_output_ty(exp_found.expected),
             self.get_impl_future_output_ty(exp_found.found),
         ) {
-            (Some(exp), Some(found)) if ty::TyS::same_type(exp, found) => match &cause.code {
+            (Some(exp), Some(found)) if same_type_modulo_infer(exp, found) => match &cause.code {
                 ObligationCauseCode::IfExpression(box IfExpressionCause { then, .. }) => {
                     diag.multipart_suggestion(
                         "consider `await`ing on both `Future`s",
@@ -1793,15 +1821,15 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     diag.help("consider `await`ing on both `Future`s");
                 }
             },
-            (_, Some(ty)) if ty::TyS::same_type(exp_found.expected, ty) => {
+            (_, Some(ty)) if same_type_modulo_infer(exp_found.expected, ty) => {
                 diag.span_suggestion_verbose(
                     exp_span.shrink_to_hi(),
                     "consider `await`ing on the `Future`",
                     ".await".to_string(),
                     Applicability::MaybeIncorrect,
                 );
             }
-            (Some(ty), _) if ty::TyS::same_type(ty, exp_found.found) => match cause.code {
+            (Some(ty), _) if same_type_modulo_infer(ty, exp_found.found) => match cause.code {
                 ObligationCauseCode::Pattern { span: Some(span), .. }
                 | ObligationCauseCode::IfExpression(box IfExpressionCause { then: span, .. }) => {
                     diag.span_suggestion_verbose(

compiler/rustc_mir_build/src/build/matches/mod.rs

@@ -1606,13 +1606,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         // encounter a candidate where the test is not relevant; at
         // that point, we stop sorting.
         while let Some(candidate) = candidates.first_mut() {
-            if let Some(idx) = self.sort_candidate(&match_place.clone(), &test, candidate) {
-                let (candidate, rest) = candidates.split_first_mut().unwrap();
-                target_candidates[idx].push(candidate);
-                candidates = rest;
-            } else {
+            let Some(idx) = self.sort_candidate(&match_place.clone(), &test, candidate) else {
                 break;
-            }
+            };
+            let (candidate, rest) = candidates.split_first_mut().unwrap();
+            target_candidates[idx].push(candidate);
+            candidates = rest;
         }
         // at least the first candidate ought to be tested
         assert!(total_candidate_count > candidates.len());

compiler/rustc_mir_build/src/build/mod.rs

@@ -966,59 +966,58 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 DropKind::Value,
             );
 
-            if let Some(arg) = arg_opt {
-                let pat = match tcx.hir().get(arg.pat.hir_id) {
-                    Node::Pat(pat) | Node::Binding(pat) => pat,
-                    node => bug!("pattern became {:?}", node),
-                };
-                let pattern = pat_from_hir(tcx, self.param_env, self.typeck_results, pat);
-                let original_source_scope = self.source_scope;
-                let span = pattern.span;
-                self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
-                match *pattern.kind {
-                    // Don't introduce extra copies for simple bindings
-                    PatKind::Binding {
-                        mutability,
-                        var,
-                        mode: BindingMode::ByValue,
-                        subpattern: None,
-                        ..
-                    } => {
-                        self.local_decls[local].mutability = mutability;
-                        self.local_decls[local].source_info.scope = self.source_scope;
-                        self.local_decls[local].local_info = if let Some(kind) = self_binding {
-                            Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(
-                                BindingForm::ImplicitSelf(*kind),
-                            ))))
-                        } else {
-                            let binding_mode = ty::BindingMode::BindByValue(mutability);
-                            Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
-                                VarBindingForm {
-                                    binding_mode,
-                                    opt_ty_info,
-                                    opt_match_place: Some((Some(place), span)),
-                                    pat_span: span,
-                                },
-                            )))))
-                        };
-                        self.var_indices.insert(var, LocalsForNode::One(local));
-                    }
-                    _ => {
-                        scope = self.declare_bindings(
-                            scope,
-                            expr.span,
-                            &pattern,
-                            matches::ArmHasGuard(false),
-                            Some((Some(&place), span)),
-                        );
-                        let place_builder = PlaceBuilder::from(local);
-                        unpack!(
-                            block = self.place_into_pattern(block, pattern, place_builder, false)
-                        );
-                    }
+            let Some(arg) = arg_opt else {
+                continue;
+            };
+            let pat = match tcx.hir().get(arg.pat.hir_id) {
+                Node::Pat(pat) | Node::Binding(pat) => pat,
+                node => bug!("pattern became {:?}", node),
+            };
+            let pattern = pat_from_hir(tcx, self.param_env, self.typeck_results, pat);
+            let original_source_scope = self.source_scope;
+            let span = pattern.span;
+            self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
+            match *pattern.kind {
+                // Don't introduce extra copies for simple bindings
+                PatKind::Binding {
+                    mutability,
+                    var,
+                    mode: BindingMode::ByValue,
+                    subpattern: None,
+                    ..
+                } => {
+                    self.local_decls[local].mutability = mutability;
+                    self.local_decls[local].source_info.scope = self.source_scope;
+                    self.local_decls[local].local_info = if let Some(kind) = self_binding {
+                        Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(
+                            BindingForm::ImplicitSelf(*kind),
+                        ))))
+                    } else {
+                        let binding_mode = ty::BindingMode::BindByValue(mutability);
+                        Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
+                            VarBindingForm {
+                                binding_mode,
+                                opt_ty_info,
+                                opt_match_place: Some((Some(place), span)),
+                                pat_span: span,
+                            },
+                        )))))
+                    };
+                    self.var_indices.insert(var, LocalsForNode::One(local));
+                }
+                _ => {
+                    scope = self.declare_bindings(
+                        scope,
+                        expr.span,
+                        &pattern,
+                        matches::ArmHasGuard(false),
+                        Some((Some(&place), span)),
+                    );
+                    let place_builder = PlaceBuilder::from(local);
+                    unpack!(block = self.place_into_pattern(block, pattern, place_builder, false));
                 }
-                self.source_scope = original_source_scope;
             }
+            self.source_scope = original_source_scope;
         }
 
         // Enter the argument pattern bindings source scope, if it exists.

compiler/rustc_mir_build/src/check_unsafety.rs

@@ -256,23 +256,22 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
             }
             PatKind::Binding { mode: BindingMode::ByRef(borrow_kind), ty, .. } => {
                 if self.inside_adt {
-                    if let ty::Ref(_, ty, _) = ty.kind() {
-                        match borrow_kind {
-                            BorrowKind::Shallow | BorrowKind::Shared | BorrowKind::Unique => {
-                                if !ty.is_freeze(self.tcx.at(pat.span), self.param_env) {
-                                    self.requires_unsafe(pat.span, BorrowOfLayoutConstrainedField);
-                                }
-                            }
-                            BorrowKind::Mut { .. } => {
-                                self.requires_unsafe(pat.span, MutationOfLayoutConstrainedField);
-                            }
-                        }
-                    } else {
+                    let ty::Ref(_, ty, _) = ty.kind() else {
                         span_bug!(
                             pat.span,
                             "BindingMode::ByRef in pattern, but found non-reference type {}",
                             ty
                         );
+                    };
+                    match borrow_kind {
+                        BorrowKind::Shallow | BorrowKind::Shared | BorrowKind::Unique => {
+                            if !ty.is_freeze(self.tcx.at(pat.span), self.param_env) {
+                                self.requires_unsafe(pat.span, BorrowOfLayoutConstrainedField);
+                            }
+                        }
+                        BorrowKind::Mut { .. } => {
+                            self.requires_unsafe(pat.span, MutationOfLayoutConstrainedField);
+                        }
                     }
                 }
                 visit::walk_pat(self, pat);

compiler/rustc_parse/src/parser/expr.rs

@@ -1032,6 +1032,8 @@ impl<'a> Parser<'a> {
             [IdentLike(_), Punct('+' | '-')] |
             // 1e+2 | 1e-2
             [IdentLike(_), Punct('+' | '-'), IdentLike(_)] |
+            // 1.2e+ | 1.2e-
+            [IdentLike(_), Punct('.'), IdentLike(_), Punct('+' | '-')] |
             // 1.2e+3 | 1.2e-3
             [IdentLike(_), Punct('.'), IdentLike(_), Punct('+' | '-'), IdentLike(_)] => {
                 // See the FIXME about `TokenCursor` above.

compiler/rustc_parse/src/parser/pat.rs

@@ -817,7 +817,7 @@ impl<'a> Parser<'a> {
             // Ensure the user doesn't receive unhelpful unexpected token errors
             self.bump();
             if self.is_pat_range_end_start(0) {
-                let _ = self.parse_pat_range_end();
+                let _ = self.parse_pat_range_end().map_err(|mut e| e.cancel());
             }
 
             self.error_inclusive_range_with_extra_equals(span_with_eq);

library/alloc/src/rc.rs

@@ -341,12 +341,12 @@ impl<T: ?Sized> Rc<T> {
         unsafe { self.ptr.as_ref() }
     }
 
-    fn from_inner(ptr: NonNull<RcBox<T>>) -> Self {
+    unsafe fn from_inner(ptr: NonNull<RcBox<T>>) -> Self {
         Self { ptr, phantom: PhantomData }
     }
 
     unsafe fn from_ptr(ptr: *mut RcBox<T>) -> Self {
-        Self::from_inner(unsafe { NonNull::new_unchecked(ptr) })
+        unsafe { Self::from_inner(NonNull::new_unchecked(ptr)) }
     }
 }
 
@@ -367,9 +367,11 @@ impl<T> Rc<T> {
         // pointers, which ensures that the weak destructor never frees
         // the allocation while the strong destructor is running, even
         // if the weak pointer is stored inside the strong one.
-        Self::from_inner(
-            Box::leak(box RcBox { strong: Cell::new(1), weak: Cell::new(1), value }).into(),
-        )
+        unsafe {
+            Self::from_inner(
+                Box::leak(box RcBox { strong: Cell::new(1), weak: Cell::new(1), value }).into(),
+            )
+        }
     }
 
     /// Constructs a new `Rc<T>` using a weak reference to itself. Attempting
@@ -420,16 +422,16 @@ impl<T> Rc<T> {
         // otherwise.
         let data = data_fn(&weak);
 
-        unsafe {
+        let strong = unsafe {
             let inner = init_ptr.as_ptr();
             ptr::write(ptr::addr_of_mut!((*inner).value), data);
 
             let prev_value = (*inner).strong.get();
             debug_assert_eq!(prev_value, 0, "No prior strong references should exist");
             (*inner).strong.set(1);
-        }
 
-        let strong = Rc::from_inner(init_ptr);
+            Rc::from_inner(init_ptr)
+        };
 
         // Strong references should collectively own a shared weak reference,
         // so don't run the destructor for our old weak reference.
@@ -521,10 +523,12 @@ impl<T> Rc<T> {
         // pointers, which ensures that the weak destructor never frees
         // the allocation while the strong destructor is running, even
         // if the weak pointer is stored inside the strong one.
-        Ok(Self::from_inner(
-            Box::leak(Box::try_new(RcBox { strong: Cell::new(1), weak: Cell::new(1), value })?)
-                .into(),
-        ))
+        unsafe {
+            Ok(Self::from_inner(
+                Box::leak(Box::try_new(RcBox { strong: Cell::new(1), weak: Cell::new(1), value })?)
+                    .into(),
+            ))
+        }
     }
 
     /// Constructs a new `Rc` with uninitialized contents, returning an error if the allocation fails
@@ -746,7 +750,7 @@ impl<T> Rc<mem::MaybeUninit<T>> {
     #[unstable(feature = "new_uninit", issue = "63291")]
     #[inline]
     pub unsafe fn assume_init(self) -> Rc<T> {
-        Rc::from_inner(mem::ManuallyDrop::new(self).ptr.cast())
+        unsafe { Rc::from_inner(mem::ManuallyDrop::new(self).ptr.cast()) }
     }
 }
 
@@ -1214,9 +1218,11 @@ impl Rc<dyn Any> {
     /// ```
     pub fn downcast<T: Any>(self) -> Result<Rc<T>, Rc<dyn Any>> {
         if (*self).is::<T>() {
-            let ptr = self.ptr.cast::<RcBox<T>>();
-            forget(self);
-            Ok(Rc::from_inner(ptr))
+            unsafe {
+                let ptr = self.ptr.cast::<RcBox<T>>();
+                forget(self);
+                Ok(Rc::from_inner(ptr))
+            }
         } else {
             Err(self)
         }
@@ -1489,8 +1495,10 @@ impl<T: ?Sized> Clone for Rc<T> {
     /// ```
     #[inline]
     fn clone(&self) -> Rc<T> {
-        self.inner().inc_strong();
-        Self::from_inner(self.ptr)
+        unsafe {
+            self.inner().inc_strong();
+            Self::from_inner(self.ptr)
+        }
     }
 }
 
@@ -2245,11 +2253,14 @@ impl<T: ?Sized> Weak<T> {
     #[stable(feature = "rc_weak", since = "1.4.0")]
     pub fn upgrade(&self) -> Option<Rc<T>> {
         let inner = self.inner()?;
+
         if inner.strong() == 0 {
             None
         } else {
-            inner.inc_strong();
-            Some(Rc::from_inner(self.ptr))
+            unsafe {
+                inner.inc_strong();
+                Some(Rc::from_inner(self.ptr))
+            }
         }
     }