Refactoring/bugfixing around definitions for struct/variant constructors

src/librustc/hir/def.rs

@@ -13,34 +13,46 @@ use util::nodemap::NodeMap;
 use syntax::ast;
 use hir;
 
+#[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+pub enum CtorKind {
+    // Constructor function automatically created by a tuple struct/variant.
+    Fn,
+    // Constructor constant automatically created by a unit struct/variant.
+    Const,
+    // Unusable name in value namespace created by a struct variant.
+    Fictive,
+}
+
 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum Def {
-    Fn(DefId),
-    SelfTy(Option<DefId> /* trait */, Option<DefId> /* impl */),
+    // Type namespace
     Mod(DefId),
-    Static(DefId, bool /* is_mutbl */),
-    Const(DefId),
-    AssociatedConst(DefId),
-    Local(DefId),
-    Variant(DefId),
+    Struct(DefId), // DefId refers to NodeId of the struct itself
+    Union(DefId),
     Enum(DefId),
+    Variant(DefId),
+    Trait(DefId),
     TyAlias(DefId),
     AssociatedTy(DefId),
-    Trait(DefId),
     PrimTy(hir::PrimTy),
     TyParam(DefId),
-    Upvar(DefId,        // def id of closed over local
-             usize,        // index in the freevars list of the closure
-             ast::NodeId), // expr node that creates the closure
+    SelfTy(Option<DefId> /* trait */, Option<DefId> /* impl */),
 
-    // If Def::Struct lives in type namespace it denotes a struct item and its DefId refers
-    // to NodeId of the struct itself.
-    // If Def::Struct lives in value namespace (e.g. tuple struct, unit struct expressions)
-    // it denotes a constructor and its DefId refers to NodeId of the struct's constructor.
-    Struct(DefId),
-    Union(DefId),
-    Label(ast::NodeId),
+    // Value namespace
+    Fn(DefId),
+    Const(DefId),
+    Static(DefId, bool /* is_mutbl */),
+    StructCtor(DefId, CtorKind), // DefId refers to NodeId of the struct's constructor
+    VariantCtor(DefId, CtorKind),
     Method(DefId),
+    AssociatedConst(DefId),
+    Local(DefId),
+    Upvar(DefId,        // def id of closed over local
+          usize,        // index in the freevars list of the closure
+          ast::NodeId), // expr node that creates the closure
+    Label(ast::NodeId),
+
+    // Both namespaces
     Err,
 }
 
@@ -93,18 +105,35 @@ pub type ExportMap = NodeMap<Vec<Export>>;
 
 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
 pub struct Export {
-    pub name: ast::Name,    // The name of the target.
-    pub def_id: DefId, // The definition of the target.
+    pub name: ast::Name, // The name of the target.
+    pub def: Def, // The definition of the target.
+}
+
+impl CtorKind {
+    pub fn from_ast(vdata: &ast::VariantData) -> CtorKind {
+        match *vdata {
+            ast::VariantData::Tuple(..) => CtorKind::Fn,
+            ast::VariantData::Unit(..) => CtorKind::Const,
+            ast::VariantData::Struct(..) => CtorKind::Fictive,
+        }
+    }
+    pub fn from_hir(vdata: &hir::VariantData) -> CtorKind {
+        match *vdata {
+            hir::VariantData::Tuple(..) => CtorKind::Fn,
+            hir::VariantData::Unit(..) => CtorKind::Const,
+            hir::VariantData::Struct(..) => CtorKind::Fictive,
+        }
+    }
 }
 
 impl Def {
     pub fn def_id(&self) -> DefId {
         match *self {
             Def::Fn(id) | Def::Mod(id) | Def::Static(id, _) |
-            Def::Variant(id) | Def::Enum(id) | Def::TyAlias(id) | Def::AssociatedTy(id) |
-            Def::TyParam(id) | Def::Struct(id) | Def::Union(id) | Def::Trait(id) |
-            Def::Method(id) | Def::Const(id) | Def::AssociatedConst(id) |
-            Def::Local(id) | Def::Upvar(id, ..) => {
+            Def::Variant(id) | Def::VariantCtor(id, ..) | Def::Enum(id) | Def::TyAlias(id) |
+            Def::AssociatedTy(id) | Def::TyParam(id) | Def::Struct(id) | Def::StructCtor(id, ..) |
+            Def::Union(id) | Def::Trait(id) | Def::Method(id) | Def::Const(id) |
+            Def::AssociatedConst(id) | Def::Local(id) | Def::Upvar(id, ..) => {
                 id
             }
 
@@ -123,10 +152,16 @@ impl Def {
             Def::Mod(..) => "module",
             Def::Static(..) => "static",
             Def::Variant(..) => "variant",
+            Def::VariantCtor(.., CtorKind::Fn) => "tuple variant",
+            Def::VariantCtor(.., CtorKind::Const) => "unit variant",
+            Def::VariantCtor(.., CtorKind::Fictive) => "struct variant",
             Def::Enum(..) => "enum",
-            Def::TyAlias(..) => "type",
+            Def::TyAlias(..) => "type alias",
             Def::AssociatedTy(..) => "associated type",
             Def::Struct(..) => "struct",
+            Def::StructCtor(.., CtorKind::Fn) => "tuple struct",
+            Def::StructCtor(.., CtorKind::Const) => "unit struct",
+            Def::StructCtor(.., CtorKind::Fictive) => bug!("impossible struct constructor"),
             Def::Union(..) => "union",
             Def::Trait(..) => "trait",
             Def::Method(..) => "method",

src/librustc/hir/lowering.rs

@@ -44,8 +44,9 @@ use hir;
 use hir::map::Definitions;
 use hir::map::definitions::DefPathData;
 use hir::def_id::{DefIndex, DefId};
-use hir::def::{Def, PathResolution};
+use hir::def::{Def, CtorKind, PathResolution};
 use session::Session;
+use lint;
 
 use std::collections::BTreeMap;
 use std::iter;
@@ -855,10 +856,23 @@ impl<'a> LoweringContext<'a> {
                     })
                 }
                 PatKind::Lit(ref e) => hir::PatKind::Lit(self.lower_expr(e)),
-                PatKind::TupleStruct(ref pth, ref pats, ddpos) => {
-                    hir::PatKind::TupleStruct(self.lower_path(pth),
-                                              pats.iter().map(|x| self.lower_pat(x)).collect(),
-                                              ddpos)
+                PatKind::TupleStruct(ref path, ref pats, ddpos) => {
+                    match self.resolver.get_resolution(p.id).map(|d| d.base_def) {
+                        Some(def @ Def::StructCtor(_, CtorKind::Const)) |
+                        Some(def @ Def::VariantCtor(_, CtorKind::Const)) => {
+                            // Temporarily lower `UnitVariant(..)` into `UnitVariant`
+                            // for backward compatibility.
+                            let msg = format!("expected tuple struct/variant, found {} `{}`",
+                                            def.kind_name(), path);
+                            self.sess.add_lint(
+                                lint::builtin::MATCH_OF_UNIT_VARIANT_VIA_PAREN_DOTDOT,
+                                p.id, p.span, msg
+                            );
+                            hir::PatKind::Path(None, self.lower_path(path))
+                        }
+                        _ => hir::PatKind::TupleStruct(self.lower_path(path),
+                                        pats.iter().map(|x| self.lower_pat(x)).collect(), ddpos)
+                    }
                 }
                 PatKind::Path(ref opt_qself, ref path) => {
                     let opt_qself = opt_qself.as_ref().map(|qself| {

src/librustc/hir/pat_util.rs

@@ -58,7 +58,7 @@ pub fn pat_is_refutable(dm: &DefMap, pat: &hir::Pat) -> bool {
         PatKind::Path(..) |
         PatKind::Struct(..) => {
             match dm.get(&pat.id).map(|d| d.full_def()) {
-                Some(Def::Variant(..)) => true,
+                Some(Def::Variant(..)) | Some(Def::VariantCtor(..)) => true,
                 _ => false
             }
         }
@@ -173,10 +173,9 @@ pub fn necessary_variants(dm: &DefMap, pat: &hir::Pat) -> Vec<DefId> {
             PatKind::TupleStruct(..) |
             PatKind::Path(..) |
             PatKind::Struct(..) => {
-                match dm.get(&p.id) {
-                    Some(&PathResolution { base_def: Def::Variant(id), .. }) => {
-                        variants.push(id);
-                    }
+                match dm.get(&p.id).map(|d| d.full_def()) {
+                    Some(Def::Variant(id)) |
+                    Some(Def::VariantCtor(id, ..)) => variants.push(id),
                     _ => ()
                 }
             }

src/librustc/middle/cstore.rs

@@ -201,8 +201,6 @@ pub trait CrateStore<'tcx> {
                              -> Option<DefIndex>;
     fn def_key(&self, def: DefId) -> hir_map::DefKey;
     fn relative_def_path(&self, def: DefId) -> Option<hir_map::DefPath>;
-    fn variant_kind(&self, def_id: DefId) -> Option<ty::VariantKind>;
-    fn struct_ctor_def_id(&self, struct_def_id: DefId) -> Option<DefId>;
     fn struct_field_names(&self, def: DefId) -> Vec<ast::Name>;
     fn item_children(&self, did: DefId) -> Vec<def::Export>;
 
@@ -378,9 +376,6 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
     fn relative_def_path(&self, def: DefId) -> Option<hir_map::DefPath> {
         bug!("relative_def_path")
     }
-    fn variant_kind(&self, def_id: DefId) -> Option<ty::VariantKind> { bug!("variant_kind") }
-    fn struct_ctor_def_id(&self, struct_def_id: DefId) -> Option<DefId>
-        { bug!("struct_ctor_def_id") }
     fn struct_field_names(&self, def: DefId) -> Vec<ast::Name> { bug!("struct_field_names") }
     fn item_children(&self, did: DefId) -> Vec<def::Export> { bug!("item_children") }
 

src/librustc/middle/dead.rs

@@ -106,9 +106,8 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
                 self.check_def_id(def.def_id());
             }
             _ if self.ignore_non_const_paths => (),
-            Def::PrimTy(_) => (),
-            Def::SelfTy(..) => (),
-            Def::Variant(variant_id) => {
+            Def::PrimTy(..) | Def::SelfTy(..) => (),
+            Def::Variant(variant_id) | Def::VariantCtor(variant_id, ..) => {
                 if let Some(enum_id) = self.tcx.parent_def_id(variant_id) {
                     self.check_def_id(enum_id);
                 }

src/librustc/middle/expr_use_visitor.rs

@@ -1003,7 +1003,8 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
         // the leaves of the pattern tree structure.
         return_if_err!(mc.cat_pattern(cmt_discr, pat, |mc, cmt_pat, pat| {
             match tcx.expect_def_or_none(pat.id) {
-                Some(Def::Variant(variant_did)) => {
+                Some(Def::Variant(variant_did)) |
+                Some(Def::VariantCtor(variant_did, ..)) => {
                     let enum_did = tcx.parent_def_id(variant_did).unwrap();
                     let downcast_cmt = if tcx.lookup_adt_def(enum_did).is_univariant() {
                         cmt_pat
@@ -1015,12 +1016,14 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
                     debug!("variant downcast_cmt={:?} pat={:?}", downcast_cmt, pat);
                     delegate.matched_pat(pat, downcast_cmt, match_mode);
                 }
-                Some(Def::Struct(..)) | Some(Def::Union(..)) |
+                Some(Def::Struct(..)) | Some(Def::StructCtor(..)) | Some(Def::Union(..)) |
                 Some(Def::TyAlias(..)) | Some(Def::AssociatedTy(..)) => {
                     debug!("struct cmt_pat={:?} pat={:?}", cmt_pat, pat);
                     delegate.matched_pat(pat, cmt_pat, match_mode);
                 }
-                _ => {}
+                None | Some(Def::Local(..)) |
+                Some(Def::Const(..)) | Some(Def::AssociatedConst(..)) => {}
+                def => bug!("unexpected definition: {:?}", def)
             }
         }));
     }

src/librustc/middle/mem_categorization.rs

@@ -74,7 +74,7 @@ use hir::def_id::DefId;
 use hir::map as ast_map;
 use infer::InferCtxt;
 use middle::const_qualif::ConstQualif;
-use hir::def::Def;
+use hir::def::{Def, CtorKind};
 use ty::adjustment;
 use ty::{self, Ty, TyCtxt};
 
@@ -524,20 +524,11 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
                id, expr_ty, def);
 
         match def {
-          Def::Struct(..) | Def::Union(..) | Def::Variant(..) | Def::Const(..) |
+          Def::StructCtor(..) | Def::VariantCtor(..) | Def::Const(..) |
           Def::AssociatedConst(..) | Def::Fn(..) | Def::Method(..) => {
                 Ok(self.cat_rvalue_node(id, span, expr_ty))
           }
 
-          Def::Mod(_) |
-          Def::Trait(_) | Def::Enum(..) | Def::TyAlias(..) | Def::PrimTy(_) |
-          Def::TyParam(..) |
-          Def::Label(_) | Def::SelfTy(..) |
-          Def::AssociatedTy(..) => {
-              span_bug!(span, "Unexpected definition in \
-                               memory categorization: {:?}", def);
-          }
-
           Def::Static(_, mutbl) => {
               Ok(Rc::new(cmt_ {
                   id:id,
@@ -598,7 +589,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
             }))
           }
 
-          Def::Err => bug!("Def::Err in memory categorization")
+          def => span_bug!(span, "unexpected definition in memory categorization: {:?}", def)
         }
     }
 
@@ -1077,7 +1068,8 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
         // alone) because PatKind::Struct can also refer to variants.
         let cmt = match self.tcx().expect_def_or_none(pat.id) {
             Some(Def::Err) => return Err(()),
-            Some(Def::Variant(variant_did)) => {
+            Some(Def::Variant(variant_did)) |
+            Some(Def::VariantCtor(variant_did, ..)) => {
                 // univariant enums do not need downcasts
                 let enum_did = self.tcx().parent_def_id(variant_did).unwrap();
                 if !self.tcx().lookup_adt_def(enum_did).is_univariant() {
@@ -1092,11 +1084,11 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
         match pat.node {
           PatKind::TupleStruct(_, ref subpats, ddpos) => {
             let expected_len = match self.tcx().expect_def(pat.id) {
-                Def::Variant(def_id) => {
+                Def::VariantCtor(def_id, CtorKind::Fn) => {
                     let enum_def = self.tcx().parent_def_id(def_id).unwrap();
                     self.tcx().lookup_adt_def(enum_def).variant_with_id(def_id).fields.len()
                 }
-                Def::Struct(..) => {
+                Def::StructCtor(_, CtorKind::Fn) => {
                     match self.pat_ty(&pat)?.sty {
                         ty::TyAdt(adt_def, _) => {
                             adt_def.struct_variant().fields.len()

src/librustc/middle/stability.rs

@@ -617,12 +617,8 @@ pub fn check_path<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                            &Option<DeprecationEntry>)) {
     // Paths in import prefixes may have no resolution.
     match tcx.expect_def_or_none(id) {
-        Some(Def::PrimTy(..)) => {}
-        Some(Def::SelfTy(..)) => {}
-        Some(def) => {
-            maybe_do_stability_check(tcx, def.def_id(), path.span, cb);
-        }
-        None => {}
+        None | Some(Def::PrimTy(..)) | Some(Def::SelfTy(..)) => {}
+        Some(def) => maybe_do_stability_check(tcx, def.def_id(), path.span, cb)
     }
 }
 
@@ -631,12 +627,7 @@ pub fn check_path_list_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                       cb: &mut FnMut(DefId, Span,
                                                      &Option<&Stability>,
                                                      &Option<DeprecationEntry>)) {
-    match tcx.expect_def(item.node.id) {
-        Def::PrimTy(..) => {}
-        def => {
-            maybe_do_stability_check(tcx, def.def_id(), item.span, cb);
-        }
-    }
+    maybe_do_stability_check(tcx, tcx.expect_def(item.node.id).def_id(), item.span, cb);
 }
 
 pub fn check_pat<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, pat: &hir::Pat,

src/librustc/mir/repr.rs

@@ -15,6 +15,7 @@ use rustc_data_structures::indexed_vec::{IndexVec, Idx};
 use rustc_data_structures::control_flow_graph::dominators::{Dominators, dominators};
 use rustc_data_structures::control_flow_graph::{GraphPredecessors, GraphSuccessors};
 use rustc_data_structures::control_flow_graph::ControlFlowGraph;
+use hir::def::CtorKind;
 use hir::def_id::DefId;
 use ty::subst::Substs;
 use ty::{self, AdtDef, ClosureSubsts, Region, Ty};
@@ -1140,10 +1141,10 @@ impl<'tcx> Debug for Rvalue<'tcx> {
                         ppaux::parameterized(fmt, substs, variant_def.did,
                                              ppaux::Ns::Value, &[])?;
 
-                        match variant_def.kind {
-                            ty::VariantKind::Unit => Ok(()),
-                            ty::VariantKind::Tuple => fmt_tuple(fmt, lvs),
-                            ty::VariantKind::Struct => {
+                        match variant_def.ctor_kind {
+                            CtorKind::Const => Ok(()),
+                            CtorKind::Fn => fmt_tuple(fmt, lvs),
+                            CtorKind::Fictive => {
                                 let mut struct_fmt = fmt.debug_struct("");
                                 for (field, lv) in variant_def.fields.iter().zip(lvs) {
                                     struct_fmt.field(&field.name.as_str(), lv);