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     helpers::{try_resolve_derive_input, FamousDefs},
   7     RootDatabase, SymbolKind,
   8 };
   9 use rustc_hash::FxHashMap;
  10 use syntax::{
  11     ast, match_ast, AstNode, AstToken, NodeOrToken, SyntaxElement,
  12     SyntaxKind::{self, *},
  13     SyntaxNode, SyntaxToken, T,
  14 };
  15
  16 use crate::{
  17     syntax_highlighting::tags::{HlOperator, HlPunct},
  18     Highlight, HlMod, HlTag,
  19 };
  20
  21 pub(super) fn element(
  22     sema: &Semantics<RootDatabase>,
  23     krate: Option<hir::Crate>,
  24     bindings_shadow_count: &mut FxHashMap<hir::Name, u32>,
  25     syntactic_name_ref_highlighting: bool,
  26     element: SyntaxElement,
  27 ) -> Option<(Highlight, Option<u64>)> {
  28     match element {
  29         NodeOrToken::Node(it) => {
  30             node(sema, krate, bindings_shadow_count, syntactic_name_ref_highlighting, it)
  31         }
  32         NodeOrToken::Token(it) => Some((token(sema, krate, it)?, None)),
  33     }
  34 }
  35
  36 fn token(
  37     sema: &Semantics<RootDatabase>,
  38     krate: Option<hir::Crate>,
  39     token: SyntaxToken,
  40 ) -> Option<Highlight> {
  41     let highlight: Highlight = if let Some(comment) = ast::Comment::cast(token.clone()) {
  42         let h = HlTag::Comment;
  43         match comment.kind().doc {
  44             Some(_) => h | HlMod::Documentation,
  45             None => h.into(),
  46         }
  47     } else {
  48         match token.kind() {
  49             STRING | BYTE_STRING => HlTag::StringLiteral.into(),
  50             INT_NUMBER if token.ancestors().nth(1).map_or(false, |it| it.kind() == FIELD_EXPR) => {
  51                 SymbolKind::Field.into()
  52             }
  53             INT_NUMBER | FLOAT_NUMBER => HlTag::NumericLiteral.into(),
  54             BYTE => HlTag::ByteLiteral.into(),
  55             CHAR => HlTag::CharLiteral.into(),
  56             T![?] => HlTag::Operator(HlOperator::Other) | HlMod::ControlFlow,
  57             IDENT if parent_matches::<ast::TokenTree>(&token) => {
  58                 if let Some(attr) = token.ancestors().nth(2).and_then(ast::Attr::cast) {
  59                     match try_resolve_derive_input(sema, &attr, &ast::Ident::cast(token).unwrap()) {
  60                         Some(res) => highlight_def(sema, krate, Definition::from(res)),
  61                         None => HlTag::None.into(),
  62                     }
  63                 } else {
  64                     HlTag::None.into()
  65                 }
  66             }
  67             p if p.is_punct() => match p {
  68                 T![&] if parent_matches::<ast::BinExpr>(&token) => HlOperator::Bitwise.into(),
  69                 T![&] => {
  70                     let h = HlTag::Operator(HlOperator::Other).into();
  71                     let is_unsafe = token
  72                         .parent()
  73                         .and_then(ast::RefExpr::cast)
  74                         .map_or(false, |ref_expr| sema.is_unsafe_ref_expr(&ref_expr));
  75                     if is_unsafe {
  76                         h | HlMod::Unsafe
  77                     } else {
  78                         h
  79                     }
  80                 }
  81                 T![::] | T![->] | T![=>] | T![..] | T![=] | T![@] | T![.] => {
  82                     HlOperator::Other.into()
  83                 }
  84                 T![!] if parent_matches::<ast::MacroCall>(&token) => SymbolKind::Macro.into(),
  85                 T![!] if parent_matches::<ast::NeverType>(&token) => HlTag::BuiltinType.into(),
  86                 T![!] if parent_matches::<ast::PrefixExpr>(&token) => HlOperator::Logical.into(),
  87                 T![*] if parent_matches::<ast::PtrType>(&token) => HlTag::Keyword.into(),
  88                 T![*] if parent_matches::<ast::PrefixExpr>(&token) => {
  89                     let prefix_expr = token.parent().and_then(ast::PrefixExpr::cast)?;
  90
  91                     let expr = prefix_expr.expr()?;
  92                     let ty = sema.type_of_expr(&expr)?.original;
  93                     if ty.is_raw_ptr() {
  94                         HlTag::Operator(HlOperator::Other) | HlMod::Unsafe
  95                     } else if let Some(ast::UnaryOp::Deref) = prefix_expr.op_kind() {
  96                         HlOperator::Other.into()
  97                     } else {
  98                         HlPunct::Other.into()
  99                     }
 100                 }
 101                 T![-] if parent_matches::<ast::PrefixExpr>(&token) => {
 102                     let prefix_expr = token.parent().and_then(ast::PrefixExpr::cast)?;
 103
 104                     let expr = prefix_expr.expr()?;
 105                     match expr {
 106                         ast::Expr::Literal(_) => HlTag::NumericLiteral,
 107                         _ => HlTag::Operator(HlOperator::Other),
 108                     }
 109                     .into()
 110                 }
 111                 _ if parent_matches::<ast::PrefixExpr>(&token) => HlOperator::Other.into(),
 112                 T![+] | T![-] | T![*] | T![/] if parent_matches::<ast::BinExpr>(&token) => {
 113                     HlOperator::Arithmetic.into()
 114                 }
 115                 T![+=] | T![-=] | T![*=] | T![/=] if parent_matches::<ast::BinExpr>(&token) => {
 116                     Highlight::from(HlOperator::Arithmetic) | HlMod::Mutable
 117                 }
 118                 T![|] | T![&] | T![!] | T![^] if parent_matches::<ast::BinExpr>(&token) => {
 119                     HlOperator::Bitwise.into()
 120                 }
 121                 T![|=] | T![&=] | T![^=] if parent_matches::<ast::BinExpr>(&token) => {
 122                     Highlight::from(HlOperator::Bitwise) | HlMod::Mutable
 123                 }
 124                 T![&&] | T![||] if parent_matches::<ast::BinExpr>(&token) => {
 125                     HlOperator::Logical.into()
 126                 }
 127                 T![>] | T![<] | T![==] | T![>=] | T![<=] | T![!=]
 128                     if parent_matches::<ast::BinExpr>(&token) =>
 129                 {
 130                     HlOperator::Comparison.into()
 131                 }
 132                 _ if parent_matches::<ast::BinExpr>(&token) => HlOperator::Other.into(),
 133                 _ if parent_matches::<ast::RangeExpr>(&token) => HlOperator::Other.into(),
 134                 _ if parent_matches::<ast::RangePat>(&token) => HlOperator::Other.into(),
 135                 _ if parent_matches::<ast::RestPat>(&token) => HlOperator::Other.into(),
 136                 _ if parent_matches::<ast::Attr>(&token) => HlTag::Attribute.into(),
 137                 kind => match kind {
 138                     T!['['] | T![']'] => HlPunct::Bracket,
 139                     T!['{'] | T!['}'] => HlPunct::Brace,
 140                     T!['('] | T![')'] => HlPunct::Parenthesis,
 141                     T![<] | T![>] => HlPunct::Angle,
 142                     T![,] => HlPunct::Comma,
 143                     T![:] => HlPunct::Colon,
 144                     T![;] => HlPunct::Semi,
 145                     T![.] => HlPunct::Dot,
 146                     _ => HlPunct::Other,
 147                 }
 148                 .into(),
 149             },
 150             k if k.is_keyword() => {
 151                 let h = Highlight::new(HlTag::Keyword);
 152                 match k {
 153                     T![await] => h | HlMod::Async | HlMod::ControlFlow,
 154                     T![break]
 155                     | T![continue]
 156                     | T![else]
 157                     | T![if]
 158                     | T![in]
 159                     | T![loop]
 160                     | T![match]
 161                     | T![return]
 162                     | T![while]
 163                     | T![yield] => h | HlMod::ControlFlow,
 164                     T![for] if !is_child_of_impl(&token) => h | HlMod::ControlFlow,
 165                     T![unsafe] => h | HlMod::Unsafe,
 166                     T![true] | T![false] => HlTag::BoolLiteral.into(),
 167                     // crate is handled just as a token if it's in an `extern crate`
 168                     T![crate] if parent_matches::<ast::ExternCrate>(&token) => h,
 169                     // self, crate and super are handled as either a Name or NameRef already
 170                     T![self] | T![crate] | T![super] => return None,
 171                     T![ref] => token
 172                         .parent()
 173                         .and_then(ast::IdentPat::cast)
 174                         .and_then(|ident_pat| {
 175                             (sema.is_unsafe_ident_pat(&ident_pat)).then(|| HlMod::Unsafe)
 176                         })
 177                         .map_or(h, |modifier| h | modifier),
 178                     T![async] => h | HlMod::Async,
 179                     _ => h,
 180                 }
 181             }
 182             _ => return None,
 183         }
 184     };
 185     Some(highlight)
 186 }
 187
 188 fn node(
 189     sema: &Semantics<RootDatabase>,
 190     krate: Option<hir::Crate>,
 191     bindings_shadow_count: &mut FxHashMap<hir::Name, u32>,
 192     syntactic_name_ref_highlighting: bool,
 193     node: SyntaxNode,
 194 ) -> Option<(Highlight, Option<u64>)> {
 195     let mut binding_hash = None;
 196     let highlight = match_ast! {
 197         match node {
 198             ast::Fn(__) => {
 199                 bindings_shadow_count.clear();
 200                 return None;
 201             },
 202             ast::Attr(__) => {
 203                 HlTag::Attribute.into()
 204             },
 205             // Highlight definitions depending on the "type" of the definition.
 206             ast::Name(name) => {
 207                 highlight_name(sema, bindings_shadow_count, &mut binding_hash, krate, name)
 208             },
 209             // Highlight references like the definitions they resolve to
 210             ast::NameRef(name_ref) => {
 211                 if node.ancestors().any(|it| it.kind() == ATTR) {
 212
 213                     // FIXME: We highlight paths in attributes slightly differently to work around this module
 214                     // currently not knowing about tool attributes and rustc builtin attributes as
 215                     // we do not want to resolve those to functions that may be defined in scope.
 216                     highlight_name_ref_in_attr(sema, name_ref)
 217                 } else {
 218                     highlight_name_ref(
 219                         sema,
 220                         krate,
 221                         bindings_shadow_count,
 222                         &mut binding_hash,
 223                         syntactic_name_ref_highlighting,
 224                         name_ref,
 225                     )
 226                 }
 227             },
 228             ast::Lifetime(lifetime) => {
 229                 match NameClass::classify_lifetime(sema, &lifetime) {
 230                     Some(NameClass::Definition(def)) => {
 231                         highlight_def(sema, krate, def) | HlMod::Definition
 232                     }
 233                     None => match NameRefClass::classify_lifetime(sema, &lifetime) {
 234                         Some(NameRefClass::Definition(def)) => highlight_def(sema, krate, def),
 235                         _ => SymbolKind::LifetimeParam.into(),
 236                     },
 237                     _ => Highlight::from(SymbolKind::LifetimeParam) | HlMod::Definition,
 238                 }
 239             },
 240             _ => return None,
 241         }
 242     };
 243     Some((highlight, binding_hash))
 244 }
 245
 246 fn highlight_name_ref_in_attr(sema: &Semantics<RootDatabase>, name_ref: ast::NameRef) -> Highlight {
 247     match NameRefClass::classify(sema, &name_ref) {
 248         Some(name_class) => match name_class {
 249             NameRefClass::Definition(Definition::Module(_))
 250                 if name_ref
 251                     .syntax()
 252                     .ancestors()
 253                     .find_map(ast::Path::cast)
 254                     .map_or(false, |it| it.parent_path().is_some()) =>
 255             {
 256                 HlTag::Symbol(SymbolKind::Module)
 257             }
 258             NameRefClass::Definition(Definition::Macro(m)) if m.kind() == hir::MacroKind::Attr => {
 259                 HlTag::Symbol(SymbolKind::Macro)
 260             }
 261             _ => HlTag::BuiltinAttr,
 262         },
 263         None => HlTag::BuiltinAttr,
 264     }
 265     .into()
 266 }
 267
 268 fn highlight_name_ref(
 269     sema: &Semantics<RootDatabase>,
 270     krate: Option<hir::Crate>,
 271     bindings_shadow_count: &mut FxHashMap<hir::Name, u32>,
 272     binding_hash: &mut Option<u64>,
 273     syntactic_name_ref_highlighting: bool,
 274     name_ref: ast::NameRef,
 275 ) -> Highlight {
 276     let db = sema.db;
 277     highlight_method_call_by_name_ref(sema, krate, &name_ref).unwrap_or_else(|| {
 278         let name_class = match NameRefClass::classify(sema, &name_ref) {
 279             Some(name_kind) => name_kind,
 280             None => {
 281                 return if syntactic_name_ref_highlighting {
 282                     highlight_name_ref_by_syntax(name_ref, sema, krate)
 283                 } else {
 284                     // Some popular proc macros (namely async_trait) will rewrite `self` in such a way that it no
 285                     // longer resolves via NameRefClass. If we can't be resolved, but we know we're a self token,
 286                     // within a function with a self param, pretend to still be `self`, rather than
 287                     // an unresolved reference.
 288                     if name_ref.self_token().is_some() && is_in_fn_with_self_param(&name_ref) {
 289                         SymbolKind::SelfParam.into()
 290                     } else {
 291                         HlTag::UnresolvedReference.into()
 292                     }
 293                 };
 294             }
 295         };
 296         let mut h = match name_class {
 297             NameRefClass::Definition(def) => {
 298                 if let Definition::Local(local) = &def {
 299                     if let Some(name) = local.name(db) {
 300                         let shadow_count = bindings_shadow_count.entry(name.clone()).or_default();
 301                         *binding_hash = Some(calc_binding_hash(&name, *shadow_count))
 302                     }
 303                 };
 304
 305                 let mut h = highlight_def(sema, krate, def);
 306
 307                 match def {
 308                     Definition::Local(local)
 309                         if is_consumed_lvalue(name_ref.syntax(), &local, db) =>
 310                     {
 311                         h |= HlMod::Consuming;
 312                     }
 313                     Definition::Trait(trait_) if trait_.is_unsafe(db) => {
 314                         if ast::Impl::for_trait_name_ref(&name_ref)
 315                             .map_or(false, |impl_| impl_.unsafe_token().is_some())
 316                         {
 317                             h |= HlMod::Unsafe;
 318                         }
 319                     }
 320                     Definition::Field(field) => {
 321                         if let Some(parent) = name_ref.syntax().parent() {
 322                             if matches!(parent.kind(), FIELD_EXPR | RECORD_PAT_FIELD) {
 323                                 if let hir::VariantDef::Union(_) = field.parent_def(db) {
 324                                     h |= HlMod::Unsafe;
 325                                 }
 326                             }
 327                         }
 328                     }
 329                     _ => (),
 330                 }
 331
 332                 h
 333             }
 334             NameRefClass::FieldShorthand { .. } => SymbolKind::Field.into(),
 335         };
 336         if h.tag == HlTag::Symbol(SymbolKind::Module) {
 337             if name_ref.self_token().is_some() {
 338                 return SymbolKind::SelfParam.into();
 339             }
 340             if name_ref.crate_token().is_some() || name_ref.super_token().is_some() {
 341                 h.tag = HlTag::Keyword;
 342             }
 343         }
 344         h
 345     })
 346 }
 347
 348 fn highlight_name(
 349     sema: &Semantics<RootDatabase>,
 350     bindings_shadow_count: &mut FxHashMap<hir::Name, u32>,
 351     binding_hash: &mut Option<u64>,
 352     krate: Option<hir::Crate>,
 353     name: ast::Name,
 354 ) -> Highlight {
 355     let db = sema.db;
 356     let name_kind = NameClass::classify(sema, &name);
 357     if let Some(NameClass::Definition(Definition::Local(local))) = &name_kind {
 358         if let Some(name) = local.name(db) {
 359             let shadow_count = bindings_shadow_count.entry(name.clone()).or_default();
 360             *shadow_count += 1;
 361             *binding_hash = Some(calc_binding_hash(&name, *shadow_count))
 362         }
 363     };
 364     match name_kind {
 365         Some(NameClass::Definition(def)) => {
 366             let mut h = highlight_def(sema, krate, def) | HlMod::Definition;
 367             if let Definition::Trait(trait_) = &def {
 368                 if trait_.is_unsafe(db) {
 369                     h |= HlMod::Unsafe;
 370                 }
 371             }
 372             h
 373         }
 374         Some(NameClass::ConstReference(def)) => highlight_def(sema, krate, def),
 375         Some(NameClass::PatFieldShorthand { field_ref, .. }) => {
 376             let mut h = HlTag::Symbol(SymbolKind::Field).into();
 377             if let hir::VariantDef::Union(_) = field_ref.parent_def(db) {
 378                 h |= HlMod::Unsafe;
 379             }
 380             h
 381         }
 382         None => highlight_name_by_syntax(name) | HlMod::Definition,
 383     }
 384 }
 385
 386 fn calc_binding_hash(name: &hir::Name, shadow_count: u32) -> u64 {
 387     fn hash<T: std::hash::Hash + std::fmt::Debug>(x: T) -> u64 {
 388         use std::{collections::hash_map::DefaultHasher, hash::Hasher};
 389
 390         let mut hasher = DefaultHasher::new();
 391         x.hash(&mut hasher);
 392         hasher.finish()
 393     }
 394
 395     hash((name, shadow_count))
 396 }
 397
 398 fn highlight_def(
 399     sema: &Semantics<RootDatabase>,
 400     krate: Option<hir::Crate>,
 401     def: Definition,
 402 ) -> Highlight {
 403     let db = sema.db;
 404     let mut h = match def {
 405         Definition::Macro(_) => Highlight::new(HlTag::Symbol(SymbolKind::Macro)),
 406         Definition::Field(_) => Highlight::new(HlTag::Symbol(SymbolKind::Field)),
 407         Definition::Module(module) => {
 408             let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Module));
 409             if module.parent(db).is_none() {
 410                 h |= HlMod::CrateRoot
 411             }
 412             h
 413         }
 414         Definition::Function(func) => {
 415             let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Function));
 416             if let Some(item) = func.as_assoc_item(db) {
 417                 h |= HlMod::Associated;
 418                 match func.self_param(db) {
 419                     Some(sp) => match sp.access(db) {
 420                         hir::Access::Exclusive => {
 421                             h |= HlMod::Mutable;
 422                             h |= HlMod::Reference;
 423                         }
 424                         hir::Access::Shared => h |= HlMod::Reference,
 425                         hir::Access::Owned => h |= HlMod::Consuming,
 426                     },
 427                     None => h |= HlMod::Static,
 428                 }
 429
 430                 match item.container(db) {
 431                     hir::AssocItemContainer::Impl(i) => {
 432                         if i.trait_(db).is_some() {
 433                             h |= HlMod::Trait;
 434                         }
 435                     }
 436                     hir::AssocItemContainer::Trait(_t) => {
 437                         h |= HlMod::Trait;
 438                     }
 439                 }
 440             }
 441
 442             if func.is_unsafe(db) {
 443                 h |= HlMod::Unsafe;
 444             }
 445             if func.is_async(db) {
 446                 h |= HlMod::Async;
 447             }
 448
 449             h
 450         }
 451         Definition::Adt(adt) => {
 452             let h = match adt {
 453                 hir::Adt::Struct(_) => HlTag::Symbol(SymbolKind::Struct),
 454                 hir::Adt::Enum(_) => HlTag::Symbol(SymbolKind::Enum),
 455                 hir::Adt::Union(_) => HlTag::Symbol(SymbolKind::Union),
 456             };
 457
 458             Highlight::new(h)
 459         }
 460         Definition::Variant(_) => Highlight::new(HlTag::Symbol(SymbolKind::Variant)),
 461         Definition::Const(konst) => {
 462             let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Const));
 463
 464             if let Some(item) = konst.as_assoc_item(db) {
 465                 h |= HlMod::Associated;
 466                 match item.container(db) {
 467                     hir::AssocItemContainer::Impl(i) => {
 468                         if i.trait_(db).is_some() {
 469                             h |= HlMod::Trait;
 470                         }
 471                     }
 472                     hir::AssocItemContainer::Trait(_t) => {
 473                         h |= HlMod::Trait;
 474                     }
 475                 }
 476             }
 477
 478             h
 479         }
 480         Definition::Trait(_) => Highlight::new(HlTag::Symbol(SymbolKind::Trait)),
 481         Definition::TypeAlias(type_) => {
 482             let mut h = Highlight::new(HlTag::Symbol(SymbolKind::TypeAlias));
 483
 484             if let Some(item) = type_.as_assoc_item(db) {
 485                 h |= HlMod::Associated;
 486                 match item.container(db) {
 487                     hir::AssocItemContainer::Impl(i) => {
 488                         if i.trait_(db).is_some() {
 489                             h |= HlMod::Trait;
 490                         }
 491                     }
 492                     hir::AssocItemContainer::Trait(_t) => {
 493                         h |= HlMod::Trait;
 494                     }
 495                 }
 496             }
 497
 498             h
 499         }
 500         Definition::BuiltinType(_) => Highlight::new(HlTag::BuiltinType),
 501         Definition::Static(s) => {
 502             let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Static));
 503
 504             if s.is_mut(db) {
 505                 h |= HlMod::Mutable;
 506                 h |= HlMod::Unsafe;
 507             }
 508
 509             h
 510         }
 511         Definition::SelfType(_) => Highlight::new(HlTag::Symbol(SymbolKind::Impl)),
 512         Definition::GenericParam(it) => match it {
 513             hir::GenericParam::TypeParam(_) => Highlight::new(HlTag::Symbol(SymbolKind::TypeParam)),
 514             hir::GenericParam::ConstParam(_) => {
 515                 Highlight::new(HlTag::Symbol(SymbolKind::ConstParam))
 516             }
 517             hir::GenericParam::LifetimeParam(_) => {
 518                 Highlight::new(HlTag::Symbol(SymbolKind::LifetimeParam))
 519             }
 520         },
 521         Definition::Local(local) => {
 522             let tag = if local.is_self(db) {
 523                 HlTag::Symbol(SymbolKind::SelfParam)
 524             } else if local.is_param(db) {
 525                 HlTag::Symbol(SymbolKind::ValueParam)
 526             } else {
 527                 HlTag::Symbol(SymbolKind::Local)
 528             };
 529             let mut h = Highlight::new(tag);
 530             let ty = local.ty(db);
 531             if local.is_mut(db) || ty.is_mutable_reference() {
 532                 h |= HlMod::Mutable;
 533             }
 534             if local.is_ref(db) || ty.is_reference() {
 535                 h |= HlMod::Reference;
 536             }
 537             if ty.as_callable(db).is_some() || ty.impls_fnonce(db) {
 538                 h |= HlMod::Callable;
 539             }
 540             h
 541         }
 542         Definition::Label(_) => Highlight::new(HlTag::Symbol(SymbolKind::Label)),
 543     };
 544
 545     let famous_defs = FamousDefs(sema, krate);
 546     let def_crate = def.module(db).map(hir::Module::krate).or_else(|| match def {
 547         Definition::Module(module) => Some(module.krate()),
 548         _ => None,
 549     });
 550     let is_from_other_crate = def_crate != krate;
 551     let is_from_builtin_crate =
 552         def_crate.map_or(false, |def_crate| famous_defs.builtin_crates().any(|it| def_crate == it));
 553     let is_builtin_type = matches!(def, Definition::BuiltinType(_));
 554     let is_public = def.visibility(db) == Some(hir::Visibility::Public);
 555
 556     match (is_from_other_crate, is_builtin_type, is_public) {
 557         (true, false, _) => h |= HlMod::Library,
 558         (false, _, true) => h |= HlMod::Public,
 559         _ => {}
 560     }
 561
 562     if is_from_builtin_crate {
 563         h |= HlMod::DefaultLibrary;
 564     }
 565
 566     h
 567 }
 568
 569 fn highlight_method_call_by_name_ref(
 570     sema: &Semantics<RootDatabase>,
 571     krate: Option<hir::Crate>,
 572     name_ref: &ast::NameRef,
 573 ) -> Option<Highlight> {
 574     let mc = name_ref.syntax().parent().and_then(ast::MethodCallExpr::cast)?;
 575     highlight_method_call(sema, krate, &mc)
 576 }
 577
 578 fn highlight_method_call(
 579     sema: &Semantics<RootDatabase>,
 580     krate: Option<hir::Crate>,
 581     method_call: &ast::MethodCallExpr,
 582 ) -> Option<Highlight> {
 583     let func = sema.resolve_method_call(method_call)?;
 584
 585     let mut h = SymbolKind::Function.into();
 586     h |= HlMod::Associated;
 587
 588     if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(method_call) {
 589         h |= HlMod::Unsafe;
 590     }
 591     if func.is_async(sema.db) {
 592         h |= HlMod::Async;
 593     }
 594     if func.as_assoc_item(sema.db).and_then(|it| it.containing_trait(sema.db)).is_some() {
 595         h |= HlMod::Trait;
 596     }
 597
 598     let famous_defs = FamousDefs(sema, krate);
 599     let def_crate = func.module(sema.db).krate();
 600     let is_from_other_crate = Some(def_crate) != krate;
 601     let is_from_builtin_crate = famous_defs.builtin_crates().any(|it| def_crate == it);
 602     let is_public = func.visibility(sema.db) == hir::Visibility::Public;
 603
 604     if is_from_other_crate {
 605         h |= HlMod::Library;
 606     } else if is_public {
 607         h |= HlMod::Public;
 608     }
 609
 610     if is_from_builtin_crate {
 611         h |= HlMod::DefaultLibrary;
 612     }
 613
 614     if let Some(self_param) = func.self_param(sema.db) {
 615         match self_param.access(sema.db) {
 616             hir::Access::Shared => h |= HlMod::Reference,
 617             hir::Access::Exclusive => {
 618                 h |= HlMod::Mutable;
 619                 h |= HlMod::Reference;
 620             }
 621             hir::Access::Owned => {
 622                 if let Some(receiver_ty) =
 623                     method_call.receiver().and_then(|it| sema.type_of_expr(&it))
 624                 {
 625                     if !receiver_ty.adjusted().is_copy(sema.db) {
 626                         h |= HlMod::Consuming
 627                     }
 628                 }
 629             }
 630         }
 631     }
 632     Some(h)
 633 }
 634
 635 fn highlight_name_by_syntax(name: ast::Name) -> Highlight {
 636     let default = HlTag::UnresolvedReference;
 637
 638     let parent = match name.syntax().parent() {
 639         Some(it) => it,
 640         _ => return default.into(),
 641     };
 642
 643     let tag = match parent.kind() {
 644         STRUCT => SymbolKind::Struct,
 645         ENUM => SymbolKind::Enum,
 646         VARIANT => SymbolKind::Variant,
 647         UNION => SymbolKind::Union,
 648         TRAIT => SymbolKind::Trait,
 649         TYPE_ALIAS => SymbolKind::TypeAlias,
 650         TYPE_PARAM => SymbolKind::TypeParam,
 651         RECORD_FIELD => SymbolKind::Field,
 652         MODULE => SymbolKind::Module,
 653         FN => SymbolKind::Function,
 654         CONST => SymbolKind::Const,
 655         STATIC => SymbolKind::Static,
 656         IDENT_PAT => SymbolKind::Local,
 657         _ => return default.into(),
 658     };
 659
 660     tag.into()
 661 }
 662
 663 fn highlight_name_ref_by_syntax(
 664     name: ast::NameRef,
 665     sema: &Semantics<RootDatabase>,
 666     krate: Option<hir::Crate>,
 667 ) -> Highlight {
 668     let default = HlTag::UnresolvedReference;
 669
 670     let parent = match name.syntax().parent() {
 671         Some(it) => it,
 672         _ => return default.into(),
 673     };
 674
 675     match parent.kind() {
 676         METHOD_CALL_EXPR => ast::MethodCallExpr::cast(parent)
 677             .and_then(|it| highlight_method_call(sema, krate, &it))
 678             .unwrap_or_else(|| SymbolKind::Function.into()),
 679         FIELD_EXPR => {
 680             let h = HlTag::Symbol(SymbolKind::Field);
 681             let is_union = ast::FieldExpr::cast(parent)
 682                 .and_then(|field_expr| sema.resolve_field(&field_expr))
 683                 .map_or(false, |field| {
 684                     matches!(field.parent_def(sema.db), hir::VariantDef::Union(_))
 685                 });
 686             if is_union {
 687                 h | HlMod::Unsafe
 688             } else {
 689                 h.into()
 690             }
 691         }
 692         PATH_SEGMENT => {
 693             let path = match parent.parent().and_then(ast::Path::cast) {
 694                 Some(it) => it,
 695                 _ => return default.into(),
 696             };
 697             let expr = match path.syntax().parent().and_then(ast::PathExpr::cast) {
 698                 Some(it) => it,
 699                 _ => {
 700                     // within path, decide whether it is module or adt by checking for uppercase name
 701                     return if name.text().chars().next().unwrap_or_default().is_uppercase() {
 702                         SymbolKind::Struct
 703                     } else {
 704                         SymbolKind::Module
 705                     }
 706                     .into();
 707                 }
 708             };
 709             let parent = match expr.syntax().parent() {
 710                 Some(it) => it,
 711                 None => return default.into(),
 712             };
 713
 714             match parent.kind() {
 715                 CALL_EXPR => SymbolKind::Function.into(),
 716                 _ => if name.text().chars().next().unwrap_or_default().is_uppercase() {
 717                     SymbolKind::Struct
 718                 } else {
 719                     SymbolKind::Const
 720                 }
 721                 .into(),
 722             }
 723         }
 724         _ => default.into(),
 725     }
 726 }
 727
 728 fn is_consumed_lvalue(node: &SyntaxNode, local: &hir::Local, db: &RootDatabase) -> bool {
 729     // When lvalues are passed as arguments and they're not Copy, then mark them as Consuming.
 730     parents_match(node.clone().into(), &[PATH_SEGMENT, PATH, PATH_EXPR, ARG_LIST])
 731         && !local.ty(db).is_copy(db)
 732 }
 733
 734 /// Returns true if the parent nodes of `node` all match the `SyntaxKind`s in `kinds` exactly.
 735 fn parents_match(mut node: NodeOrToken<SyntaxNode, SyntaxToken>, mut kinds: &[SyntaxKind]) -> bool {
 736     while let (Some(parent), [kind, rest @ ..]) = (&node.parent(), kinds) {
 737         if parent.kind() != *kind {
 738             return false;
 739         }
 740
 741         // FIXME: Would be nice to get parent out of the match, but binding by-move and by-value
 742         // in the same pattern is unstable: rust-lang/rust#68354.
 743         node = node.parent().unwrap().into();
 744         kinds = rest;
 745     }
 746
 747     // Only true if we matched all expected kinds
 748     kinds.is_empty()
 749 }
 750
 751 #[inline]
 752 fn parent_matches<N: AstNode>(token: &SyntaxToken) -> bool {
 753     token.parent().map_or(false, |it| N::can_cast(it.kind()))
 754 }
 755
 756 fn is_child_of_impl(token: &SyntaxToken) -> bool {
 757     match token.parent() {
 758         Some(e) => e.kind() == IMPL,
 759         _ => false,
 760     }
 761 }
 762
 763 fn is_in_fn_with_self_param<N: AstNode>(node: &N) -> bool {
 764     node.syntax()
 765         .ancestors()
 766         .find_map(ast::Fn::cast)
 767         .and_then(|s| s.param_list()?.self_param())
 768         .is_some()
 769 }