crates/ide/src/syntax_highlighting/highlight.rs

   1 //! Computes color for a single element.
   2
   3 use hir::{AsAssocItem, HasVisibility, Semantics};
   4 use ide_db::{
   5     defs::{Definition, NameClass, NameRefClass},
   6     RootDatabase, SymbolKind,
   7 };
   8 use rustc_hash::FxHashMap;
   9 use syntax::{
  10     ast, AstNode, AstToken, NodeOrToken, SyntaxElement,
  11     SyntaxKind::{self, *},
  12     SyntaxNode, SyntaxToken, T,
  13 };
  14
  15 use crate::{
  16     syntax_highlighting::tags::{HlOperator, HlPunct},
  17     Highlight, HlMod, HlTag,
  18 };
  19
  20 pub(super) fn element(
  21     sema: &Semantics<RootDatabase>,
  22     krate: Option<hir::Crate>,
  23     bindings_shadow_count: &mut FxHashMap<hir::Name, u32>,
  24     syntactic_name_ref_highlighting: bool,
  25     element: SyntaxElement,
  26 ) -> Option<(Highlight, Option<u64>)> {
  27     let db = sema.db;
  28     let mut binding_hash = None;
  29     let highlight: Highlight = match element.kind() {
  30         FN => {
  31             bindings_shadow_count.clear();
  32             return None;
  33         }
  34
  35         // Highlight definitions depending on the "type" of the definition.
  36         NAME => {
  37             let name = element.into_node().and_then(ast::Name::cast).unwrap();
  38             let name_kind = NameClass::classify(sema, &name);
  39
  40             if let Some(NameClass::Definition(Definition::Local(local))) = &name_kind {
  41                 if let Some(name) = local.name(db) {
  42                     let shadow_count = bindings_shadow_count.entry(name.clone()).or_default();
  43                     *shadow_count += 1;
  44                     binding_hash = Some(calc_binding_hash(&name, *shadow_count))
  45                 }
  46             };
  47
  48             match name_kind {
  49                 Some(NameClass::Definition(def)) => {
  50                     let mut h = highlight_def(db, krate, def) | HlMod::Definition;
  51                     if let Definition::ModuleDef(hir::ModuleDef::Trait(trait_)) = &def {
  52                         if trait_.is_unsafe(db) {
  53                             h |= HlMod::Unsafe;
  54                         }
  55                     }
  56                     h
  57                 }
  58                 Some(NameClass::ConstReference(def)) => highlight_def(db, krate, def),
  59                 Some(NameClass::PatFieldShorthand { field_ref, .. }) => {
  60                     let mut h = HlTag::Symbol(SymbolKind::Field).into();
  61                     if let hir::VariantDef::Union(_) = field_ref.parent_def(db) {
  62                         h |= HlMod::Unsafe;
  63                     }
  64                     h
  65                 }
  66                 None => highlight_name_by_syntax(name) | HlMod::Definition,
  67             }
  68         }
  69         // Highlight references like the definitions they resolve to
  70         NAME_REF if element.ancestors().any(|it| it.kind() == ATTR) => {
  71             // FIXME: We highlight paths in attributes slightly differently to work around this module
  72             // currently not knowing about tool attributes and rustc builtin attributes as
  73             // we do not want to resolve those to functions that may be defined in scope.
  74             let name_ref = element.into_node().and_then(ast::NameRef::cast).unwrap();
  75             match NameRefClass::classify(sema, &name_ref) {
  76                 Some(name_class) => match name_class {
  77                     NameRefClass::Definition(Definition::ModuleDef(hir::ModuleDef::Module(_)))
  78                         if name_ref
  79                             .syntax()
  80                             .ancestors()
  81                             .find_map(ast::Path::cast)
  82                             .map_or(false, |it| it.parent_path().is_some()) =>
  83                     {
  84                         HlTag::Symbol(SymbolKind::Module)
  85                     }
  86                     NameRefClass::Definition(Definition::Macro(m))
  87                         if m.kind() == hir::MacroKind::Attr =>
  88                     {
  89                         HlTag::Symbol(SymbolKind::Macro)
  90                     }
  91                     _ => HlTag::BuiltinAttr,
  92                 },
  93                 None => HlTag::BuiltinAttr,
  94             }
  95             .into()
  96         }
  97         NAME_REF => {
  98             let name_ref = element.into_node().and_then(ast::NameRef::cast).unwrap();
  99             highlight_method_call_by_name_ref(sema, krate, &name_ref).unwrap_or_else(|| {
 100                 let name_class = match NameRefClass::classify(sema, &name_ref) {
 101                     Some(name_kind) => name_kind,
 102                     None => {
 103                         return if syntactic_name_ref_highlighting {
 104                             highlight_name_ref_by_syntax(name_ref, sema, krate)
 105                         } else {
 106                             HlTag::UnresolvedReference.into()
 107                         }
 108                     }
 109                 };
 110                 let h = match name_class {
 111                     NameRefClass::Definition(def) => {
 112                         if let Definition::Local(local) = &def {
 113                             if let Some(name) = local.name(db) {
 114                                 let shadow_count =
 115                                     bindings_shadow_count.entry(name.clone()).or_default();
 116                                 binding_hash = Some(calc_binding_hash(&name, *shadow_count))
 117                             }
 118                         };
 119
 120                         let mut h = highlight_def(db, krate, def);
 121
 122                         match def {
 123                             Definition::Local(local)
 124                                 if is_consumed_lvalue(name_ref.syntax(), &local, db) =>
 125                             {
 126                                 h |= HlMod::Consuming;
 127                             }
 128                             Definition::ModuleDef(hir::ModuleDef::Trait(trait_))
 129                                 if trait_.is_unsafe(db) =>
 130                             {
 131                                 if ast::Impl::for_trait_name_ref(&name_ref).is_some() {
 132                                     h |= HlMod::Unsafe;
 133                                 }
 134                             }
 135                             Definition::Field(field) => {
 136                                 if let Some(parent) = name_ref.syntax().parent() {
 137                                     if matches!(parent.kind(), FIELD_EXPR | RECORD_PAT_FIELD) {
 138                                         if let hir::VariantDef::Union(_) = field.parent_def(db) {
 139                                             h |= HlMod::Unsafe;
 140                                         }
 141                                     }
 142                                 }
 143                             }
 144                             _ => (),
 145                         }
 146
 147                         h
 148                     }
 149                     NameRefClass::FieldShorthand { .. } => SymbolKind::Field.into(),
 150                 };
 151                 if h.tag == HlTag::Symbol(SymbolKind::Module) && name_ref.self_token().is_some() {
 152                     SymbolKind::SelfParam.into()
 153                 } else {
 154                     h
 155                 }
 156             })
 157         }
 158
 159         // Simple token-based highlighting
 160         COMMENT => {
 161             let comment = element.into_token().and_then(ast::Comment::cast)?;
 162             let h = HlTag::Comment;
 163             match comment.kind().doc {
 164                 Some(_) => h | HlMod::Documentation,
 165                 None => h.into(),
 166             }
 167         }
 168         STRING | BYTE_STRING => HlTag::StringLiteral.into(),
 169         ATTR => HlTag::Attribute.into(),
 170         INT_NUMBER if element.ancestors().nth(1).map_or(false, |it| it.kind() == FIELD_EXPR) => {
 171             SymbolKind::Field.into()
 172         }
 173         INT_NUMBER | FLOAT_NUMBER => HlTag::NumericLiteral.into(),
 174         BYTE => HlTag::ByteLiteral.into(),
 175         CHAR => HlTag::CharLiteral.into(),
 176         QUESTION => HlTag::Operator(HlOperator::Other) | HlMod::ControlFlow,
 177         LIFETIME => {
 178             let lifetime = element.into_node().and_then(ast::Lifetime::cast).unwrap();
 179
 180             match NameClass::classify_lifetime(sema, &lifetime) {
 181                 Some(NameClass::Definition(def)) => {
 182                     highlight_def(db, krate, def) | HlMod::Definition
 183                 }
 184                 None => match NameRefClass::classify_lifetime(sema, &lifetime) {
 185                     Some(NameRefClass::Definition(def)) => highlight_def(db, krate, def),
 186                     _ => SymbolKind::LifetimeParam.into(),
 187                 },
 188                 _ => Highlight::from(SymbolKind::LifetimeParam) | HlMod::Definition,
 189             }
 190         }
 191         IDENT if parent_matches::<ast::TokenTree>(&element) => HlTag::None.into(),
 192         p if p.is_punct() => match p {
 193             T![&] if parent_matches::<ast::BinExpr>(&element) => HlOperator::Bitwise.into(),
 194             T![&] => {
 195                 let h = HlTag::Operator(HlOperator::Other).into();
 196                 let is_unsafe = element
 197                     .parent()
 198                     .and_then(ast::RefExpr::cast)
 199                     .map_or(false, |ref_expr| sema.is_unsafe_ref_expr(&ref_expr));
 200                 if is_unsafe {
 201                     h | HlMod::Unsafe
 202                 } else {
 203                     h
 204                 }
 205             }
 206             T![::] | T![->] | T![=>] | T![..] | T![=] | T![@] | T![.] => HlOperator::Other.into(),
 207             T![!] if parent_matches::<ast::MacroCall>(&element) => SymbolKind::Macro.into(),
 208             T![!] if parent_matches::<ast::NeverType>(&element) => HlTag::BuiltinType.into(),
 209             T![!] if parent_matches::<ast::PrefixExpr>(&element) => HlOperator::Logical.into(),
 210             T![*] if parent_matches::<ast::PtrType>(&element) => HlTag::Keyword.into(),
 211             T![*] if parent_matches::<ast::PrefixExpr>(&element) => {
 212                 let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?;
 213
 214                 let expr = prefix_expr.expr()?;
 215                 let ty = sema.type_of_expr(&expr)?;
 216                 if ty.is_raw_ptr() {
 217                     HlTag::Operator(HlOperator::Other) | HlMod::Unsafe
 218                 } else if let Some(ast::PrefixOp::Deref) = prefix_expr.op_kind() {
 219                     HlOperator::Other.into()
 220                 } else {
 221                     HlPunct::Other.into()
 222                 }
 223             }
 224             T![-] if parent_matches::<ast::PrefixExpr>(&element) => {
 225                 let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?;
 226
 227                 let expr = prefix_expr.expr()?;
 228                 match expr {
 229                     ast::Expr::Literal(_) => HlTag::NumericLiteral,
 230                     _ => HlTag::Operator(HlOperator::Other),
 231                 }
 232                 .into()
 233             }
 234             _ if parent_matches::<ast::PrefixExpr>(&element) => HlOperator::Other.into(),
 235             T![+] | T![-] | T![*] | T![/] | T![+=] | T![-=] | T![*=] | T![/=]
 236                 if parent_matches::<ast::BinExpr>(&element) =>
 237             {
 238                 HlOperator::Arithmetic.into()
 239             }
 240             T![|] | T![&] | T![!] | T![^] | T![|=] | T![&=] | T![^=]
 241                 if parent_matches::<ast::BinExpr>(&element) =>
 242             {
 243                 HlOperator::Bitwise.into()
 244             }
 245             T![&&] | T![||] if parent_matches::<ast::BinExpr>(&element) => {
 246                 HlOperator::Logical.into()
 247             }
 248             T![>] | T![<] | T![==] | T![>=] | T![<=] | T![!=]
 249                 if parent_matches::<ast::BinExpr>(&element) =>
 250             {
 251                 HlOperator::Comparison.into()
 252             }
 253             _ if parent_matches::<ast::BinExpr>(&element) => HlOperator::Other.into(),
 254             _ if parent_matches::<ast::RangeExpr>(&element) => HlOperator::Other.into(),
 255             _ if parent_matches::<ast::RangePat>(&element) => HlOperator::Other.into(),
 256             _ if parent_matches::<ast::RestPat>(&element) => HlOperator::Other.into(),
 257             _ if parent_matches::<ast::Attr>(&element) => HlTag::Attribute.into(),
 258             kind => match kind {
 259                 T!['['] | T![']'] => HlPunct::Bracket,
 260                 T!['{'] | T!['}'] => HlPunct::Brace,
 261                 T!['('] | T![')'] => HlPunct::Parenthesis,
 262                 T![<] | T![>] => HlPunct::Angle,
 263                 T![,] => HlPunct::Comma,
 264                 T![:] => HlPunct::Colon,
 265                 T![;] => HlPunct::Semi,
 266                 T![.] => HlPunct::Dot,
 267                 _ => HlPunct::Other,
 268             }
 269             .into(),
 270         },
 271
 272         k if k.is_keyword() => {
 273             let h = Highlight::new(HlTag::Keyword);
 274             match k {
 275                 T![await] => h | HlMod::Async | HlMod::ControlFlow,
 276                 T![break]
 277                 | T![continue]
 278                 | T![else]
 279                 | T![if]
 280                 | T![in]
 281                 | T![loop]
 282                 | T![match]
 283                 | T![return]
 284                 | T![while]
 285                 | T![yield] => h | HlMod::ControlFlow,
 286                 T![for] if !is_child_of_impl(&element) => h | HlMod::ControlFlow,
 287                 T![unsafe] => h | HlMod::Unsafe,
 288                 T![true] | T![false] => HlTag::BoolLiteral.into(),
 289                 // self is handled as either a Name or NameRef already
 290                 T![self] => return None,
 291                 T![ref] => element
 292                     .parent()
 293                     .and_then(ast::IdentPat::cast)
 294                     .and_then(|ident_pat| {
 295                         if sema.is_unsafe_ident_pat(&ident_pat) {
 296                             Some(HlMod::Unsafe)
 297                         } else {
 298                             None
 299                         }
 300                     })
 301                     .map(|modifier| h | modifier)
 302                     .unwrap_or(h),
 303                 T![async] => h | HlMod::Async,
 304                 _ => h,
 305             }
 306         }
 307
 308         _ => return None,
 309     };
 310
 311     return Some((highlight, binding_hash));
 312
 313     fn calc_binding_hash(name: &hir::Name, shadow_count: u32) -> u64 {
 314         fn hash<T: std::hash::Hash + std::fmt::Debug>(x: T) -> u64 {
 315             use std::{collections::hash_map::DefaultHasher, hash::Hasher};
 316
 317             let mut hasher = DefaultHasher::new();
 318             x.hash(&mut hasher);
 319             hasher.finish()
 320         }
 321
 322         hash((name, shadow_count))
 323     }
 324 }
 325 fn highlight_def(db: &RootDatabase, krate: Option<hir::Crate>, def: Definition) -> Highlight {
 326     let mut h = match def {
 327         Definition::Macro(_) => Highlight::new(HlTag::Symbol(SymbolKind::Macro)),
 328         Definition::Field(_) => Highlight::new(HlTag::Symbol(SymbolKind::Field)),
 329         Definition::ModuleDef(def) => match def {
 330             hir::ModuleDef::Module(_) => Highlight::new(HlTag::Symbol(SymbolKind::Module)),
 331             hir::ModuleDef::Function(func) => {
 332                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Function));
 333                 if let Some(item) = func.as_assoc_item(db) {
 334                     h |= HlMod::Associated;
 335                     match func.self_param(db) {
 336                         Some(sp) => {
 337                             if let hir::Access::Exclusive = sp.access(db) {
 338                                 h |= HlMod::Mutable;
 339                             }
 340                         }
 341                         None => h |= HlMod::Static,
 342                     }
 343
 344                     match item.container(db) {
 345                         hir::AssocItemContainer::Impl(i) => {
 346                             if i.trait_(db).is_some() {
 347                                 h |= HlMod::Trait;
 348                             }
 349                         }
 350                         hir::AssocItemContainer::Trait(_t) => {
 351                             h |= HlMod::Trait;
 352                         }
 353                     }
 354                 }
 355
 356                 if func.is_unsafe(db) {
 357                     h |= HlMod::Unsafe;
 358                 }
 359                 if func.is_async(db) {
 360                     h |= HlMod::Async;
 361                 }
 362
 363                 h
 364             }
 365             hir::ModuleDef::Adt(adt) => {
 366                 let h = match adt {
 367                     hir::Adt::Struct(_) => HlTag::Symbol(SymbolKind::Struct),
 368                     hir::Adt::Enum(_) => HlTag::Symbol(SymbolKind::Enum),
 369                     hir::Adt::Union(_) => HlTag::Symbol(SymbolKind::Union),
 370                 };
 371
 372                 Highlight::new(h)
 373             }
 374             hir::ModuleDef::Variant(_) => Highlight::new(HlTag::Symbol(SymbolKind::Variant)),
 375             hir::ModuleDef::Const(konst) => {
 376                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Const));
 377
 378                 if let Some(item) = konst.as_assoc_item(db) {
 379                     h |= HlMod::Associated;
 380                     match item.container(db) {
 381                         hir::AssocItemContainer::Impl(i) => {
 382                             if i.trait_(db).is_some() {
 383                                 h |= HlMod::Trait;
 384                             }
 385                         }
 386                         hir::AssocItemContainer::Trait(_t) => {
 387                             h |= HlMod::Trait;
 388                         }
 389                     }
 390                 }
 391
 392                 h
 393             }
 394             hir::ModuleDef::Trait(_) => Highlight::new(HlTag::Symbol(SymbolKind::Trait)),
 395             hir::ModuleDef::TypeAlias(type_) => {
 396                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::TypeAlias));
 397
 398                 if let Some(item) = type_.as_assoc_item(db) {
 399                     h |= HlMod::Associated;
 400                     match item.container(db) {
 401                         hir::AssocItemContainer::Impl(i) => {
 402                             if i.trait_(db).is_some() {
 403                                 h |= HlMod::Trait;
 404                             }
 405                         }
 406                         hir::AssocItemContainer::Trait(_t) => {
 407                             h |= HlMod::Trait;
 408                         }
 409                     }
 410                 }
 411
 412                 h
 413             }
 414             hir::ModuleDef::BuiltinType(_) => Highlight::new(HlTag::BuiltinType),
 415             hir::ModuleDef::Static(s) => {
 416                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Static));
 417
 418                 if s.is_mut(db) {
 419                     h |= HlMod::Mutable;
 420                     h |= HlMod::Unsafe;
 421                 }
 422
 423                 h
 424             }
 425         },
 426         Definition::SelfType(_) => Highlight::new(HlTag::Symbol(SymbolKind::Impl)),
 427         Definition::GenericParam(it) => match it {
 428             hir::GenericParam::TypeParam(_) => Highlight::new(HlTag::Symbol(SymbolKind::TypeParam)),
 429             hir::GenericParam::ConstParam(_) => {
 430                 Highlight::new(HlTag::Symbol(SymbolKind::ConstParam))
 431             }
 432             hir::GenericParam::LifetimeParam(_) => {
 433                 Highlight::new(HlTag::Symbol(SymbolKind::LifetimeParam))
 434             }
 435         },
 436         Definition::Local(local) => {
 437             let tag = if local.is_self(db) {
 438                 HlTag::Symbol(SymbolKind::SelfParam)
 439             } else if local.is_param(db) {
 440                 HlTag::Symbol(SymbolKind::ValueParam)
 441             } else {
 442                 HlTag::Symbol(SymbolKind::Local)
 443             };
 444             let mut h = Highlight::new(tag);
 445             let ty = local.ty(db);
 446             if local.is_mut(db) || ty.is_mutable_reference() {
 447                 h |= HlMod::Mutable;
 448             }
 449             if ty.as_callable(db).is_some() || ty.impls_fnonce(db) {
 450                 h |= HlMod::Callable;
 451             }
 452             h
 453         }
 454         Definition::Label(_) => Highlight::new(HlTag::Symbol(SymbolKind::Label)),
 455     };
 456
 457     let is_from_other_crate = def.module(db).map(hir::Module::krate) != krate;
 458     let is_builtin_type = matches!(def, Definition::ModuleDef(hir::ModuleDef::BuiltinType(_)));
 459     let is_public = def.visibility(db) == Some(hir::Visibility::Public);
 460
 461     match (is_from_other_crate, is_builtin_type, is_public) {
 462         (true, false, _) => h |= HlMod::Library,
 463         (false, _, true) => h |= HlMod::Public,
 464         _ => {}
 465     }
 466
 467     h
 468 }
 469
 470 fn highlight_method_call_by_name_ref(
 471     sema: &Semantics<RootDatabase>,
 472     krate: Option<hir::Crate>,
 473     name_ref: &ast::NameRef,
 474 ) -> Option<Highlight> {
 475     let mc = name_ref.syntax().parent().and_then(ast::MethodCallExpr::cast)?;
 476     highlight_method_call(sema, krate, &mc)
 477 }
 478
 479 fn highlight_method_call(
 480     sema: &Semantics<RootDatabase>,
 481     krate: Option<hir::Crate>,
 482     method_call: &ast::MethodCallExpr,
 483 ) -> Option<Highlight> {
 484     let func = sema.resolve_method_call(method_call)?;
 485
 486     let mut h = SymbolKind::Function.into();
 487     h |= HlMod::Associated;
 488
 489     if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(method_call) {
 490         h |= HlMod::Unsafe;
 491     }
 492     if func.is_async(sema.db) {
 493         h |= HlMod::Async;
 494     }
 495     if func.as_assoc_item(sema.db).and_then(|it| it.containing_trait(sema.db)).is_some() {
 496         h |= HlMod::Trait;
 497     }
 498
 499     let is_from_other_crate = Some(func.module(sema.db).krate()) != krate;
 500     let is_public = func.visibility(sema.db) == hir::Visibility::Public;
 501
 502     if is_from_other_crate {
 503         h |= HlMod::Library;
 504     } else if is_public {
 505         h |= HlMod::Public;
 506     }
 507
 508     if let Some(self_param) = func.self_param(sema.db) {
 509         match self_param.access(sema.db) {
 510             hir::Access::Shared => (),
 511             hir::Access::Exclusive => h |= HlMod::Mutable,
 512             hir::Access::Owned => {
 513                 if let Some(receiver_ty) =
 514                     method_call.receiver().and_then(|it| sema.type_of_expr(&it))
 515                 {
 516                     if !receiver_ty.is_copy(sema.db) {
 517                         h |= HlMod::Consuming
 518                     }
 519                 }
 520             }
 521         }
 522     }
 523     Some(h)
 524 }
 525
 526 fn highlight_name_by_syntax(name: ast::Name) -> Highlight {
 527     let default = HlTag::UnresolvedReference;
 528
 529     let parent = match name.syntax().parent() {
 530         Some(it) => it,
 531         _ => return default.into(),
 532     };
 533
 534     let tag = match parent.kind() {
 535         STRUCT => SymbolKind::Struct,
 536         ENUM => SymbolKind::Enum,
 537         VARIANT => SymbolKind::Variant,
 538         UNION => SymbolKind::Union,
 539         TRAIT => SymbolKind::Trait,
 540         TYPE_ALIAS => SymbolKind::TypeAlias,
 541         TYPE_PARAM => SymbolKind::TypeParam,
 542         RECORD_FIELD => SymbolKind::Field,
 543         MODULE => SymbolKind::Module,
 544         FN => SymbolKind::Function,
 545         CONST => SymbolKind::Const,
 546         STATIC => SymbolKind::Static,
 547         IDENT_PAT => SymbolKind::Local,
 548         _ => return default.into(),
 549     };
 550
 551     tag.into()
 552 }
 553
 554 fn highlight_name_ref_by_syntax(
 555     name: ast::NameRef,
 556     sema: &Semantics<RootDatabase>,
 557     krate: Option<hir::Crate>,
 558 ) -> Highlight {
 559     let default = HlTag::UnresolvedReference;
 560
 561     let parent = match name.syntax().parent() {
 562         Some(it) => it,
 563         _ => return default.into(),
 564     };
 565
 566     match parent.kind() {
 567         METHOD_CALL_EXPR => ast::MethodCallExpr::cast(parent)
 568             .and_then(|it| highlight_method_call(sema, krate, &it))
 569             .unwrap_or_else(|| SymbolKind::Function.into()),
 570         FIELD_EXPR => {
 571             let h = HlTag::Symbol(SymbolKind::Field);
 572             let is_union = ast::FieldExpr::cast(parent)
 573                 .and_then(|field_expr| sema.resolve_field(&field_expr))
 574                 .map_or(false, |field| {
 575                     matches!(field.parent_def(sema.db), hir::VariantDef::Union(_))
 576                 });
 577             if is_union {
 578                 h | HlMod::Unsafe
 579             } else {
 580                 h.into()
 581             }
 582         }
 583         PATH_SEGMENT => {
 584             let path = match parent.parent().and_then(ast::Path::cast) {
 585                 Some(it) => it,
 586                 _ => return default.into(),
 587             };
 588             let expr = match path.syntax().parent().and_then(ast::PathExpr::cast) {
 589                 Some(it) => it,
 590                 _ => {
 591                     // within path, decide whether it is module or adt by checking for uppercase name
 592                     return if name.text().chars().next().unwrap_or_default().is_uppercase() {
 593                         SymbolKind::Struct
 594                     } else {
 595                         SymbolKind::Module
 596                     }
 597                     .into();
 598                 }
 599             };
 600             let parent = match expr.syntax().parent() {
 601                 Some(it) => it,
 602                 None => return default.into(),
 603             };
 604
 605             match parent.kind() {
 606                 CALL_EXPR => SymbolKind::Function.into(),
 607                 _ => if name.text().chars().next().unwrap_or_default().is_uppercase() {
 608                     SymbolKind::Struct
 609                 } else {
 610                     SymbolKind::Const
 611                 }
 612                 .into(),
 613             }
 614         }
 615         _ => default.into(),
 616     }
 617 }
 618
 619 fn is_consumed_lvalue(node: &SyntaxNode, local: &hir::Local, db: &RootDatabase) -> bool {
 620     // When lvalues are passed as arguments and they're not Copy, then mark them as Consuming.
 621     parents_match(node.clone().into(), &[PATH_SEGMENT, PATH, PATH_EXPR, ARG_LIST])
 622         && !local.ty(db).is_copy(db)
 623 }
 624
 625 /// Returns true if the parent nodes of `node` all match the `SyntaxKind`s in `kinds` exactly.
 626 fn parents_match(mut node: NodeOrToken<SyntaxNode, SyntaxToken>, mut kinds: &[SyntaxKind]) -> bool {
 627     while let (Some(parent), [kind, rest @ ..]) = (&node.parent(), kinds) {
 628         if parent.kind() != *kind {
 629             return false;
 630         }
 631
 632         // FIXME: Would be nice to get parent out of the match, but binding by-move and by-value
 633         // in the same pattern is unstable: rust-lang/rust#68354.
 634         node = node.parent().unwrap().into();
 635         kinds = rest;
 636     }
 637
 638     // Only true if we matched all expected kinds
 639     kinds.len() == 0
 640 }
 641
 642 #[inline]
 643 fn parent_matches<N: AstNode>(element: &SyntaxElement) -> bool {
 644     element.parent().map_or(false, |it| N::can_cast(it.kind()))
 645 }
 646
 647 fn is_child_of_impl(element: &SyntaxElement) -> bool {
 648     match element.parent() {
 649         Some(e) => e.kind() == IMPL,
 650         _ => false,
 651     }
 652 }