1 //! Computes color for a single element.
3 use hir::{AsAssocItem, Semantics};
5 defs::{Definition, NameClass, NameRefClass},
6 RootDatabase, SymbolKind,
8 use rustc_hash::FxHashMap;
10 ast, AstNode, AstToken, NodeOrToken, SyntaxElement,
11 SyntaxKind::{self, *},
12 SyntaxNode, SyntaxToken, T,
16 syntax_highlighting::tags::{HlOperator, HlPunct},
17 Highlight, HlMod, HlTag,
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>)> {
27 let mut binding_hash = None;
28 let highlight: Highlight = match element.kind() {
30 bindings_shadow_count.clear();
34 // Highlight definitions depending on the "type" of the definition.
36 let name = element.into_node().and_then(ast::Name::cast).unwrap();
37 let name_kind = NameClass::classify(sema, &name);
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();
43 binding_hash = Some(calc_binding_hash(&name, *shadow_count))
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) {
60 None => highlight_name_by_syntax(name) | HlMod::Definition,
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()
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) {
80 bindings_shadow_count.entry(name.clone()).or_default();
81 binding_hash = Some(calc_binding_hash(&name, *shadow_count))
85 let mut h = highlight_def(db, def);
87 if let Definition::Local(local) = &def {
88 if is_consumed_lvalue(name_ref.syntax().clone().into(), local, db) {
89 h |= HlMod::Consuming;
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) {
105 NameRefClass::FieldShorthand { .. } => SymbolKind::Field.into(),
107 None if syntactic_name_ref_highlighting => {
108 highlight_name_ref_by_syntax(name_ref, sema)
110 None => HlTag::UnresolvedReference.into(),
112 if h.tag == HlTag::Symbol(SymbolKind::Module) && is_self {
113 SymbolKind::SelfParam.into()
120 // Simple token-based highlighting
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,
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,
136 let lifetime = element.into_node().and_then(ast::Lifetime::cast).unwrap();
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(),
144 _ => Highlight::from(SymbolKind::LifetimeParam) | HlMod::Definition,
147 p if p.is_punct() => match p {
148 T![&] if parent_matches::<ast::BinExpr>(&element) => HlOperator::Bitwise.into(),
150 let h = HlTag::Operator(HlOperator::Other).into();
151 let is_unsafe = element
153 .and_then(ast::RefExpr::cast)
154 .map_or(false, |ref_expr| sema.is_unsafe_ref_expr(&ref_expr));
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)?;
169 let expr = prefix_expr.expr()?;
170 let ty = sema.type_of_expr(&expr)?;
172 HlTag::Operator(HlOperator::Other) | HlMod::Unsafe
173 } else if let Some(ast::PrefixOp::Deref) = prefix_expr.op_kind() {
174 HlOperator::Other.into()
176 HlPunct::Other.into()
179 T![-] if parent_matches::<ast::PrefixExpr>(&element) => {
180 let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?;
182 let expr = prefix_expr.expr()?;
184 ast::Expr::Literal(_) => HlTag::NumericLiteral,
185 _ => HlTag::Operator(HlOperator::Other),
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) =>
193 HlOperator::Arithmetic.into()
195 T![|] | T![&] | T![!] | T![^] | T![|=] | T![&=] | T![^=]
196 if parent_matches::<ast::BinExpr>(&element) =>
198 HlOperator::Bitwise.into()
200 T![&&] | T![||] if parent_matches::<ast::BinExpr>(&element) => {
201 HlOperator::Logical.into()
203 T![>] | T![<] | T![==] | T![>=] | T![<=] | T![!=]
204 if parent_matches::<ast::BinExpr>(&element) =>
206 HlOperator::Comparison.into()
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(),
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,
227 k if k.is_keyword() => {
228 let h = Highlight::new(HlTag::Keyword);
230 T![await] => h | HlMod::Async | HlMod::ControlFlow,
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,
248 .and_then(ast::IdentPat::cast)
249 .and_then(|ident_pat| {
250 if sema.is_unsafe_ident_pat(&ident_pat) {
256 .map(|modifier| h | modifier)
258 T![async] => h | HlMod::Async,
266 return Some((highlight, binding_hash));
268 fn calc_binding_hash(name: &hir::Name, shadow_count: u32) -> u64 {
269 fn hash<T: std::hash::Hash + std::fmt::Debug>(x: T) -> u64 {
270 use std::{collections::hash_map::DefaultHasher, hash::Hasher};
272 let mut hasher = DefaultHasher::new();
277 hash((name, shadow_count))
280 fn highlight_def(db: &RootDatabase, def: Definition) -> Highlight {
282 Definition::Macro(_) => HlTag::Symbol(SymbolKind::Macro),
283 Definition::Field(_) => HlTag::Symbol(SymbolKind::Field),
284 Definition::ModuleDef(def) => match def {
285 hir::ModuleDef::Module(_) => HlTag::Symbol(SymbolKind::Module),
286 hir::ModuleDef::Function(func) => {
287 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Function));
288 if let Some(item) = func.as_assoc_item(db) {
289 h |= HlMod::Associated;
290 match func.self_param(db) {
292 if let hir::Access::Exclusive = sp.access(db) {
296 None => h |= HlMod::Static,
299 match item.container(db) {
300 hir::AssocItemContainer::Impl(i) => {
301 if i.trait_(db).is_some() {
305 hir::AssocItemContainer::Trait(_t) => {
311 if func.is_unsafe(db) {
314 if func.is_async(db) {
319 hir::ModuleDef::Adt(hir::Adt::Struct(_)) => HlTag::Symbol(SymbolKind::Struct),
320 hir::ModuleDef::Adt(hir::Adt::Enum(_)) => HlTag::Symbol(SymbolKind::Enum),
321 hir::ModuleDef::Adt(hir::Adt::Union(_)) => HlTag::Symbol(SymbolKind::Union),
322 hir::ModuleDef::Variant(_) => HlTag::Symbol(SymbolKind::Variant),
323 hir::ModuleDef::Const(konst) => {
324 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Const));
325 if let Some(item) = konst.as_assoc_item(db) {
326 h |= HlMod::Associated;
327 match item.container(db) {
328 hir::AssocItemContainer::Impl(i) => {
329 if i.trait_(db).is_some() {
333 hir::AssocItemContainer::Trait(_t) => {
341 hir::ModuleDef::Trait(_) => HlTag::Symbol(SymbolKind::Trait),
342 hir::ModuleDef::TypeAlias(type_) => {
343 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::TypeAlias));
344 if let Some(item) = type_.as_assoc_item(db) {
345 h |= HlMod::Associated;
346 match item.container(db) {
347 hir::AssocItemContainer::Impl(i) => {
348 if i.trait_(db).is_some() {
352 hir::AssocItemContainer::Trait(_t) => {
359 hir::ModuleDef::BuiltinType(_) => HlTag::BuiltinType,
360 hir::ModuleDef::Static(s) => {
361 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Static));
369 Definition::SelfType(_) => HlTag::Symbol(SymbolKind::Impl),
370 Definition::GenericParam(it) => match it {
371 hir::GenericParam::TypeParam(_) => HlTag::Symbol(SymbolKind::TypeParam),
372 hir::GenericParam::ConstParam(_) => HlTag::Symbol(SymbolKind::ConstParam),
373 hir::GenericParam::LifetimeParam(_) => HlTag::Symbol(SymbolKind::LifetimeParam),
375 Definition::Local(local) => {
376 let tag = if local.is_self(db) {
377 HlTag::Symbol(SymbolKind::SelfParam)
378 } else if local.is_param(db) {
379 HlTag::Symbol(SymbolKind::ValueParam)
381 HlTag::Symbol(SymbolKind::Local)
383 let mut h = Highlight::new(tag);
384 let ty = local.ty(db);
385 if local.is_mut(db) || ty.is_mutable_reference() {
388 if ty.as_callable(db).is_some() || ty.impls_fnonce(db) {
389 h |= HlMod::Callable;
393 Definition::Label(_) => HlTag::Symbol(SymbolKind::Label),
398 fn highlight_func_by_name_ref(
399 sema: &Semantics<RootDatabase>,
400 name_ref: &ast::NameRef,
401 ) -> Option<Highlight> {
402 let mc = name_ref.syntax().parent().and_then(ast::MethodCallExpr::cast)?;
403 highlight_method_call(sema, &mc)
406 fn highlight_method_call(
407 sema: &Semantics<RootDatabase>,
408 method_call: &ast::MethodCallExpr,
409 ) -> Option<Highlight> {
410 let func = sema.resolve_method_call(&method_call)?;
411 let mut h = SymbolKind::Function.into();
412 h |= HlMod::Associated;
413 if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(&method_call) {
416 if func.is_async(sema.db) {
419 if func.as_assoc_item(sema.db).and_then(|it| it.containing_trait(sema.db)).is_some() {
423 if let Some(self_param) = func.self_param(sema.db) {
424 match self_param.access(sema.db) {
425 hir::Access::Shared => (),
426 hir::Access::Exclusive => h |= HlMod::Mutable,
427 hir::Access::Owned => {
428 if let Some(receiver_ty) =
429 method_call.receiver().and_then(|it| sema.type_of_expr(&it))
431 if !receiver_ty.is_copy(sema.db) {
432 h |= HlMod::Consuming
441 fn highlight_name_by_syntax(name: ast::Name) -> Highlight {
442 let default = HlTag::UnresolvedReference;
444 let parent = match name.syntax().parent() {
446 _ => return default.into(),
449 let tag = match parent.kind() {
450 STRUCT => SymbolKind::Struct,
451 ENUM => SymbolKind::Enum,
452 VARIANT => SymbolKind::Variant,
453 UNION => SymbolKind::Union,
454 TRAIT => SymbolKind::Trait,
455 TYPE_ALIAS => SymbolKind::TypeAlias,
456 TYPE_PARAM => SymbolKind::TypeParam,
457 RECORD_FIELD => SymbolKind::Field,
458 MODULE => SymbolKind::Module,
459 FN => SymbolKind::Function,
460 CONST => SymbolKind::Const,
461 STATIC => SymbolKind::Static,
462 IDENT_PAT => SymbolKind::Local,
463 _ => return default.into(),
469 fn highlight_name_ref_by_syntax(name: ast::NameRef, sema: &Semantics<RootDatabase>) -> Highlight {
470 let default = HlTag::UnresolvedReference;
472 let parent = match name.syntax().parent() {
474 _ => return default.into(),
477 match parent.kind() {
478 METHOD_CALL_EXPR => {
479 return ast::MethodCallExpr::cast(parent)
480 .and_then(|it| highlight_method_call(sema, &it))
481 .unwrap_or_else(|| SymbolKind::Function.into());
484 let h = HlTag::Symbol(SymbolKind::Field);
485 let is_union = ast::FieldExpr::cast(parent)
486 .and_then(|field_expr| sema.resolve_field(&field_expr))
487 .map_or(false, |field| {
488 matches!(field.parent_def(sema.db), hir::VariantDef::Union(_))
497 let path = match parent.parent().and_then(ast::Path::cast) {
499 _ => return default.into(),
501 let expr = match path.syntax().parent().and_then(ast::PathExpr::cast) {
504 // within path, decide whether it is module or adt by checking for uppercase name
505 return if name.text().chars().next().unwrap_or_default().is_uppercase() {
513 let parent = match expr.syntax().parent() {
515 None => return default.into(),
518 match parent.kind() {
519 CALL_EXPR => SymbolKind::Function.into(),
520 _ => if name.text().chars().next().unwrap_or_default().is_uppercase() {
532 fn is_consumed_lvalue(
533 node: NodeOrToken<SyntaxNode, SyntaxToken>,
537 // When lvalues are passed as arguments and they're not Copy, then mark them as Consuming.
538 parents_match(node, &[PATH_SEGMENT, PATH, PATH_EXPR, ARG_LIST]) && !local.ty(db).is_copy(db)
541 /// Returns true if the parent nodes of `node` all match the `SyntaxKind`s in `kinds` exactly.
542 fn parents_match(mut node: NodeOrToken<SyntaxNode, SyntaxToken>, mut kinds: &[SyntaxKind]) -> bool {
543 while let (Some(parent), [kind, rest @ ..]) = (&node.parent(), kinds) {
544 if parent.kind() != *kind {
548 // FIXME: Would be nice to get parent out of the match, but binding by-move and by-value
549 // in the same pattern is unstable: rust-lang/rust#68354.
550 node = node.parent().unwrap().into();
554 // Only true if we matched all expected kinds
559 fn parent_matches<N: AstNode>(element: &SyntaxElement) -> bool {
560 element.parent().map_or(false, |it| N::can_cast(it.kind()))
563 fn is_child_of_impl(element: &SyntaxElement) -> bool {
564 match element.parent() {
565 Some(e) => e.kind() == IMPL,