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     db::HirDatabase, Crate, Field, GenericParam, HasVisibility, Impl, Label, Local, MacroDef,
  10     Module, ModuleDef, Name, 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 call
 105 /// the code handles 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     ExternCrate(Crate),
 112     Definition(Definition),
 113     /// `None` in `if let None = Some(82) {}`.
 114     /// Syntactically, it is a name, but semantically it is a reference.
 115     ConstReference(Definition),
 116     /// `field` in `if let Foo { field } = foo`. Here, `ast::Name` both Here the
 117     /// name both introduces a definition into a local scope, and refers to an
 118     /// existing definition.
 119     PatFieldShorthand {
 120         local_def: Local,
 121         field_ref: Definition,
 122     },
 123 }
 124
 125 impl NameClass {
 126     /// `Definition` defined by this name.
 127     pub fn defined(self, db: &dyn HirDatabase) -> Option<Definition> {
 128         let res = match self {
 129             NameClass::ExternCrate(krate) => Definition::ModuleDef(krate.root_module(db).into()),
 130             NameClass::Definition(it) => it,
 131             NameClass::ConstReference(_) => return None,
 132             NameClass::PatFieldShorthand { local_def, field_ref: _ } => {
 133                 Definition::Local(local_def)
 134             }
 135         };
 136         Some(res)
 137     }
 138
 139     /// `Definition` referenced or defined by this name.
 140     pub fn referenced_or_defined(self, db: &dyn HirDatabase) -> Definition {
 141         match self {
 142             NameClass::ExternCrate(krate) => Definition::ModuleDef(krate.root_module(db).into()),
 143             NameClass::Definition(it) | NameClass::ConstReference(it) => it,
 144             NameClass::PatFieldShorthand { local_def: _, field_ref } => field_ref,
 145         }
 146     }
 147
 148     pub fn classify(sema: &Semantics<RootDatabase>, name: &ast::Name) -> Option<NameClass> {
 149         let _p = profile::span("classify_name");
 150
 151         let parent = name.syntax().parent()?;
 152
 153         if let Some(bind_pat) = ast::IdentPat::cast(parent.clone()) {
 154             if let Some(def) = sema.resolve_bind_pat_to_const(&bind_pat) {
 155                 return Some(NameClass::ConstReference(Definition::ModuleDef(def)));
 156             }
 157         }
 158
 159         match_ast! {
 160             match parent {
 161                 ast::Rename(it) => {
 162                     if let Some(use_tree) = it.syntax().parent().and_then(ast::UseTree::cast) {
 163                         let path = use_tree.path()?;
 164                         let path_segment = path.segment()?;
 165                         let name_ref_class = path_segment
 166                             .kind()
 167                             .and_then(|kind| {
 168                                 match kind {
 169                                     // The rename might be from a `self` token, so fallback to the name higher
 170                                     // in the use tree.
 171                                     PathSegmentKind::SelfKw => {
 172                                         let use_tree = use_tree
 173                                             .syntax()
 174                                             .parent()
 175                                             .as_ref()
 176                                             // Skip over UseTreeList
 177                                             .and_then(SyntaxNode::parent)
 178                                             .and_then(ast::UseTree::cast)?;
 179                                         let path = use_tree.path()?;
 180                                         let path_segment = path.segment()?;
 181                                         path_segment.name_ref()
 182                                     },
 183                                     PathSegmentKind::Name(name_ref) => Some(name_ref),
 184                                     _ => return None,
 185                                 }
 186                             })
 187                             .and_then(|name_ref| NameRefClass::classify(sema, &name_ref))?;
 188
 189                         Some(NameClass::Definition(name_ref_class.referenced(sema.db)))
 190                     } else {
 191                         let extern_crate = it.syntax().parent().and_then(ast::ExternCrate::cast)?;
 192                         let resolved = sema.resolve_extern_crate(&extern_crate)?;
 193                         Some(NameClass::ExternCrate(resolved))
 194                     }
 195                 },
 196                 ast::IdentPat(it) => {
 197                     let local = sema.to_def(&it)?;
 198
 199                     if let Some(record_pat_field) = it.syntax().parent().and_then(ast::RecordPatField::cast) {
 200                         if record_pat_field.name_ref().is_none() {
 201                             if let Some(field) = sema.resolve_record_pat_field(&record_pat_field) {
 202                                 let field = Definition::Field(field);
 203                                 return Some(NameClass::PatFieldShorthand { local_def: local, field_ref: field });
 204                             }
 205                         }
 206                     }
 207
 208                     Some(NameClass::Definition(Definition::Local(local)))
 209                 },
 210                 ast::SelfParam(it) => {
 211                     let def = sema.to_def(&it)?;
 212                     Some(NameClass::Definition(Definition::Local(def)))
 213                 },
 214                 ast::RecordField(it) => {
 215                     let field: hir::Field = sema.to_def(&it)?;
 216                     Some(NameClass::Definition(Definition::Field(field)))
 217                 },
 218                 ast::Module(it) => {
 219                     let def = sema.to_def(&it)?;
 220                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 221                 },
 222                 ast::Struct(it) => {
 223                     let def: hir::Struct = sema.to_def(&it)?;
 224                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 225                 },
 226                 ast::Union(it) => {
 227                     let def: hir::Union = sema.to_def(&it)?;
 228                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 229                 },
 230                 ast::Enum(it) => {
 231                     let def: hir::Enum = sema.to_def(&it)?;
 232                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 233                 },
 234                 ast::Trait(it) => {
 235                     let def: hir::Trait = sema.to_def(&it)?;
 236                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 237                 },
 238                 ast::Static(it) => {
 239                     let def: hir::Static = sema.to_def(&it)?;
 240                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 241                 },
 242                 ast::Variant(it) => {
 243                     let def: hir::Variant = sema.to_def(&it)?;
 244                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 245                 },
 246                 ast::Fn(it) => {
 247                     let def: hir::Function = sema.to_def(&it)?;
 248                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 249                 },
 250                 ast::Const(it) => {
 251                     let def: hir::Const = sema.to_def(&it)?;
 252                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 253                 },
 254                 ast::TypeAlias(it) => {
 255                     let def: hir::TypeAlias = sema.to_def(&it)?;
 256                     Some(NameClass::Definition(Definition::ModuleDef(def.into())))
 257                 },
 258                 ast::Macro(it) => {
 259                     let def = sema.to_def(&it)?;
 260                     Some(NameClass::Definition(Definition::Macro(def)))
 261                 },
 262                 ast::TypeParam(it) => {
 263                     let def = sema.to_def(&it)?;
 264                     Some(NameClass::Definition(Definition::GenericParam(def.into())))
 265                 },
 266                 ast::ConstParam(it) => {
 267                     let def = sema.to_def(&it)?;
 268                     Some(NameClass::Definition(Definition::GenericParam(def.into())))
 269                 },
 270                 _ => None,
 271             }
 272         }
 273     }
 274
 275     pub fn classify_lifetime(
 276         sema: &Semantics<RootDatabase>,
 277         lifetime: &ast::Lifetime,
 278     ) -> Option<NameClass> {
 279         let _p = profile::span("classify_lifetime").detail(|| lifetime.to_string());
 280         let parent = lifetime.syntax().parent()?;
 281
 282         match_ast! {
 283             match parent {
 284                 ast::LifetimeParam(it) => {
 285                     let def = sema.to_def(&it)?;
 286                     Some(NameClass::Definition(Definition::GenericParam(def.into())))
 287                 },
 288                 ast::Label(it) => {
 289                     let def = sema.to_def(&it)?;
 290                     Some(NameClass::Definition(Definition::Label(def)))
 291                 },
 292                 _ => None,
 293             }
 294         }
 295     }
 296 }
 297
 298 /// This is similar to [`NameClass`], but works for [`ast::NameRef`] rather than
 299 /// for [`ast::Name`]. Similarly, what looks like a reference in syntax is a
 300 /// reference most of the time, but there are a couple of annoying exceptions.
 301 ///
 302 /// A model special case is field shorthand syntax, which uses a single
 303 /// reference to point to two different defs.
 304 #[derive(Debug)]
 305 pub enum NameRefClass {
 306     ExternCrate(Crate),
 307     Definition(Definition),
 308     FieldShorthand { local_ref: Local, field_ref: Definition },
 309 }
 310
 311 impl NameRefClass {
 312     /// `Definition`, which this name refers to.
 313     pub fn referenced(self, db: &dyn HirDatabase) -> Definition {
 314         match self {
 315             NameRefClass::ExternCrate(krate) => Definition::ModuleDef(krate.root_module(db).into()),
 316             NameRefClass::Definition(def) => def,
 317             NameRefClass::FieldShorthand { local_ref, field_ref: _ } => {
 318                 // FIXME: this is inherently ambiguous -- this name refers to
 319                 // two different defs....
 320                 Definition::Local(local_ref)
 321             }
 322         }
 323     }
 324
 325     // Note: we don't have unit-tests for this rather important function.
 326     // It is primarily exercised via goto definition tests in `ide`.
 327     pub fn classify(
 328         sema: &Semantics<RootDatabase>,
 329         name_ref: &ast::NameRef,
 330     ) -> Option<NameRefClass> {
 331         let _p = profile::span("classify_name_ref").detail(|| name_ref.to_string());
 332
 333         let parent = name_ref.syntax().parent()?;
 334
 335         if let Some(method_call) = ast::MethodCallExpr::cast(parent.clone()) {
 336             if let Some(func) = sema.resolve_method_call(&method_call) {
 337                 return Some(NameRefClass::Definition(Definition::ModuleDef(func.into())));
 338             }
 339         }
 340
 341         if let Some(field_expr) = ast::FieldExpr::cast(parent.clone()) {
 342             if let Some(field) = sema.resolve_field(&field_expr) {
 343                 return Some(NameRefClass::Definition(Definition::Field(field)));
 344             }
 345         }
 346
 347         if let Some(record_field) = ast::RecordExprField::for_field_name(name_ref) {
 348             if let Some((field, local, _)) = sema.resolve_record_field(&record_field) {
 349                 let field = Definition::Field(field);
 350                 let res = match local {
 351                     None => NameRefClass::Definition(field),
 352                     Some(local) => {
 353                         NameRefClass::FieldShorthand { field_ref: field, local_ref: local }
 354                     }
 355                 };
 356                 return Some(res);
 357             }
 358         }
 359
 360         if let Some(record_pat_field) = ast::RecordPatField::cast(parent.clone()) {
 361             if let Some(field) = sema.resolve_record_pat_field(&record_pat_field) {
 362                 let field = Definition::Field(field);
 363                 return Some(NameRefClass::Definition(field));
 364             }
 365         }
 366
 367         if let Some(assoc_type_arg) = ast::AssocTypeArg::cast(parent.clone()) {
 368             if assoc_type_arg.name_ref().as_ref() == Some(name_ref) {
 369                 // `Trait<Assoc = Ty>`
 370                 //        ^^^^^
 371                 let path = name_ref.syntax().ancestors().find_map(ast::Path::cast)?;
 372                 let resolved = sema.resolve_path(&path)?;
 373                 if let PathResolution::Def(ModuleDef::Trait(tr)) = resolved {
 374                     // FIXME: resolve in supertraits
 375                     if let Some(ty) = tr
 376                         .items(sema.db)
 377                         .iter()
 378                         .filter_map(|assoc| match assoc {
 379                             hir::AssocItem::TypeAlias(it) => Some(*it),
 380                             _ => None,
 381                         })
 382                         .find(|alias| &alias.name(sema.db).to_string() == &name_ref.text())
 383                     {
 384                         return Some(NameRefClass::Definition(Definition::ModuleDef(
 385                             ModuleDef::TypeAlias(ty),
 386                         )));
 387                     }
 388                 }
 389
 390                 return None;
 391             }
 392         }
 393
 394         if let Some(path) = name_ref.syntax().ancestors().find_map(ast::Path::cast) {
 395             if path.qualifier().is_none() {
 396                 if let Some(macro_call) = path.syntax().parent().and_then(ast::MacroCall::cast) {
 397                     // Only use this to resolve single-segment macro calls like `foo!()`. Multi-segment
 398                     // paths are handled below (allowing `log$0::info!` to resolve to the log crate).
 399                     if let Some(macro_def) = sema.resolve_macro_call(&macro_call) {
 400                         return Some(NameRefClass::Definition(Definition::Macro(macro_def)));
 401                     }
 402                 }
 403             }
 404             let top_path = path.top_path();
 405             let is_attribute_path = top_path
 406                 .syntax()
 407                 .ancestors()
 408                 .find_map(ast::Attr::cast)
 409                 .map(|attr| attr.path().as_ref() == Some(&top_path));
 410             return match is_attribute_path {
 411                 Some(true) => sema.resolve_path(&path).and_then(|resolved| {
 412                     match resolved {
 413                         // Don't wanna collide with builtin attributes here like `test` hence guard
 414                         // so only resolve to modules that aren't the last segment
 415                         PathResolution::Def(module @ ModuleDef::Module(_)) if path != top_path => {
 416                             cov_mark::hit!(name_ref_classify_attr_path_qualifier);
 417                             Some(NameRefClass::Definition(Definition::ModuleDef(module)))
 418                         }
 419                         PathResolution::Macro(mac) if mac.kind() == hir::MacroKind::Attr => {
 420                             Some(NameRefClass::Definition(Definition::Macro(mac)))
 421                         }
 422                         _ => None,
 423                     }
 424                 }),
 425                 Some(false) => None,
 426                 None => sema.resolve_path(&path).map(Into::into).map(NameRefClass::Definition),
 427             };
 428         }
 429
 430         let extern_crate = ast::ExternCrate::cast(parent)?;
 431         let resolved = sema.resolve_extern_crate(&extern_crate)?;
 432         Some(NameRefClass::ExternCrate(resolved))
 433     }
 434
 435     pub fn classify_lifetime(
 436         sema: &Semantics<RootDatabase>,
 437         lifetime: &ast::Lifetime,
 438     ) -> Option<NameRefClass> {
 439         let _p = profile::span("classify_lifetime_ref").detail(|| lifetime.to_string());
 440         let parent = lifetime.syntax().parent()?;
 441         match parent.kind() {
 442             SyntaxKind::BREAK_EXPR | SyntaxKind::CONTINUE_EXPR => {
 443                 sema.resolve_label(lifetime).map(Definition::Label).map(NameRefClass::Definition)
 444             }
 445             SyntaxKind::LIFETIME_ARG
 446             | SyntaxKind::SELF_PARAM
 447             | SyntaxKind::TYPE_BOUND
 448             | SyntaxKind::WHERE_PRED
 449             | SyntaxKind::REF_TYPE => sema
 450                 .resolve_lifetime_param(lifetime)
 451                 .map(GenericParam::LifetimeParam)
 452                 .map(Definition::GenericParam)
 453                 .map(NameRefClass::Definition),
 454             // lifetime bounds, as in the 'b in 'a: 'b aren't wrapped in TypeBound nodes so we gotta check
 455             // if our lifetime is in a LifetimeParam without being the constrained lifetime
 456             _ if ast::LifetimeParam::cast(parent).and_then(|param| param.lifetime()).as_ref()
 457                 != Some(lifetime) =>
 458             {
 459                 sema.resolve_lifetime_param(lifetime)
 460                     .map(GenericParam::LifetimeParam)
 461                     .map(Definition::GenericParam)
 462                     .map(NameRefClass::Definition)
 463             }
 464             _ => None,
 465         }
 466     }
 467 }
 468
 469 impl From<PathResolution> for Definition {
 470     fn from(path_resolution: PathResolution) -> Self {
 471         match path_resolution {
 472             PathResolution::Def(def) => Definition::ModuleDef(def),
 473             PathResolution::AssocItem(item) => {
 474                 let def = match item {
 475                     hir::AssocItem::Function(it) => it.into(),
 476                     hir::AssocItem::Const(it) => it.into(),
 477                     hir::AssocItem::TypeAlias(it) => it.into(),
 478                 };
 479                 Definition::ModuleDef(def)
 480             }
 481             PathResolution::Local(local) => Definition::Local(local),
 482             PathResolution::TypeParam(par) => Definition::GenericParam(par.into()),
 483             PathResolution::Macro(def) => Definition::Macro(def),
 484             PathResolution::SelfType(impl_def) => Definition::SelfType(impl_def),
 485             PathResolution::ConstParam(par) => Definition::GenericParam(par.into()),
 486         }
 487     }
 488 }