src/librustc_resolve/def_collector.rs

   1 use crate::Resolver;
   2 use rustc_ast::token::{self, Token};
   3 use rustc_ast::visit::{self, FnKind};
   4 use rustc_ast::walk_list;
   5 use rustc_ast::*;
   6 use rustc_ast_lowering::ResolverAstLowering;
   7 use rustc_expand::expand::AstFragment;
   8 use rustc_hir::def_id::LocalDefId;
   9 use rustc_hir::definitions::*;
  10 use rustc_span::hygiene::ExpnId;
  11 use rustc_span::symbol::{kw, sym};
  12 use rustc_span::Span;
  13 use tracing::debug;
  14
  15 crate fn collect_definitions(
  16     resolver: &mut Resolver<'_>,
  17     fragment: &AstFragment,
  18     expansion: ExpnId,
  19 ) {
  20     let parent_def = resolver.invocation_parents[&expansion];
  21     fragment.visit_with(&mut DefCollector { resolver, parent_def, expansion });
  22 }
  23
  24 /// Creates `DefId`s for nodes in the AST.
  25 struct DefCollector<'a, 'b> {
  26     resolver: &'a mut Resolver<'b>,
  27     parent_def: LocalDefId,
  28     expansion: ExpnId,
  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(parent_def, node_id, data, self.expansion, span)
  36     }
  37
  38     fn with_parent<F: FnOnce(&mut Self)>(&mut self, parent_def: LocalDefId, f: F) {
  39         let orig_parent_def = std::mem::replace(&mut self.parent_def, parent_def);
  40         f(self);
  41         self.parent_def = orig_parent_def;
  42     }
  43
  44     fn collect_field(&mut self, field: &'a StructField, index: Option<usize>) {
  45         let index = |this: &Self| {
  46             index.unwrap_or_else(|| {
  47                 let node_id = NodeId::placeholder_from_expn_id(this.expansion);
  48                 this.resolver.placeholder_field_indices[&node_id]
  49             })
  50         };
  51
  52         if field.is_placeholder {
  53             let old_index = self.resolver.placeholder_field_indices.insert(field.id, index(self));
  54             assert!(old_index.is_none(), "placeholder field index is reset for a node ID");
  55             self.visit_macro_invoc(field.id);
  56         } else {
  57             let name = field.ident.map_or_else(|| sym::integer(index(self)), |ident| ident.name);
  58             let def = self.create_def(field.id, DefPathData::ValueNs(name), field.span);
  59             self.with_parent(def, |this| visit::walk_struct_field(this, field));
  60         }
  61     }
  62
  63     fn visit_macro_invoc(&mut self, id: NodeId) {
  64         let old_parent =
  65             self.resolver.invocation_parents.insert(id.placeholder_to_expn_id(), self.parent_def);
  66         assert!(old_parent.is_none(), "parent `LocalDefId` is reset for an invocation");
  67     }
  68 }
  69
  70 impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
  71     fn visit_item(&mut self, i: &'a Item) {
  72         debug!("visit_item: {:?}", i);
  73
  74         // Pick the def data. This need not be unique, but the more
  75         // information we encapsulate into, the better
  76         let def_data = match &i.kind {
  77             ItemKind::Impl { .. } => DefPathData::Impl,
  78             ItemKind::Mod(..) if i.ident.name == kw::Invalid => {
  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(..) => return self.visit_macro_invoc(i.id),
  95             ItemKind::GlobalAsm(..) => DefPathData::Misc,
  96             ItemKind::Use(..) => {
  97                 return visit::walk_item(self, i);
  98             }
  99         };
 100         let def = self.create_def(i.id, def_data, i.span);
 101
 102         self.with_parent(def, |this| {
 103             match i.kind {
 104                 ItemKind::Struct(ref struct_def, _) | ItemKind::Union(ref struct_def, _) => {
 105                     // If this is a unit or tuple-like struct, register the constructor.
 106                     if let Some(ctor_hir_id) = struct_def.ctor_id() {
 107                         this.create_def(ctor_hir_id, DefPathData::Ctor, i.span);
 108                     }
 109                 }
 110                 _ => {}
 111             }
 112             visit::walk_item(this, i);
 113         });
 114     }
 115
 116     fn visit_fn(&mut self, fn_kind: FnKind<'a>, span: Span, _: NodeId) {
 117         if let FnKind::Fn(_, _, sig, _, body) = fn_kind {
 118             if let Async::Yes { closure_id, return_impl_trait_id, .. } = sig.header.asyncness {
 119                 self.create_def(return_impl_trait_id, DefPathData::ImplTrait, span);
 120
 121                 // For async functions, we need to create their inner defs inside of a
 122                 // closure to match their desugared representation. Besides that,
 123                 // we must mirror everything that `visit::walk_fn` below does.
 124                 self.visit_fn_header(&sig.header);
 125                 visit::walk_fn_decl(self, &sig.decl);
 126                 let closure_def = self.create_def(closure_id, DefPathData::ClosureExpr, span);
 127                 self.with_parent(closure_def, |this| walk_list!(this, visit_block, body));
 128                 return;
 129             }
 130         }
 131
 132         visit::walk_fn(self, fn_kind, span);
 133     }
 134
 135     fn visit_use_tree(&mut self, use_tree: &'a UseTree, id: NodeId, _nested: bool) {
 136         self.create_def(id, DefPathData::Misc, use_tree.span);
 137         visit::walk_use_tree(self, use_tree, id);
 138     }
 139
 140     fn visit_foreign_item(&mut self, foreign_item: &'a ForeignItem) {
 141         if let ForeignItemKind::MacCall(_) = foreign_item.kind {
 142             return self.visit_macro_invoc(foreign_item.id);
 143         }
 144
 145         let def = self.create_def(
 146             foreign_item.id,
 147             DefPathData::ValueNs(foreign_item.ident.name),
 148             foreign_item.span,
 149         );
 150
 151         self.with_parent(def, |this| {
 152             visit::walk_foreign_item(this, foreign_item);
 153         });
 154     }
 155
 156     fn visit_variant(&mut self, v: &'a Variant) {
 157         if v.is_placeholder {
 158             return self.visit_macro_invoc(v.id);
 159         }
 160         let def = self.create_def(v.id, DefPathData::TypeNs(v.ident.name), v.span);
 161         self.with_parent(def, |this| {
 162             if let Some(ctor_hir_id) = v.data.ctor_id() {
 163                 this.create_def(ctor_hir_id, DefPathData::Ctor, v.span);
 164             }
 165             visit::walk_variant(this, v)
 166         });
 167     }
 168
 169     fn visit_variant_data(&mut self, data: &'a VariantData) {
 170         // The assumption here is that non-`cfg` macro expansion cannot change field indices.
 171         // It currently holds because only inert attributes are accepted on fields,
 172         // and every such attribute expands into a single field after it's resolved.
 173         for (index, field) in data.fields().iter().enumerate() {
 174             self.collect_field(field, Some(index));
 175         }
 176     }
 177
 178     fn visit_generic_param(&mut self, param: &'a GenericParam) {
 179         if param.is_placeholder {
 180             self.visit_macro_invoc(param.id);
 181             return;
 182         }
 183         let name = param.ident.name;
 184         let def_path_data = match param.kind {
 185             GenericParamKind::Lifetime { .. } => DefPathData::LifetimeNs(name),
 186             GenericParamKind::Type { .. } => DefPathData::TypeNs(name),
 187             GenericParamKind::Const { .. } => DefPathData::ValueNs(name),
 188         };
 189         self.create_def(param.id, def_path_data, param.ident.span);
 190
 191         visit::walk_generic_param(self, param);
 192     }
 193
 194     fn visit_assoc_item(&mut self, i: &'a AssocItem, ctxt: visit::AssocCtxt) {
 195         let def_data = match &i.kind {
 196             AssocItemKind::Fn(..) | AssocItemKind::Const(..) => DefPathData::ValueNs(i.ident.name),
 197             AssocItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
 198             AssocItemKind::MacCall(..) => return self.visit_macro_invoc(i.id),
 199         };
 200
 201         let def = self.create_def(i.id, def_data, i.span);
 202         self.with_parent(def, |this| visit::walk_assoc_item(this, i, ctxt));
 203     }
 204
 205     fn visit_pat(&mut self, pat: &'a Pat) {
 206         match pat.kind {
 207             PatKind::MacCall(..) => self.visit_macro_invoc(pat.id),
 208             _ => visit::walk_pat(self, pat),
 209         }
 210     }
 211
 212     fn visit_anon_const(&mut self, constant: &'a AnonConst) {
 213         let def = self.create_def(constant.id, DefPathData::AnonConst, constant.value.span);
 214         self.with_parent(def, |this| visit::walk_anon_const(this, constant));
 215     }
 216
 217     fn visit_expr(&mut self, expr: &'a Expr) {
 218         let parent_def = match expr.kind {
 219             ExprKind::MacCall(..) => return self.visit_macro_invoc(expr.id),
 220             ExprKind::Closure(_, asyncness, ..) => {
 221                 // Async closures desugar to closures inside of closures, so
 222                 // we must create two defs.
 223                 let closure_def = self.create_def(expr.id, DefPathData::ClosureExpr, expr.span);
 224                 match asyncness {
 225                     Async::Yes { closure_id, .. } => {
 226                         self.create_def(closure_id, DefPathData::ClosureExpr, expr.span)
 227                     }
 228                     Async::No => closure_def,
 229                 }
 230             }
 231             ExprKind::Async(_, async_id, _) => {
 232                 self.create_def(async_id, DefPathData::ClosureExpr, expr.span)
 233             }
 234             _ => self.parent_def,
 235         };
 236
 237         self.with_parent(parent_def, |this| visit::walk_expr(this, expr));
 238     }
 239
 240     fn visit_ty(&mut self, ty: &'a Ty) {
 241         match ty.kind {
 242             TyKind::MacCall(..) => return self.visit_macro_invoc(ty.id),
 243             TyKind::ImplTrait(node_id, _) => {
 244                 self.create_def(node_id, DefPathData::ImplTrait, ty.span);
 245             }
 246             _ => {}
 247         }
 248         visit::walk_ty(self, ty);
 249     }
 250
 251     fn visit_stmt(&mut self, stmt: &'a Stmt) {
 252         match stmt.kind {
 253             StmtKind::MacCall(..) => self.visit_macro_invoc(stmt.id),
 254             _ => visit::walk_stmt(self, stmt),
 255         }
 256     }
 257
 258     fn visit_token(&mut self, t: Token) {
 259         if let token::Interpolated(nt) = t.kind {
 260             if let token::NtExpr(ref expr) = *nt {
 261                 if let ExprKind::MacCall(..) = expr.kind {
 262                     self.visit_macro_invoc(expr.id);
 263                 }
 264             }
 265         }
 266     }
 267
 268     fn visit_arm(&mut self, arm: &'a Arm) {
 269         if arm.is_placeholder { self.visit_macro_invoc(arm.id) } else { visit::walk_arm(self, arm) }
 270     }
 271
 272     fn visit_field(&mut self, f: &'a Field) {
 273         if f.is_placeholder { self.visit_macro_invoc(f.id) } else { visit::walk_field(self, f) }
 274     }
 275
 276     fn visit_field_pattern(&mut self, fp: &'a FieldPat) {
 277         if fp.is_placeholder {
 278             self.visit_macro_invoc(fp.id)
 279         } else {
 280             visit::walk_field_pattern(self, fp)
 281         }
 282     }
 283
 284     fn visit_param(&mut self, p: &'a Param) {
 285         if p.is_placeholder { self.visit_macro_invoc(p.id) } else { visit::walk_param(self, p) }
 286     }
 287
 288     // This method is called only when we are visiting an individual field
 289     // after expanding an attribute on it.
 290     fn visit_struct_field(&mut self, field: &'a StructField) {
 291         self.collect_field(field, None);
 292     }
 293 }