Rollup merge of #47258 - rkruppe:struct-assert, r=eddyb

rustc::ty: Rename struct_variant to non_enum_variant

r? @EddyB

src/librustc/middle/dead.rs

@@ -102,7 +102,7 @@ fn lookup_and_handle_method(&mut self, id: hir::HirId) {
     fn handle_field_access(&mut self, lhs: &hir::Expr, name: ast::Name) {
         match self.tables.expr_ty_adjusted(lhs).sty {
             ty::TyAdt(def, _) => {
-                self.insert_def_id(def.struct_variant().field_named(name).did);
+                self.insert_def_id(def.non_enum_variant().field_named(name).did);
             }
             _ => span_bug!(lhs.span, "named field access on non-ADT"),
         }
@@ -111,7 +111,7 @@ fn handle_field_access(&mut self, lhs: &hir::Expr, name: ast::Name) {
     fn handle_tup_field_access(&mut self, lhs: &hir::Expr, idx: usize) {
         match self.tables.expr_ty_adjusted(lhs).sty {
             ty::TyAdt(def, _) => {
-                self.insert_def_id(def.struct_variant().fields[idx].did);
+                self.insert_def_id(def.non_enum_variant().fields[idx].did);
             }
             ty::TyTuple(..) => {}
             _ => span_bug!(lhs.span, "numeric field access on non-ADT"),

src/librustc/middle/expr_use_visitor.rs

@@ -663,7 +663,7 @@ fn walk_struct_expr(&mut self,
         match with_cmt.ty.sty {
             ty::TyAdt(adt, substs) if adt.is_struct() => {
                 // Consume those fields of the with expression that are needed.
-                for with_field in &adt.struct_variant().fields {
+                for with_field in &adt.non_enum_variant().fields {
                     if !contains_field_named(with_field, fields) {
                         let cmt_field = self.mc.cat_field(
                             &*with_expr,

src/librustc/middle/mem_categorization.rs

@@ -1248,7 +1248,7 @@ fn cat_pattern_<F>(&self, mut cmt: cmt<'tcx>, pat: &hir::Pat, op: &mut F) -> McR
                 Def::StructCtor(_, CtorKind::Fn) => {
                     match self.pat_ty(&pat)?.sty {
                         ty::TyAdt(adt_def, _) => {
-                            (cmt, adt_def.struct_variant().fields.len())
+                            (cmt, adt_def.non_enum_variant().fields.len())
                         }
                         ref ty => {
                             span_bug!(pat.span, "tuple struct pattern unexpected type {:?}", ty);

src/librustc/ty/mod.rs

@@ -1691,10 +1691,9 @@ pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
         self.destructor(tcx).is_some()
     }
 
-    /// Asserts this is a struct and returns the struct's unique
-    /// variant.
-    pub fn struct_variant(&self) -> &VariantDef {
-        assert!(!self.is_enum());
+    /// Asserts this is a struct or union and returns its unique variant.
+    pub fn non_enum_variant(&self) -> &VariantDef {
+        assert!(self.is_struct() || self.is_union());
         &self.variants[0]
     }
 
@@ -1733,7 +1732,7 @@ pub fn variant_of_def(&self, def: Def) -> &VariantDef {
         match def {
             Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
             Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
-            Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
+            Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.non_enum_variant(),
             _ => bug!("unexpected def {:?} in variant_of_def", def)
         }
     }
@@ -2319,11 +2318,11 @@ pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
                 self.adt_def(enum_did).variant_with_id(did)
             }
             Def::Struct(did) | Def::Union(did) => {
-                self.adt_def(did).struct_variant()
+                self.adt_def(did).non_enum_variant()
             }
             Def::StructCtor(ctor_did, ..) => {
                 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
-                self.adt_def(did).struct_variant()
+                self.adt_def(did).non_enum_variant()
             }
             _ => bug!("expect_variant_def used with unexpected def {:?}", def)
         }

src/librustc/ty/sty.rs

@@ -1351,7 +1351,7 @@ pub fn sequence_element_type(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
     pub fn simd_type(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
         match self.sty {
             TyAdt(def, substs) => {
-                def.struct_variant().fields[0].ty(tcx, substs)
+                def.non_enum_variant().fields[0].ty(tcx, substs)
             }
             _ => bug!("simd_type called on invalid type")
         }
@@ -1359,7 +1359,7 @@ pub fn simd_type(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
 
     pub fn simd_size(&self, _cx: TyCtxt) -> usize {
         match self.sty {
-            TyAdt(def, _) => def.struct_variant().fields.len(),
+            TyAdt(def, _) => def.non_enum_variant().fields.len(),
             _ => bug!("simd_size called on invalid type")
         }
     }

src/librustc/ty/util.rs

@@ -258,7 +258,7 @@ pub fn positional_element_ty(self,
                 adt.variant_with_id(vid).fields.get(i).map(|f| f.ty(self, substs))
             }
             (&TyAdt(adt, substs), None) => {
-                // Don't use `struct_variant`, this may be a univariant enum.
+                // Don't use `non_enum_variant`, this may be a univariant enum.
                 adt.variants[0].fields.get(i).map(|f| f.ty(self, substs))
             }
             (&TyTuple(ref v, _), None) => v.get(i).cloned(),
@@ -277,7 +277,7 @@ pub fn named_element_ty(self,
                 adt.variant_with_id(vid).find_field_named(n).map(|f| f.ty(self, substs))
             }
             (&TyAdt(adt, substs), None) => {
-                adt.struct_variant().find_field_named(n).map(|f| f.ty(self, substs))
+                adt.non_enum_variant().find_field_named(n).map(|f| f.ty(self, substs))
             }
             _ => return None
         }
@@ -293,7 +293,7 @@ pub fn struct_tail(self, mut ty: Ty<'tcx>) -> Ty<'tcx> {
                     if !def.is_struct() {
                         break;
                     }
-                    match def.struct_variant().fields.last() {
+                    match def.non_enum_variant().fields.last() {
                         Some(f) => ty = f.ty(self, substs),
                         None => break,
                     }
@@ -329,7 +329,7 @@ pub fn struct_lockstep_tails(self,
             match (&a.sty, &b.sty) {
                 (&TyAdt(a_def, a_substs), &TyAdt(b_def, b_substs))
                         if a_def == b_def && a_def.is_struct() => {
-                    if let Some(f) = a_def.struct_variant().fields.last() {
+                    if let Some(f) = a_def.non_enum_variant().fields.last() {
                         a = f.ty(self, a_substs);
                         b = f.ty(self, b_substs);
                     } else {

src/librustc_borrowck/borrowck/gather_loans/restrictions.rs

@@ -107,7 +107,7 @@ fn restrict(&self,
                     ty::TyAdt(adt_def, _) if adt_def.is_union() => match result {
                         RestrictionResult::Safe => RestrictionResult::Safe,
                         RestrictionResult::SafeIf(base_lp, mut base_vec) => {
-                            for field in &adt_def.struct_variant().fields {
+                            for field in &adt_def.non_enum_variant().fields {
                                 let field = InteriorKind::InteriorField(mc::NamedField(field.name));
                                 let field_ty = if field == interior {
                                     cmt.ty

src/librustc_borrowck/borrowck/move_data.rs

@@ -343,7 +343,7 @@ pub fn add_move(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>,
             if let (&ty::TyAdt(adt_def, _), LpInterior(opt_variant_id, interior))
                     = (&base_lp.ty.sty, lp_elem) {
                 if adt_def.is_union() {
-                    for field in &adt_def.struct_variant().fields {
+                    for field in &adt_def.non_enum_variant().fields {
                         let field = InteriorKind::InteriorField(mc::NamedField(field.name));
                         if field != interior {
                             let sibling_lp_kind =
@@ -395,7 +395,7 @@ pub fn add_assignment(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>,
         if let LpExtend(ref base_lp, mutbl, LpInterior(opt_variant_id, interior)) = lp.kind {
             if let ty::TyAdt(adt_def, _) = base_lp.ty.sty {
                 if adt_def.is_union() {
-                    for field in &adt_def.struct_variant().fields {
+                    for field in &adt_def.non_enum_variant().fields {
                         let field = InteriorKind::InteriorField(mc::NamedField(field.name));
                         let field_ty = if field == interior {
                             lp.ty

src/librustc_lint/types.rs

@@ -422,7 +422,7 @@ fn check_type_for_ffi(&self,
                                               consider adding a #[repr(C)] attribute to the type");
                         }
 
-                        if def.struct_variant().fields.is_empty() {
+                        if def.non_enum_variant().fields.is_empty() {
                             return FfiUnsafe("found zero-size struct in foreign module, consider \
                                               adding a member to this struct");
                         }
@@ -430,7 +430,7 @@ fn check_type_for_ffi(&self,
                         // We can't completely trust repr(C) markings; make sure the
                         // fields are actually safe.
                         let mut all_phantom = true;
-                        for field in &def.struct_variant().fields {
+                        for field in &def.non_enum_variant().fields {
                             let field_ty = cx.fully_normalize_associated_types_in(
                                 &field.ty(cx, substs)
                             );
@@ -458,13 +458,13 @@ fn check_type_for_ffi(&self,
                                               consider adding a #[repr(C)] attribute to the type");
                         }
 
-                        if def.struct_variant().fields.is_empty() {
+                        if def.non_enum_variant().fields.is_empty() {
                             return FfiUnsafe("found zero-size union in foreign module, consider \
                                               adding a member to this union");
                         }
 
                         let mut all_phantom = true;
-                        for field in &def.struct_variant().fields {
+                        for field in &def.non_enum_variant().fields {
                             let field_ty = cx.fully_normalize_associated_types_in(
                                 &field.ty(cx, substs)
                             );

src/librustc_metadata/encoder.rs

@@ -625,7 +625,7 @@ fn encode_struct_ctor(&mut self, (adt_def_id, def_id): (DefId, DefId)) -> Entry<
         debug!("IsolatedEncoder::encode_struct_ctor({:?})", def_id);
         let tcx = self.tcx;
         let adt_def = tcx.adt_def(adt_def_id);
-        let variant = adt_def.struct_variant();
+        let variant = adt_def.non_enum_variant();
 
         let data = VariantData {
             ctor_kind: variant.ctor_kind,
@@ -935,7 +935,7 @@ fn encode_info_for_item(&mut self, (def_id, item): (DefId, &'tcx hir::Item)) ->
             hir::ItemTy(..) => EntryKind::Type,
             hir::ItemEnum(..) => EntryKind::Enum(get_repr_options(&tcx, def_id)),
             hir::ItemStruct(ref struct_def, _) => {
-                let variant = tcx.adt_def(def_id).struct_variant();
+                let variant = tcx.adt_def(def_id).non_enum_variant();
 
                 // Encode def_ids for each field and method
                 // for methods, write all the stuff get_trait_method
@@ -956,7 +956,7 @@ fn encode_info_for_item(&mut self, (def_id, item): (DefId, &'tcx hir::Item)) ->
                 }), repr_options)
             }
             hir::ItemUnion(..) => {
-                let variant = tcx.adt_def(def_id).struct_variant();
+                let variant = tcx.adt_def(def_id).non_enum_variant();
                 let repr_options = get_repr_options(&tcx, def_id);
 
                 EntryKind::Union(self.lazy(&VariantData {
@@ -1049,7 +1049,7 @@ fn encode_info_for_item(&mut self, (def_id, item): (DefId, &'tcx hir::Item)) ->
                 hir::ItemStruct(..) |
                 hir::ItemUnion(..) => {
                     let def = self.tcx.adt_def(def_id);
-                    self.lazy_seq(def.struct_variant().fields.iter().map(|f| {
+                    self.lazy_seq(def.non_enum_variant().fields.iter().map(|f| {
                         assert!(f.did.is_local());
                         f.did.index
                     }))

src/librustc_mir/borrow_check/error_reporting.rs

@@ -719,7 +719,7 @@ fn describe_field_from_ty(&self, ty: &ty::Ty, field: Field) -> String {
                 ty::TyAdt(def, _) => if def.is_enum() {
                     format!("{}", field.index())
                 } else {
-                    format!("{}", def.struct_variant().fields[field.index()].name)
+                    format!("{}", def.non_enum_variant().fields[field.index()].name)
                 },
                 ty::TyTuple(_, _) => format!("{}", field.index()),
                 ty::TyRef(_, tnm) | ty::TyRawPtr(tnm) => {

src/librustc_mir/interpret/const_eval.rs

@@ -488,7 +488,7 @@ fn check_ctfe_against_miri<'a, 'tcx>(
                 miri_place = ecx.place_downcast(miri_place, variant).unwrap();
                 &def.variants[variant]
             } else {
-                def.struct_variant()
+                def.non_enum_variant()
             };
             let vec = match ctfe {
                 ConstVal::Aggregate(Struct(v)) => v,

src/librustc_mir/monomorphize/collector.rs

@@ -838,8 +838,8 @@ fn find_vtable_types_for_unsizing<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 CustomCoerceUnsized::Struct(i) => i
             };
 
-            let source_fields = &source_adt_def.struct_variant().fields;
-            let target_fields = &target_adt_def.struct_variant().fields;
+            let source_fields = &source_adt_def.non_enum_variant().fields;
+            let target_fields = &target_adt_def.non_enum_variant().fields;
 
             assert!(coerce_index < source_fields.len() &&
                     source_fields.len() == target_fields.len());

src/librustc_save_analysis/dump_visitor.rs

@@ -1583,10 +1583,12 @@ fn visit_expr(&mut self, ex: &'l ast::Expr) {
                         if !self.span.filter_generated(sub_span, ex.span) {
                             let span =
                                 self.span_from_span(sub_span.expect("No span found for var ref"));
+                            let ref_id =
+                                ::id_from_def_id(def.non_enum_variant().fields[idx.node].did);
                             self.dumper.dump_ref(Ref {
                                 kind: RefKind::Variable,
                                 span,
-                                ref_id: ::id_from_def_id(def.struct_variant().fields[idx.node].did),
+                                ref_id,
                             });
                         }
                     }

src/librustc_save_analysis/lib.rs

@@ -528,7 +528,7 @@ pub fn get_expr_data(&self, expr: &ast::Expr) -> Option<Data> {
                 };
                 match self.tables.expr_ty_adjusted(&hir_node).sty {
                     ty::TyAdt(def, _) if !def.is_enum() => {
-                        let f = def.struct_variant().field_named(ident.node.name);
+                        let f = def.non_enum_variant().field_named(ident.node.name);
                         let sub_span = self.span_utils.span_for_last_ident(expr.span);
                         filter!(self.span_utils, sub_span, expr.span, None);
                         let span = self.span_from_span(sub_span.unwrap());

src/librustc_trans/debuginfo/metadata.rs

@@ -969,7 +969,7 @@ fn prepare_struct_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
     let struct_name = compute_debuginfo_type_name(cx, struct_type, false);
 
     let (struct_def_id, variant) = match struct_type.sty {
-        ty::TyAdt(def, _) => (def.did, def.struct_variant()),
+        ty::TyAdt(def, _) => (def.did, def.non_enum_variant()),
         _ => bug!("prepare_struct_metadata on a non-ADT")
     };
 
@@ -1084,7 +1084,7 @@ fn prepare_union_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
     let union_name = compute_debuginfo_type_name(cx, union_type, false);
 
     let (union_def_id, variant) = match union_type.sty {
-        ty::TyAdt(def, _) => (def.did, def.struct_variant()),
+        ty::TyAdt(def, _) => (def.did, def.non_enum_variant()),
         _ => bug!("prepare_union_metadata on a non-ADT")
     };
 

src/librustc_typeck/check/cast.rs

@@ -107,7 +107,7 @@ fn pointer_kind(&self, t: Ty<'tcx>, span: Span) ->
             ty::TyDynamic(ref tty, ..) =>
                 Some(PointerKind::Vtable(tty.principal().map(|p| p.def_id()))),
             ty::TyAdt(def, substs) if def.is_struct() => {
-                match def.struct_variant().fields.last() {
+                match def.non_enum_variant().fields.last() {
                     None => Some(PointerKind::Thin),
                     Some(f) => {
                         let field_ty = self.field_ty(span, f, substs);

src/librustc_typeck/check/method/suggest.rs

@@ -289,7 +289,7 @@ pub fn report_method_error(&self,
                     for (ty, _) in self.autoderef(span, rcvr_ty) {
                         match ty.sty {
                             ty::TyAdt(def, substs) if !def.is_enum() => {
-                                if let Some(field) = def.struct_variant()
+                                if let Some(field) = def.non_enum_variant()
                                     .find_field_named(item_name) {
                                     let snippet = tcx.sess.codemap().span_to_snippet(expr.span);
                                     let expr_string = match snippet {

src/librustc_typeck/check/mod.rs

@@ -1444,7 +1444,7 @@ pub fn check_simd<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, sp: Span, def_id: DefId
     let t = tcx.type_of(def_id);
     match t.sty {
         ty::TyAdt(def, substs) if def.is_struct() => {
-            let fields = &def.struct_variant().fields;
+            let fields = &def.non_enum_variant().fields;
             if fields.is_empty() {
                 span_err!(tcx.sess, sp, E0075, "SIMD vector cannot be empty");
                 return;
@@ -1498,7 +1498,7 @@ fn check_packed_inner<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             }
             // push struct def_id before checking fields
             stack.push(def_id);
-            for field in &def.struct_variant().fields {
+            for field in &def.non_enum_variant().fields {
                 let f = field.ty(tcx, substs);
                 match f.sty {
                     ty::TyAdt(def, _) => {
@@ -2945,7 +2945,7 @@ fn check_field(&self,
                     debug!("struct named {:?}",  base_t);
                     let (ident, def_scope) =
                         self.tcx.adjust(field.node, base_def.did, self.body_id);
-                    let fields = &base_def.struct_variant().fields;
+                    let fields = &base_def.non_enum_variant().fields;
                     if let Some(field) = fields.iter().find(|f| f.name.to_ident() == ident) {
                         let field_ty = self.field_ty(expr.span, field, substs);
                         if field.vis.is_accessible_from(def_scope, self.tcx) {
@@ -2993,12 +2993,12 @@ fn check_field(&self,
                 match expr_t.sty {
                     ty::TyAdt(def, _) if !def.is_enum() => {
                         if let Some(suggested_field_name) =
-                            Self::suggest_field_name(def.struct_variant(), field, vec![]) {
+                            Self::suggest_field_name(def.non_enum_variant(), field, vec![]) {
                                 err.span_label(field.span,
                                                format!("did you mean `{}`?", suggested_field_name));
                             } else {
                                 err.span_label(field.span, "unknown field");
-                                let struct_variant_def = def.struct_variant();
+                                let struct_variant_def = def.non_enum_variant();
                                 let field_names = self.available_field_names(struct_variant_def);
                                 if !field_names.is_empty() {
                                     err.note(&format!("available fields are: {}",
@@ -3080,7 +3080,7 @@ fn check_tup_field(&self,
         while let Some((base_t, _)) = autoderef.next() {
             let field = match base_t.sty {
                 ty::TyAdt(base_def, substs) if base_def.is_struct() => {
-                    tuple_like = base_def.struct_variant().ctor_kind == CtorKind::Fn;
+                    tuple_like = base_def.non_enum_variant().ctor_kind == CtorKind::Fn;
                     if !tuple_like { continue }
 
                     debug!("tuple struct named {:?}",  base_t);
@@ -3090,7 +3090,7 @@ fn check_tup_field(&self,
                     };
                     let (ident, def_scope) =
                         self.tcx.adjust_ident(ident, base_def.did, self.body_id);
-                    let fields = &base_def.struct_variant().fields;
+                    let fields = &base_def.non_enum_variant().fields;
                     if let Some(field) = fields.iter().find(|f| f.name.to_ident() == ident) {
                         let field_ty = self.field_ty(expr.span, field, substs);
                         if field.vis.is_accessible_from(def_scope, self.tcx) {
@@ -3350,7 +3350,7 @@ pub fn check_struct_path(&self,
             Def::AssociatedTy(..) | Def::SelfTy(..) => {
                 match ty.sty {
                     ty::TyAdt(adt, substs) if !adt.is_enum() => {
-                        Some((adt.struct_variant(), adt.did, substs))
+                        Some((adt.non_enum_variant(), adt.did, substs))
                     }
                     _ => None,
                 }
@@ -3412,7 +3412,7 @@ fn check_expr_struct(&self,
             self.check_expr_has_type_or_error(base_expr, struct_ty);
             match struct_ty.sty {
                 ty::TyAdt(adt, substs) if adt.is_struct() => {
-                    let fru_field_types = adt.struct_variant().fields.iter().map(|f| {
+                    let fru_field_types = adt.non_enum_variant().fields.iter().map(|f| {
                         self.normalize_associated_types_in(expr.span, &f.ty(self.tcx, substs))
                     }).collect();
 

src/librustc_typeck/check/wfcheck.rs

@@ -130,14 +130,14 @@ fn check_item_well_formed(&mut self, item: &hir::Item) {
             }
             hir::ItemStruct(ref struct_def, ref ast_generics) => {
                 self.check_type_defn(item, false, |fcx| {
-                    vec![fcx.struct_variant(struct_def)]
+                    vec![fcx.non_enum_variant(struct_def)]
                 });
 
                 self.check_variances_for_type_defn(item, ast_generics);
             }
             hir::ItemUnion(ref struct_def, ref ast_generics) => {
                 self.check_type_defn(item, true, |fcx| {
-                    vec![fcx.struct_variant(struct_def)]
+                    vec![fcx.non_enum_variant(struct_def)]
                 });
 
                 self.check_variances_for_type_defn(item, ast_generics);
@@ -689,7 +689,7 @@ struct AdtField<'tcx> {
 }
 
 impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
-    fn struct_variant(&self, struct_def: &hir::VariantData) -> AdtVariant<'tcx> {
+    fn non_enum_variant(&self, struct_def: &hir::VariantData) -> AdtVariant<'tcx> {
         let fields =
             struct_def.fields().iter()
             .map(|field| {
@@ -704,7 +704,7 @@ fn struct_variant(&self, struct_def: &hir::VariantData) -> AdtVariant<'tcx> {
 
     fn enum_variants(&self, enum_def: &hir::EnumDef) -> Vec<AdtVariant<'tcx>> {
         enum_def.variants.iter()
-            .map(|variant| self.struct_variant(&variant.node.data))
+            .map(|variant| self.non_enum_variant(&variant.node.data))
             .collect()
     }
 

src/librustc_typeck/coherence/builtin.rs

@@ -288,7 +288,7 @@ pub fn coerce_unsized_info<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 // conversion). This will work out because `U:
                 // Unsize<V>`, and we have a builtin rule that `*mut
                 // U` can be coerced to `*mut V` if `U: Unsize<V>`.
-                let fields = &def_a.struct_variant().fields;
+                let fields = &def_a.non_enum_variant().fields;
                 let diff_fields = fields.iter()
                     .enumerate()
                     .filter_map(|(i, f)| {

src/librustdoc/clean/inline.rs

@@ -186,7 +186,7 @@ fn build_enum(cx: &DocContext, did: DefId) -> clean::Enum {
 
 fn build_struct(cx: &DocContext, did: DefId) -> clean::Struct {
     let predicates = cx.tcx.predicates_of(did);
-    let variant = cx.tcx.adt_def(did).struct_variant();
+    let variant = cx.tcx.adt_def(did).non_enum_variant();
 
     clean::Struct {
         struct_type: match variant.ctor_kind {
@@ -202,7 +202,7 @@ fn build_struct(cx: &DocContext, did: DefId) -> clean::Struct {
 
 fn build_union(cx: &DocContext, did: DefId) -> clean::Union {
     let predicates = cx.tcx.predicates_of(did);
-    let variant = cx.tcx.adt_def(did).struct_variant();
+    let variant = cx.tcx.adt_def(did).non_enum_variant();
 
     clean::Union {
         struct_type: doctree::Plain,