Do not complain about non-existing fields after parse recovery

When failing to parse struct-like enum variants, the ADT gets recorded
as having no fields. Record that we have actually recovered during
parsing of this variant to avoid complaing about non-existing fields
when actually using it.

src/librustc/hir/lowering.rs

@@ -2672,7 +2672,7 @@ impl<'a> LoweringContext<'a> {
 
     fn lower_variant_data(&mut self, vdata: &VariantData) -> hir::VariantData {
         match *vdata {
-            VariantData::Struct(ref fields, id) => {
+            VariantData::Struct(ref fields, id, recovered) => {
                 let LoweredNodeId { node_id: _, hir_id } = self.lower_node_id(id);
 
                 hir::VariantData::Struct(
@@ -2682,6 +2682,7 @@ impl<'a> LoweringContext<'a> {
                         .map(|f| self.lower_struct_field(f))
                         .collect(),
                     hir_id,
+                    recovered,
                 )
             },
             VariantData::Tuple(ref fields, id) => {

src/librustc/hir/mod.rs

@@ -2173,7 +2173,7 @@ impl StructField {
 /// Id of the whole struct lives in `Item`.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable)]
 pub enum VariantData {
-    Struct(HirVec<StructField>, HirId),
+    Struct(HirVec<StructField>, HirId, bool),
     Tuple(HirVec<StructField>, HirId),
     Unit(HirId),
 }
@@ -2187,7 +2187,7 @@ impl VariantData {
     }
     pub fn hir_id(&self) -> HirId {
         match *self {
-            VariantData::Struct(_, hir_id)
+            VariantData::Struct(_, hir_id, _)
             | VariantData::Tuple(_, hir_id)
             | VariantData::Unit(hir_id) => hir_id,
         }

src/librustc/ty/mod.rs

@@ -1811,6 +1811,7 @@ pub struct VariantDef {
     pub fields: Vec<FieldDef>,
     pub ctor_kind: CtorKind,
     flags: VariantFlags,
+    pub recovered: bool,
 }
 
 impl<'a, 'gcx, 'tcx> VariantDef {
@@ -1829,16 +1830,17 @@ impl<'a, 'gcx, 'tcx> VariantDef {
     ///
     /// If someone speeds up attribute loading to not be a performance concern, they can
     /// remove this hack and use the constructor `DefId` everywhere.
-    pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
+    pub fn new(
+        tcx: TyCtxt<'a, 'gcx, 'tcx>,
         did: DefId,
         ident: Ident,
         discr: VariantDiscr,
         fields: Vec<FieldDef>,
         adt_kind: AdtKind,
         ctor_kind: CtorKind,
-               attribute_def_id: DefId)
-               -> Self
-    {
+        attribute_def_id: DefId,
+        recovered: bool,
+    ) -> Self {
         debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, ident, discr,
                fields, adt_kind, ctor_kind, attribute_def_id);
         let mut flags = VariantFlags::NO_VARIANT_FLAGS;
@@ -1852,7 +1854,8 @@ impl<'a, 'gcx, 'tcx> VariantDef {
             discr,
             fields,
             ctor_kind,
-            flags
+            flags,
+            recovered,
         }
     }
 
@@ -1868,7 +1871,8 @@ impl_stable_hash_for!(struct VariantDef {
     discr,
     fields,
     ctor_kind,
-    flags
+    flags,
+    recovered
 });
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]

src/librustc_metadata/decoder.rs

@@ -576,7 +576,8 @@ impl<'a, 'tcx> CrateMetadata {
             }).collect(),
             adt_kind,
             data.ctor_kind,
-            attribute_def_id
+            attribute_def_id,
+            false,
         )
     }
 

src/librustc_save_analysis/dump_visitor.rs

@@ -481,8 +481,8 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
         };
 
         let (value, fields) = match item.node {
-            ast::ItemKind::Struct(ast::VariantData::Struct(ref fields, _), _) |
-            ast::ItemKind::Union(ast::VariantData::Struct(ref fields, _), _) => {
+            ast::ItemKind::Struct(ast::VariantData::Struct(ref fields, ..), _) |
+            ast::ItemKind::Union(ast::VariantData::Struct(ref fields, ..), _) => {
                 let include_priv_fields = !self.save_ctxt.config.pub_only;
                 let fields_str = fields
                     .iter()
@@ -560,7 +560,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
             let name_span = variant.node.ident.span;
 
             match variant.node.data {
-                ast::VariantData::Struct(ref fields, _) => {
+                ast::VariantData::Struct(ref fields, ..) => {
                     let fields_str = fields
                         .iter()
                         .enumerate()

src/librustc_save_analysis/sig.rs

@@ -703,7 +703,7 @@ impl Sig for ast::Variant_ {
     fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result {
         let mut text = self.ident.to_string();
         match self.data {
-            ast::VariantData::Struct(ref fields, id) => {
+            ast::VariantData::Struct(ref fields, id, r) => {
                 let name_def = SigElement {
                     id: id_from_node_id(id, scx),
                     start: offset,
@@ -712,6 +712,9 @@ impl Sig for ast::Variant_ {
                 text.push_str(" { ");
                 let mut defs = vec![name_def];
                 let mut refs = vec![];
+                if r {
+                    text.push_str("/* parse error */ ");
+                } else {
                     for f in fields {
                         let field_sig = f.make(offset + text.len(), Some(id), scx)?;
                         text.push_str(&field_sig.text);
@@ -719,6 +722,7 @@ impl Sig for ast::Variant_ {
                         defs.extend(field_sig.defs.into_iter());
                         refs.extend(field_sig.refs.into_iter());
                     }
+                }
                 text.push('}');
                 Ok(Signature { text, defs, refs })
             }

src/librustc_typeck/check/_match.rs

@@ -918,14 +918,16 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
         pat_ty
     }
 
-    fn check_struct_pat_fields(&self,
+    fn check_struct_pat_fields(
+        &self,
         adt_ty: Ty<'tcx>,
         pat_id: hir::HirId,
         span: Span,
         variant: &'tcx ty::VariantDef,
         fields: &'gcx [Spanned<hir::FieldPat>],
         etc: bool,
-                               def_bm: ty::BindingMode) -> bool {
+        def_bm: ty::BindingMode,
+    ) -> bool {
         let tcx = self.tcx;
 
         let (substs, adt) = match adt_ty.sty {
@@ -985,7 +987,7 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
                 .map(|field| field.ident.modern())
                 .filter(|ident| !used_fields.contains_key(&ident))
                 .collect::<Vec<_>>();
-        if inexistent_fields.len() > 0 {
+        if inexistent_fields.len() > 0 && !variant.recovered {
             let (field_names, t, plural) = if inexistent_fields.len() == 1 {
                 (format!("a field named `{}`", inexistent_fields[0].1), "this", "")
             } else {

src/librustc_typeck/check/mod.rs

@@ -3689,12 +3689,17 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                            field, expr_t)
     }
 
-    fn report_unknown_field(&self,
+    fn report_unknown_field(
+        &self,
         ty: Ty<'tcx>,
         variant: &'tcx ty::VariantDef,
         field: &hir::Field,
         skip_fields: &[hir::Field],
-                            kind_name: &str) {
+        kind_name: &str,
+    ) {
+        if variant.recovered {
+            return;
+        }
         let mut err = self.type_error_struct_with_diag(
             field.ident.span,
             |actual| match ty.sty {

src/librustc_typeck/collect.rs

@@ -598,6 +598,10 @@ fn convert_variant<'a, 'tcx>(
             }
         })
         .collect();
+    let recovered = match def {
+        hir::VariantData::Struct(_, _, r) => *r,
+        _ => false,
+    };
     ty::VariantDef::new(tcx,
         did,
         ident,
@@ -605,7 +609,8 @@ fn convert_variant<'a, 'tcx>(
         fields,
         adt_kind,
         CtorKind::from_hir(def),
-        attribute_def_id
+        attribute_def_id,
+        recovered,
     )
 }
 

src/libsyntax/ast.rs

@@ -2133,7 +2133,7 @@ pub enum VariantData {
     /// Struct variant.
     ///
     /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
-    Struct(Vec<StructField>, NodeId),
+    Struct(Vec<StructField>, NodeId, bool),
     /// Tuple variant.
     ///
     /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
@@ -2147,13 +2147,13 @@ pub enum VariantData {
 impl VariantData {
     pub fn fields(&self) -> &[StructField] {
         match *self {
-            VariantData::Struct(ref fields, _) | VariantData::Tuple(ref fields, _) => fields,
+            VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, _) => fields,
             _ => &[],
         }
     }
     pub fn id(&self) -> NodeId {
         match *self {
-            VariantData::Struct(_, id) | VariantData::Tuple(_, id) | VariantData::Unit(id) => id,
+            VariantData::Struct(_, id, _) | VariantData::Tuple(_, id) | VariantData::Unit(id) => id,
         }
     }
     pub fn is_struct(&self) -> bool {

src/libsyntax/config.rs

@@ -225,7 +225,7 @@ impl<'a> StripUnconfigured<'a> {
 
     fn configure_variant_data(&mut self, vdata: &mut ast::VariantData) {
         match vdata {
-            ast::VariantData::Struct(fields, _id) |
+            ast::VariantData::Struct(fields, _id, _) |
             ast::VariantData::Tuple(fields, _id) =>
                 fields.flat_map_in_place(|field| self.configure(field)),
             ast::VariantData::Unit(_id) => {}

src/libsyntax/mut_visit.rs

@@ -765,7 +765,7 @@ pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis:
 
 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
     match vdata {
-        VariantData::Struct(fields, id) |
+        VariantData::Struct(fields, id, _) |
         VariantData::Tuple(fields, id) => {
             visit_vec(fields, |field| vis.visit_struct_field(field));
             vis.visit_id(id);

src/libsyntax/parse/parser.rs

@@ -6829,14 +6829,16 @@ impl<'a> Parser<'a> {
                 VariantData::Unit(ast::DUMMY_NODE_ID)
             } else {
                 // If we see: `struct Foo<T> where T: Copy { ... }`
-                VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID)
+                let (fields, recovered) = self.parse_record_struct_body()?;
+                VariantData::Struct(fields, ast::DUMMY_NODE_ID, recovered)
             }
         // No `where` so: `struct Foo<T>;`
         } else if self.eat(&token::Semi) {
             VariantData::Unit(ast::DUMMY_NODE_ID)
         // Record-style struct definition
         } else if self.token == token::OpenDelim(token::Brace) {
-            VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID)
+            let (fields, recovered) = self.parse_record_struct_body()?;
+            VariantData::Struct(fields, ast::DUMMY_NODE_ID, recovered)
         // Tuple-style struct definition with optional where-clause.
         } else if self.token == token::OpenDelim(token::Paren) {
             let body = VariantData::Tuple(self.parse_tuple_struct_body()?, ast::DUMMY_NODE_ID);
@@ -6864,9 +6866,11 @@ impl<'a> Parser<'a> {
 
         let vdata = if self.token.is_keyword(keywords::Where) {
             generics.where_clause = self.parse_where_clause()?;
-            VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID)
+            let (fields, recovered) = self.parse_record_struct_body()?;
+            VariantData::Struct(fields, ast::DUMMY_NODE_ID, recovered)
         } else if self.token == token::OpenDelim(token::Brace) {
-            VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID)
+            let (fields, recovered) = self.parse_record_struct_body()?;
+            VariantData::Struct(fields, ast::DUMMY_NODE_ID, recovered)
         } else {
             let token_str = self.this_token_descr();
             let mut err = self.fatal(&format!(
@@ -6898,12 +6902,14 @@ impl<'a> Parser<'a> {
         }
     }
 
-    fn parse_record_struct_body(&mut self) -> PResult<'a, Vec<StructField>> {
+    fn parse_record_struct_body(&mut self) -> PResult<'a, (Vec<StructField>, bool)> {
         let mut fields = Vec::new();
+        let mut recovered = false;
         if self.eat(&token::OpenDelim(token::Brace)) {
             while self.token != token::CloseDelim(token::Brace) {
                 let field = self.parse_struct_decl_field().map_err(|e| {
                     self.recover_stmt();
+                    recovered = true;
                     e
                 });
                 match field {
@@ -6922,7 +6928,7 @@ impl<'a> Parser<'a> {
             return Err(err);
         }
 
-        Ok(fields)
+        Ok((fields, recovered))
     }
 
     fn parse_tuple_struct_body(&mut self) -> PResult<'a, Vec<StructField>> {
@@ -7684,12 +7690,14 @@ impl<'a> Parser<'a> {
             if self.check(&token::OpenDelim(token::Brace)) {
                 // Parse a struct variant.
                 all_nullary = false;
-                struct_def = VariantData::Struct(self.parse_record_struct_body()?,
-                                                 ast::DUMMY_NODE_ID);
+                let (fields, recovered) = self.parse_record_struct_body()?;
+                struct_def = VariantData::Struct(fields, ast::DUMMY_NODE_ID, recovered);
             } else if self.check(&token::OpenDelim(token::Paren)) {
                 all_nullary = false;
-                struct_def = VariantData::Tuple(self.parse_tuple_struct_body()?,
-                                                ast::DUMMY_NODE_ID);
+                struct_def = VariantData::Tuple(
+                    self.parse_tuple_struct_body()?,
+                    ast::DUMMY_NODE_ID,
+                );
             } else if self.eat(&token::Eq) {
                 disr_expr = Some(AnonConst {
                     id: ast::DUMMY_NODE_ID,

src/test/ui/parser/recovered-struct-variant.rs

@@ -0,0 +1,13 @@
+enum Foo {
+    A { a, b: usize }
+    //~^ ERROR expected `:`, found `,`
+}
+
+fn main() {
+    // no complaints about non-existing fields
+    let f = Foo::A { a:3, b: 4};
+    match f {
+        // no complaints about non-existing fields
+        Foo::A {a, b} => {}
+    }
+}

src/test/ui/parser/recovered-struct-variant.stderr

@@ -0,0 +1,8 @@
+error: expected `:`, found `,`
+  --> $DIR/recovered-struct-variant.rs:2:10
+   |
+LL |     A { a, b: usize }
+   |          ^ expected `:`
+
+error: aborting due to previous error
+