Auto merge of #102234 - matthiaskrgr:rollup-5cb20l1, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #100823 (Refactor some `std` code that works with pointer offstes)
 - #102088 (Fix wrongly refactored Lift impl)
 - #102109 (resolve: Set effective visibilities for imports more precisely)
 - #102186 (Add const_closure, Constify Try trait)
 - #102203 (rustdoc: remove no-op CSS `#source-sidebar { z-index }`)
 - #102204 (Make `ManuallyDrop` satisfy `~const Destruct`)
 - #102210 (diagnostics: avoid syntactically invalid suggestion in if conditionals)
 - #102226 (bootstrap/miri: switch to non-deprecated env var for setting the sysroot folder)

Failed merges:

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

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -272,7 +272,10 @@ impl<'tcx, A: Lift<'tcx>, B: Lift<'tcx>, C: Lift<'tcx>> Lift<'tcx> for (A, B, C)
 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Option<T> {
     type Lifted = Option<T::Lifted>;
     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self?).map(Some)
+        Some(match self {
+            Some(x) => Some(tcx.lift(x)?),
+            None => None,
+        })
     }
 }
 

compiler/rustc_resolve/src/access_levels.rs

@@ -1,4 +1,3 @@
-use crate::imports::ImportKind;
 use crate::NameBinding;
 use crate::NameBindingKind;
 use crate::Resolver;
@@ -54,15 +53,11 @@ impl<'r, 'a> AccessLevelsVisitor<'r, 'a> {
         // sets the rest of the `use` chain to `AccessLevel::Exported` until
         // we hit the actual exported item.
         let set_import_binding_access_level =
-            |this: &mut Self, mut binding: &NameBinding<'a>, mut access_level| {
+            |this: &mut Self, mut binding: &NameBinding<'a>, mut access_level, ns| {
                 while let NameBindingKind::Import { binding: nested_binding, import, .. } =
                     binding.kind
                 {
-                    this.set_access_level(import.id, access_level);
-                    if let ImportKind::Single { additional_ids, .. } = import.kind {
-                        this.set_access_level(additional_ids.0, access_level);
-                        this.set_access_level(additional_ids.1, access_level);
-                    }
+                    this.set_access_level(this.r.import_id_for_ns(import, ns), access_level);
 
                     access_level = Some(AccessLevel::Exported);
                     binding = nested_binding;
@@ -72,11 +67,11 @@ impl<'r, 'a> AccessLevelsVisitor<'r, 'a> {
         let module = self.r.get_module(module_id.to_def_id()).unwrap();
         let resolutions = self.r.resolutions(module);
 
-        for (.., name_resolution) in resolutions.borrow().iter() {
+        for (key, name_resolution) in resolutions.borrow().iter() {
             if let Some(binding) = name_resolution.borrow().binding() && binding.vis.is_public() && !binding.is_ambiguity() {
                 let access_level = match binding.is_import() {
                     true => {
-                        set_import_binding_access_level(self, binding, module_level);
+                        set_import_binding_access_level(self, binding, module_level, key.ns);
                         Some(AccessLevel::Exported)
                     },
                     false => module_level,

compiler/rustc_resolve/src/imports.rs

@@ -2,7 +2,7 @@
 
 use crate::diagnostics::Suggestion;
 use crate::Determinacy::{self, *};
-use crate::Namespace::{MacroNS, TypeNS};
+use crate::Namespace::{self, *};
 use crate::{module_to_string, names_to_string};
 use crate::{AmbiguityKind, BindingKey, ModuleKind, ResolutionError, Resolver, Segment};
 use crate::{Finalize, Module, ModuleOrUniformRoot, ParentScope, PerNS, ScopeSet};
@@ -371,6 +371,31 @@ impl<'a> Resolver<'a> {
             self.used_imports.insert(import.id);
         }
     }
+
+    /// Take primary and additional node IDs from an import and select one that corresponds to the
+    /// given namespace. The logic must match the corresponding logic from `fn lower_use_tree` that
+    /// assigns resolutons to IDs.
+    pub(crate) fn import_id_for_ns(&self, import: &Import<'_>, ns: Namespace) -> NodeId {
+        if let ImportKind::Single { additional_ids: (id1, id2), .. } = import.kind {
+            if let Some(resolutions) = self.import_res_map.get(&import.id) {
+                assert!(resolutions[ns].is_some(), "incorrectly finalized import");
+                return match ns {
+                    TypeNS => import.id,
+                    ValueNS => match resolutions.type_ns {
+                        Some(_) => id1,
+                        None => import.id,
+                    },
+                    MacroNS => match (resolutions.type_ns, resolutions.value_ns) {
+                        (Some(_), Some(_)) => id2,
+                        (Some(_), None) | (None, Some(_)) => id1,
+                        (None, None) => import.id,
+                    },
+                };
+            }
+        }
+
+        import.id
+    }
 }
 
 /// An error that may be transformed into a diagnostic later. Used to combine multiple unresolved

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

@@ -1224,6 +1224,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | ty::Never
                 | ty::Foreign(_) => {}
 
+                // `ManuallyDrop` is trivially drop
+                ty::Adt(def, _) if Some(def.did()) == tcx.lang_items().manually_drop() => {}
+
                 // These types are built-in, so we can fast-track by registering
                 // nested predicates for their constituent type(s)
                 ty::Array(ty, _) | ty::Slice(ty) => {

compiler/rustc_typeck/src/check/demand.rs

@@ -417,6 +417,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     hir::def::CtorKind::Const => unreachable!(),
                 };
 
+                // Suggest constructor as deep into the block tree as possible.
+                // This fixes https://github.com/rust-lang/rust/issues/101065,
+                // and also just helps make the most minimal suggestions.
+                let mut expr = expr;
+                while let hir::ExprKind::Block(block, _) = &expr.kind
+                    && let Some(expr_) = &block.expr
+                {
+                    expr = expr_
+                }
+
                 vec![
                     (expr.span.shrink_to_lo(), format!("{prefix}{variant}{open}")),
                     (expr.span.shrink_to_hi(), close.to_owned()),

library/core/src/const_closure.rs

@@ -0,0 +1,63 @@
+use crate::marker::Destruct;
+
+/// Struct representing a closure with mutably borrowed data.
+///
+/// Example:
+/// ```no_build
+/// #![feature(const_mut_refs)]
+/// use crate::const_closure::ConstFnMutClosure;
+/// const fn imp(state: &mut i32, (arg,): (i32,)) -> i32 {
+///   *state += arg;
+///   *state
+/// }
+/// let mut i = 5;
+/// let mut cl = ConstFnMutClosure::new(&mut i, imp);
+///
+/// assert!(7 == cl(2));
+/// assert!(8 == cl(1));
+/// ```
+pub(crate) struct ConstFnMutClosure<'a, CapturedData: ?Sized, Function> {
+    data: &'a mut CapturedData,
+    func: Function,
+}
+
+impl<'a, CapturedData: ?Sized, Function> ConstFnMutClosure<'a, CapturedData, Function> {
+    /// Function for creating a new closure.
+    ///
+    /// `data` is the a mutable borrow of data that is captured from the environment.
+    ///
+    /// `func` is the function of the closure, it gets the data and a tuple of the arguments closure
+    ///   and return the return value of the closure.
+    pub(crate) const fn new<ClosureArguments, ClosureReturnValue>(
+        data: &'a mut CapturedData,
+        func: Function,
+    ) -> Self
+    where
+        Function: ~const Fn(&mut CapturedData, ClosureArguments) -> ClosureReturnValue,
+    {
+        Self { data, func }
+    }
+}
+
+impl<'a, CapturedData: ?Sized, ClosureArguments, Function, ClosureReturnValue> const
+    FnOnce<ClosureArguments> for ConstFnMutClosure<'a, CapturedData, Function>
+where
+    Function:
+        ~const Fn(&mut CapturedData, ClosureArguments) -> ClosureReturnValue + ~const Destruct,
+{
+    type Output = ClosureReturnValue;
+
+    extern "rust-call" fn call_once(mut self, args: ClosureArguments) -> Self::Output {
+        self.call_mut(args)
+    }
+}
+
+impl<'a, CapturedData: ?Sized, ClosureArguments, Function, ClosureReturnValue> const
+    FnMut<ClosureArguments> for ConstFnMutClosure<'a, CapturedData, Function>
+where
+    Function: ~const Fn(&mut CapturedData, ClosureArguments) -> ClosureReturnValue,
+{
+    extern "rust-call" fn call_mut(&mut self, args: ClosureArguments) -> Self::Output {
+        (self.func)(self.data, args)
+    }
+}