Rollup merge of #145783 - Erk-:et-cetera-span, r=compiler-errors

add span to struct pattern rest (..)

Struct pattern rest (`..`) did not retain span information compared to normal fields. This patch adds span information for it.

The motivation of this patch comes from when I implemented this PR for Clippy: https://github.com/rust-lang/rust-clippy/pull/15000#discussion_r2134145163

It is possible to get the span of the Et cetera in a bit roundabout way, but I thought this would be nicer.

compiler/rustc_ast/src/ast.rs

@@ -937,7 +937,7 @@ pub enum PatKind {
 #[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq, Walkable)]
 pub enum PatFieldsRest {
     /// `module::StructName { field, ..}`
-    Rest,
+    Rest(Span),
     /// `module::StructName { field, syntax error }`
     Recovered(ErrorGuaranteed),
     /// `module::StructName { field }`
@@ -4051,8 +4051,8 @@ mod size_asserts {
     static_assert_size!(Local, 96);
     static_assert_size!(MetaItemLit, 40);
     static_assert_size!(Param, 40);
-    static_assert_size!(Pat, 72);
+    static_assert_size!(Pat, 80);
-    static_assert_size!(PatKind, 48);
+    static_assert_size!(PatKind, 56);
     static_assert_size!(Path, 24);
     static_assert_size!(PathSegment, 24);
     static_assert_size!(Stmt, 32);

compiler/rustc_ast_lowering/src/expr.rs

@@ -1434,10 +1434,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         self.dcx().emit_err(FunctionalRecordUpdateDestructuringAssignment {
                             span: e.span,
                         });
-                        true
+                        Some(self.lower_span(e.span))
                     }
-                    StructRest::Rest(_) => true,
+                    StructRest::Rest(span) => Some(self.lower_span(*span)),
-                    StructRest::None => false,
+                    StructRest::None => None,
                 };
                 let struct_pat = hir::PatKind::Struct(qpath, field_pats, fields_omitted);
                 return self.pat_without_dbm(lhs.span, struct_pat);

compiler/rustc_ast_lowering/src/lib.rs

@@ -2508,7 +2508,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         fields: &'hir [hir::PatField<'hir>],
     ) -> &'hir hir::Pat<'hir> {
         let qpath = hir::QPath::LangItem(lang_item, self.lower_span(span));
-        self.pat(span, hir::PatKind::Struct(qpath, fields, false))
+        self.pat(span, hir::PatKind::Struct(qpath, fields, None))
     }
 
     fn pat_ident(&mut self, span: Span, ident: Ident) -> (&'hir hir::Pat<'hir>, HirId) {

compiler/rustc_ast_lowering/src/pat.rs

@@ -106,10 +106,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         break hir::PatKind::Struct(
                             qpath,
                             fs,
-                            matches!(
+                            match etc {
-                                etc,
+                                ast::PatFieldsRest::Rest(sp) => Some(self.lower_span(*sp)),
-                                ast::PatFieldsRest::Rest | ast::PatFieldsRest::Recovered(_)
+                                ast::PatFieldsRest::Recovered(_) => Some(Span::default()),
-                            ),
+                                _ => None,
+                            },
                         );
                     }
                     PatKind::Tuple(pats) => {

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -1769,7 +1769,7 @@ impl<'a> State<'a> {
                     },
                     |f| f.pat.span,
                 );
-                if let ast::PatFieldsRest::Rest | ast::PatFieldsRest::Recovered(_) = etc {
+                if let ast::PatFieldsRest::Rest(_) | ast::PatFieldsRest::Recovered(_) = etc {
                     if !fields.is_empty() {
                         self.word_space(",");
                     }

compiler/rustc_hir/src/hir.rs

@@ -1884,8 +1884,8 @@ pub enum PatKind<'hir> {
     Binding(BindingMode, HirId, Ident, Option<&'hir Pat<'hir>>),
 
     /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
-    /// The `bool` is `true` in the presence of a `..`.
+    /// The `Option` contains the span of a possible `..`.
-    Struct(QPath<'hir>, &'hir [PatField<'hir>], bool),
+    Struct(QPath<'hir>, &'hir [PatField<'hir>], Option<Span>),
 
     /// A tuple struct/variant pattern `Variant(x, y, .., z)`.
     /// If the `..` pattern fragment is present, then `DotDotPos` denotes its position.
@@ -4979,8 +4979,8 @@ mod size_asserts {
     static_assert_size!(ItemKind<'_>, 64);
     static_assert_size!(LetStmt<'_>, 72);
     static_assert_size!(Param<'_>, 32);
-    static_assert_size!(Pat<'_>, 72);
+    static_assert_size!(Pat<'_>, 80);
-    static_assert_size!(PatKind<'_>, 48);
+    static_assert_size!(PatKind<'_>, 56);
     static_assert_size!(Path<'_>, 40);
     static_assert_size!(PathSegment<'_>, 48);
     static_assert_size!(QPath<'_>, 24);

compiler/rustc_hir_pretty/src/lib.rs

@@ -1958,12 +1958,12 @@ impl<'a> State<'a> {
                 self.print_qpath(qpath, true);
                 self.nbsp();
                 self.word("{");
-                let empty = fields.is_empty() && !etc;
+                let empty = fields.is_empty() && etc.is_none();
                 if !empty {
                     self.space();
                 }
                 self.commasep_cmnt(Consistent, fields, |s, f| s.print_patfield(f), |f| f.pat.span);
-                if etc {
+                if etc.is_some() {
                     if !fields.is_empty() {
                         self.word_space(",");
                     }

compiler/rustc_hir_typeck/src/pat.rs

@@ -605,7 +605,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             },
             PatKind::Struct(_, fields, has_rest_pat) => match opt_path_res.unwrap() {
                 Ok(ResolvedPat { ty, kind: ResolvedPatKind::Struct { variant } }) => self
-                    .check_pat_struct(pat, fields, has_rest_pat, ty, variant, expected, pat_info),
+                    .check_pat_struct(
+                        pat,
+                        fields,
+                        has_rest_pat.is_some(),
+                        ty,
+                        variant,
+                        expected,
+                        pat_info,
+                    ),
                 Err(guar) => {
                     let ty_err = Ty::new_error(self.tcx, guar);
                     for field in fields {
@@ -2428,7 +2436,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let len = unmentioned_fields.len();
         let (prefix, postfix, sp) = match fields {
             [] => match &pat.kind {
-                PatKind::Struct(path, [], false) => {
+                PatKind::Struct(path, [], None) => {
                     (" { ", " }", path.span().shrink_to_hi().until(pat.span.shrink_to_hi()))
                 }
                 _ => return err,

compiler/rustc_parse/src/parser/pat.rs

@@ -1516,7 +1516,7 @@ impl<'a> Parser<'a> {
                 || self.check_noexpect(&token::DotDotDot)
                 || self.check_keyword(exp!(Underscore))
             {
-                etc = PatFieldsRest::Rest;
+                etc = PatFieldsRest::Rest(self.token.span);
                 let mut etc_sp = self.token.span;
                 if first_etc_and_maybe_comma_span.is_none() {
                     if let Some(comma_tok) =

compiler/rustc_passes/src/liveness.rs

@@ -1583,7 +1583,7 @@ impl<'tcx> Liveness<'_, 'tcx> {
         });
 
         let can_remove = match pat.kind {
-            hir::PatKind::Struct(_, fields, true) => {
+            hir::PatKind::Struct(_, fields, Some(_)) => {
                 // if all fields are shorthand, remove the struct field, otherwise, mark with _ as prefix
                 fields.iter().all(|f| f.is_shorthand)
             }

compiler/rustc_resolve/src/late.rs

@@ -3922,7 +3922,7 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
 
     fn record_patterns_with_skipped_bindings(&mut self, pat: &Pat, rest: &ast::PatFieldsRest) {
         match rest {
-            ast::PatFieldsRest::Rest | ast::PatFieldsRest::Recovered(_) => {
+            ast::PatFieldsRest::Rest(_) | ast::PatFieldsRest::Recovered(_) => {
                 // Record that the pattern doesn't introduce all the bindings it could.
                 if let Some(partial_res) = self.r.partial_res_map.get(&pat.id)
                     && let Some(res) = partial_res.full_res()

src/tools/clippy/clippy_lints/src/equatable_if_let.rs

@@ -53,7 +53,7 @@ fn unary_pattern(pat: &Pat<'_>) -> bool {
         | PatKind::Never
         | PatKind::Or(_)
         | PatKind::Err(_) => false,
-        PatKind::Struct(_, a, etc) => !etc && a.iter().all(|x| unary_pattern(x.pat)),
+        PatKind::Struct(_, a, etc) => etc.is_none() && a.iter().all(|x| unary_pattern(x.pat)),
         PatKind::Tuple(a, etc) | PatKind::TupleStruct(_, a, etc) => etc.as_opt_usize().is_none() && array_rec(a),
         PatKind::Ref(x, _) | PatKind::Box(x) | PatKind::Deref(x) | PatKind::Guard(x, _) => unary_pattern(x),
         PatKind::Expr(_) => true,

src/tools/clippy/clippy_lints/src/manual_let_else.rs

@@ -287,7 +287,7 @@ fn replace_in_pattern(
                 }
                 return or_pat;
             },
-            PatKind::Struct(path, fields, has_dot_dot) => {
+            PatKind::Struct(path, fields, dot_dot) => {
                 let fields = fields
                     .iter()
                     .map(|fld| {
@@ -311,7 +311,7 @@ fn replace_in_pattern(
                     .collect::<Vec<_>>();
                 let fields_string = fields.join(", ");
 
-                let dot_dot_str = if has_dot_dot { " .." } else { "" };
+                let dot_dot_str = if dot_dot.is_some() { " .." } else { "" };
                 let (sn_pth, _) = snippet_with_context(cx, path.span(), span.ctxt(), "", app);
                 return format!("{sn_pth} {{ {fields_string}{dot_dot_str} }}");
             },

src/tools/clippy/clippy_lints/src/matches/rest_pat_in_fully_bound_struct.rs

@@ -7,7 +7,7 @@ use super::REST_PAT_IN_FULLY_BOUND_STRUCTS;
 
 pub(crate) fn check(cx: &LateContext<'_>, pat: &Pat<'_>) {
     if !pat.span.from_expansion()
-        && let PatKind::Struct(QPath::Resolved(_, path), fields, true) = pat.kind
+        && let PatKind::Struct(QPath::Resolved(_, path), fields, Some(_)) = pat.kind
         && let Some(def_id) = path.res.opt_def_id()
         && let ty = cx.tcx.type_of(def_id).instantiate_identity()
         && let ty::Adt(def, _) = ty.kind()

src/tools/clippy/clippy_lints/src/utils/author.rs

@@ -754,7 +754,8 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
                 self.ident(name);
                 sub.if_some(|p| self.pat(p));
             },
-            PatKind::Struct(ref qpath, fields, ignore) => {
+            PatKind::Struct(ref qpath, fields, etc) => {
+                let ignore = etc.is_some();
                 bind!(self, qpath, fields);
                 kind!("Struct(ref {qpath}, {fields}, {ignore})");
                 self.qpath(qpath, pat);

src/tools/clippy/clippy_utils/src/lib.rs

@@ -2011,7 +2011,7 @@ pub fn is_expr_identity_of_pat(cx: &LateContext<'_>, pat: &Pat<'_>, expr: &Expr<
                 false
             }
         },
-        (PatKind::Struct(pat_ident, field_pats, false), ExprKind::Struct(ident, fields, hir::StructTailExpr::None))
+        (PatKind::Struct(pat_ident, field_pats, None), ExprKind::Struct(ident, fields, hir::StructTailExpr::None))
             if field_pats.len() == fields.len() =>
         {
             // check ident

src/tools/rustfmt/src/patterns.rs

@@ -303,7 +303,7 @@ impl Rewrite for Pat {
                 qself,
                 path,
                 fields,
-                rest == ast::PatFieldsRest::Rest,
+                matches!(rest, ast::PatFieldsRest::Rest(_)),
                 self.span,
                 context,
                 shape,

tests/ui/stats/input-stats.stderr

@@ -23,10 +23,10 @@ ast-stats - Path                      72 (NN.N%)             1
 ast-stats - Struct                    72 (NN.N%)             1
 ast-stats - Lit                      144 (NN.N%)             2
 ast-stats - Block                    216 (NN.N%)             3
-ast-stats Pat                      504 (NN.N%)             7            72
+ast-stats Pat                      560 (NN.N%)             7            80
-ast-stats - Struct                    72 (NN.N%)             1
+ast-stats - Struct                    80 (NN.N%)             1
-ast-stats - Wild                      72 (NN.N%)             1
+ast-stats - Wild                      80 (NN.N%)             1
-ast-stats - Ident                    360 (NN.N%)             5
+ast-stats - Ident                    400 (NN.N%)             5
 ast-stats GenericParam             480 (NN.N%)             5            96
 ast-stats GenericBound             352 (NN.N%)             4            88
 ast-stats - Trait                    352 (NN.N%)             4
@@ -57,7 +57,7 @@ ast-stats GenericArgs               40 (NN.N%)             1            40
 ast-stats - AngleBracketed            40 (NN.N%)             1
 ast-stats Crate                     40 (NN.N%)             1            40
 ast-stats ----------------------------------------------------------------
-ast-stats Total                  7_472                   129
+ast-stats Total                  7_528                   129
 ast-stats ================================================================
 hir-stats ================================================================
 hir-stats HIR STATS: input_stats
@@ -85,11 +85,11 @@ hir-stats - Ptr                       48 (NN.N%)             1
 hir-stats - Ref                       48 (NN.N%)             1
 hir-stats - Path                     624 (NN.N%)            13
 hir-stats Generics                 560 (NN.N%)            10            56
+hir-stats Pat                      400 (NN.N%)             5            80
+hir-stats - Struct                    80 (NN.N%)             1
+hir-stats - Wild                      80 (NN.N%)             1
+hir-stats - Binding                  240 (NN.N%)             3
 hir-stats GenericParam             400 (NN.N%)             5            80
-hir-stats Pat                      360 (NN.N%)             5            72
-hir-stats - Struct                    72 (NN.N%)             1
-hir-stats - Wild                      72 (NN.N%)             1
-hir-stats - Binding                  216 (NN.N%)             3
 hir-stats Block                    288 (NN.N%)             6            48
 hir-stats GenericBound             256 (NN.N%)             4            64
 hir-stats - Trait                    256 (NN.N%)             4
@@ -119,5 +119,5 @@ hir-stats TraitItemId                8 (NN.N%)             2             4
 hir-stats ImplItemId                 8 (NN.N%)             2             4
 hir-stats ForeignItemId              4 (NN.N%)             1             4
 hir-stats ----------------------------------------------------------------
-hir-stats Total                  8_584                   173
+hir-stats Total                  8_624                   173
 hir-stats ================================================================