compiler/rustc_resolve/src/def_collector.rs

   1 use crate::{ImplTraitContext, Resolver};
   2 use rustc_ast::visit::{self, FnKind};
   3 use rustc_ast::walk_list;
   4 use rustc_ast::*;
   5 use rustc_ast_lowering::ResolverAstLowering;
   6 use rustc_expand::expand::AstFragment;
   7 use rustc_hir::def_id::LocalDefId;
   8 use rustc_hir::definitions::*;
   9 use rustc_span::hygiene::LocalExpnId;
  10 use rustc_span::symbol::sym;
  11 use rustc_span::Span;
  12 use tracing::debug;
  13
  14 crate fn collect_definitions(
  15     resolver: &mut Resolver<'_>,
  16     fragment: &AstFragment,
  17     expansion: LocalExpnId,
  18 ) {
  19     let (parent_def, impl_trait_context) = resolver.invocation_parents[&expansion];
  20     fragment.visit_with(&mut DefCollector { resolver, parent_def, expansion, impl_trait_context });
  21 }
  22
  23 /// Creates `DefId`s for nodes in the AST.
  24 struct DefCollector<'a, 'b> {
  25     resolver: &'a mut Resolver<'b>,
  26     parent_def: LocalDefId,
  27     impl_trait_context: ImplTraitContext,
  28     expansion: LocalExpnId,
  29 }
  30
  31 impl<'a, 'b> DefCollector<'a, 'b> {
  32     fn create_def(&mut self, node_id: NodeId, data: DefPathData, span: Span) -> LocalDefId {
  33         let parent_def = self.parent_def;
  34         debug!("create_def(node_id={:?}, data={:?}, parent_def={:?})", node_id, data, parent_def);
  35         self.resolver.create_def(
  36             parent_def,
  37             node_id,
  38             data,
  39             self.expansion.to_expn_id(),
  40             span.with_parent(None),
  41         )
  42     }
  43
  44     fn with_parent<F: FnOnce(&mut Self)>(&mut self, parent_def: LocalDefId, f: F) {
  45         let orig_parent_def = std::mem::replace(&mut self.parent_def, parent_def);
  46         f(self);
  47         self.parent_def = orig_parent_def;
  48     }
  49
  50     fn with_impl_trait<F: FnOnce(&mut Self)>(
  51         &mut self,
  52         impl_trait_context: ImplTraitContext,
  53         f: F,
  54     ) {
  55         let orig_itc = std::mem::replace(&mut self.impl_trait_context, impl_trait_context);
  56         f(self);
  57         self.impl_trait_context = orig_itc;
  58     }
  59
  60     fn collect_field(&mut self, field: &'a FieldDef, index: Option<usize>) {
  61         let index = |this: &Self| {
  62             index.unwrap_or_else(|| {
  63                 let node_id = NodeId::placeholder_from_expn_id(this.expansion);
  64                 this.resolver.placeholder_field_indices[&node_id]
  65             })
  66         };
  67
  68         if field.is_placeholder {
  69             let old_index = self.resolver.placeholder_field_indices.insert(field.id, index(self));
  70             assert!(old_index.is_none(), "placeholder field index is reset for a node ID");
  71             self.visit_macro_invoc(field.id);
  72         } else {
  73             let name = field.ident.map_or_else(|| sym::integer(index(self)), |ident| ident.name);
  74             let def = self.create_def(field.id, DefPathData::ValueNs(name), field.span);
  75             self.with_parent(def, |this| visit::walk_field_def(this, field));
  76         }
  77     }
  78
  79     fn visit_macro_invoc(&mut self, id: NodeId) {
  80         let id = id.placeholder_to_expn_id();
  81         let old_parent =
  82             self.resolver.invocation_parents.insert(id, (self.parent_def, self.impl_trait_context));
  83         assert!(old_parent.is_none(), "parent `LocalDefId` is reset for an invocation");
  84     }
  85 }
  86
  87 impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
  88     fn visit_item(&mut self, i: &'a Item) {
  89         debug!("visit_item: {:?}", i);
  90
  91         // Pick the def data. This need not be unique, but the more
  92         // information we encapsulate into, the better
  93         let def_data = match &i.kind {
  94             ItemKind::Impl { .. } => DefPathData::Impl,
  95             ItemKind::ForeignMod(..) => DefPathData::ForeignMod,
  96             ItemKind::Mod(..)
  97             | ItemKind::Trait(..)
  98             | ItemKind::TraitAlias(..)
  99             | ItemKind::Enum(..)
 100             | ItemKind::Struct(..)
 101             | ItemKind::Union(..)
 102             | ItemKind::ExternCrate(..)
 103             | ItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
 104             ItemKind::Static(..) | ItemKind::Const(..) | ItemKind::Fn(..) => {
 105                 DefPathData::ValueNs(i.ident.name)
 106             }
 107             ItemKind::MacroDef(..) => DefPathData::MacroNs(i.ident.name),
 108             ItemKind::MacCall(..) => {
 109                 visit::walk_item(self, i);
 110                 return self.visit_macro_invoc(i.id);
 111             }
 112             ItemKind::GlobalAsm(..) => DefPathData::Misc,
 113             ItemKind::Use(..) => {
 114                 return visit::walk_item(self, i);
 115             }
 116         };
 117         let def = self.create_def(i.id, def_data, i.span);
 118
 119         self.with_parent(def, |this| {
 120             this.with_impl_trait(ImplTraitContext::Existential, |this| {
 121                 match i.kind {
 122                     ItemKind::Struct(ref struct_def, _) | ItemKind::Union(ref struct_def, _) => {
 123                         // If this is a unit or tuple-like struct, register the constructor.
 124                         if let Some(ctor_hir_id) = struct_def.ctor_id() {
 125                             this.create_def(ctor_hir_id, DefPathData::Ctor, i.span);
 126                         }
 127                     }
 128                     _ => {}
 129                 }
 130                 visit::walk_item(this, i);
 131             })
 132         });
 133     }
 134
 135     fn visit_fn(&mut self, fn_kind: FnKind<'a>, span: Span, _: NodeId) {
 136         if let FnKind::Fn(_, _, sig, _, body) = fn_kind {
 137             if let Async::Yes { closure_id, return_impl_trait_id, .. } = sig.header.asyncness {
 138                 let return_impl_trait_id =
 139                     self.create_def(return_impl_trait_id, DefPathData::ImplTrait, span);
 140
 141                 // For async functions, we need to create their inner defs inside of a
 142                 // closure to match their desugared representation. Besides that,
 143                 // we must mirror everything that `visit::walk_fn` below does.
 144                 self.visit_fn_header(&sig.header);
 145                 for param in &sig.decl.inputs {
 146                     self.visit_param(param);
 147                 }
 148                 self.with_parent(return_impl_trait_id, |this| {
 149                     this.visit_fn_ret_ty(&sig.decl.output)
 150                 });
 151                 let closure_def = self.create_def(closure_id, DefPathData::ClosureExpr, span);
 152                 self.with_parent(closure_def, |this| walk_list!(this, visit_block, body));
 153                 return;
 154             }
 155         }
 156
 157         visit::walk_fn(self, fn_kind, span);
 158     }
 159
 160     fn visit_use_tree(&mut self, use_tree: &'a UseTree, id: NodeId, _nested: bool) {
 161         self.create_def(id, DefPathData::Misc, use_tree.span);
 162         match use_tree.kind {
 163             UseTreeKind::Simple(_, id1, id2) => {
 164                 self.create_def(id1, DefPathData::Misc, use_tree.prefix.span);
 165                 self.create_def(id2, DefPathData::Misc, use_tree.prefix.span);
 166             }
 167             UseTreeKind::Glob => (),
 168             UseTreeKind::Nested(..) => {}
 169         }
 170         visit::walk_use_tree(self, use_tree, id);
 171     }
 172
 173     fn visit_foreign_item(&mut self, foreign_item: &'a ForeignItem) {
 174         if let ForeignItemKind::MacCall(_) = foreign_item.kind {
 175             return self.visit_macro_invoc(foreign_item.id);
 176         }
 177
 178         let def = self.create_def(
 179             foreign_item.id,
 180             DefPathData::ValueNs(foreign_item.ident.name),
 181             foreign_item.span,
 182         );
 183
 184         self.with_parent(def, |this| {
 185             visit::walk_foreign_item(this, foreign_item);
 186         });
 187     }
 188
 189     fn visit_variant(&mut self, v: &'a Variant) {
 190         if v.is_placeholder {
 191             return self.visit_macro_invoc(v.id);
 192         }
 193         let def = self.create_def(v.id, DefPathData::TypeNs(v.ident.name), v.span);
 194         self.with_parent(def, |this| {
 195             if let Some(ctor_hir_id) = v.data.ctor_id() {
 196                 this.create_def(ctor_hir_id, DefPathData::Ctor, v.span);
 197             }
 198             visit::walk_variant(this, v)
 199         });
 200     }
 201
 202     fn visit_variant_data(&mut self, data: &'a VariantData) {
 203         // The assumption here is that non-`cfg` macro expansion cannot change field indices.
 204         // It currently holds because only inert attributes are accepted on fields,
 205         // and every such attribute expands into a single field after it's resolved.
 206         for (index, field) in data.fields().iter().enumerate() {
 207             self.collect_field(field, Some(index));
 208         }
 209     }
 210
 211     fn visit_generic_param(&mut self, param: &'a GenericParam) {
 212         if param.is_placeholder {
 213             self.visit_macro_invoc(param.id);
 214             return;
 215         }
 216         let name = param.ident.name;
 217         let def_path_data = match param.kind {
 218             GenericParamKind::Lifetime { .. } => DefPathData::LifetimeNs(name),
 219             GenericParamKind::Type { .. } => DefPathData::TypeNs(name),
 220             GenericParamKind::Const { .. } => DefPathData::ValueNs(name),
 221         };
 222         self.create_def(param.id, def_path_data, param.ident.span);
 223
 224         // impl-Trait can happen inside generic parameters, like
 225         // ```
 226         // fn foo<U: Iterator<Item = impl Clone>>() {}
 227         // ```
 228         //
 229         // In that case, the impl-trait is lowered as an additional generic parameter.
 230         self.with_impl_trait(ImplTraitContext::Universal(self.parent_def), |this| {
 231             visit::walk_generic_param(this, param)
 232         });
 233     }
 234
 235     fn visit_assoc_item(&mut self, i: &'a AssocItem, ctxt: visit::AssocCtxt) {
 236         let def_data = match &i.kind {
 237             AssocItemKind::Fn(..) | AssocItemKind::Const(..) => DefPathData::ValueNs(i.ident.name),
 238             AssocItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
 239             AssocItemKind::MacCall(..) => return self.visit_macro_invoc(i.id),
 240         };
 241
 242         let def = self.create_def(i.id, def_data, i.span);
 243         self.with_parent(def, |this| visit::walk_assoc_item(this, i, ctxt));
 244     }
 245
 246     fn visit_pat(&mut self, pat: &'a Pat) {
 247         match pat.kind {
 248             PatKind::MacCall(..) => self.visit_macro_invoc(pat.id),
 249             _ => visit::walk_pat(self, pat),
 250         }
 251     }
 252
 253     fn visit_anon_const(&mut self, constant: &'a AnonConst) {
 254         let def = self.create_def(constant.id, DefPathData::AnonConst, constant.value.span);
 255         self.with_parent(def, |this| visit::walk_anon_const(this, constant));
 256     }
 257
 258     fn visit_expr(&mut self, expr: &'a Expr) {
 259         let parent_def = match expr.kind {
 260             ExprKind::MacCall(..) => return self.visit_macro_invoc(expr.id),
 261             ExprKind::Closure(_, asyncness, ..) => {
 262                 // Async closures desugar to closures inside of closures, so
 263                 // we must create two defs.
 264                 let closure_def = self.create_def(expr.id, DefPathData::ClosureExpr, expr.span);
 265                 match asyncness {
 266                     Async::Yes { closure_id, .. } => {
 267                         self.create_def(closure_id, DefPathData::ClosureExpr, expr.span)
 268                     }
 269                     Async::No => closure_def,
 270                 }
 271             }
 272             ExprKind::Async(_, async_id, _) => {
 273                 self.create_def(async_id, DefPathData::ClosureExpr, expr.span)
 274             }
 275             _ => self.parent_def,
 276         };
 277
 278         self.with_parent(parent_def, |this| visit::walk_expr(this, expr));
 279     }
 280
 281     fn visit_ty(&mut self, ty: &'a Ty) {
 282         match ty.kind {
 283             TyKind::MacCall(..) => self.visit_macro_invoc(ty.id),
 284             TyKind::ImplTrait(node_id, _) => {
 285                 let parent_def = match self.impl_trait_context {
 286                     ImplTraitContext::Universal(item_def) => self.resolver.create_def(
 287                         item_def,
 288                         node_id,
 289                         DefPathData::ImplTrait,
 290                         self.expansion.to_expn_id(),
 291                         ty.span,
 292                     ),
 293                     ImplTraitContext::Existential => {
 294                         self.create_def(node_id, DefPathData::ImplTrait, ty.span)
 295                     }
 296                 };
 297                 self.with_parent(parent_def, |this| visit::walk_ty(this, ty))
 298             }
 299             _ => visit::walk_ty(self, ty),
 300         }
 301     }
 302
 303     fn visit_stmt(&mut self, stmt: &'a Stmt) {
 304         match stmt.kind {
 305             StmtKind::MacCall(..) => self.visit_macro_invoc(stmt.id),
 306             _ => visit::walk_stmt(self, stmt),
 307         }
 308     }
 309
 310     fn visit_arm(&mut self, arm: &'a Arm) {
 311         if arm.is_placeholder { self.visit_macro_invoc(arm.id) } else { visit::walk_arm(self, arm) }
 312     }
 313
 314     fn visit_expr_field(&mut self, f: &'a ExprField) {
 315         if f.is_placeholder {
 316             self.visit_macro_invoc(f.id)
 317         } else {
 318             visit::walk_expr_field(self, f)
 319         }
 320     }
 321
 322     fn visit_pat_field(&mut self, fp: &'a PatField) {
 323         if fp.is_placeholder {
 324             self.visit_macro_invoc(fp.id)
 325         } else {
 326             visit::walk_pat_field(self, fp)
 327         }
 328     }
 329
 330     fn visit_param(&mut self, p: &'a Param) {
 331         if p.is_placeholder {
 332             self.visit_macro_invoc(p.id)
 333         } else {
 334             self.with_impl_trait(ImplTraitContext::Universal(self.parent_def), |this| {
 335                 visit::walk_param(this, p)
 336             })
 337         }
 338     }
 339
 340     // This method is called only when we are visiting an individual field
 341     // after expanding an attribute on it.
 342     fn visit_field_def(&mut self, field: &'a FieldDef) {
 343         self.collect_field(field, None);
 344     }
 345
 346     fn visit_crate(&mut self, krate: &'a Crate) {
 347         if krate.is_placeholder {
 348             self.visit_macro_invoc(krate.id)
 349         } else {
 350             visit::walk_crate(self, krate)
 351         }
 352     }
 353 }