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