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::AttributeBracket.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::AttributeBracket.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                 highlight_name_ref(
 212                     sema,
 213                     krate,
 214                     bindings_shadow_count,
 215                     &mut binding_hash,
 216                     syntactic_name_ref_highlighting,
 217                     name_ref,
 218                 )
 219             },
 220             ast::Lifetime(lifetime) => {
 221                 match NameClass::classify_lifetime(sema, &lifetime) {
 222                     Some(NameClass::Definition(def)) => {
 223                         highlight_def(sema, krate, def) | HlMod::Definition
 224                     }
 225                     None => match NameRefClass::classify_lifetime(sema, &lifetime) {
 226                         Some(NameRefClass::Definition(def)) => highlight_def(sema, krate, def),
 227                         _ => SymbolKind::LifetimeParam.into(),
 228                     },
 229                     _ => Highlight::from(SymbolKind::LifetimeParam) | HlMod::Definition,
 230                 }
 231             },
 232             _ => return None,
 233         }
 234     };
 235     Some((highlight, binding_hash))
 236 }
 237
 238 fn highlight_name_ref(
 239     sema: &Semantics<RootDatabase>,
 240     krate: Option<hir::Crate>,
 241     bindings_shadow_count: &mut FxHashMap<hir::Name, u32>,
 242     binding_hash: &mut Option<u64>,
 243     syntactic_name_ref_highlighting: bool,
 244     name_ref: ast::NameRef,
 245 ) -> Highlight {
 246     let db = sema.db;
 247     if let Some(res) = highlight_method_call_by_name_ref(sema, krate, &name_ref) {
 248         return res;
 249     }
 250
 251     let name_class = match NameRefClass::classify(sema, &name_ref) {
 252         Some(name_kind) => name_kind,
 253         None if syntactic_name_ref_highlighting => {
 254             return highlight_name_ref_by_syntax(name_ref, sema, krate)
 255         }
 256         // FIXME: Workaround for https://github.com/rust-analyzer/rust-analyzer/issues/10708
 257         //
 258         // Some popular proc macros (namely async_trait) will rewrite `self` in such a way that it no
 259         // longer resolves via NameRefClass. If we can't be resolved, but we know we're a self token,
 260         // within a function with a self param, pretend to still be `self`, rather than
 261         // an unresolved reference.
 262         None if name_ref.self_token().is_some() && is_in_fn_with_self_param(&name_ref) => {
 263             return SymbolKind::SelfParam.into()
 264         }
 265         // FIXME: This is required for helper attributes used by proc-macros, as those do not map down
 266         // to anything when used.
 267         // We can fix this for derive attributes since derive helpers are recorded, but not for
 268         // general attributes.
 269         None if name_ref.syntax().ancestors().any(|it| it.kind() == ATTR) => {
 270             return HlTag::Symbol(SymbolKind::Attribute).into();
 271         }
 272         None => return HlTag::UnresolvedReference.into(),
 273     };
 274     let mut h = match name_class {
 275         NameRefClass::Definition(def) => {
 276             if let Definition::Local(local) = &def {
 277                 if let Some(name) = local.name(db) {
 278                     let shadow_count = bindings_shadow_count.entry(name.clone()).or_default();
 279                     *binding_hash = Some(calc_binding_hash(&name, *shadow_count))
 280                 }
 281             };
 282
 283             let mut h = highlight_def(sema, krate, def);
 284
 285             match def {
 286                 Definition::Local(local) if is_consumed_lvalue(name_ref.syntax(), &local, db) => {
 287                     h |= HlMod::Consuming;
 288                 }
 289                 Definition::Trait(trait_) if trait_.is_unsafe(db) => {
 290                     if ast::Impl::for_trait_name_ref(&name_ref)
 291                         .map_or(false, |impl_| impl_.unsafe_token().is_some())
 292                     {
 293                         h |= HlMod::Unsafe;
 294                     }
 295                 }
 296                 Definition::Field(field) => {
 297                     if let Some(parent) = name_ref.syntax().parent() {
 298                         if matches!(parent.kind(), FIELD_EXPR | RECORD_PAT_FIELD) {
 299                             if let hir::VariantDef::Union(_) = field.parent_def(db) {
 300                                 h |= HlMod::Unsafe;
 301                             }
 302                         }
 303                     }
 304                 }
 305                 _ => (),
 306             }
 307
 308             h
 309         }
 310         NameRefClass::FieldShorthand { .. } => SymbolKind::Field.into(),
 311     };
 312     if name_ref.self_token().is_some() {
 313         h.tag = HlTag::Symbol(SymbolKind::SelfParam);
 314     }
 315     if name_ref.crate_token().is_some() || name_ref.super_token().is_some() {
 316         h.tag = HlTag::Keyword;
 317     }
 318     h
 319 }
 320
 321 fn highlight_name(
 322     sema: &Semantics<RootDatabase>,
 323     bindings_shadow_count: &mut FxHashMap<hir::Name, u32>,
 324     binding_hash: &mut Option<u64>,
 325     krate: Option<hir::Crate>,
 326     name: ast::Name,
 327 ) -> Highlight {
 328     let db = sema.db;
 329     let name_kind = NameClass::classify(sema, &name);
 330     if let Some(NameClass::Definition(Definition::Local(local))) = &name_kind {
 331         if let Some(name) = local.name(db) {
 332             let shadow_count = bindings_shadow_count.entry(name.clone()).or_default();
 333             *shadow_count += 1;
 334             *binding_hash = Some(calc_binding_hash(&name, *shadow_count))
 335         }
 336     };
 337     match name_kind {
 338         Some(NameClass::Definition(def)) => {
 339             let mut h = highlight_def(sema, krate, def) | HlMod::Definition;
 340             if let Definition::Trait(trait_) = &def {
 341                 if trait_.is_unsafe(db) {
 342                     h |= HlMod::Unsafe;
 343                 }
 344             }
 345             h
 346         }
 347         Some(NameClass::ConstReference(def)) => highlight_def(sema, krate, def),
 348         Some(NameClass::PatFieldShorthand { field_ref, .. }) => {
 349             let mut h = HlTag::Symbol(SymbolKind::Field).into();
 350             if let hir::VariantDef::Union(_) = field_ref.parent_def(db) {
 351                 h |= HlMod::Unsafe;
 352             }
 353             h
 354         }
 355         None => highlight_name_by_syntax(name) | HlMod::Definition,
 356     }
 357 }
 358
 359 fn calc_binding_hash(name: &hir::Name, shadow_count: u32) -> u64 {
 360     fn hash<T: std::hash::Hash + std::fmt::Debug>(x: T) -> u64 {
 361         use std::{collections::hash_map::DefaultHasher, hash::Hasher};
 362
 363         let mut hasher = DefaultHasher::new();
 364         x.hash(&mut hasher);
 365         hasher.finish()
 366     }
 367
 368     hash((name, shadow_count))
 369 }
 370
 371 fn highlight_def(
 372     sema: &Semantics<RootDatabase>,
 373     krate: Option<hir::Crate>,
 374     def: Definition,
 375 ) -> Highlight {
 376     let db = sema.db;
 377     let mut h = match def {
 378         Definition::Macro(m) => Highlight::new(HlTag::Symbol(match m.kind() {
 379             hir::MacroKind::Declarative | hir::MacroKind::BuiltIn | hir::MacroKind::ProcMacro => {
 380                 SymbolKind::Macro
 381             }
 382             hir::MacroKind::Derive => SymbolKind::Derive,
 383             hir::MacroKind::Attr => SymbolKind::Attribute,
 384         })),
 385         Definition::Field(_) => Highlight::new(HlTag::Symbol(SymbolKind::Field)),
 386         Definition::Module(module) => {
 387             let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Module));
 388             if module.parent(db).is_none() {
 389                 h |= HlMod::CrateRoot
 390             }
 391             h
 392         }
 393         Definition::Function(func) => {
 394             let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Function));
 395             if let Some(item) = func.as_assoc_item(db) {
 396                 h |= HlMod::Associated;
 397                 match func.self_param(db) {
 398                     Some(sp) => match sp.access(db) {
 399                         hir::Access::Exclusive => {
 400                             h |= HlMod::Mutable;
 401                             h |= HlMod::Reference;
 402                         }
 403                         hir::Access::Shared => h |= HlMod::Reference,
 404                         hir::Access::Owned => h |= HlMod::Consuming,
 405                     },
 406                     None => h |= HlMod::Static,
 407                 }
 408
 409                 match item.container(db) {
 410                     hir::AssocItemContainer::Impl(i) => {
 411                         if i.trait_(db).is_some() {
 412                             h |= HlMod::Trait;
 413                         }
 414                     }
 415                     hir::AssocItemContainer::Trait(_t) => {
 416                         h |= HlMod::Trait;
 417                     }
 418                 }
 419             }
 420
 421             if func.is_unsafe(db) {
 422                 h |= HlMod::Unsafe;
 423             }
 424             if func.is_async(db) {
 425                 h |= HlMod::Async;
 426             }
 427
 428             h
 429         }
 430         Definition::Adt(adt) => {
 431             let h = match adt {
 432                 hir::Adt::Struct(_) => HlTag::Symbol(SymbolKind::Struct),
 433                 hir::Adt::Enum(_) => HlTag::Symbol(SymbolKind::Enum),
 434                 hir::Adt::Union(_) => HlTag::Symbol(SymbolKind::Union),
 435             };
 436
 437             Highlight::new(h)
 438         }
 439         Definition::Variant(_) => Highlight::new(HlTag::Symbol(SymbolKind::Variant)),
 440         Definition::Const(konst) => {
 441             let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Const));
 442
 443             if let Some(item) = konst.as_assoc_item(db) {
 444                 h |= HlMod::Associated;
 445                 match item.container(db) {
 446                     hir::AssocItemContainer::Impl(i) => {
 447                         if i.trait_(db).is_some() {
 448                             h |= HlMod::Trait;
 449                         }
 450                     }
 451                     hir::AssocItemContainer::Trait(_t) => {
 452                         h |= HlMod::Trait;
 453                     }
 454                 }
 455             }
 456
 457             h
 458         }
 459         Definition::Trait(_) => Highlight::new(HlTag::Symbol(SymbolKind::Trait)),
 460         Definition::TypeAlias(type_) => {
 461             let mut h = Highlight::new(HlTag::Symbol(SymbolKind::TypeAlias));
 462
 463             if let Some(item) = type_.as_assoc_item(db) {
 464                 h |= HlMod::Associated;
 465                 match item.container(db) {
 466                     hir::AssocItemContainer::Impl(i) => {
 467                         if i.trait_(db).is_some() {
 468                             h |= HlMod::Trait;
 469                         }
 470                     }
 471                     hir::AssocItemContainer::Trait(_t) => {
 472                         h |= HlMod::Trait;
 473                     }
 474                 }
 475             }
 476
 477             h
 478         }
 479         Definition::BuiltinType(_) => Highlight::new(HlTag::BuiltinType),
 480         Definition::Static(s) => {
 481             let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Static));
 482
 483             if s.is_mut(db) {
 484                 h |= HlMod::Mutable;
 485                 h |= HlMod::Unsafe;
 486             }
 487
 488             h
 489         }
 490         Definition::SelfType(_) => Highlight::new(HlTag::Symbol(SymbolKind::Impl)),
 491         Definition::GenericParam(it) => match it {
 492             hir::GenericParam::TypeParam(_) => Highlight::new(HlTag::Symbol(SymbolKind::TypeParam)),
 493             hir::GenericParam::ConstParam(_) => {
 494                 Highlight::new(HlTag::Symbol(SymbolKind::ConstParam))
 495             }
 496             hir::GenericParam::LifetimeParam(_) => {
 497                 Highlight::new(HlTag::Symbol(SymbolKind::LifetimeParam))
 498             }
 499         },
 500         Definition::Local(local) => {
 501             let tag = if local.is_self(db) {
 502                 HlTag::Symbol(SymbolKind::SelfParam)
 503             } else if local.is_param(db) {
 504                 HlTag::Symbol(SymbolKind::ValueParam)
 505             } else {
 506                 HlTag::Symbol(SymbolKind::Local)
 507             };
 508             let mut h = Highlight::new(tag);
 509             let ty = local.ty(db);
 510             if local.is_mut(db) || ty.is_mutable_reference() {
 511                 h |= HlMod::Mutable;
 512             }
 513             if local.is_ref(db) || ty.is_reference() {
 514                 h |= HlMod::Reference;
 515             }
 516             if ty.as_callable(db).is_some() || ty.impls_fnonce(db) {
 517                 h |= HlMod::Callable;
 518             }
 519             h
 520         }
 521         Definition::Label(_) => Highlight::new(HlTag::Symbol(SymbolKind::Label)),
 522         Definition::BuiltinAttr(_) => Highlight::new(HlTag::Symbol(SymbolKind::BuiltinAttr)),
 523         Definition::ToolModule(_) => Highlight::new(HlTag::Symbol(SymbolKind::ToolModule)),
 524     };
 525
 526     let famous_defs = FamousDefs(sema, krate);
 527     let def_crate = def.module(db).map(hir::Module::krate).or_else(|| match def {
 528         Definition::Module(module) => Some(module.krate()),
 529         _ => None,
 530     });
 531     let is_from_other_crate = def_crate != krate;
 532     let is_from_builtin_crate =
 533         def_crate.map_or(false, |def_crate| famous_defs.builtin_crates().any(|it| def_crate == it));
 534     let is_builtin_type = matches!(def, Definition::BuiltinType(_));
 535     let is_public = def.visibility(db) == Some(hir::Visibility::Public);
 536
 537     match (is_from_other_crate, is_builtin_type, is_public) {
 538         (true, false, _) => h |= HlMod::Library,
 539         (false, _, true) => h |= HlMod::Public,
 540         _ => {}
 541     }
 542
 543     if is_from_builtin_crate {
 544         h |= HlMod::DefaultLibrary;
 545     }
 546
 547     h
 548 }
 549
 550 fn highlight_method_call_by_name_ref(
 551     sema: &Semantics<RootDatabase>,
 552     krate: Option<hir::Crate>,
 553     name_ref: &ast::NameRef,
 554 ) -> Option<Highlight> {
 555     let mc = name_ref.syntax().parent().and_then(ast::MethodCallExpr::cast)?;
 556     highlight_method_call(sema, krate, &mc)
 557 }
 558
 559 fn highlight_method_call(
 560     sema: &Semantics<RootDatabase>,
 561     krate: Option<hir::Crate>,
 562     method_call: &ast::MethodCallExpr,
 563 ) -> Option<Highlight> {
 564     let func = sema.resolve_method_call(method_call)?;
 565
 566     let mut h = SymbolKind::Function.into();
 567     h |= HlMod::Associated;
 568
 569     if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(method_call) {
 570         h |= HlMod::Unsafe;
 571     }
 572     if func.is_async(sema.db) {
 573         h |= HlMod::Async;
 574     }
 575     if func.as_assoc_item(sema.db).and_then(|it| it.containing_trait(sema.db)).is_some() {
 576         h |= HlMod::Trait;
 577     }
 578
 579     let famous_defs = FamousDefs(sema, krate);
 580     let def_crate = func.module(sema.db).krate();
 581     let is_from_other_crate = Some(def_crate) != krate;
 582     let is_from_builtin_crate = famous_defs.builtin_crates().any(|it| def_crate == it);
 583     let is_public = func.visibility(sema.db) == hir::Visibility::Public;
 584
 585     if is_from_other_crate {
 586         h |= HlMod::Library;
 587     } else if is_public {
 588         h |= HlMod::Public;
 589     }
 590
 591     if is_from_builtin_crate {
 592         h |= HlMod::DefaultLibrary;
 593     }
 594
 595     if let Some(self_param) = func.self_param(sema.db) {
 596         match self_param.access(sema.db) {
 597             hir::Access::Shared => h |= HlMod::Reference,
 598             hir::Access::Exclusive => {
 599                 h |= HlMod::Mutable;
 600                 h |= HlMod::Reference;
 601             }
 602             hir::Access::Owned => {
 603                 if let Some(receiver_ty) =
 604                     method_call.receiver().and_then(|it| sema.type_of_expr(&it))
 605                 {
 606                     if !receiver_ty.adjusted().is_copy(sema.db) {
 607                         h |= HlMod::Consuming
 608                     }
 609                 }
 610             }
 611         }
 612     }
 613     Some(h)
 614 }
 615
 616 fn highlight_name_by_syntax(name: ast::Name) -> Highlight {
 617     let default = HlTag::UnresolvedReference;
 618
 619     let parent = match name.syntax().parent() {
 620         Some(it) => it,
 621         _ => return default.into(),
 622     };
 623
 624     let tag = match parent.kind() {
 625         STRUCT => SymbolKind::Struct,
 626         ENUM => SymbolKind::Enum,
 627         VARIANT => SymbolKind::Variant,
 628         UNION => SymbolKind::Union,
 629         TRAIT => SymbolKind::Trait,
 630         TYPE_ALIAS => SymbolKind::TypeAlias,
 631         TYPE_PARAM => SymbolKind::TypeParam,
 632         RECORD_FIELD => SymbolKind::Field,
 633         MODULE => SymbolKind::Module,
 634         FN => SymbolKind::Function,
 635         CONST => SymbolKind::Const,
 636         STATIC => SymbolKind::Static,
 637         IDENT_PAT => SymbolKind::Local,
 638         _ => return default.into(),
 639     };
 640
 641     tag.into()
 642 }
 643
 644 fn highlight_name_ref_by_syntax(
 645     name: ast::NameRef,
 646     sema: &Semantics<RootDatabase>,
 647     krate: Option<hir::Crate>,
 648 ) -> Highlight {
 649     let default = HlTag::UnresolvedReference;
 650
 651     let parent = match name.syntax().parent() {
 652         Some(it) => it,
 653         _ => return default.into(),
 654     };
 655
 656     match parent.kind() {
 657         METHOD_CALL_EXPR => ast::MethodCallExpr::cast(parent)
 658             .and_then(|it| highlight_method_call(sema, krate, &it))
 659             .unwrap_or_else(|| SymbolKind::Function.into()),
 660         FIELD_EXPR => {
 661             let h = HlTag::Symbol(SymbolKind::Field);
 662             let is_union = ast::FieldExpr::cast(parent)
 663                 .and_then(|field_expr| sema.resolve_field(&field_expr))
 664                 .map_or(false, |field| {
 665                     matches!(field.parent_def(sema.db), hir::VariantDef::Union(_))
 666                 });
 667             if is_union {
 668                 h | HlMod::Unsafe
 669             } else {
 670                 h.into()
 671             }
 672         }
 673         PATH_SEGMENT => {
 674             let path = match parent.parent().and_then(ast::Path::cast) {
 675                 Some(it) => it,
 676                 _ => return default.into(),
 677             };
 678             let expr = match path.syntax().parent().and_then(ast::PathExpr::cast) {
 679                 Some(it) => it,
 680                 _ => {
 681                     // within path, decide whether it is module or adt by checking for uppercase name
 682                     return if name.text().chars().next().unwrap_or_default().is_uppercase() {
 683                         SymbolKind::Struct
 684                     } else {
 685                         SymbolKind::Module
 686                     }
 687                     .into();
 688                 }
 689             };
 690             let parent = match expr.syntax().parent() {
 691                 Some(it) => it,
 692                 None => return default.into(),
 693             };
 694
 695             match parent.kind() {
 696                 CALL_EXPR => SymbolKind::Function.into(),
 697                 _ => if name.text().chars().next().unwrap_or_default().is_uppercase() {
 698                     SymbolKind::Struct
 699                 } else {
 700                     SymbolKind::Const
 701                 }
 702                 .into(),
 703             }
 704         }
 705         _ => default.into(),
 706     }
 707 }
 708
 709 fn is_consumed_lvalue(node: &SyntaxNode, local: &hir::Local, db: &RootDatabase) -> bool {
 710     // When lvalues are passed as arguments and they're not Copy, then mark them as Consuming.
 711     parents_match(node.clone().into(), &[PATH_SEGMENT, PATH, PATH_EXPR, ARG_LIST])
 712         && !local.ty(db).is_copy(db)
 713 }
 714
 715 /// Returns true if the parent nodes of `node` all match the `SyntaxKind`s in `kinds` exactly.
 716 fn parents_match(mut node: NodeOrToken<SyntaxNode, SyntaxToken>, mut kinds: &[SyntaxKind]) -> bool {
 717     while let (Some(parent), [kind, rest @ ..]) = (&node.parent(), kinds) {
 718         if parent.kind() != *kind {
 719             return false;
 720         }
 721
 722         // FIXME: Would be nice to get parent out of the match, but binding by-move and by-value
 723         // in the same pattern is unstable: rust-lang/rust#68354.
 724         node = node.parent().unwrap().into();
 725         kinds = rest;
 726     }
 727
 728     // Only true if we matched all expected kinds
 729     kinds.is_empty()
 730 }
 731
 732 #[inline]
 733 fn parent_matches<N: AstNode>(token: &SyntaxToken) -> bool {
 734     token.parent().map_or(false, |it| N::can_cast(it.kind()))
 735 }
 736
 737 fn is_child_of_impl(token: &SyntaxToken) -> bool {
 738     match token.parent() {
 739         Some(e) => e.kind() == IMPL,
 740         _ => false,
 741     }
 742 }
 743
 744 fn is_in_fn_with_self_param<N: AstNode>(node: &N) -> bool {
 745     node.syntax()
 746         .ancestors()
 747         .find_map(ast::Fn::cast)
 748         .and_then(|s| s.param_list()?.self_param())
 749         .is_some()
 750 }