crates/ide/src/syntax_highlighting/highlight.rs

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