Merge pull request #4404 from rust-lang/rustup-2025-06-18

Automatic Rustup

Author: RalfJung

compiler/rustc_ast/src/ast.rs

@@ -710,6 +710,12 @@ impl Pat {
     }
 }
 
+impl From<P<Pat>> for Pat {
+    fn from(value: P<Pat>) -> Self {
+        *value
+    }
+}
+
 /// A single field in a struct pattern.
 ///
 /// Patterns like the fields of `Foo { x, ref y, ref mut z }`
@@ -1553,17 +1559,23 @@ impl Expr {
         )
     }
 
-    /// Creates a dummy `P<Expr>`.
+    /// Creates a dummy `Expr`.
     ///
     /// Should only be used when it will be replaced afterwards or as a return value when an error was encountered.
-    pub fn dummy() -> P<Expr> {
-        P(Expr {
+    pub fn dummy() -> Expr {
+        Expr {
             id: DUMMY_NODE_ID,
             kind: ExprKind::Dummy,
             span: DUMMY_SP,
             attrs: ThinVec::new(),
             tokens: None,
-        })
+        }
+    }
+}
+
+impl From<P<Expr>> for Expr {
+    fn from(value: P<Expr>) -> Self {
+        *value
     }
 }
 
@@ -2374,6 +2386,12 @@ impl Clone for Ty {
     }
 }
 
+impl From<P<Ty>> for Ty {
+    fn from(value: P<Ty>) -> Self {
+        *value
+    }
+}
+
 impl Ty {
     pub fn peel_refs(&self) -> &Self {
         let mut final_ty = self;

compiler/rustc_ast/src/mut_visit.rs

@@ -168,15 +168,15 @@ pub trait MutVisitor: Sized + MutVisitorResult<Result = ()> {
         walk_flat_map_arm(self, arm)
     }
 
-    fn visit_pat(&mut self, p: &mut P<Pat>) {
+    fn visit_pat(&mut self, p: &mut Pat) {
         walk_pat(self, p);
     }
 
     fn visit_anon_const(&mut self, c: &mut AnonConst) {
         walk_anon_const(self, c);
     }
 
-    fn visit_expr(&mut self, e: &mut P<Expr>) {
+    fn visit_expr(&mut self, e: &mut Expr) {
         walk_expr(self, e);
     }
 
@@ -194,7 +194,7 @@ pub trait MutVisitor: Sized + MutVisitorResult<Result = ()> {
         walk_generic_arg(self, arg);
     }
 
-    fn visit_ty(&mut self, t: &mut P<Ty>) {
+    fn visit_ty(&mut self, t: &mut Ty) {
         walk_ty(self, t);
     }
 

compiler/rustc_ast/src/token.rs

@@ -1085,6 +1085,7 @@ pub enum NtExprKind {
     Expr2021 { inferred: bool },
 }
 
+/// A macro nonterminal, known in documentation as a fragment specifier.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Encodable, Decodable, Hash, HashStable_Generic)]
 pub enum NonterminalKind {
     Item,

compiler/rustc_ast/src/visit.rs

@@ -884,7 +884,7 @@ macro_rules! common_visitor_and_walkers {
                 TyKind::BareFn(function_declaration) => {
                     let BareFnTy { safety, ext: _, generic_params, decl, decl_span } =
                         &$($mut)? **function_declaration;
-                    visit_safety(vis, safety);
+                    try_visit!(visit_safety(vis, safety));
                     try_visit!(visit_generic_params(vis, generic_params));
                     try_visit!(vis.visit_fn_decl(decl));
                     try_visit!(visit_span(vis, decl_span));
@@ -1235,7 +1235,7 @@ macro_rules! common_visitor_and_walkers {
                     bounds,
                     bound_generic_params,
                 }) => {
-                    visit_generic_params(vis, bound_generic_params);
+                    try_visit!(visit_generic_params(vis, bound_generic_params));
                     try_visit!(vis.visit_ty(bounded_ty));
                     walk_list!(vis, visit_param_bound, bounds, BoundKind::Bound);
                 }
@@ -1420,7 +1420,7 @@ macro_rules! common_visitor_and_walkers {
                     let StructExpr { qself, path, fields, rest } = &$($mut)?**se;
                     try_visit!(vis.visit_qself(qself));
                     try_visit!(vis.visit_path(path));
-                    visit_expr_fields(vis, fields);
+                    try_visit!(visit_expr_fields(vis, fields));
                     match rest {
                         StructRest::Base(expr) => try_visit!(vis.visit_expr(expr)),
                         StructRest::Rest(_span) => {}

compiler/rustc_ast_lowering/messages.ftl

@@ -179,6 +179,8 @@ ast_lowering_underscore_expr_lhs_assign =
     in expressions, `_` can only be used on the left-hand side of an assignment
     .label = `_` not allowed here
 
+ast_lowering_union_default_field_values = unions cannot have default field values
+
 ast_lowering_unstable_inline_assembly = inline assembly is not stable yet on this architecture
 ast_lowering_unstable_inline_assembly_label_operand_with_outputs =
     using both label and output operands for inline assembly is unstable

compiler/rustc_ast_lowering/src/errors.rs

@@ -475,3 +475,10 @@ pub(crate) struct UseConstGenericArg {
     #[suggestion_part(code = "{other_args}")]
     pub call_args: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(ast_lowering_union_default_field_values)]
+pub(crate) struct UnionWithDefault {
+    #[primary_span]
+    pub span: Span,
+}

compiler/rustc_ast_lowering/src/item.rs

@@ -17,6 +17,7 @@ use tracing::instrument;
 
 use super::errors::{
     InvalidAbi, InvalidAbiSuggestion, MisplacedRelaxTraitBound, TupleStructWithDefault,
+    UnionWithDefault,
 };
 use super::stability::{enabled_names, gate_unstable_abi};
 use super::{
@@ -316,7 +317,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| {
                         this.arena.alloc_from_iter(
-                            enum_definition.variants.iter().map(|x| this.lower_variant(x)),
+                            enum_definition.variants.iter().map(|x| this.lower_variant(i, x)),
                         )
                     },
                 );
@@ -328,7 +329,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     generics,
                     id,
                     ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
-                    |this| this.lower_variant_data(hir_id, struct_def),
+                    |this| this.lower_variant_data(hir_id, i, struct_def),
                 );
                 hir::ItemKind::Struct(ident, generics, struct_def)
             }
@@ -338,7 +339,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     generics,
                     id,
                     ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
-                    |this| this.lower_variant_data(hir_id, vdata),
+                    |this| this.lower_variant_data(hir_id, i, vdata),
                 );
                 hir::ItemKind::Union(ident, generics, vdata)
             }
@@ -714,13 +715,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
         }
     }
 
-    fn lower_variant(&mut self, v: &Variant) -> hir::Variant<'hir> {
+    fn lower_variant(&mut self, item_kind: &ItemKind, v: &Variant) -> hir::Variant<'hir> {
         let hir_id = self.lower_node_id(v.id);
         self.lower_attrs(hir_id, &v.attrs, v.span);
         hir::Variant {
             hir_id,
             def_id: self.local_def_id(v.id),
-            data: self.lower_variant_data(hir_id, &v.data),
+            data: self.lower_variant_data(hir_id, item_kind, &v.data),
             disr_expr: v.disr_expr.as_ref().map(|e| self.lower_anon_const_to_anon_const(e)),
             ident: self.lower_ident(v.ident),
             span: self.lower_span(v.span),
@@ -730,15 +731,36 @@ impl<'hir> LoweringContext<'_, 'hir> {
     fn lower_variant_data(
         &mut self,
         parent_id: hir::HirId,
+        item_kind: &ItemKind,
         vdata: &VariantData,
     ) -> hir::VariantData<'hir> {
         match vdata {
-            VariantData::Struct { fields, recovered } => hir::VariantData::Struct {
-                fields: self
+            VariantData::Struct { fields, recovered } => {
+                let fields = self
                     .arena
-                    .alloc_from_iter(fields.iter().enumerate().map(|f| self.lower_field_def(f))),
-                recovered: *recovered,
-            },
+                    .alloc_from_iter(fields.iter().enumerate().map(|f| self.lower_field_def(f)));
+
+                if let ItemKind::Union(..) = item_kind {
+                    for field in &fields[..] {
+                        if let Some(default) = field.default {
+                            // Unions cannot derive `Default`, and it's not clear how to use default
+                            // field values of unions if that was supported. Therefore, blanket reject
+                            // trying to use field values with unions.
+                            if self.tcx.features().default_field_values() {
+                                self.dcx().emit_err(UnionWithDefault { span: default.span });
+                            } else {
+                                let _ = self.dcx().span_delayed_bug(
+                                default.span,
+                                "expected union default field values feature gate error but none \
+                                was produced",
+                            );
+                            }
+                        }
+                    }
+                }
+
+                hir::VariantData::Struct { fields, recovered: *recovered }
+            }
             VariantData::Tuple(fields, id) => {
                 let ctor_id = self.lower_node_id(*id);
                 self.alias_attrs(ctor_id, parent_id);

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -224,20 +224,6 @@ impl<'a> AstValidator<'a> {
         }
     }
 
-    fn visit_struct_field_def(&mut self, field: &'a FieldDef) {
-        if let Some(ref ident) = field.ident
-            && ident.name == kw::Underscore
-        {
-            self.visit_vis(&field.vis);
-            self.visit_ident(ident);
-            self.visit_ty_common(&field.ty);
-            self.walk_ty(&field.ty);
-            walk_list!(self, visit_attribute, &field.attrs);
-        } else {
-            self.visit_field_def(field);
-        }
-    }
-
     fn dcx(&self) -> DiagCtxtHandle<'a> {
         self.sess.dcx()
     }
@@ -1135,8 +1121,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 VariantData::Struct { fields, .. } => {
                     self.visit_attrs_vis_ident(&item.attrs, &item.vis, ident);
                     self.visit_generics(generics);
-                    // Permit `Anon{Struct,Union}` as field type.
-                    walk_list!(self, visit_struct_field_def, fields);
+                    walk_list!(self, visit_field_def, fields);
                 }
                 _ => visit::walk_item(self, item),
             },
@@ -1148,8 +1133,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     VariantData::Struct { fields, .. } => {
                         self.visit_attrs_vis_ident(&item.attrs, &item.vis, ident);
                         self.visit_generics(generics);
-                        // Permit `Anon{Struct,Union}` as field type.
-                        walk_list!(self, visit_struct_field_def, fields);
+                        walk_list!(self, visit_field_def, fields);
                     }
                     _ => visit::walk_item(self, item),
                 }

compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs

@@ -342,10 +342,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
                                 }
                             }
                         } else if let LocalInfo::BlockTailTemp(info) = local_decl.local_info() {
-                            let sp = info
-                                .span
-                                .find_ancestor_in_same_ctxt(local_decl.source_info.span)
-                                .unwrap_or(info.span);
+                            let sp = info.span.find_oldest_ancestor_in_same_ctxt();
                             if info.tail_result_is_ignored {
                                 // #85581: If the first mutable borrow's scope contains
                                 // the second borrow, this suggestion isn't helpful.

compiler/rustc_builtin_macros/src/cfg_eval.rs

@@ -155,7 +155,7 @@ impl CfgEval<'_> {
 
 impl MutVisitor for CfgEval<'_> {
     #[instrument(level = "trace", skip(self))]
-    fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
+    fn visit_expr(&mut self, expr: &mut ast::Expr) {
         self.0.configure_expr(expr, false);
         mut_visit::walk_expr(self, expr);
     }