Auto merge of rust-lang#79377 - jonas-schievink:rollup-ye81i66, r=jonas-schievink

Rollup of 10 pull requests

Successful merges:

 - rust-lang#76858 (Add exploit mitigations chapter to the rustc book)
 - rust-lang#79310 (Make `fold_item_recur` non-nullable)
 - rust-lang#79312 (Get rid of `doctree::Impl`)
 - rust-lang#79321 (Accept '!' in intra-doc links)
 - rust-lang#79346 (Allow using `-Z fewer-names=no` to retain value names)
 - rust-lang#79351 (Fix typo in `keyword` docs for traits)
 - rust-lang#79354 (BTreeMap: cut out the ceremony around BoxedNode)
 - rust-lang#79358 (BTreeMap/BTreeSet: make public doc more consistent)
 - rust-lang#79367 (Allow disabling TrapUnreachable via -Ztrap-unreachable=no)
 - rust-lang#79374 (Add note to use nightly when using expr in const generics)

Failed merges:

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

Author: bors

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -152,7 +152,8 @@ pub fn target_machine_factory(
     let features = features.join(",");
     let features = CString::new(features).unwrap();
     let abi = SmallCStr::new(&sess.target.llvm_abiname);
-    let trap_unreachable = sess.target.trap_unreachable;
+    let trap_unreachable =
+        sess.opts.debugging_opts.trap_unreachable.unwrap_or(sess.target.trap_unreachable);
     let emit_stack_size_section = sess.opts.debugging_opts.emit_stack_sizes;
 
     let asm_comments = sess.asm_comments();

compiler/rustc_interface/src/tests.rs

@@ -547,7 +547,7 @@ fn test_debugging_options_tracking_hash() {
     tracked!(debug_macros, true);
     tracked!(dep_info_omit_d_target, true);
     tracked!(dual_proc_macros, true);
-    tracked!(fewer_names, true);
+    tracked!(fewer_names, Some(true));
     tracked!(force_overflow_checks, Some(true));
     tracked!(force_unstable_if_unmarked, true);
     tracked!(fuel, Some(("abc".to_string(), 99)));
@@ -592,6 +592,7 @@ fn test_debugging_options_tracking_hash() {
     tracked!(thinlto, Some(true));
     tracked!(tune_cpu, Some(String::from("abc")));
     tracked!(tls_model, Some(TlsModel::GeneralDynamic));
+    tracked!(trap_unreachable, Some(false));
     tracked!(treat_err_as_bug, Some(1));
     tracked!(unleash_the_miri_inside_of_you, true);
     tracked!(use_ctors_section, Some(true));

compiler/rustc_resolve/src/diagnostics.rs

@@ -481,6 +481,7 @@ impl<'a> Resolver<'a> {
                         name
                     ));
                 }
+                err.help("use `#![feature(const_generics)]` and `#![feature(const_evaluatable_checked)]` to allow generic const expressions");
 
                 err
             }

compiler/rustc_session/src/options.rs

@@ -900,7 +900,7 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "emits a future-incompatibility report for lints (RFC 2834)"),
     emit_stack_sizes: bool = (false, parse_bool, [UNTRACKED],
         "emit a section containing stack size metadata (default: no)"),
-    fewer_names: bool = (false, parse_bool, [TRACKED],
+    fewer_names: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "reduce memory use by retaining fewer names within compilation artifacts (LLVM-IR) \
         (default: no)"),
     force_overflow_checks: Option<bool> = (None, parse_opt_bool, [TRACKED],
@@ -1113,6 +1113,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "choose the TLS model to use (`rustc --print tls-models` for details)"),
     trace_macros: bool = (false, parse_bool, [UNTRACKED],
         "for every macro invocation, print its name and arguments (default: no)"),
+    trap_unreachable: Option<bool> = (None, parse_opt_bool, [TRACKED],
+        "generate trap instructions for unreachable intrinsics (default: use target setting, usually yes)"),
     treat_err_as_bug: Option<usize> = (None, parse_treat_err_as_bug, [TRACKED],
         "treat error number `val` that occurs as bug"),
     trim_diagnostic_paths: bool = (true, parse_bool, [UNTRACKED],

compiler/rustc_session/src/session.rs

@@ -734,12 +734,15 @@ impl Session {
         self.opts.cg.panic.unwrap_or(self.target.panic_strategy)
     }
     pub fn fewer_names(&self) -> bool {
-        let more_names = self.opts.output_types.contains_key(&OutputType::LlvmAssembly)
-            || self.opts.output_types.contains_key(&OutputType::Bitcode)
-            // AddressSanitizer and MemorySanitizer use alloca name when reporting an issue.
-            || self.opts.debugging_opts.sanitizer.intersects(SanitizerSet::ADDRESS | SanitizerSet::MEMORY);
-
-        self.opts.debugging_opts.fewer_names || !more_names
+        if let Some(fewer_names) = self.opts.debugging_opts.fewer_names {
+            fewer_names
+        } else {
+            let more_names = self.opts.output_types.contains_key(&OutputType::LlvmAssembly)
+                || self.opts.output_types.contains_key(&OutputType::Bitcode)
+                // AddressSanitizer and MemorySanitizer use alloca name when reporting an issue.
+                || self.opts.debugging_opts.sanitizer.intersects(SanitizerSet::ADDRESS | SanitizerSet::MEMORY);
+            !more_names
+        }
     }
 
     pub fn unstable_options(&self) -> bool {

compiler/rustc_typeck/src/check/wfcheck.rs

@@ -329,7 +329,7 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) {
                             ),
                         )
                         .note("the only supported types are integers, `bool` and `char`")
-                        .note("more complex types are supported with `#[feature(const_generics)]`")
+                        .help("more complex types are supported with `#[feature(const_generics)]`")
                         .emit()
                 }
             };

library/alloc/src/collections/btree/map.rs

@@ -458,7 +458,7 @@ impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for RangeMut<'_, K, V> {
 }
 
 impl<K: Ord, V> BTreeMap<K, V> {
-    /// Makes a new empty BTreeMap.
+    /// Makes a new, empty `BTreeMap`.
     ///
     /// Does not allocate anything on its own.
     ///
@@ -1924,7 +1924,7 @@ impl<K: Hash, V: Hash> Hash for BTreeMap<K, V> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<K: Ord, V> Default for BTreeMap<K, V> {
-    /// Creates an empty `BTreeMap<K, V>`.
+    /// Creates an empty `BTreeMap`.
     fn default() -> BTreeMap<K, V> {
         BTreeMap::new()
     }

library/alloc/src/collections/btree/node.rs

@@ -112,20 +112,8 @@ impl<K, V> InternalNode<K, V> {
 ///
 /// However, `BoxedNode` contains no information as to which of the two types
 /// of nodes it actually contains, and, partially due to this lack of information,
-/// has no destructor.
-struct BoxedNode<K, V> {
-    ptr: NonNull<LeafNode<K, V>>,
-}
-
-impl<K, V> BoxedNode<K, V> {
-    fn from_owned(ptr: NonNull<LeafNode<K, V>>) -> Self {
-        BoxedNode { ptr }
-    }
-
-    fn as_ptr(&self) -> NonNull<LeafNode<K, V>> {
-        self.ptr
-    }
-}
+/// is not a separate type and has no destructor.
+type BoxedNode<K, V> = NonNull<LeafNode<K, V>>;
 
 /// An owned tree.
 ///
@@ -168,11 +156,6 @@ impl<K, V, Type> NodeRef<marker::Owned, K, V, Type> {
     pub fn borrow_valmut(&mut self) -> NodeRef<marker::ValMut<'_>, K, V, Type> {
         NodeRef { height: self.height, node: self.node, _marker: PhantomData }
     }
-
-    /// Packs the reference, aware of type and height, into a type-agnostic pointer.
-    fn into_boxed_node(self) -> BoxedNode<K, V> {
-        BoxedNode::from_owned(self.node)
-    }
 }
 
 impl<K, V> NodeRef<marker::Owned, K, V, marker::LeafOrInternal> {
@@ -181,7 +164,7 @@ impl<K, V> NodeRef<marker::Owned, K, V, marker::LeafOrInternal> {
     /// and is the opposite of `pop_internal_level`.
     pub fn push_internal_level(&mut self) -> NodeRef<marker::Mut<'_>, K, V, marker::Internal> {
         let mut new_node = Box::new(unsafe { InternalNode::new() });
-        new_node.edges[0].write(BoxedNode::from_owned(self.node));
+        new_node.edges[0].write(self.node);
         let mut new_root = NodeRef::from_new_internal(new_node, self.height + 1);
         new_root.borrow_mut().first_edge().correct_parent_link();
         *self = new_root.forget_type();
@@ -288,13 +271,6 @@ unsafe impl<'a, K: Send + 'a, V: Send + 'a, Type> Send for NodeRef<marker::Mut<'
 unsafe impl<'a, K: Send + 'a, V: Send + 'a, Type> Send for NodeRef<marker::ValMut<'a>, K, V, Type> {}
 unsafe impl<K: Send, V: Send, Type> Send for NodeRef<marker::Owned, K, V, Type> {}
 
-impl<BorrowType, K, V> NodeRef<BorrowType, K, V, marker::LeafOrInternal> {
-    /// Unpack a node reference that was packed by `Root::into_boxed_node`.
-    fn from_boxed_node(boxed_node: BoxedNode<K, V>, height: usize) -> Self {
-        NodeRef { height, node: boxed_node.as_ptr(), _marker: PhantomData }
-    }
-}
-
 impl<BorrowType, K, V> NodeRef<BorrowType, K, V, marker::Internal> {
     /// Unpack a node reference that was packed as `NodeRef::parent`.
     fn from_internal(node: NonNull<InternalNode<K, V>>, height: usize) -> Self {
@@ -695,7 +671,7 @@ impl<'a, K: 'a, V: 'a> NodeRef<marker::Mut<'a>, K, V, marker::Internal> {
         unsafe {
             self.reborrow_mut().into_key_area_mut_at(idx).write(key);
             self.reborrow_mut().into_val_area_mut_at(idx).write(val);
-            self.reborrow_mut().into_edge_area_mut_at(idx + 1).write(edge.into_boxed_node());
+            self.reborrow_mut().into_edge_area_mut_at(idx + 1).write(edge.node);
             Handle::new_edge(self.reborrow_mut(), idx + 1).correct_parent_link();
         }
     }
@@ -710,7 +686,7 @@ impl<'a, K: 'a, V: 'a> NodeRef<marker::Mut<'a>, K, V, marker::Internal> {
             *self.reborrow_mut().into_len_mut() += 1;
             slice_insert(self.reborrow_mut().into_key_area_slice(), 0, key);
             slice_insert(self.reborrow_mut().into_val_area_slice(), 0, val);
-            slice_insert(self.reborrow_mut().into_edge_area_slice(), 0, edge.into_boxed_node());
+            slice_insert(self.reborrow_mut().into_edge_area_slice(), 0, edge.node);
         }
 
         self.correct_all_childrens_parent_links();
@@ -732,8 +708,8 @@ impl<'a, K: 'a, V: 'a> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
             let edge = match self.reborrow_mut().force() {
                 ForceResult::Leaf(_) => None,
                 ForceResult::Internal(internal) => {
-                    let boxed_node = ptr::read(internal.reborrow().edge_at(idx + 1));
-                    let mut edge = Root::from_boxed_node(boxed_node, internal.height - 1);
+                    let node = ptr::read(internal.reborrow().edge_at(idx + 1));
+                    let mut edge = Root { node, height: internal.height - 1, _marker: PhantomData };
                     // In practice, clearing the parent is a waste of time, because we will
                     // insert the node elsewhere and set its parent link again.
                     edge.borrow_mut().clear_parent_link();
@@ -760,9 +736,8 @@ impl<'a, K: 'a, V: 'a> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
             let edge = match self.reborrow_mut().force() {
                 ForceResult::Leaf(_) => None,
                 ForceResult::Internal(mut internal) => {
-                    let boxed_node =
-                        slice_remove(internal.reborrow_mut().into_edge_area_slice(), 0);
-                    let mut edge = Root::from_boxed_node(boxed_node, internal.height - 1);
+                    let node = slice_remove(internal.reborrow_mut().into_edge_area_slice(), 0);
+                    let mut edge = Root { node, height: internal.height - 1, _marker: PhantomData };
                     // In practice, clearing the parent is a waste of time, because we will
                     // insert the node elsewhere and set its parent link again.
                     edge.borrow_mut().clear_parent_link();
@@ -1041,12 +1016,11 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>,
         debug_assert!(self.node.len() < CAPACITY);
         debug_assert!(edge.height == self.node.height - 1);
 
-        let boxed_node = edge.into_boxed_node();
         unsafe {
             *self.node.reborrow_mut().into_len_mut() += 1;
             slice_insert(self.node.reborrow_mut().into_key_area_slice(), self.idx, key);
             slice_insert(self.node.reborrow_mut().into_val_area_slice(), self.idx, val);
-            slice_insert(self.node.reborrow_mut().into_edge_area_slice(), self.idx + 1, boxed_node);
+            slice_insert(self.node.reborrow_mut().into_edge_area_slice(), self.idx + 1, edge.node);
 
             self.node.correct_childrens_parent_links((self.idx + 1)..=self.node.len());
         }
@@ -1135,8 +1109,8 @@ impl<BorrowType, K, V> Handle<NodeRef<BorrowType, K, V, marker::Internal>, marke
         // reference (Rust issue #73987) and invalidate any other references
         // to or inside the array, should any be around.
         let parent_ptr = NodeRef::as_internal_ptr(&self.node);
-        let boxed_node = unsafe { (*parent_ptr).edges.get_unchecked(self.idx).assume_init_read() };
-        NodeRef::from_boxed_node(boxed_node, self.node.height - 1)
+        let node = unsafe { (*parent_ptr).edges.get_unchecked(self.idx).assume_init_read() };
+        NodeRef { node, height: self.node.height - 1, _marker: PhantomData }
     }
 }
 

library/alloc/src/collections/btree/set.rs

@@ -220,7 +220,9 @@ impl<T: fmt::Debug> fmt::Debug for Union<'_, T> {
 const ITER_PERFORMANCE_TIPPING_SIZE_DIFF: usize = 16;
 
 impl<T: Ord> BTreeSet<T> {
-    /// Makes a new `BTreeSet` with a reasonable choice of B.
+    /// Makes a new, empty `BTreeSet`.
+    ///
+    /// Does not allocate anything on its own.
     ///
     /// # Examples
     ///
@@ -1121,7 +1123,7 @@ impl<'a, T: 'a + Ord + Copy> Extend<&'a T> for BTreeSet<T> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Ord> Default for BTreeSet<T> {
-    /// Makes an empty `BTreeSet<T>` with a reasonable choice of B.
+    /// Creates an empty `BTreeSet`.
     fn default() -> BTreeSet<T> {
         BTreeSet::new()
     }

library/std/src/keyword_docs.rs

@@ -1739,7 +1739,7 @@ mod super_keyword {}
 ///
 /// # Differences between the 2015 and 2018 editions
 ///
-/// In the 2015 edition parameters pattern where not needed for traits:
+/// In the 2015 edition the parameters pattern was not needed for traits:
 ///
 /// ```rust,edition2015
 /// trait Tr {