crates/ide_db/src/defs.rs

   1 //! `NameDefinition` keeps information about the element we want to search references for.
   2 //! The element is represented by `NameKind`. It's located inside some `container` and
   3 //! has a `visibility`, which defines a search scope.
   4 //! Note that the reference search is possible for not all of the classified items.
   5
   6 // FIXME: this badly needs rename/rewrite (matklad, 2020-02-06).
   7
   8 use hir::{
   9     Field, GenericParam, HasVisibility, Impl, Label, Local, MacroDef, Module, ModuleDef, Name,
  10     PathResolution, Semantics, Visibility,
  11 };
  12 use syntax::{
  13     ast::{self, AstNode, PathSegmentKind},
  14     match_ast, SyntaxKind, SyntaxNode,
  15 };
  16
  17 use crate::RootDatabase;
  18
  19 // FIXME: a more precise name would probably be `Symbol`?
  20 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
  21 pub enum Definition {
  22     Macro(MacroDef),
  23     Field(Field),
  24     ModuleDef(ModuleDef),
  25     SelfType(Impl),
  26     Local(Local),
  27     GenericParam(GenericParam),
  28     Label(Label),
  29 }
  30
  31 impl Definition {
  32     pub fn module(&self, db: &RootDatabase) -> Option<Module> {
  33         match self {
  34             Definition::Macro(it) => it.module(db),
  35             Definition::Field(it) => Some(it.parent_def(db).module(db)),
  36             Definition::ModuleDef(it) => it.module(db),
  37             Definition::SelfType(it) => Some(it.module(db)),
  38             Definition::Local(it) => Some(it.module(db)),
  39             Definition::GenericParam(it) => Some(it.module(db)),
  40             Definition::Label(it) => Some(it.module(db)),
  41         }
  42     }
  43
  44     pub fn visibility(&self, db: &RootDatabase) -> Option<Visibility> {
  45         match self {
  46             Definition::Field(sf) => Some(sf.visibility(db)),
  47             Definition::ModuleDef(def) => match def {
  48                 ModuleDef::Module(it) => {
  49                     // FIXME: should work like other cases here.
  50                     let parent = it.parent(db)?;
  51                     parent.visibility_of(db, def)
  52                 }
  53                 ModuleDef::Function(it) => Some(it.visibility(db)),
  54                 ModuleDef::Adt(it) => Some(it.visibility(db)),
  55                 ModuleDef::Const(it) => Some(it.visibility(db)),
  56                 ModuleDef::Static(it) => Some(it.visibility(db)),
  57                 ModuleDef::Trait(it) => Some(it.visibility(db)),
  58                 ModuleDef::TypeAlias(it) => Some(it.visibility(db)),
  59                 // NB: Variants don't have their own visibility, and just inherit
  60                 // one from the parent. Not sure if that's the right thing to do.
  61                 ModuleDef::Variant(it) => Some(it.parent_enum(db).visibility(db)),
  62                 ModuleDef::BuiltinType(_) => None,
  63             },
  64             Definition::Macro(_)
  65             | Definition::SelfType(_)
  66             | Definition::Local(_)
  67             | Definition::GenericParam(_)
  68             | Definition::Label(_) => None,
  69         }
  70     }
  71
  72     pub fn name(&self, db: &RootDatabase) -> Option<Name> {
  73         let name = match self {
  74             Definition::Macro(it) => it.name(db)?,
  75             Definition::Field(it) => it.name(db),
  76             Definition::ModuleDef(def) => match def {
  77                 hir::ModuleDef::Module(it) => it.name(db)?,
  78                 hir::ModuleDef::Function(it) => it.name(db),
  79                 hir::ModuleDef::Adt(def) => match def {
  80                     hir::Adt::Struct(it) => it.name(db),
  81                     hir::Adt::Union(it) => it.name(db),
  82                     hir::Adt::Enum(it) => it.name(db),
  83                 },
  84                 hir::ModuleDef::Variant(it) => it.name(db),
  85                 hir::ModuleDef::Const(it) => it.name(db)?,
  86                 hir::ModuleDef::Static(it) => it.name(db)?,
  87                 hir::ModuleDef::Trait(it) => it.name(db),
  88                 hir::ModuleDef::TypeAlias(it) => it.name(db),
  89                 hir::ModuleDef::BuiltinType(it) => it.name(),
  90             },
  91             Definition::SelfType(_) => return None,
  92             Definition::Local(it) => it.name(db)?,
  93             Definition::GenericParam(it) => it.name(db),
  94             Definition::Label(it) => it.name(db),
  95         };
  96         Some(name)
  97     }
  98 }
  99
 100 /// On a first blush, a single `ast::Name` defines a single definition at some
 101 /// scope. That is, that, by just looking at the syntactical category, we can
 102 /// unambiguously define the semantic category.
 103 ///
 104 /// Sadly, that's not 100% true, there are special cases. To make sure that
 105 /// callers handle all the special cases correctly via exhaustive matching, we
 106 /// add a [`NameClass`] enum which lists all of them!
 107 ///
 108 /// A model special case is `None` constant in pattern.
 109 #[derive(Debug)]
 110 pub enum NameClass {
 111     Definition(Definition),
 112     /// `None` in `if let None = Some(82) {}`.
 113     /// Syntactically, it is a name, but semantically it is a reference.
 114     ConstReference(Definition),
 115     /// `field` in `if let Foo { field } = foo`. Here, `ast::Name` both introduces
 116     /// a definition into a local scope, and refers to an existing definition.
 117     PatFieldShorthand {
 118         local_def: Local,
 119         field_ref: Field,
 120     },
 121 }
 122
 123 impl NameClass {
 124     /// `Definition` defined by this name.
 125     pub fn defined(self) -> Option<Definition> {
 126         let res = match self {
 127             NameClass::Definition(it) => it,
 128             NameClass::ConstReference(_) => return None,
 129             NameClass::PatFieldShorthand { local_def, field_ref: _ } => {
 130                 Definition::Local(local_def)
 131             }
 132         };
 133         Some(res)
 134     }
 135
 136     /// `Definition` referenced or defined by this name, in case of a shorthand this will yield the field reference.
 137     pub fn defined_or_referenced_field(self) -> Definition {
 138         match self {
 139             NameClass::Definition(it) | NameClass::ConstReference(it) => it,
 140             NameClass::PatFieldShorthand { local_def: _, field_ref } => {
 141                 Definition::Field(field_ref)
 142             }
 143         }
 144     }
 145
 146     /// `Definition` referenced or defined by this name, in case of a shorthand this will yield the local definition.
 147     pub fn defined_or_referenced_local(self) -> Definition {
 148         match self {
 149             NameClass::Definition(it) | NameClass::ConstReference(it) => it,
 150             NameClass::PatFieldShorthand { local_def, field_ref: _ } => {
 151                 Definition::Local(local_def)
 152             }
 153         }
 154     }
 155
 156     pub fn classify(sema: &Semantics<RootDatabase>, name: &ast::Name) -> Option<NameClass> {
 157         let _p = profile::span("classify_name");
 158
 159         let parent = name.syntax().parent()?;
 160
 161         if let Some(bind_pat) = ast::IdentPat::cast(parent.clone()) {
 162             if let Some(def) = sema.resolve_bind_pat_to_const(&bind_pat) {
 163                 return Some(NameClass::ConstReference(Definition::ModuleDef(def)));
 164             }
 165         }
 166
 167         match_ast! {
 168             match parent {
 169                 ast::Rename(it) => {
 170                     if let Some(use_tree) = it.syntax().parent().and_then(ast::UseTree::cast) {
 171                         let path = use_tree.path()?;
 172                         let path_segment = path.segment()?;
 173                         let name_ref_class = path_segment
 174                             .kind()
 175                             .and_then(|kind| {
 176                                 match kind {
 177                                     // The rename might be from a `self` token, so fallback to the name higher
 178                                     // in the use tree.
 179                                     PathSegmentKind::SelfKw => {
 180                                         let use_tree = use_tree
 181                                             .syntax()
 182                                             .parent()
 183                                             .as_ref()
 184                                             // Skip over UseTreeList
 185                                             .and_then(SyntaxNode::parent)
 186                                             .and_then(ast::UseTree::cast)?;
 187                                         let path = use_tree.path()?;
 188                                         let path_segment = path.segment()?;
 189                                         path_segment.name_ref()
 190                                     },
 191                                     PathSegmentKind::Name(name_ref) => Some(name_ref),
 192                                     _ => return None,
 193                                 }
 194                             })
 195                             .and_then(|name_ref| NameRefClass::classify(sema, &name_ref))?;
 196
 197                         Some(NameClass::Definition(name_ref_class.referenced_field()))
 198                     } else {
 199                         let extern_crate = it.syntax().parent().and_then(ast::ExternCrate::cast)?;
 200                         let krate = sema.resolve_extern_crate(&extern_crate)?;
 201                         let root_module = krate.root_module(sema.db);
 202                         Some(NameClass::Definition(Definition::ModuleDef(root_module.into())))
 203                     }
 204                 },
 205                 ast::IdentPat(it) => {
 206                     let local = sema.to_def(&it)?;
 207
 208                     if let Some(record_pat_field) = it.syntax().parent().and_then(ast::RecordPatField::cast) {
 209                         if record_pat_field.name_ref().is_none() {
 210                             if let Some(field) = sema.resolve_record_pat_field(&record_pat_field) {
 211                                 return Some(NameClass::PatFieldShorthand { local_def: local, field_ref: field });
 212                             }
 213                         }
 214                     }
 215
 216                     Some(NameClass::Definition(Definition::Local(local)))
 217                 },
 218                 ast::SelfParam(it) => {
 219                     let def = sema.to_def(&it)?;
 220                     Some(NameClass::Definition(Definition::Local(def)))
 221                 },
 222                 ast::RecordField(it) => {
 223                     let field: hir::Field = sema.to_def(&it)?;
 224                     Some(NameClass::Definition(Definition::Field(field)))
 225                 },
 226                 ast::Module(it) => {
 227                     let def = sema.to_def(&it)?;
 228                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 229                 },
 230                 ast::Struct(it) => {
 231                     let def: hir::Struct = sema.to_def(&it)?;
 232                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 233                 },
 234                 ast::Union(it) => {
 235                     let def: hir::Union = sema.to_def(&it)?;
 236                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 237                 },
 238                 ast::Enum(it) => {
 239                     let def: hir::Enum = sema.to_def(&it)?;
 240                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 241                 },
 242                 ast::Trait(it) => {
 243                     let def: hir::Trait = sema.to_def(&it)?;
 244                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 245                 },
 246                 ast::Static(it) => {
 247                     let def: hir::Static = sema.to_def(&it)?;
 248                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 249                 },
 250                 ast::Variant(it) => {
 251                     let def: hir::Variant = sema.to_def(&it)?;
 252                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 253                 },
 254                 ast::Fn(it) => {
 255                     let def: hir::Function = sema.to_def(&it)?;
 256                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 257                 },
 258                 ast::Const(it) => {
 259                     let def: hir::Const = sema.to_def(&it)?;
 260                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 261                 },
 262                 ast::TypeAlias(it) => {
 263                     let def: hir::TypeAlias = sema.to_def(&it)?;
 264                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 265                 },
 266                 ast::Macro(it) => {
 267                     let def = sema.to_def(&it)?;
 268                     Some(NameClass::Definition(Definition::Macro(def)))
 269                 },
 270                 ast::TypeParam(it) => {
 271                     let def = sema.to_def(&it)?;
 272                     Some(NameClass::Definition(Definition::GenericParam(def.into())))
 273                 },
 274                 ast::ConstParam(it) => {
 275                     let def = sema.to_def(&it)?;
 276                     Some(NameClass::Definition(Definition::GenericParam(def.into())))
 277                 },
 278                 _ => None,
 279             }
 280         }
 281     }
 282
 283     pub fn classify_lifetime(
 284         sema: &Semantics<RootDatabase>,
 285         lifetime: &ast::Lifetime,
 286     ) -> Option<NameClass> {
 287         let _p = profile::span("classify_lifetime").detail(|| lifetime.to_string());
 288         let parent = lifetime.syntax().parent()?;
 289
 290         match_ast! {
 291             match parent {
 292                 ast::LifetimeParam(it) => {
 293                     let def = sema.to_def(&it)?;
 294                     Some(NameClass::Definition(Definition::GenericParam(def.into())))
 295                 },
 296                 ast::Label(it) => {
 297                     let def = sema.to_def(&it)?;
 298                     Some(NameClass::Definition(Definition::Label(def)))
 299                 },
 300                 _ => None,
 301             }
 302         }
 303     }
 304 }
 305
 306 /// This is similar to [`NameClass`], but works for [`ast::NameRef`] rather than
 307 /// for [`ast::Name`]. Similarly, what looks like a reference in syntax is a
 308 /// reference most of the time, but there are a couple of annoying exceptions.
 309 ///
 310 /// A model special case is field shorthand syntax, which uses a single
 311 /// reference to point to two different defs.
 312 #[derive(Debug)]
 313 pub enum NameRefClass {
 314     Definition(Definition),
 315     FieldShorthand { local_ref: Local, field_ref: Field },
 316 }
 317
 318 impl NameRefClass {
 319     /// `Definition`, which this name refers to with a preference for the field reference in case of a field shorthand.
 320     pub fn referenced_field(self) -> Definition {
 321         match self {
 322             NameRefClass::Definition(def) => def,
 323             NameRefClass::FieldShorthand { local_ref: _, field_ref } => {
 324                 Definition::Field(field_ref)
 325             }
 326         }
 327     }
 328
 329     /// `Definition`, which this name refers to with a preference for the local reference in case of a field shorthand.
 330     pub fn referenced_local(self) -> Definition {
 331         match self {
 332             NameRefClass::Definition(def) => def,
 333             NameRefClass::FieldShorthand { local_ref, field_ref: _ } => {
 334                 Definition::Local(local_ref)
 335             }
 336         }
 337     }
 338
 339     // Note: we don't have unit-tests for this rather important function.
 340     // It is primarily exercised via goto definition tests in `ide`.
 341     pub fn classify(
 342         sema: &Semantics<RootDatabase>,
 343         name_ref: &ast::NameRef,
 344     ) -> Option<NameRefClass> {
 345         let _p = profile::span("classify_name_ref").detail(|| name_ref.to_string());
 346
 347         let parent = name_ref.syntax().parent()?;
 348
 349         if let Some(method_call) = ast::MethodCallExpr::cast(parent.clone()) {
 350             if let Some(func) = sema.resolve_method_call(&method_call) {
 351                 return Some(NameRefClass::Definition(Definition::ModuleDef(func.into())));
 352             }
 353         }
 354
 355         if let Some(field_expr) = ast::FieldExpr::cast(parent.clone()) {
 356             if let Some(field) = sema.resolve_field(&field_expr) {
 357                 return Some(NameRefClass::Definition(Definition::Field(field)));
 358             }
 359         }
 360
 361         if let Some(record_field) = ast::RecordExprField::for_field_name(name_ref) {
 362             if let Some((field, local, _)) = sema.resolve_record_field(&record_field) {
 363                 let res = match local {
 364                     None => NameRefClass::Definition(Definition::Field(field)),
 365                     Some(local) => {
 366                         NameRefClass::FieldShorthand { field_ref: field, local_ref: local }
 367                     }
 368                 };
 369                 return Some(res);
 370             }
 371         }
 372
 373         if let Some(record_pat_field) = ast::RecordPatField::cast(parent.clone()) {
 374             if let Some(field) = sema.resolve_record_pat_field(&record_pat_field) {
 375                 let field = Definition::Field(field);
 376                 return Some(NameRefClass::Definition(field));
 377             }
 378         }
 379
 380         if let Some(assoc_type_arg) = ast::AssocTypeArg::cast(parent.clone()) {
 381             if assoc_type_arg.name_ref().as_ref() == Some(name_ref) {
 382                 // `Trait<Assoc = Ty>`
 383                 //        ^^^^^
 384                 let path = name_ref.syntax().ancestors().find_map(ast::Path::cast)?;
 385                 let resolved = sema.resolve_path(&path)?;
 386                 if let PathResolution::Def(ModuleDef::Trait(tr)) = resolved {
 387                     // FIXME: resolve in supertraits
 388                     if let Some(ty) = tr
 389                         .items(sema.db)
 390                         .iter()
 391                         .filter_map(|assoc| match assoc {
 392                             hir::AssocItem::TypeAlias(it) => Some(*it),
 393                             _ => None,
 394                         })
 395                         .find(|alias| &alias.name(sema.db).to_string() == &name_ref.text())
 396                     {
 397                         return Some(NameRefClass::Definition(Definition::ModuleDef(
 398                             ModuleDef::TypeAlias(ty),
 399                         )));
 400                     }
 401                 }
 402
 403                 return None;
 404             }
 405         }
 406
 407         if let Some(path) = name_ref.syntax().ancestors().find_map(ast::Path::cast) {
 408             if path.qualifier().is_none() {
 409                 if let Some(macro_call) = path.syntax().parent().and_then(ast::MacroCall::cast) {
 410                     // Only use this to resolve single-segment macro calls like `foo!()`. Multi-segment
 411                     // paths are handled below (allowing `log$0::info!` to resolve to the log crate).
 412                     if let Some(macro_def) = sema.resolve_macro_call(&macro_call) {
 413                         return Some(NameRefClass::Definition(Definition::Macro(macro_def)));
 414                     }
 415                 }
 416             }
 417             let top_path = path.top_path();
 418             let is_attribute_path = top_path
 419                 .syntax()
 420                 .ancestors()
 421                 .find_map(ast::Attr::cast)
 422                 .map(|attr| attr.path().as_ref() == Some(&top_path));
 423             return match is_attribute_path {
 424                 Some(true) => sema.resolve_path(&path).and_then(|resolved| {
 425                     match resolved {
 426                         // Don't wanna collide with builtin attributes here like `test` hence guard
 427                         // so only resolve to modules that aren't the last segment
 428                         PathResolution::Def(module @ ModuleDef::Module(_)) if path != top_path => {
 429                             cov_mark::hit!(name_ref_classify_attr_path_qualifier);
 430                             Some(NameRefClass::Definition(Definition::ModuleDef(module)))
 431                         }
 432                         PathResolution::Macro(mac) if mac.kind() == hir::MacroKind::Attr => {
 433                             Some(NameRefClass::Definition(Definition::Macro(mac)))
 434                         }
 435                         _ => None,
 436                     }
 437                 }),
 438                 Some(false) => None,
 439                 None => sema.resolve_path(&path).map(Into::into).map(NameRefClass::Definition),
 440             };
 441         }
 442
 443         let extern_crate = ast::ExternCrate::cast(parent)?;
 444         let krate = sema.resolve_extern_crate(&extern_crate)?;
 445         let root_module = krate.root_module(sema.db);
 446         Some(NameRefClass::Definition(Definition::ModuleDef(root_module.into())))
 447     }
 448
 449     pub fn classify_lifetime(
 450         sema: &Semantics<RootDatabase>,
 451         lifetime: &ast::Lifetime,
 452     ) -> Option<NameRefClass> {
 453         let _p = profile::span("classify_lifetime_ref").detail(|| lifetime.to_string());
 454         let parent = lifetime.syntax().parent()?;
 455         match parent.kind() {
 456             SyntaxKind::BREAK_EXPR | SyntaxKind::CONTINUE_EXPR => {
 457                 sema.resolve_label(lifetime).map(Definition::Label).map(NameRefClass::Definition)
 458             }
 459             SyntaxKind::LIFETIME_ARG
 460             | SyntaxKind::SELF_PARAM
 461             | SyntaxKind::TYPE_BOUND
 462             | SyntaxKind::WHERE_PRED
 463             | SyntaxKind::REF_TYPE => sema
 464                 .resolve_lifetime_param(lifetime)
 465                 .map(GenericParam::LifetimeParam)
 466                 .map(Definition::GenericParam)
 467                 .map(NameRefClass::Definition),
 468             // lifetime bounds, as in the 'b in 'a: 'b aren't wrapped in TypeBound nodes so we gotta check
 469             // if our lifetime is in a LifetimeParam without being the constrained lifetime
 470             _ if ast::LifetimeParam::cast(parent).and_then(|param| param.lifetime()).as_ref()
 471                 != Some(lifetime) =>
 472             {
 473                 sema.resolve_lifetime_param(lifetime)
 474                     .map(GenericParam::LifetimeParam)
 475                     .map(Definition::GenericParam)
 476                     .map(NameRefClass::Definition)
 477             }
 478             _ => None,
 479         }
 480     }
 481 }
 482
 483 impl From<PathResolution> for Definition {
 484     fn from(path_resolution: PathResolution) -> Self {
 485         match path_resolution {
 486             PathResolution::Def(def) => Definition::ModuleDef(def),
 487             PathResolution::AssocItem(item) => {
 488                 let def = match item {
 489                     hir::AssocItem::Function(it) => it.into(),
 490                     hir::AssocItem::Const(it) => it.into(),
 491                     hir::AssocItem::TypeAlias(it) => it.into(),
 492                 };
 493                 Definition::ModuleDef(def)
 494             }
 495             PathResolution::Local(local) => Definition::Local(local),
 496             PathResolution::TypeParam(par) => Definition::GenericParam(par.into()),
 497             PathResolution::Macro(def) => Definition::Macro(def),
 498             PathResolution::SelfType(impl_def) => Definition::SelfType(impl_def),
 499             PathResolution::ConstParam(par) => Definition::GenericParam(par.into()),
 500         }
 501     }
 502 }