Rollup of 4 pull requests

compiler/rustc_errors/src/emitter.rs

@@ -2154,11 +2154,11 @@ impl HumanEmitter {
 
             assert!(!file_lines.lines.is_empty() || parts[0].span.is_dummy());
 
-            let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
+            let line_start = sm.lookup_char_pos(parts[0].original_span.lo()).line;
             let mut lines = complete.lines();
             if lines.clone().next().is_none() {
                 // Account for a suggestion to completely remove a line(s) with whitespace (#94192).
-                let line_end = sm.lookup_char_pos(parts[0].span.hi()).line;
+                let line_end = sm.lookup_char_pos(parts[0].original_span.hi()).line;
                 for line in line_start..=line_end {
                     self.draw_line_num(
                         &mut buffer,

compiler/rustc_errors/src/lib.rs

@@ -224,6 +224,13 @@ pub struct SubstitutionPart {
     pub snippet: String,
 }
 
+#[derive(Clone, Debug, PartialEq, Hash, Encodable, Decodable)]
+pub struct TrimmedSubstitutionPart {
+    pub original_span: Span,
+    pub span: Span,
+    pub snippet: String,
+}
+
 /// Used to translate between `Span`s and byte positions within a single output line in highlighted
 /// code of structured suggestions.
 #[derive(Debug, Clone, Copy)]
@@ -233,6 +240,35 @@ pub(crate) struct SubstitutionHighlight {
 }
 
 impl SubstitutionPart {
+    /// Try to turn a replacement into an addition when the span that is being
+    /// overwritten matches either the prefix or suffix of the replacement.
+    fn trim_trivial_replacements(self, sm: &SourceMap) -> TrimmedSubstitutionPart {
+        let mut trimmed_part = TrimmedSubstitutionPart {
+            original_span: self.span,
+            span: self.span,
+            snippet: self.snippet,
+        };
+        if trimmed_part.snippet.is_empty() {
+            return trimmed_part;
+        }
+        let Ok(snippet) = sm.span_to_snippet(trimmed_part.span) else {
+            return trimmed_part;
+        };
+
+        if let Some((prefix, substr, suffix)) = as_substr(&snippet, &trimmed_part.snippet) {
+            trimmed_part.span = Span::new(
+                trimmed_part.span.lo() + BytePos(prefix as u32),
+                trimmed_part.span.hi() - BytePos(suffix as u32),
+                trimmed_part.span.ctxt(),
+                trimmed_part.span.parent(),
+            );
+            trimmed_part.snippet = substr.to_string();
+        }
+        trimmed_part
+    }
+}
+
+impl TrimmedSubstitutionPart {
     pub fn is_addition(&self, sm: &SourceMap) -> bool {
         !self.snippet.is_empty() && !self.replaces_meaningful_content(sm)
     }
@@ -260,27 +296,6 @@ impl SubstitutionPart {
         sm.span_to_snippet(self.span)
             .map_or(!self.span.is_empty(), |snippet| !snippet.trim().is_empty())
     }
-
-    /// Try to turn a replacement into an addition when the span that is being
-    /// overwritten matches either the prefix or suffix of the replacement.
-    fn trim_trivial_replacements(&mut self, sm: &SourceMap) {
-        if self.snippet.is_empty() {
-            return;
-        }
-        let Ok(snippet) = sm.span_to_snippet(self.span) else {
-            return;
-        };
-
-        if let Some((prefix, substr, suffix)) = as_substr(&snippet, &self.snippet) {
-            self.span = Span::new(
-                self.span.lo() + BytePos(prefix as u32),
-                self.span.hi() - BytePos(suffix as u32),
-                self.span.ctxt(),
-                self.span.parent(),
-            );
-            self.snippet = substr.to_string();
-        }
-    }
 }
 
 /// Given an original string like `AACC`, and a suggestion like `AABBCC`, try to detect
@@ -310,7 +325,8 @@ impl CodeSuggestion {
     pub(crate) fn splice_lines(
         &self,
         sm: &SourceMap,
-    ) -> Vec<(String, Vec<SubstitutionPart>, Vec<Vec<SubstitutionHighlight>>, ConfusionType)> {
+    ) -> Vec<(String, Vec<TrimmedSubstitutionPart>, Vec<Vec<SubstitutionHighlight>>, ConfusionType)>
+    {
         // For the `Vec<Vec<SubstitutionHighlight>>` value, the first level of the vector
         // corresponds to the output snippet's lines, while the second level corresponds to the
         // substrings within that line that should be highlighted.
@@ -428,12 +444,17 @@ impl CodeSuggestion {
                 // or deleted code in order to point at the correct column *after* substitution.
                 let mut acc = 0;
                 let mut confusion_type = ConfusionType::None;
-                for part in &mut substitution.parts {
+
+                let trimmed_parts = substitution
+                    .parts
+                    .into_iter()
                     // If this is a replacement of, e.g. `"a"` into `"ab"`, adjust the
                     // suggestion and snippet to look as if we just suggested to add
                     // `"b"`, which is typically much easier for the user to understand.
-                    part.trim_trivial_replacements(sm);
+                    .map(|part| part.trim_trivial_replacements(sm))
+                    .collect::<Vec<_>>();
 
+                for part in &trimmed_parts {
                     let part_confusion = detect_confusion_type(sm, &part.snippet, part.span);
                     confusion_type = confusion_type.combine(part_confusion);
                     let cur_lo = sm.lookup_char_pos(part.span.lo());
@@ -521,7 +542,7 @@ impl CodeSuggestion {
                 if highlights.iter().all(|parts| parts.is_empty()) {
                     None
                 } else {
-                    Some((buf, substitution.parts, highlights, confusion_type))
+                    Some((buf, trimmed_parts, highlights, confusion_type))
                 }
             })
             .collect()

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -2547,6 +2547,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             "you must specify a type for this binding, like `{concrete_type}`",
                         );
 
+                        // FIXME: Maybe FileName::Anon should also be handled,
+                        // otherwise there would be no suggestion if the source is STDIN for example.
                         match (filename, parent_node) {
                             (
                                 FileName::Real(_),
@@ -2568,6 +2570,44 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                     Applicability::MaybeIncorrect,
                                 );
                             }
+                            // For closure parameters with reference patterns (e.g., |&v|), suggest the type annotation
+                            // on the pattern itself, e.g., |&v: &i32|
+                            (FileName::Real(_), Node::Pat(pat))
+                                if let Node::Pat(binding_pat) = self.tcx.hir_node(hir_id)
+                                    && let hir::PatKind::Binding(..) = binding_pat.kind
+                                    && let Node::Pat(parent_pat) = parent_node
+                                    && matches!(parent_pat.kind, hir::PatKind::Ref(..)) =>
+                            {
+                                err.span_label(span, "you must specify a type for this binding");
+
+                                let mut ref_muts = Vec::new();
+                                let mut current_node = parent_node;
+
+                                while let Node::Pat(parent_pat) = current_node {
+                                    if let hir::PatKind::Ref(_, mutability) = parent_pat.kind {
+                                        ref_muts.push(mutability);
+                                        current_node = self.tcx.parent_hir_node(parent_pat.hir_id);
+                                    } else {
+                                        break;
+                                    }
+                                }
+
+                                let mut type_annotation = String::new();
+                                for mutability in ref_muts.iter().rev() {
+                                    match mutability {
+                                        hir::Mutability::Mut => type_annotation.push_str("&mut "),
+                                        hir::Mutability::Not => type_annotation.push('&'),
+                                    }
+                                }
+                                type_annotation.push_str(&concrete_type);
+
+                                err.span_suggestion_verbose(
+                                    pat.span.shrink_to_hi(),
+                                    "specify the type in the closure argument list",
+                                    format!(": {type_annotation}"),
+                                    Applicability::MaybeIncorrect,
+                                );
+                            }
                             _ => {
                                 err.span_label(span, msg);
                             }

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

@@ -33,6 +33,7 @@
 
 use core::marker::PhantomData;
 use core::mem::{self, MaybeUninit};
+use core::num::NonZero;
 use core::ptr::{self, NonNull};
 use core::slice::SliceIndex;
 
@@ -143,7 +144,7 @@ type BoxedNode<K, V> = NonNull<LeafNode<K, V>>;
 ///
 /// A reference to a node.
 ///
-/// This type has a number of parameters that controls how it acts:
+/// This type has a number of parameters that control how it acts:
 /// - `BorrowType`: A dummy type that describes the kind of borrow and carries a lifetime.
 ///    - When this is `Immut<'a>`, the `NodeRef` acts roughly like `&'a Node`.
 ///    - When this is `ValMut<'a>`, the `NodeRef` acts roughly like `&'a Node`
@@ -226,33 +227,27 @@ impl<K, V> NodeRef<marker::Owned, K, V, marker::Leaf> {
 
     fn from_new_leaf<A: Allocator + Clone>(leaf: Box<LeafNode<K, V>, A>) -> Self {
         // The allocator must be dropped, not leaked.  See also `BTreeMap::alloc`.
-        let (leaf, _alloc) = Box::into_raw_with_allocator(leaf);
-        // SAFETY: the node was just allocated.
-        let node = unsafe { NonNull::new_unchecked(leaf) };
+        let (node, _alloc) = Box::into_non_null_with_allocator(leaf);
         NodeRef { height: 0, node, _marker: PhantomData }
     }
 }
 
 impl<K, V> NodeRef<marker::Owned, K, V, marker::Internal> {
+    /// Creates a new internal (height > 0) `NodeRef`
     fn new_internal<A: Allocator + Clone>(child: Root<K, V>, alloc: A) -> Self {
         let mut new_node = unsafe { InternalNode::new(alloc) };
         new_node.edges[0].write(child.node);
-        unsafe { NodeRef::from_new_internal(new_node, child.height + 1) }
+        NodeRef::from_new_internal(new_node, NonZero::new(child.height + 1).unwrap())
     }
 
-    /// # Safety
-    /// `height` must not be zero.
-    unsafe fn from_new_internal<A: Allocator + Clone>(
+    /// Creates a new internal (height > 0) `NodeRef` from an existing internal node
+    fn from_new_internal<A: Allocator + Clone>(
         internal: Box<InternalNode<K, V>, A>,
-        height: usize,
+        height: NonZero<usize>,
     ) -> Self {
-        debug_assert!(height > 0);
         // The allocator must be dropped, not leaked.  See also `BTreeMap::alloc`.
-        let (internal, _alloc) = Box::into_raw_with_allocator(internal);
-        // SAFETY: the node was just allocated.
-        let internal = unsafe { NonNull::new_unchecked(internal) };
-        let node = internal.cast();
-        let mut this = NodeRef { height, node, _marker: PhantomData };
+        let (node, _alloc) = Box::into_non_null_with_allocator(internal);
+        let mut this = NodeRef { height: height.into(), node: node.cast(), _marker: PhantomData };
         this.borrow_mut().correct_all_childrens_parent_links();
         this
     }
@@ -625,9 +620,8 @@ impl<K, V> NodeRef<marker::Owned, K, V, marker::LeafOrInternal> {
         let top = self.node;
 
         // SAFETY: we asserted to be internal.
-        let internal_self = unsafe { self.borrow_mut().cast_to_internal_unchecked() };
-        // SAFETY: we borrowed `self` exclusively and its borrow type is exclusive.
-        let internal_node = unsafe { &mut *NodeRef::as_internal_ptr(&internal_self) };
+        let mut internal_self = unsafe { self.borrow_mut().cast_to_internal_unchecked() };
+        let internal_node = internal_self.as_internal_mut();
         // SAFETY: the first edge is always initialized.
         self.node = unsafe { internal_node.edges[0].assume_init_read() };
         self.height -= 1;
@@ -1305,7 +1299,8 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>,
                 &mut new_node.edges[..new_len + 1],
             );
 
-            let height = self.node.height;
+            // SAFETY: self is `marker::Internal`, so `self.node.height` is positive
+            let height = NonZero::new_unchecked(self.node.height);
             let right = NodeRef::from_new_internal(new_node, height);
 
             SplitResult { left: self.node, kv, right }