crates/ide/src/syntax_highlighting/highlight.rs

   1 //! Computes color for a single element.
   2
   3 use hir::{AsAssocItem, Semantics, VariantDef};
   4 use ide_db::{
   5     defs::{Definition, NameClass, NameRefClass},
   6     RootDatabase,
   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::{syntax_highlighting::tags::HlPunct, Highlight, HlMod, HlTag, SymbolKind};
  16
  17 pub(super) fn element(
  18     sema: &Semantics<RootDatabase>,
  19     bindings_shadow_count: &mut FxHashMap<hir::Name, u32>,
  20     syntactic_name_ref_highlighting: bool,
  21     element: SyntaxElement,
  22 ) -> Option<(Highlight, Option<u64>)> {
  23     let db = sema.db;
  24     let mut binding_hash = None;
  25     let highlight: Highlight = match element.kind() {
  26         FN => {
  27             bindings_shadow_count.clear();
  28             return None;
  29         }
  30
  31         // Highlight definitions depending on the "type" of the definition.
  32         NAME => {
  33             let name = element.into_node().and_then(ast::Name::cast).unwrap();
  34             let name_kind = NameClass::classify(sema, &name);
  35
  36             if let Some(NameClass::Definition(Definition::Local(local))) = &name_kind {
  37                 if let Some(name) = local.name(db) {
  38                     let shadow_count = bindings_shadow_count.entry(name.clone()).or_default();
  39                     *shadow_count += 1;
  40                     binding_hash = Some(calc_binding_hash(&name, *shadow_count))
  41                 }
  42             };
  43
  44             match name_kind {
  45                 Some(NameClass::ExternCrate(_)) => HlTag::Symbol(SymbolKind::Module).into(),
  46                 Some(NameClass::Definition(def)) => highlight_def(db, def) | HlMod::Definition,
  47                 Some(NameClass::ConstReference(def)) => highlight_def(db, def),
  48                 Some(NameClass::PatFieldShorthand { field_ref, .. }) => {
  49                     let mut h = HlTag::Symbol(SymbolKind::Field).into();
  50                     if let Definition::Field(field) = field_ref {
  51                         if let VariantDef::Union(_) = field.parent_def(db) {
  52                             h |= HlMod::Unsafe;
  53                         }
  54                     }
  55
  56                     h
  57                 }
  58                 None => highlight_name_by_syntax(name) | HlMod::Definition,
  59             }
  60         }
  61
  62         // Highlight references like the definitions they resolve to
  63         NAME_REF if element.ancestors().any(|it| it.kind() == ATTR) => {
  64             // even though we track whether we are in an attribute or not we still need this special case
  65             // as otherwise we would emit unresolved references for name refs inside attributes
  66             Highlight::from(HlTag::Symbol(SymbolKind::Function))
  67         }
  68         NAME_REF => {
  69             let name_ref = element.into_node().and_then(ast::NameRef::cast).unwrap();
  70             highlight_func_by_name_ref(sema, &name_ref).unwrap_or_else(|| {
  71                 match NameRefClass::classify(sema, &name_ref) {
  72                     Some(name_kind) => match name_kind {
  73                         NameRefClass::ExternCrate(_) => HlTag::Symbol(SymbolKind::Module).into(),
  74                         NameRefClass::Definition(def) => {
  75                             if let Definition::Local(local) = &def {
  76                                 if let Some(name) = local.name(db) {
  77                                     let shadow_count =
  78                                         bindings_shadow_count.entry(name.clone()).or_default();
  79                                     binding_hash = Some(calc_binding_hash(&name, *shadow_count))
  80                                 }
  81                             };
  82
  83                             let mut h = highlight_def(db, def);
  84
  85                             if let Definition::Local(local) = &def {
  86                                 if is_consumed_lvalue(name_ref.syntax().clone().into(), local, db) {
  87                                     h |= HlMod::Consuming;
  88                                 }
  89                             }
  90
  91                             if let Some(parent) = name_ref.syntax().parent() {
  92                                 if matches!(parent.kind(), FIELD_EXPR | RECORD_PAT_FIELD) {
  93                                     if let Definition::Field(field) = def {
  94                                         if let VariantDef::Union(_) = field.parent_def(db) {
  95                                             h |= HlMod::Unsafe;
  96                                         }
  97                                     }
  98                                 }
  99                             }
 100
 101                             h
 102                         }
 103                         NameRefClass::FieldShorthand { .. } => {
 104                             HlTag::Symbol(SymbolKind::Field).into()
 105                         }
 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             })
 113         }
 114
 115         // Simple token-based highlighting
 116         COMMENT => {
 117             let comment = element.into_token().and_then(ast::Comment::cast)?;
 118             let h = HlTag::Comment;
 119             match comment.kind().doc {
 120                 Some(_) => h | HlMod::Documentation,
 121                 None => h.into(),
 122             }
 123         }
 124         STRING | BYTE_STRING => HlTag::StringLiteral.into(),
 125         ATTR => HlTag::Attribute.into(),
 126         INT_NUMBER | FLOAT_NUMBER => HlTag::NumericLiteral.into(),
 127         BYTE => HlTag::ByteLiteral.into(),
 128         CHAR => HlTag::CharLiteral.into(),
 129         QUESTION => Highlight::new(HlTag::Operator) | HlMod::ControlFlow,
 130         LIFETIME => {
 131             let lifetime = element.into_node().and_then(ast::Lifetime::cast).unwrap();
 132
 133             match NameClass::classify_lifetime(sema, &lifetime) {
 134                 Some(NameClass::Definition(def)) => highlight_def(db, def) | HlMod::Definition,
 135                 None => match NameRefClass::classify_lifetime(sema, &lifetime) {
 136                     Some(NameRefClass::Definition(def)) => highlight_def(db, def),
 137                     _ => Highlight::new(HlTag::Symbol(SymbolKind::LifetimeParam)),
 138                 },
 139                 _ => Highlight::new(HlTag::Symbol(SymbolKind::LifetimeParam)) | HlMod::Definition,
 140             }
 141         }
 142         p if p.is_punct() => match p {
 143             T![&] => {
 144                 let h = HlTag::Operator.into();
 145                 let is_unsafe = element
 146                     .parent()
 147                     .and_then(ast::RefExpr::cast)
 148                     .map(|ref_expr| sema.is_unsafe_ref_expr(&ref_expr))
 149                     .unwrap_or(false);
 150                 if is_unsafe {
 151                     h | HlMod::Unsafe
 152                 } else {
 153                     h
 154                 }
 155             }
 156             T![::] | T![->] | T![=>] | T![..] | T![=] | T![@] | T![.] => HlTag::Operator.into(),
 157             T![!] if element.parent().and_then(ast::MacroCall::cast).is_some() => {
 158                 HlTag::Symbol(SymbolKind::Macro).into()
 159             }
 160             T![!] if element.parent().and_then(ast::NeverType::cast).is_some() => {
 161                 HlTag::BuiltinType.into()
 162             }
 163             T![*] if element.parent().and_then(ast::PtrType::cast).is_some() => {
 164                 HlTag::Keyword.into()
 165             }
 166             T![*] if element.parent().and_then(ast::PrefixExpr::cast).is_some() => {
 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 | HlMod::Unsafe
 173                 } else if let Some(ast::PrefixOp::Deref) = prefix_expr.op_kind() {
 174                     HlTag::Operator.into()
 175                 } else {
 176                     HlTag::Punctuation(HlPunct::Other).into()
 177                 }
 178             }
 179             T![-] if element.parent().and_then(ast::PrefixExpr::cast).is_some() => {
 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,
 186                 }
 187                 .into()
 188             }
 189             _ if element.parent().and_then(ast::PrefixExpr::cast).is_some() => {
 190                 HlTag::Operator.into()
 191             }
 192             _ if element.parent().and_then(ast::BinExpr::cast).is_some() => HlTag::Operator.into(),
 193             _ if element.parent().and_then(ast::RangeExpr::cast).is_some() => {
 194                 HlTag::Operator.into()
 195             }
 196             _ if element.parent().and_then(ast::RangePat::cast).is_some() => HlTag::Operator.into(),
 197             _ if element.parent().and_then(ast::RestPat::cast).is_some() => HlTag::Operator.into(),
 198             _ if element.parent().and_then(ast::Attr::cast).is_some() => HlTag::Attribute.into(),
 199             kind => HlTag::Punctuation(match kind {
 200                 T!['['] | T![']'] => HlPunct::Bracket,
 201                 T!['{'] | T!['}'] => HlPunct::Brace,
 202                 T!['('] | T![')'] => HlPunct::Parenthesis,
 203                 T![<] | T![>] => HlPunct::Angle,
 204                 T![,] => HlPunct::Comma,
 205                 T![:] => HlPunct::Colon,
 206                 T![;] => HlPunct::Semi,
 207                 T![.] => HlPunct::Dot,
 208                 _ => HlPunct::Other,
 209             })
 210             .into(),
 211         },
 212
 213         k if k.is_keyword() => {
 214             let h = Highlight::new(HlTag::Keyword);
 215             match k {
 216                 T![break]
 217                 | T![continue]
 218                 | T![else]
 219                 | T![if]
 220                 | T![loop]
 221                 | T![match]
 222                 | T![return]
 223                 | T![while]
 224                 | T![in] => h | HlMod::ControlFlow,
 225                 T![for] if !is_child_of_impl(&element) => h | HlMod::ControlFlow,
 226                 T![unsafe] => h | HlMod::Unsafe,
 227                 T![true] | T![false] => HlTag::BoolLiteral.into(),
 228                 T![self] => {
 229                     let self_param = element.parent().and_then(ast::SelfParam::cast);
 230                     if let Some(NameClass::Definition(def)) = self_param
 231                         .and_then(|self_param| NameClass::classify_self_param(sema, &self_param))
 232                     {
 233                         highlight_def(db, def) | HlMod::Definition
 234                     } else if element.ancestors().any(|it| it.kind() == USE_TREE) {
 235                         HlTag::Symbol(SymbolKind::SelfParam).into()
 236                     } else {
 237                         return None;
 238                     }
 239                 }
 240                 T![ref] => element
 241                     .parent()
 242                     .and_then(ast::IdentPat::cast)
 243                     .and_then(|ident_pat| {
 244                         if sema.is_unsafe_ident_pat(&ident_pat) {
 245                             Some(HlMod::Unsafe)
 246                         } else {
 247                             None
 248                         }
 249                     })
 250                     .map(|modifier| h | modifier)
 251                     .unwrap_or(h),
 252                 _ => h,
 253             }
 254         }
 255
 256         _ => return None,
 257     };
 258
 259     return Some((highlight, binding_hash));
 260
 261     fn calc_binding_hash(name: &hir::Name, shadow_count: u32) -> u64 {
 262         fn hash<T: std::hash::Hash + std::fmt::Debug>(x: T) -> u64 {
 263             use std::{collections::hash_map::DefaultHasher, hash::Hasher};
 264
 265             let mut hasher = DefaultHasher::new();
 266             x.hash(&mut hasher);
 267             hasher.finish()
 268         }
 269
 270         hash((name, shadow_count))
 271     }
 272 }
 273
 274 fn highlight_def(db: &RootDatabase, def: Definition) -> Highlight {
 275     match def {
 276         Definition::Macro(_) => HlTag::Symbol(SymbolKind::Macro),
 277         Definition::Field(_) => HlTag::Symbol(SymbolKind::Field),
 278         Definition::ModuleDef(def) => match def {
 279             hir::ModuleDef::Module(_) => HlTag::Symbol(SymbolKind::Module),
 280             hir::ModuleDef::Function(func) => {
 281                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Function));
 282                 if func.as_assoc_item(db).is_some() {
 283                     h |= HlMod::Associated;
 284                     if func.self_param(db).is_none() {
 285                         h |= HlMod::Static
 286                     }
 287                 }
 288                 if func.is_unsafe(db) {
 289                     h |= HlMod::Unsafe;
 290                 }
 291                 return h;
 292             }
 293             hir::ModuleDef::Adt(hir::Adt::Struct(_)) => HlTag::Symbol(SymbolKind::Struct),
 294             hir::ModuleDef::Adt(hir::Adt::Enum(_)) => HlTag::Symbol(SymbolKind::Enum),
 295             hir::ModuleDef::Adt(hir::Adt::Union(_)) => HlTag::Symbol(SymbolKind::Union),
 296             hir::ModuleDef::Variant(_) => HlTag::Symbol(SymbolKind::Variant),
 297             hir::ModuleDef::Const(konst) => {
 298                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Const));
 299                 if konst.as_assoc_item(db).is_some() {
 300                     h |= HlMod::Associated
 301                 }
 302                 return h;
 303             }
 304             hir::ModuleDef::Trait(_) => HlTag::Symbol(SymbolKind::Trait),
 305             hir::ModuleDef::TypeAlias(type_) => {
 306                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::TypeAlias));
 307                 if type_.as_assoc_item(db).is_some() {
 308                     h |= HlMod::Associated
 309                 }
 310                 return h;
 311             }
 312             hir::ModuleDef::BuiltinType(_) => HlTag::BuiltinType,
 313             hir::ModuleDef::Static(s) => {
 314                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Static));
 315                 if s.is_mut(db) {
 316                     h |= HlMod::Mutable;
 317                     h |= HlMod::Unsafe;
 318                 }
 319                 return h;
 320             }
 321         },
 322         Definition::SelfType(_) => HlTag::Symbol(SymbolKind::Impl),
 323         Definition::GenericParam(it) => match it {
 324             hir::GenericParam::TypeParam(_) => HlTag::Symbol(SymbolKind::TypeParam),
 325             hir::GenericParam::ConstParam(_) => HlTag::Symbol(SymbolKind::ConstParam),
 326             hir::GenericParam::LifetimeParam(_) => HlTag::Symbol(SymbolKind::LifetimeParam),
 327         },
 328         Definition::Local(local) => {
 329             let tag = if local.is_self(db) {
 330                 HlTag::Symbol(SymbolKind::SelfParam)
 331             } else if local.is_param(db) {
 332                 HlTag::Symbol(SymbolKind::ValueParam)
 333             } else {
 334                 HlTag::Symbol(SymbolKind::Local)
 335             };
 336             let mut h = Highlight::new(tag);
 337             if local.is_mut(db) || local.ty(db).is_mutable_reference() {
 338                 h |= HlMod::Mutable;
 339             }
 340             if local.ty(db).as_callable(db).is_some() || local.ty(db).impls_fnonce(db) {
 341                 h |= HlMod::Callable;
 342             }
 343             return h;
 344         }
 345         Definition::Label(_) => HlTag::Symbol(SymbolKind::Label),
 346     }
 347     .into()
 348 }
 349
 350 fn highlight_func_by_name_ref(
 351     sema: &Semantics<RootDatabase>,
 352     name_ref: &ast::NameRef,
 353 ) -> Option<Highlight> {
 354     let mc = name_ref.syntax().parent().and_then(ast::MethodCallExpr::cast)?;
 355     highlight_method_call(sema, &mc)
 356 }
 357
 358 fn highlight_method_call(
 359     sema: &Semantics<RootDatabase>,
 360     method_call: &ast::MethodCallExpr,
 361 ) -> Option<Highlight> {
 362     let func = sema.resolve_method_call(&method_call)?;
 363     let mut h = HlTag::Symbol(SymbolKind::Function).into();
 364     h |= HlMod::Associated;
 365     if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(&method_call) {
 366         h |= HlMod::Unsafe;
 367     }
 368     if let Some(self_param) = func.self_param(sema.db) {
 369         match self_param.access(sema.db) {
 370             hir::Access::Shared => (),
 371             hir::Access::Exclusive => h |= HlMod::Mutable,
 372             hir::Access::Owned => {
 373                 if let Some(receiver_ty) =
 374                     method_call.receiver().and_then(|it| sema.type_of_expr(&it))
 375                 {
 376                     if !receiver_ty.is_copy(sema.db) {
 377                         h |= HlMod::Consuming
 378                     }
 379                 }
 380             }
 381         }
 382     }
 383     Some(h)
 384 }
 385
 386 fn highlight_name_by_syntax(name: ast::Name) -> Highlight {
 387     let default = HlTag::UnresolvedReference;
 388
 389     let parent = match name.syntax().parent() {
 390         Some(it) => it,
 391         _ => return default.into(),
 392     };
 393
 394     let tag = match parent.kind() {
 395         STRUCT => HlTag::Symbol(SymbolKind::Struct),
 396         ENUM => HlTag::Symbol(SymbolKind::Enum),
 397         VARIANT => HlTag::Symbol(SymbolKind::Variant),
 398         UNION => HlTag::Symbol(SymbolKind::Union),
 399         TRAIT => HlTag::Symbol(SymbolKind::Trait),
 400         TYPE_ALIAS => HlTag::Symbol(SymbolKind::TypeAlias),
 401         TYPE_PARAM => HlTag::Symbol(SymbolKind::TypeParam),
 402         RECORD_FIELD => HlTag::Symbol(SymbolKind::Field),
 403         MODULE => HlTag::Symbol(SymbolKind::Module),
 404         FN => HlTag::Symbol(SymbolKind::Function),
 405         CONST => HlTag::Symbol(SymbolKind::Const),
 406         STATIC => HlTag::Symbol(SymbolKind::Static),
 407         IDENT_PAT => HlTag::Symbol(SymbolKind::Local),
 408         _ => default,
 409     };
 410
 411     tag.into()
 412 }
 413
 414 fn highlight_name_ref_by_syntax(name: ast::NameRef, sema: &Semantics<RootDatabase>) -> Highlight {
 415     let default = HlTag::UnresolvedReference;
 416
 417     let parent = match name.syntax().parent() {
 418         Some(it) => it,
 419         _ => return default.into(),
 420     };
 421
 422     match parent.kind() {
 423         METHOD_CALL_EXPR => {
 424             return ast::MethodCallExpr::cast(parent)
 425                 .and_then(|it| highlight_method_call(sema, &it))
 426                 .unwrap_or_else(|| HlTag::Symbol(SymbolKind::Function).into());
 427         }
 428         FIELD_EXPR => {
 429             let h = HlTag::Symbol(SymbolKind::Field);
 430             let is_union = ast::FieldExpr::cast(parent)
 431                 .and_then(|field_expr| {
 432                     let field = sema.resolve_field(&field_expr)?;
 433                     Some(if let VariantDef::Union(_) = field.parent_def(sema.db) {
 434                         true
 435                     } else {
 436                         false
 437                     })
 438                 })
 439                 .unwrap_or(false);
 440             if is_union {
 441                 h | HlMod::Unsafe
 442             } else {
 443                 h.into()
 444             }
 445         }
 446         PATH_SEGMENT => {
 447             let path = match parent.parent().and_then(ast::Path::cast) {
 448                 Some(it) => it,
 449                 _ => return default.into(),
 450             };
 451             let expr = match path.syntax().parent().and_then(ast::PathExpr::cast) {
 452                 Some(it) => it,
 453                 _ => {
 454                     // within path, decide whether it is module or adt by checking for uppercase name
 455                     return if name.text().chars().next().unwrap_or_default().is_uppercase() {
 456                         HlTag::Symbol(SymbolKind::Struct)
 457                     } else {
 458                         HlTag::Symbol(SymbolKind::Module)
 459                     }
 460                     .into();
 461                 }
 462             };
 463             let parent = match expr.syntax().parent() {
 464                 Some(it) => it,
 465                 None => return default.into(),
 466             };
 467
 468             match parent.kind() {
 469                 CALL_EXPR => HlTag::Symbol(SymbolKind::Function).into(),
 470                 _ => if name.text().chars().next().unwrap_or_default().is_uppercase() {
 471                     HlTag::Symbol(SymbolKind::Struct)
 472                 } else {
 473                     HlTag::Symbol(SymbolKind::Const)
 474                 }
 475                 .into(),
 476             }
 477         }
 478         _ => default.into(),
 479     }
 480 }
 481
 482 fn is_consumed_lvalue(
 483     node: NodeOrToken<SyntaxNode, SyntaxToken>,
 484     local: &hir::Local,
 485     db: &RootDatabase,
 486 ) -> bool {
 487     // When lvalues are passed as arguments and they're not Copy, then mark them as Consuming.
 488     parents_match(node, &[PATH_SEGMENT, PATH, PATH_EXPR, ARG_LIST]) && !local.ty(db).is_copy(db)
 489 }
 490
 491 /// Returns true if the parent nodes of `node` all match the `SyntaxKind`s in `kinds` exactly.
 492 fn parents_match(mut node: NodeOrToken<SyntaxNode, SyntaxToken>, mut kinds: &[SyntaxKind]) -> bool {
 493     while let (Some(parent), [kind, rest @ ..]) = (&node.parent(), kinds) {
 494         if parent.kind() != *kind {
 495             return false;
 496         }
 497
 498         // FIXME: Would be nice to get parent out of the match, but binding by-move and by-value
 499         // in the same pattern is unstable: rust-lang/rust#68354.
 500         node = node.parent().unwrap().into();
 501         kinds = rest;
 502     }
 503
 504     // Only true if we matched all expected kinds
 505     kinds.len() == 0
 506 }
 507
 508 fn is_child_of_impl(element: &SyntaxElement) -> bool {
 509     match element.parent() {
 510         Some(e) => e.kind() == IMPL,
 511         _ => false,
 512     }
 513 }