mod tags; mod html; mod injection; #[cfg(test)] mod tests; use hir::{Name, Semantics, VariantDef}; use ide_db::{ defs::{classify_name, classify_name_ref, Definition, NameClass, NameRefClass}, RootDatabase, }; use rustc_hash::FxHashMap; use syntax::{ ast::{self, HasFormatSpecifier}, AstNode, AstToken, Direction, NodeOrToken, SyntaxElement, SyntaxKind::*, TextRange, WalkEvent, T, }; use crate::FileId; use ast::FormatSpecifier; pub(crate) use html::highlight_as_html; pub use tags::{Highlight, HighlightModifier, HighlightModifiers, HighlightTag}; #[derive(Debug, Clone)] pub struct HighlightedRange { pub range: TextRange, pub highlight: Highlight, pub binding_hash: Option, } // Feature: Semantic Syntax Highlighting // // rust-analyzer highlights the code semantically. // For example, `bar` in `foo::Bar` might be colored differently depending on whether `Bar` is an enum or a trait. // rust-analyzer does not specify colors directly, instead it assigns tag (like `struct`) and a set of modifiers (like `declaration`) to each token. // It's up to the client to map those to specific colors. // // The general rule is that a reference to an entity gets colored the same way as the entity itself. // We also give special modifier for `mut` and `&mut` local variables. pub(crate) fn highlight( db: &RootDatabase, file_id: FileId, range_to_highlight: Option, syntactic_name_ref_highlighting: bool, ) -> Vec { let _p = profile::span("highlight"); let sema = Semantics::new(db); // Determine the root based on the given range. let (root, range_to_highlight) = { let source_file = sema.parse(file_id); match range_to_highlight { Some(range) => { let node = match source_file.syntax().covering_element(range) { NodeOrToken::Node(it) => it, NodeOrToken::Token(it) => it.parent(), }; (node, range) } None => (source_file.syntax().clone(), source_file.syntax().text_range()), } }; let mut bindings_shadow_count: FxHashMap = FxHashMap::default(); // We use a stack for the DFS traversal below. // When we leave a node, the we use it to flatten the highlighted ranges. let mut stack = HighlightedRangeStack::new(); let mut current_macro_call: Option = None; let mut format_string: Option = None; // Walk all nodes, keeping track of whether we are inside a macro or not. // If in macro, expand it first and highlight the expanded code. for event in root.preorder_with_tokens() { match &event { WalkEvent::Enter(_) => stack.push(), WalkEvent::Leave(_) => stack.pop(), }; let event_range = match &event { WalkEvent::Enter(it) => it.text_range(), WalkEvent::Leave(it) => it.text_range(), }; // Element outside of the viewport, no need to highlight if range_to_highlight.intersect(event_range).is_none() { continue; } // Track "inside macro" state match event.clone().map(|it| it.into_node().and_then(ast::MacroCall::cast)) { WalkEvent::Enter(Some(mc)) => { current_macro_call = Some(mc.clone()); if let Some(range) = macro_call_range(&mc) { stack.add(HighlightedRange { range, highlight: HighlightTag::Macro.into(), binding_hash: None, }); } if let Some(name) = mc.is_macro_rules() { if let Some((highlight, binding_hash)) = highlight_element( &sema, &mut bindings_shadow_count, syntactic_name_ref_highlighting, name.syntax().clone().into(), ) { stack.add(HighlightedRange { range: name.syntax().text_range(), highlight, binding_hash, }); } } continue; } WalkEvent::Leave(Some(mc)) => { assert!(current_macro_call == Some(mc)); current_macro_call = None; format_string = None; } _ => (), } // Check for Rust code in documentation match &event { WalkEvent::Leave(NodeOrToken::Node(node)) => { if let Some((doctest, range_mapping, new_comments)) = injection::extract_doc_comments(node) { injection::highlight_doc_comment( doctest, range_mapping, new_comments, &mut stack, ); } } _ => (), } let element = match event { WalkEvent::Enter(it) => it, WalkEvent::Leave(_) => continue, }; let range = element.text_range(); let element_to_highlight = if current_macro_call.is_some() && element.kind() != COMMENT { // Inside a macro -- expand it first let token = match element.clone().into_token() { Some(it) if it.parent().kind() == TOKEN_TREE => it, _ => continue, }; let token = sema.descend_into_macros(token.clone()); let parent = token.parent(); // Check if macro takes a format string and remember it for highlighting later. // The macros that accept a format string expand to a compiler builtin macros // `format_args` and `format_args_nl`. if let Some(name) = parent .parent() .and_then(ast::MacroCall::cast) .and_then(|mc| mc.path()) .and_then(|p| p.segment()) .and_then(|s| s.name_ref()) { match name.text().as_str() { "format_args" | "format_args_nl" => { format_string = parent .children_with_tokens() .filter(|t| t.kind() != WHITESPACE) .nth(1) .filter(|e| { ast::String::can_cast(e.kind()) || ast::RawString::can_cast(e.kind()) }) } _ => {} } } // We only care Name and Name_ref match (token.kind(), parent.kind()) { (IDENT, NAME) | (IDENT, NAME_REF) => parent.into(), _ => token.into(), } } else { element.clone() }; if let Some(token) = element.as_token().cloned().and_then(ast::RawString::cast) { let expanded = element_to_highlight.as_token().unwrap().clone(); if injection::highlight_injection(&mut stack, &sema, token, expanded).is_some() { continue; } } let is_format_string = format_string.as_ref() == Some(&element_to_highlight); if let Some((highlight, binding_hash)) = highlight_element( &sema, &mut bindings_shadow_count, syntactic_name_ref_highlighting, element_to_highlight.clone(), ) { stack.add(HighlightedRange { range, highlight, binding_hash }); if let Some(string) = element_to_highlight.as_token().cloned().and_then(ast::String::cast) { if is_format_string { stack.push(); string.lex_format_specifier(|piece_range, kind| { if let Some(highlight) = highlight_format_specifier(kind) { stack.add(HighlightedRange { range: piece_range + range.start(), highlight: highlight.into(), binding_hash: None, }); } }); stack.pop(); } // Highlight escape sequences if let Some(char_ranges) = string.char_ranges() { stack.push(); for (piece_range, _) in char_ranges.iter().filter(|(_, char)| char.is_ok()) { if string.text()[piece_range.start().into()..].starts_with('\\') { stack.add(HighlightedRange { range: piece_range + range.start(), highlight: HighlightTag::EscapeSequence.into(), binding_hash: None, }); } } stack.pop_and_inject(None); } } else if let Some(string) = element_to_highlight.as_token().cloned().and_then(ast::RawString::cast) { if is_format_string { stack.push(); string.lex_format_specifier(|piece_range, kind| { if let Some(highlight) = highlight_format_specifier(kind) { stack.add(HighlightedRange { range: piece_range + range.start(), highlight: highlight.into(), binding_hash: None, }); } }); stack.pop(); } } } } stack.flattened() } #[derive(Debug)] struct HighlightedRangeStack { stack: Vec>, } /// We use a stack to implement the flattening logic for the highlighted /// syntax ranges. impl HighlightedRangeStack { fn new() -> Self { Self { stack: vec![Vec::new()] } } fn push(&mut self) { self.stack.push(Vec::new()); } /// Flattens the highlighted ranges. /// /// For example `#[cfg(feature = "foo")]` contains the nested ranges: /// 1) parent-range: Attribute [0, 23) /// 2) child-range: String [16, 21) /// /// The following code implements the flattening, for our example this results to: /// `[Attribute [0, 16), String [16, 21), Attribute [21, 23)]` fn pop(&mut self) { let children = self.stack.pop().unwrap(); let prev = self.stack.last_mut().unwrap(); let needs_flattening = !children.is_empty() && !prev.is_empty() && prev.last().unwrap().range.contains_range(children.first().unwrap().range); if !needs_flattening { prev.extend(children); } else { let mut parent = prev.pop().unwrap(); for ele in children { assert!(parent.range.contains_range(ele.range)); let cloned = Self::intersect(&mut parent, &ele); if !parent.range.is_empty() { prev.push(parent); } prev.push(ele); parent = cloned; } if !parent.range.is_empty() { prev.push(parent); } } } /// Intersects the `HighlightedRange` `parent` with `child`. /// `parent` is mutated in place, becoming the range before `child`. /// Returns the range (of the same type as `parent`) *after* `child`. fn intersect(parent: &mut HighlightedRange, child: &HighlightedRange) -> HighlightedRange { assert!(parent.range.contains_range(child.range)); let mut cloned = parent.clone(); parent.range = TextRange::new(parent.range.start(), child.range.start()); cloned.range = TextRange::new(child.range.end(), cloned.range.end()); cloned } /// Remove the `HighlightRange` of `parent` that's currently covered by `child`. fn intersect_partial(parent: &mut HighlightedRange, child: &HighlightedRange) { assert!( parent.range.start() <= child.range.start() && parent.range.end() >= child.range.start() && child.range.end() > parent.range.end() ); parent.range = TextRange::new(parent.range.start(), child.range.start()); } /// Similar to `pop`, but can modify arbitrary prior ranges (where `pop`) /// can only modify the last range currently on the stack. /// Can be used to do injections that span multiple ranges, like the /// doctest injection below. /// If `overwrite_parent` is non-optional, the highlighting of the parent range /// is overwritten with the argument. /// /// Note that `pop` can be simulated by `pop_and_inject(false)` but the /// latter is computationally more expensive. fn pop_and_inject(&mut self, overwrite_parent: Option) { let mut children = self.stack.pop().unwrap(); let prev = self.stack.last_mut().unwrap(); children.sort_by_key(|range| range.range.start()); prev.sort_by_key(|range| range.range.start()); for child in children { if let Some(idx) = prev.iter().position(|parent| parent.range.contains_range(child.range)) { if let Some(tag) = overwrite_parent { prev[idx].highlight = tag; } let cloned = Self::intersect(&mut prev[idx], &child); let insert_idx = if prev[idx].range.is_empty() { prev.remove(idx); idx } else { idx + 1 }; prev.insert(insert_idx, child); if !cloned.range.is_empty() { prev.insert(insert_idx + 1, cloned); } } else { let maybe_idx = prev.iter().position(|parent| parent.range.contains(child.range.start())); match (overwrite_parent, maybe_idx) { (Some(_), Some(idx)) => { Self::intersect_partial(&mut prev[idx], &child); let insert_idx = if prev[idx].range.is_empty() { prev.remove(idx); idx } else { idx + 1 }; prev.insert(insert_idx, child); } (_, None) => { let idx = prev .binary_search_by_key(&child.range.start(), |range| range.range.start()) .unwrap_or_else(|x| x); prev.insert(idx, child); } _ => { unreachable!("child range should be completely contained in parent range"); } } } } } fn add(&mut self, range: HighlightedRange) { self.stack .last_mut() .expect("during DFS traversal, the stack must not be empty") .push(range) } fn flattened(mut self) -> Vec { assert_eq!( self.stack.len(), 1, "after DFS traversal, the stack should only contain a single element" ); let mut res = self.stack.pop().unwrap(); res.sort_by_key(|range| range.range.start()); // Check that ranges are sorted and disjoint assert!(res .iter() .zip(res.iter().skip(1)) .all(|(left, right)| left.range.end() <= right.range.start())); res } } fn highlight_format_specifier(kind: FormatSpecifier) -> Option { Some(match kind { FormatSpecifier::Open | FormatSpecifier::Close | FormatSpecifier::Colon | FormatSpecifier::Fill | FormatSpecifier::Align | FormatSpecifier::Sign | FormatSpecifier::NumberSign | FormatSpecifier::DollarSign | FormatSpecifier::Dot | FormatSpecifier::Asterisk | FormatSpecifier::QuestionMark => HighlightTag::FormatSpecifier, FormatSpecifier::Integer | FormatSpecifier::Zero => HighlightTag::NumericLiteral, FormatSpecifier::Identifier => HighlightTag::Local, }) } fn macro_call_range(macro_call: &ast::MacroCall) -> Option { let path = macro_call.path()?; let name_ref = path.segment()?.name_ref()?; let range_start = name_ref.syntax().text_range().start(); let mut range_end = name_ref.syntax().text_range().end(); for sibling in path.syntax().siblings_with_tokens(Direction::Next) { match sibling.kind() { T![!] | IDENT => range_end = sibling.text_range().end(), _ => (), } } Some(TextRange::new(range_start, range_end)) } fn highlight_element( sema: &Semantics, bindings_shadow_count: &mut FxHashMap, syntactic_name_ref_highlighting: bool, element: SyntaxElement, ) -> Option<(Highlight, Option)> { let db = sema.db; let mut binding_hash = None; let highlight: Highlight = match element.kind() { FN => { bindings_shadow_count.clear(); return None; } // Highlight definitions depending on the "type" of the definition. NAME => { let name = element.into_node().and_then(ast::Name::cast).unwrap(); let name_kind = classify_name(sema, &name); if let Some(NameClass::Definition(Definition::Local(local))) = &name_kind { if let Some(name) = local.name(db) { let shadow_count = bindings_shadow_count.entry(name.clone()).or_default(); *shadow_count += 1; binding_hash = Some(calc_binding_hash(&name, *shadow_count)) } }; match name_kind { Some(NameClass::ExternCrate(_)) => HighlightTag::Module.into(), Some(NameClass::Definition(def)) => { highlight_def(db, def) | HighlightModifier::Definition } Some(NameClass::ConstReference(def)) => highlight_def(db, def), Some(NameClass::FieldShorthand { field, .. }) => { let mut h = HighlightTag::Field.into(); if let Definition::Field(field) = field { if let VariantDef::Union(_) = field.parent_def(db) { h |= HighlightModifier::Unsafe; } } h } None => highlight_name_by_syntax(name) | HighlightModifier::Definition, } } // Highlight references like the definitions they resolve to NAME_REF if element.ancestors().any(|it| it.kind() == ATTR) => { Highlight::from(HighlightTag::Function) | HighlightModifier::Attribute } NAME_REF => { let name_ref = element.into_node().and_then(ast::NameRef::cast).unwrap(); highlight_func_by_name_ref(sema, &name_ref).unwrap_or_else(|| { match classify_name_ref(sema, &name_ref) { Some(name_kind) => match name_kind { NameRefClass::ExternCrate(_) => HighlightTag::Module.into(), NameRefClass::Definition(def) => { if let Definition::Local(local) = &def { if let Some(name) = local.name(db) { let shadow_count = bindings_shadow_count.entry(name.clone()).or_default(); binding_hash = Some(calc_binding_hash(&name, *shadow_count)) } }; let mut h = highlight_def(db, def); if let Some(parent) = name_ref.syntax().parent() { if matches!(parent.kind(), FIELD_EXPR | RECORD_PAT_FIELD) { if let Definition::Field(field) = def { if let VariantDef::Union(_) = field.parent_def(db) { h |= HighlightModifier::Unsafe; } } } } h } NameRefClass::FieldShorthand { .. } => HighlightTag::Field.into(), }, None if syntactic_name_ref_highlighting => { highlight_name_ref_by_syntax(name_ref, sema) } None => HighlightTag::UnresolvedReference.into(), } }) } // Simple token-based highlighting COMMENT => { let comment = element.into_token().and_then(ast::Comment::cast)?; let h = HighlightTag::Comment; match comment.kind().doc { Some(_) => h | HighlightModifier::Documentation, None => h.into(), } } STRING | RAW_STRING | RAW_BYTE_STRING | BYTE_STRING => HighlightTag::StringLiteral.into(), ATTR => HighlightTag::Attribute.into(), INT_NUMBER | FLOAT_NUMBER => HighlightTag::NumericLiteral.into(), BYTE => HighlightTag::ByteLiteral.into(), CHAR => HighlightTag::CharLiteral.into(), QUESTION => Highlight::new(HighlightTag::Operator) | HighlightModifier::ControlFlow, LIFETIME => { let h = Highlight::new(HighlightTag::Lifetime); match element.parent().map(|it| it.kind()) { Some(LIFETIME_PARAM) | Some(LABEL) => h | HighlightModifier::Definition, _ => h, } } p if p.is_punct() => match p { T![&] => { let h = HighlightTag::Operator.into(); let is_unsafe = element .parent() .and_then(ast::RefExpr::cast) .map(|ref_expr| sema.is_unsafe_ref_expr(&ref_expr)) .unwrap_or(false); if is_unsafe { h | HighlightModifier::Unsafe } else { h } } T![::] | T![->] | T![=>] | T![..] | T![=] | T![@] => HighlightTag::Operator.into(), T![!] if element.parent().and_then(ast::MacroCall::cast).is_some() => { HighlightTag::Macro.into() } T![*] if element.parent().and_then(ast::PtrType::cast).is_some() => { HighlightTag::Keyword.into() } T![*] if element.parent().and_then(ast::PrefixExpr::cast).is_some() => { let prefix_expr = element.parent().and_then(ast::PrefixExpr::cast)?; let expr = prefix_expr.expr()?; let ty = sema.type_of_expr(&expr)?; if ty.is_raw_ptr() { HighlightTag::Operator | HighlightModifier::Unsafe } else if let Some(ast::PrefixOp::Deref) = prefix_expr.op_kind() { HighlightTag::Operator.into() } else { HighlightTag::Punctuation.into() } } T![-] if element.parent().and_then(ast::PrefixExpr::cast).is_some() => { HighlightTag::NumericLiteral.into() } _ if element.parent().and_then(ast::PrefixExpr::cast).is_some() => { HighlightTag::Operator.into() } _ if element.parent().and_then(ast::BinExpr::cast).is_some() => { HighlightTag::Operator.into() } _ if element.parent().and_then(ast::RangeExpr::cast).is_some() => { HighlightTag::Operator.into() } _ if element.parent().and_then(ast::RangePat::cast).is_some() => { HighlightTag::Operator.into() } _ if element.parent().and_then(ast::RestPat::cast).is_some() => { HighlightTag::Operator.into() } _ if element.parent().and_then(ast::Attr::cast).is_some() => { HighlightTag::Attribute.into() } _ => HighlightTag::Punctuation.into(), }, k if k.is_keyword() => { let h = Highlight::new(HighlightTag::Keyword); match k { T![break] | T![continue] | T![else] | T![if] | T![loop] | T![match] | T![return] | T![while] | T![in] => h | HighlightModifier::ControlFlow, T![for] if !is_child_of_impl(&element) => h | HighlightModifier::ControlFlow, T![unsafe] => h | HighlightModifier::Unsafe, T![true] | T![false] => HighlightTag::BoolLiteral.into(), T![self] => { let self_param_is_mut = element .parent() .and_then(ast::SelfParam::cast) .and_then(|p| p.mut_token()) .is_some(); // closure to enforce lazyness let self_path = || { sema.resolve_path(&element.parent()?.parent().and_then(ast::Path::cast)?) }; if self_param_is_mut || matches!(self_path(), Some(hir::PathResolution::Local(local)) if local.is_self(db) && (local.is_mut(db) || local.ty(db).is_mutable_reference()) ) { HighlightTag::SelfKeyword | HighlightModifier::Mutable } else { HighlightTag::SelfKeyword.into() } } T![ref] => element .parent() .and_then(ast::IdentPat::cast) .and_then(|ident_pat| { if sema.is_unsafe_ident_pat(&ident_pat) { Some(HighlightModifier::Unsafe) } else { None } }) .map(|modifier| h | modifier) .unwrap_or(h), _ => h, } } _ => return None, }; return Some((highlight, binding_hash)); fn calc_binding_hash(name: &Name, shadow_count: u32) -> u64 { fn hash(x: T) -> u64 { use std::{collections::hash_map::DefaultHasher, hash::Hasher}; let mut hasher = DefaultHasher::new(); x.hash(&mut hasher); hasher.finish() } hash((name, shadow_count)) } } fn is_child_of_impl(element: &SyntaxElement) -> bool { match element.parent() { Some(e) => e.kind() == IMPL, _ => false, } } fn highlight_func_by_name_ref( sema: &Semantics, name_ref: &ast::NameRef, ) -> Option { let method_call = name_ref.syntax().parent().and_then(ast::MethodCallExpr::cast)?; highlight_method_call(sema, &method_call) } fn highlight_method_call( sema: &Semantics, method_call: &ast::MethodCallExpr, ) -> Option { let func = sema.resolve_method_call(&method_call)?; let mut h = HighlightTag::Function.into(); if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(&method_call) { h |= HighlightModifier::Unsafe; } if let Some(self_param) = func.self_param(sema.db) { match self_param.access(sema.db) { hir::Access::Shared => (), hir::Access::Exclusive => h |= HighlightModifier::Mutable, hir::Access::Owned => { if let Some(receiver_ty) = method_call.receiver().and_then(|it| sema.type_of_expr(&it)) { if !receiver_ty.is_copy(sema.db) { h |= HighlightModifier::Consuming } } } } } Some(h) } fn highlight_def(db: &RootDatabase, def: Definition) -> Highlight { match def { Definition::Macro(_) => HighlightTag::Macro, Definition::Field(_) => HighlightTag::Field, Definition::ModuleDef(def) => match def { hir::ModuleDef::Module(_) => HighlightTag::Module, hir::ModuleDef::Function(func) => { let mut h = HighlightTag::Function.into(); if func.is_unsafe(db) { h |= HighlightModifier::Unsafe; } if let Some(self_param) = func.self_param(db) { match self_param.access(db) { hir::Access::Exclusive => h |= HighlightModifier::Mutable, hir::Access::Shared | hir::Access::Owned => (), } } return h; } hir::ModuleDef::Adt(hir::Adt::Struct(_)) => HighlightTag::Struct, hir::ModuleDef::Adt(hir::Adt::Enum(_)) => HighlightTag::Enum, hir::ModuleDef::Adt(hir::Adt::Union(_)) => HighlightTag::Union, hir::ModuleDef::EnumVariant(_) => HighlightTag::EnumVariant, hir::ModuleDef::Const(_) => HighlightTag::Constant, hir::ModuleDef::Trait(_) => HighlightTag::Trait, hir::ModuleDef::TypeAlias(_) => HighlightTag::TypeAlias, hir::ModuleDef::BuiltinType(_) => HighlightTag::BuiltinType, hir::ModuleDef::Static(s) => { let mut h = Highlight::new(HighlightTag::Static); if s.is_mut(db) { h |= HighlightModifier::Mutable; h |= HighlightModifier::Unsafe; } return h; } }, Definition::SelfType(_) => HighlightTag::SelfType, Definition::TypeParam(_) => HighlightTag::TypeParam, Definition::Local(local) => { let tag = if local.is_param(db) { HighlightTag::ValueParam } else { HighlightTag::Local }; let mut h = Highlight::new(tag); if local.is_mut(db) || local.ty(db).is_mutable_reference() { h |= HighlightModifier::Mutable; } return h; } } .into() } fn highlight_name_by_syntax(name: ast::Name) -> Highlight { let default = HighlightTag::UnresolvedReference; let parent = match name.syntax().parent() { Some(it) => it, _ => return default.into(), }; let tag = match parent.kind() { STRUCT => HighlightTag::Struct, ENUM => HighlightTag::Enum, UNION => HighlightTag::Union, TRAIT => HighlightTag::Trait, TYPE_ALIAS => HighlightTag::TypeAlias, TYPE_PARAM => HighlightTag::TypeParam, RECORD_FIELD => HighlightTag::Field, MODULE => HighlightTag::Module, FN => HighlightTag::Function, CONST => HighlightTag::Constant, STATIC => HighlightTag::Static, VARIANT => HighlightTag::EnumVariant, IDENT_PAT => HighlightTag::Local, _ => default, }; tag.into() } fn highlight_name_ref_by_syntax(name: ast::NameRef, sema: &Semantics) -> Highlight { let default = HighlightTag::UnresolvedReference; let parent = match name.syntax().parent() { Some(it) => it, _ => return default.into(), }; match parent.kind() { METHOD_CALL_EXPR => { return ast::MethodCallExpr::cast(parent) .and_then(|method_call| highlight_method_call(sema, &method_call)) .unwrap_or_else(|| HighlightTag::Function.into()); } FIELD_EXPR => { let h = HighlightTag::Field; let is_union = ast::FieldExpr::cast(parent) .and_then(|field_expr| { let field = sema.resolve_field(&field_expr)?; Some(if let VariantDef::Union(_) = field.parent_def(sema.db) { true } else { false }) }) .unwrap_or(false); if is_union { h | HighlightModifier::Unsafe } else { h.into() } } PATH_SEGMENT => { let path = match parent.parent().and_then(ast::Path::cast) { Some(it) => it, _ => return default.into(), }; let expr = match path.syntax().parent().and_then(ast::PathExpr::cast) { Some(it) => it, _ => { // within path, decide whether it is module or adt by checking for uppercase name return if name.text().chars().next().unwrap_or_default().is_uppercase() { HighlightTag::Struct } else { HighlightTag::Module } .into(); } }; let parent = match expr.syntax().parent() { Some(it) => it, None => return default.into(), }; match parent.kind() { CALL_EXPR => HighlightTag::Function.into(), _ => if name.text().chars().next().unwrap_or_default().is_uppercase() { HighlightTag::Struct.into() } else { HighlightTag::Constant } .into(), } } _ => default.into(), } }