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 krate: Option<hir::Crate>,
23 bindings_shadow_count: &mut FxHashMap<hir::Name, u32>,
24 syntactic_name_ref_highlighting: bool,
25 element: SyntaxElement,
26 ) -> Option<(Highlight, Option<u64>)> {
28 let mut binding_hash = None;
29 let highlight: Highlight = match element.kind() {
31 bindings_shadow_count.clear();
35 // Highlight definitions depending on the "type" of the definition.
37 let name = element.into_node().and_then(ast::Name::cast).unwrap();
38 let name_kind = NameClass::classify(sema, &name);
40 if let Some(NameClass::Definition(Definition::Local(local))) = &name_kind {
41 if let Some(name) = local.name(db) {
42 let shadow_count = bindings_shadow_count.entry(name.clone()).or_default();
44 binding_hash = Some(calc_binding_hash(&name, *shadow_count))
49 Some(NameClass::ExternCrate(_)) => SymbolKind::Module.into(),
50 Some(NameClass::Definition(def)) => {
51 highlight_def(db, krate, def) | HlMod::Definition
53 Some(NameClass::ConstReference(def)) => highlight_def(db, krate, def),
54 Some(NameClass::PatFieldShorthand { field_ref, .. }) => {
55 let mut h = HlTag::Symbol(SymbolKind::Field).into();
56 if let Definition::Field(field) = field_ref {
57 if let hir::VariantDef::Union(_) = field.parent_def(db) {
63 None => highlight_name_by_syntax(name) | HlMod::Definition,
66 // Highlight references like the definitions they resolve to
67 NAME_REF if element.ancestors().any(|it| it.kind() == ATTR) => {
68 // even though we track whether we are in an attribute or not we still need this special case
69 // as otherwise we would emit unresolved references for name refs inside attributes
70 SymbolKind::Function.into()
73 let name_ref = element.into_node().and_then(ast::NameRef::cast).unwrap();
74 highlight_func_by_name_ref(sema, krate, &name_ref).unwrap_or_else(|| {
75 let is_self = name_ref.self_token().is_some();
76 let h = match NameRefClass::classify(sema, &name_ref) {
77 Some(name_kind) => match name_kind {
78 NameRefClass::ExternCrate(_) => SymbolKind::Module.into(),
79 NameRefClass::Definition(def) => {
80 if let Definition::Local(local) = &def {
81 if let Some(name) = local.name(db) {
83 bindings_shadow_count.entry(name.clone()).or_default();
84 binding_hash = Some(calc_binding_hash(&name, *shadow_count))
88 let mut h = highlight_def(db, krate, def);
90 if let Definition::Local(local) = &def {
91 if is_consumed_lvalue(name_ref.syntax().clone().into(), local, db) {
92 h |= HlMod::Consuming;
96 if let Some(parent) = name_ref.syntax().parent() {
97 if matches!(parent.kind(), FIELD_EXPR | RECORD_PAT_FIELD) {
98 if let Definition::Field(field) = def {
99 if let hir::VariantDef::Union(_) = field.parent_def(db) {
108 NameRefClass::FieldShorthand { .. } => SymbolKind::Field.into(),
110 None if syntactic_name_ref_highlighting => {
111 highlight_name_ref_by_syntax(name_ref, sema, krate)
113 None => HlTag::UnresolvedReference.into(),
115 if h.tag == HlTag::Symbol(SymbolKind::Module) && is_self {
116 SymbolKind::SelfParam.into()
123 // Simple token-based highlighting
125 let comment = element.into_token().and_then(ast::Comment::cast)?;
126 let h = HlTag::Comment;
127 match comment.kind().doc {
128 Some(_) => h | HlMod::Documentation,
132 STRING | BYTE_STRING => HlTag::StringLiteral.into(),
133 ATTR => HlTag::Attribute.into(),
134 INT_NUMBER if element.ancestors().nth(1).map_or(false, |it| it.kind() == FIELD_EXPR) => {
135 SymbolKind::Field.into()
137 INT_NUMBER | FLOAT_NUMBER => HlTag::NumericLiteral.into(),
138 BYTE => HlTag::ByteLiteral.into(),
139 CHAR => HlTag::CharLiteral.into(),
140 QUESTION => HlTag::Operator(HlOperator::Other) | HlMod::ControlFlow,
142 let lifetime = element.into_node().and_then(ast::Lifetime::cast).unwrap();
144 match NameClass::classify_lifetime(sema, &lifetime) {
145 Some(NameClass::Definition(def)) => {
146 highlight_def(db, krate, def) | HlMod::Definition
148 None => match NameRefClass::classify_lifetime(sema, &lifetime) {
149 Some(NameRefClass::Definition(def)) => highlight_def(db, krate, def),
150 _ => SymbolKind::LifetimeParam.into(),
152 _ => Highlight::from(SymbolKind::LifetimeParam) | HlMod::Definition,
155 p if p.is_punct() => match p {
156 T![&] if parent_matches::<ast::BinExpr>(&element) => HlOperator::Bitwise.into(),
158 let h = HlTag::Operator(HlOperator::Other).into();
159 let is_unsafe = element
161 .and_then(ast::RefExpr::cast)
162 .map_or(false, |ref_expr| sema.is_unsafe_ref_expr(&ref_expr));
169 T![::] | T![->] | T![=>] | T![..] | T![=] | T![@] | T![.] => HlOperator::Other.into(),
170 T![!] if parent_matches::<ast::MacroCall>(&element) => SymbolKind::Macro.into(),
171 T![!] if parent_matches::<ast::NeverType>(&element) => HlTag::BuiltinType.into(),
172 T![!] if parent_matches::<ast::PrefixExpr>(&element) => HlOperator::Logical.into(),
173 T![*] if parent_matches::<ast::PtrType>(&element) => HlTag::Keyword.into(),
174 T![*] if parent_matches::<ast::PrefixExpr>(&element) => {
175 let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?;
177 let expr = prefix_expr.expr()?;
178 let ty = sema.type_of_expr(&expr)?;
180 HlTag::Operator(HlOperator::Other) | HlMod::Unsafe
181 } else if let Some(ast::PrefixOp::Deref) = prefix_expr.op_kind() {
182 HlOperator::Other.into()
184 HlPunct::Other.into()
187 T![-] if parent_matches::<ast::PrefixExpr>(&element) => {
188 let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?;
190 let expr = prefix_expr.expr()?;
192 ast::Expr::Literal(_) => HlTag::NumericLiteral,
193 _ => HlTag::Operator(HlOperator::Other),
197 _ if parent_matches::<ast::PrefixExpr>(&element) => HlOperator::Other.into(),
198 T![+] | T![-] | T![*] | T![/] | T![+=] | T![-=] | T![*=] | T![/=]
199 if parent_matches::<ast::BinExpr>(&element) =>
201 HlOperator::Arithmetic.into()
203 T![|] | T![&] | T![!] | T![^] | T![|=] | T![&=] | T![^=]
204 if parent_matches::<ast::BinExpr>(&element) =>
206 HlOperator::Bitwise.into()
208 T![&&] | T![||] if parent_matches::<ast::BinExpr>(&element) => {
209 HlOperator::Logical.into()
211 T![>] | T![<] | T![==] | T![>=] | T![<=] | T![!=]
212 if parent_matches::<ast::BinExpr>(&element) =>
214 HlOperator::Comparison.into()
216 _ if parent_matches::<ast::BinExpr>(&element) => HlOperator::Other.into(),
217 _ if parent_matches::<ast::RangeExpr>(&element) => HlOperator::Other.into(),
218 _ if parent_matches::<ast::RangePat>(&element) => HlOperator::Other.into(),
219 _ if parent_matches::<ast::RestPat>(&element) => HlOperator::Other.into(),
220 _ if parent_matches::<ast::Attr>(&element) => HlTag::Attribute.into(),
222 T!['['] | T![']'] => HlPunct::Bracket,
223 T!['{'] | T!['}'] => HlPunct::Brace,
224 T!['('] | T![')'] => HlPunct::Parenthesis,
225 T![<] | T![>] => HlPunct::Angle,
226 T![,] => HlPunct::Comma,
227 T![:] => HlPunct::Colon,
228 T![;] => HlPunct::Semi,
229 T![.] => HlPunct::Dot,
235 k if k.is_keyword() => {
236 let h = Highlight::new(HlTag::Keyword);
238 T![await] => h | HlMod::Async | HlMod::ControlFlow,
248 | T![yield] => h | HlMod::ControlFlow,
249 T![for] if !is_child_of_impl(&element) => h | HlMod::ControlFlow,
250 T![unsafe] => h | HlMod::Unsafe,
251 T![true] | T![false] => HlTag::BoolLiteral.into(),
252 // self is handled as either a Name or NameRef already
253 T![self] => return None,
256 .and_then(ast::IdentPat::cast)
257 .and_then(|ident_pat| {
258 if sema.is_unsafe_ident_pat(&ident_pat) {
264 .map(|modifier| h | modifier)
266 T![async] => h | HlMod::Async,
274 return Some((highlight, binding_hash));
276 fn calc_binding_hash(name: &hir::Name, shadow_count: u32) -> u64 {
277 fn hash<T: std::hash::Hash + std::fmt::Debug>(x: T) -> u64 {
278 use std::{collections::hash_map::DefaultHasher, hash::Hasher};
280 let mut hasher = DefaultHasher::new();
285 hash((name, shadow_count))
288 fn highlight_def(db: &RootDatabase, krate: Option<hir::Crate>, def: Definition) -> Highlight {
289 let mut h = match def {
290 Definition::Macro(_) => Highlight::new(HlTag::Symbol(SymbolKind::Macro)),
291 Definition::Field(_) => Highlight::new(HlTag::Symbol(SymbolKind::Field)),
292 Definition::ModuleDef(def) => match def {
293 hir::ModuleDef::Module(_) => Highlight::new(HlTag::Symbol(SymbolKind::Module)),
294 hir::ModuleDef::Function(func) => {
295 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Function));
296 if let Some(item) = func.as_assoc_item(db) {
297 h |= HlMod::Associated;
298 match func.self_param(db) {
300 if let hir::Access::Exclusive = sp.access(db) {
304 None => h |= HlMod::Static,
307 match item.container(db) {
308 hir::AssocItemContainer::Impl(i) => {
309 if i.trait_(db).is_some() {
313 hir::AssocItemContainer::Trait(_t) => {
319 if func.is_unsafe(db) {
322 if func.is_async(db) {
328 hir::ModuleDef::Adt(adt) => {
330 hir::Adt::Struct(_) => HlTag::Symbol(SymbolKind::Struct),
331 hir::Adt::Enum(_) => HlTag::Symbol(SymbolKind::Enum),
332 hir::Adt::Union(_) => HlTag::Symbol(SymbolKind::Union),
337 hir::ModuleDef::Variant(_) => Highlight::new(HlTag::Symbol(SymbolKind::Variant)),
338 hir::ModuleDef::Const(konst) => {
339 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Const));
341 if let Some(item) = konst.as_assoc_item(db) {
342 h |= HlMod::Associated;
343 match item.container(db) {
344 hir::AssocItemContainer::Impl(i) => {
345 if i.trait_(db).is_some() {
349 hir::AssocItemContainer::Trait(_t) => {
357 hir::ModuleDef::Trait(trait_) => {
358 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Trait));
360 if trait_.is_unsafe(db) {
366 hir::ModuleDef::TypeAlias(type_) => {
367 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::TypeAlias));
369 if let Some(item) = type_.as_assoc_item(db) {
370 h |= HlMod::Associated;
371 match item.container(db) {
372 hir::AssocItemContainer::Impl(i) => {
373 if i.trait_(db).is_some() {
377 hir::AssocItemContainer::Trait(_t) => {
385 hir::ModuleDef::BuiltinType(_) => Highlight::new(HlTag::BuiltinType),
386 hir::ModuleDef::Static(s) => {
387 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Static));
397 Definition::SelfType(_) => Highlight::new(HlTag::Symbol(SymbolKind::Impl)),
398 Definition::GenericParam(it) => match it {
399 hir::GenericParam::TypeParam(_) => Highlight::new(HlTag::Symbol(SymbolKind::TypeParam)),
400 hir::GenericParam::ConstParam(_) => {
401 Highlight::new(HlTag::Symbol(SymbolKind::ConstParam))
403 hir::GenericParam::LifetimeParam(_) => {
404 Highlight::new(HlTag::Symbol(SymbolKind::LifetimeParam))
407 Definition::Local(local) => {
408 let tag = if local.is_self(db) {
409 HlTag::Symbol(SymbolKind::SelfParam)
410 } else if local.is_param(db) {
411 HlTag::Symbol(SymbolKind::ValueParam)
413 HlTag::Symbol(SymbolKind::Local)
415 let mut h = Highlight::new(tag);
416 let ty = local.ty(db);
417 if local.is_mut(db) || ty.is_mutable_reference() {
420 if ty.as_callable(db).is_some() || ty.impls_fnonce(db) {
421 h |= HlMod::Callable;
425 Definition::Label(_) => Highlight::new(HlTag::Symbol(SymbolKind::Label)),
428 let is_from_other_crate = def.module(db).map(hir::Module::krate) != krate;
429 let is_builtin_type = matches!(def, Definition::ModuleDef(hir::ModuleDef::BuiltinType(_)));
431 if is_from_other_crate && !is_builtin_type {
438 fn highlight_func_by_name_ref(
439 sema: &Semantics<RootDatabase>,
440 krate: Option<hir::Crate>,
441 name_ref: &ast::NameRef,
442 ) -> Option<Highlight> {
443 let mc = name_ref.syntax().parent().and_then(ast::MethodCallExpr::cast)?;
444 highlight_method_call(sema, krate, &mc)
447 fn highlight_method_call(
448 sema: &Semantics<RootDatabase>,
449 krate: Option<hir::Crate>,
450 method_call: &ast::MethodCallExpr,
451 ) -> Option<Highlight> {
452 let func = sema.resolve_method_call(method_call)?;
454 let mut h = SymbolKind::Function.into();
455 h |= HlMod::Associated;
457 if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(method_call) {
460 if func.is_async(sema.db) {
463 if func.as_assoc_item(sema.db).and_then(|it| it.containing_trait(sema.db)).is_some() {
466 if Some(func.module(sema.db).krate()) != krate {
470 if let Some(self_param) = func.self_param(sema.db) {
471 match self_param.access(sema.db) {
472 hir::Access::Shared => (),
473 hir::Access::Exclusive => h |= HlMod::Mutable,
474 hir::Access::Owned => {
475 if let Some(receiver_ty) =
476 method_call.receiver().and_then(|it| sema.type_of_expr(&it))
478 if !receiver_ty.is_copy(sema.db) {
479 h |= HlMod::Consuming
488 fn highlight_name_by_syntax(name: ast::Name) -> Highlight {
489 let default = HlTag::UnresolvedReference;
491 let parent = match name.syntax().parent() {
493 _ => return default.into(),
496 let tag = match parent.kind() {
497 STRUCT => SymbolKind::Struct,
498 ENUM => SymbolKind::Enum,
499 VARIANT => SymbolKind::Variant,
500 UNION => SymbolKind::Union,
501 TRAIT => SymbolKind::Trait,
502 TYPE_ALIAS => SymbolKind::TypeAlias,
503 TYPE_PARAM => SymbolKind::TypeParam,
504 RECORD_FIELD => SymbolKind::Field,
505 MODULE => SymbolKind::Module,
506 FN => SymbolKind::Function,
507 CONST => SymbolKind::Const,
508 STATIC => SymbolKind::Static,
509 IDENT_PAT => SymbolKind::Local,
510 _ => return default.into(),
516 fn highlight_name_ref_by_syntax(
518 sema: &Semantics<RootDatabase>,
519 krate: Option<hir::Crate>,
521 let default = HlTag::UnresolvedReference;
523 let parent = match name.syntax().parent() {
525 _ => return default.into(),
528 match parent.kind() {
529 METHOD_CALL_EXPR => {
530 ast::MethodCallExpr::cast(parent)
531 .and_then(|it| highlight_method_call(sema, krate, &it))
532 .unwrap_or_else(|| SymbolKind::Function.into())
535 let h = HlTag::Symbol(SymbolKind::Field);
536 let is_union = ast::FieldExpr::cast(parent)
537 .and_then(|field_expr| sema.resolve_field(&field_expr))
538 .map_or(false, |field| {
539 matches!(field.parent_def(sema.db), hir::VariantDef::Union(_))
548 let path = match parent.parent().and_then(ast::Path::cast) {
550 _ => return default.into(),
552 let expr = match path.syntax().parent().and_then(ast::PathExpr::cast) {
555 // within path, decide whether it is module or adt by checking for uppercase name
556 return if name.text().chars().next().unwrap_or_default().is_uppercase() {
564 let parent = match expr.syntax().parent() {
566 None => return default.into(),
569 match parent.kind() {
570 CALL_EXPR => SymbolKind::Function.into(),
571 _ => if name.text().chars().next().unwrap_or_default().is_uppercase() {
583 fn is_consumed_lvalue(
584 node: NodeOrToken<SyntaxNode, SyntaxToken>,
588 // When lvalues are passed as arguments and they're not Copy, then mark them as Consuming.
589 parents_match(node, &[PATH_SEGMENT, PATH, PATH_EXPR, ARG_LIST]) && !local.ty(db).is_copy(db)
592 /// Returns true if the parent nodes of `node` all match the `SyntaxKind`s in `kinds` exactly.
593 fn parents_match(mut node: NodeOrToken<SyntaxNode, SyntaxToken>, mut kinds: &[SyntaxKind]) -> bool {
594 while let (Some(parent), [kind, rest @ ..]) = (&node.parent(), kinds) {
595 if parent.kind() != *kind {
599 // FIXME: Would be nice to get parent out of the match, but binding by-move and by-value
600 // in the same pattern is unstable: rust-lang/rust#68354.
601 node = node.parent().unwrap().into();
605 // Only true if we matched all expected kinds
610 fn parent_matches<N: AstNode>(element: &SyntaxElement) -> bool {
611 element.parent().map_or(false, |it| N::can_cast(it.kind()))
614 fn is_child_of_impl(element: &SyntaxElement) -> bool {
615 match element.parent() {
616 Some(e) => e.kind() == IMPL,