compiler/rustc_resolve/src/def_collector.rs

   1 use crate::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::ExpnId;
  10 use rustc_span::symbol::{kw, 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: ExpnId,
  18 ) {
  19     let parent_def = resolver.invocation_parents[&expansion];
  20     fragment.visit_with(&mut DefCollector { resolver, parent_def, expansion });
  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     expansion: ExpnId,
  28 }
  29
  30 impl<'a, 'b> DefCollector<'a, 'b> {
  31     fn create_def(&mut self, node_id: NodeId, data: DefPathData, span: Span) -> LocalDefId {
  32         let parent_def = self.parent_def;
  33         debug!("create_def(node_id={:?}, data={:?}, parent_def={:?})", node_id, data, parent_def);
  34         self.resolver.create_def(parent_def, node_id, data, self.expansion, span)
  35     }
  36
  37     fn with_parent<F: FnOnce(&mut Self)>(&mut self, parent_def: LocalDefId, f: F) {
  38         let orig_parent_def = std::mem::replace(&mut self.parent_def, parent_def);
  39         f(self);
  40         self.parent_def = orig_parent_def;
  41     }
  42
  43     fn collect_field(&mut self, field: &'a StructField, index: Option<usize>) {
  44         let index = |this: &Self| {
  45             index.unwrap_or_else(|| {
  46                 let node_id = NodeId::placeholder_from_expn_id(this.expansion);
  47                 this.resolver.placeholder_field_indices[&node_id]
  48             })
  49         };
  50
  51         if field.is_placeholder {
  52             let old_index = self.resolver.placeholder_field_indices.insert(field.id, index(self));
  53             assert!(old_index.is_none(), "placeholder field index is reset for a node ID");
  54             self.visit_macro_invoc(field.id);
  55         } else {
  56             let name = field.ident.map_or_else(|| sym::integer(index(self)), |ident| ident.name);
  57             let def = self.create_def(field.id, DefPathData::ValueNs(name), field.span);
  58             self.with_parent(def, |this| visit::walk_struct_field(this, field));
  59         }
  60     }
  61
  62     fn visit_macro_invoc(&mut self, id: NodeId) {
  63         let old_parent =
  64             self.resolver.invocation_parents.insert(id.placeholder_to_expn_id(), self.parent_def);
  65         assert!(old_parent.is_none(), "parent `LocalDefId` is reset for an invocation");
  66     }
  67 }
  68
  69 impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
  70     fn visit_item(&mut self, i: &'a Item) {
  71         debug!("visit_item: {:?}", i);
  72
  73         // Pick the def data. This need not be unique, but the more
  74         // information we encapsulate into, the better
  75         let def_data = match &i.kind {
  76             ItemKind::Impl { .. } => DefPathData::Impl,
  77             ItemKind::Mod(..) if i.ident.name == kw::Empty => {
  78                 // Fake crate root item from expand.
  79                 return visit::walk_item(self, i);
  80             }
  81             ItemKind::Mod(..)
  82             | ItemKind::Trait(..)
  83             | ItemKind::TraitAlias(..)
  84             | ItemKind::Enum(..)
  85             | ItemKind::Struct(..)
  86             | ItemKind::Union(..)
  87             | ItemKind::ExternCrate(..)
  88             | ItemKind::ForeignMod(..)
  89             | ItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
  90             ItemKind::Static(..) | ItemKind::Const(..) | ItemKind::Fn(..) => {
  91                 DefPathData::ValueNs(i.ident.name)
  92             }
  93             ItemKind::MacroDef(..) => DefPathData::MacroNs(i.ident.name),
  94             ItemKind::MacCall(..) => {
  95                 visit::walk_item(self, i);
  96                 return self.visit_macro_invoc(i.id);
  97             }
  98             ItemKind::GlobalAsm(..) => DefPathData::Misc,
  99             ItemKind::Use(..) => {
 100                 return visit::walk_item(self, i);
 101             }
 102         };
 103         let def = self.create_def(i.id, def_data, i.span);
 104
 105         self.with_parent(def, |this| {
 106             match i.kind {
 107                 ItemKind::Struct(ref struct_def, _) | ItemKind::Union(ref struct_def, _) => {
 108                     // If this is a unit or tuple-like struct, register the constructor.
 109                     if let Some(ctor_hir_id) = struct_def.ctor_id() {
 110                         this.create_def(ctor_hir_id, DefPathData::Ctor, i.span);
 111                     }
 112                 }
 113                 _ => {}
 114             }
 115             visit::walk_item(this, i);
 116         });
 117     }
 118
 119     fn visit_fn(&mut self, fn_kind: FnKind<'a>, span: Span, _: NodeId) {
 120         if let FnKind::Fn(_, _, sig, _, body) = fn_kind {
 121             if let Async::Yes { closure_id, return_impl_trait_id, .. } = sig.header.asyncness {
 122                 self.create_def(return_impl_trait_id, DefPathData::ImplTrait, span);
 123
 124                 // For async functions, we need to create their inner defs inside of a
 125                 // closure to match their desugared representation. Besides that,
 126                 // we must mirror everything that `visit::walk_fn` below does.
 127                 self.visit_fn_header(&sig.header);
 128                 visit::walk_fn_decl(self, &sig.decl);
 129                 let closure_def = self.create_def(closure_id, DefPathData::ClosureExpr, span);
 130                 self.with_parent(closure_def, |this| walk_list!(this, visit_block, body));
 131                 return;
 132             }
 133         }
 134
 135         visit::walk_fn(self, fn_kind, span);
 136     }
 137
 138     fn visit_use_tree(&mut self, use_tree: &'a UseTree, id: NodeId, _nested: bool) {
 139         self.create_def(id, DefPathData::Misc, use_tree.span);
 140         visit::walk_use_tree(self, use_tree, id);
 141     }
 142
 143     fn visit_foreign_item(&mut self, foreign_item: &'a ForeignItem) {
 144         if let ForeignItemKind::MacCall(_) = foreign_item.kind {
 145             return self.visit_macro_invoc(foreign_item.id);
 146         }
 147
 148         let def = self.create_def(
 149             foreign_item.id,
 150             DefPathData::ValueNs(foreign_item.ident.name),
 151             foreign_item.span,
 152         );
 153
 154         self.with_parent(def, |this| {
 155             visit::walk_foreign_item(this, foreign_item);
 156         });
 157     }
 158
 159     fn visit_variant(&mut self, v: &'a Variant) {
 160         if v.is_placeholder {
 161             return self.visit_macro_invoc(v.id);
 162         }
 163         let def = self.create_def(v.id, DefPathData::TypeNs(v.ident.name), v.span);
 164         self.with_parent(def, |this| {
 165             if let Some(ctor_hir_id) = v.data.ctor_id() {
 166                 this.create_def(ctor_hir_id, DefPathData::Ctor, v.span);
 167             }
 168             visit::walk_variant(this, v)
 169         });
 170     }
 171
 172     fn visit_variant_data(&mut self, data: &'a VariantData) {
 173         // The assumption here is that non-`cfg` macro expansion cannot change field indices.
 174         // It currently holds because only inert attributes are accepted on fields,
 175         // and every such attribute expands into a single field after it's resolved.
 176         for (index, field) in data.fields().iter().enumerate() {
 177             self.collect_field(field, Some(index));
 178         }
 179     }
 180
 181     fn visit_generic_param(&mut self, param: &'a GenericParam) {
 182         if param.is_placeholder {
 183             self.visit_macro_invoc(param.id);
 184             return;
 185         }
 186         let name = param.ident.name;
 187         let def_path_data = match param.kind {
 188             GenericParamKind::Lifetime { .. } => DefPathData::LifetimeNs(name),
 189             GenericParamKind::Type { .. } => DefPathData::TypeNs(name),
 190             GenericParamKind::Const { .. } => DefPathData::ValueNs(name),
 191         };
 192         self.create_def(param.id, def_path_data, param.ident.span);
 193
 194         visit::walk_generic_param(self, param);
 195     }
 196
 197     fn visit_assoc_item(&mut self, i: &'a AssocItem, ctxt: visit::AssocCtxt) {
 198         let def_data = match &i.kind {
 199             AssocItemKind::Fn(..) | AssocItemKind::Const(..) => DefPathData::ValueNs(i.ident.name),
 200             AssocItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
 201             AssocItemKind::MacCall(..) => return self.visit_macro_invoc(i.id),
 202         };
 203
 204         let def = self.create_def(i.id, def_data, i.span);
 205         self.with_parent(def, |this| visit::walk_assoc_item(this, i, ctxt));
 206     }
 207
 208     fn visit_pat(&mut self, pat: &'a Pat) {
 209         match pat.kind {
 210             PatKind::MacCall(..) => self.visit_macro_invoc(pat.id),
 211             _ => visit::walk_pat(self, pat),
 212         }
 213     }
 214
 215     fn visit_anon_const(&mut self, constant: &'a AnonConst) {
 216         let def = self.create_def(constant.id, DefPathData::AnonConst, constant.value.span);
 217         self.with_parent(def, |this| visit::walk_anon_const(this, constant));
 218     }
 219
 220     fn visit_expr(&mut self, expr: &'a Expr) {
 221         let parent_def = match expr.kind {
 222             ExprKind::MacCall(..) => return self.visit_macro_invoc(expr.id),
 223             ExprKind::Closure(_, asyncness, ..) => {
 224                 // Async closures desugar to closures inside of closures, so
 225                 // we must create two defs.
 226                 let closure_def = self.create_def(expr.id, DefPathData::ClosureExpr, expr.span);
 227                 match asyncness {
 228                     Async::Yes { closure_id, .. } => {
 229                         self.create_def(closure_id, DefPathData::ClosureExpr, expr.span)
 230                     }
 231                     Async::No => closure_def,
 232                 }
 233             }
 234             ExprKind::Async(_, async_id, _) => {
 235                 self.create_def(async_id, DefPathData::ClosureExpr, expr.span)
 236             }
 237             _ => self.parent_def,
 238         };
 239
 240         self.with_parent(parent_def, |this| visit::walk_expr(this, expr));
 241     }
 242
 243     fn visit_ty(&mut self, ty: &'a Ty) {
 244         match ty.kind {
 245             TyKind::MacCall(..) => self.visit_macro_invoc(ty.id),
 246             TyKind::ImplTrait(node_id, _) => {
 247                 let parent_def = self.create_def(node_id, DefPathData::ImplTrait, ty.span);
 248                 self.with_parent(parent_def, |this| visit::walk_ty(this, ty));
 249             }
 250             _ => visit::walk_ty(self, ty),
 251         }
 252     }
 253
 254     fn visit_stmt(&mut self, stmt: &'a Stmt) {
 255         match stmt.kind {
 256             StmtKind::MacCall(..) => self.visit_macro_invoc(stmt.id),
 257             _ => visit::walk_stmt(self, stmt),
 258         }
 259     }
 260
 261     fn visit_arm(&mut self, arm: &'a Arm) {
 262         if arm.is_placeholder { self.visit_macro_invoc(arm.id) } else { visit::walk_arm(self, arm) }
 263     }
 264
 265     fn visit_field(&mut self, f: &'a Field) {
 266         if f.is_placeholder { self.visit_macro_invoc(f.id) } else { visit::walk_field(self, f) }
 267     }
 268
 269     fn visit_field_pattern(&mut self, fp: &'a FieldPat) {
 270         if fp.is_placeholder {
 271             self.visit_macro_invoc(fp.id)
 272         } else {
 273             visit::walk_field_pattern(self, fp)
 274         }
 275     }
 276
 277     fn visit_param(&mut self, p: &'a Param) {
 278         if p.is_placeholder { self.visit_macro_invoc(p.id) } else { visit::walk_param(self, p) }
 279     }
 280
 281     // This method is called only when we are visiting an individual field
 282     // after expanding an attribute on it.
 283     fn visit_struct_field(&mut self, field: &'a StructField) {
 284         self.collect_field(field, None);
 285     }
 286 }