9 use hir::{HasSource, Semantics};
13 helpers::{pick_best_token, FamousDefs},
14 FxIndexSet, RootDatabase,
16 use itertools::Itertools;
17 use syntax::{ast, match_ast, AstNode, SyntaxKind::*, SyntaxNode, SyntaxToken, T};
20 doc_links::token_as_doc_comment,
22 runnables::{runnable_fn, runnable_mod},
23 FileId, FilePosition, NavigationTarget, RangeInfo, Runnable, TryToNav,
26 #[derive(Clone, Debug, PartialEq, Eq)]
27 pub struct HoverConfig {
28 pub links_in_hover: bool,
29 pub documentation: Option<HoverDocFormat>,
33 fn markdown(&self) -> bool {
34 matches!(self.documentation, Some(HoverDocFormat::Markdown))
38 #[derive(Clone, Debug, PartialEq, Eq)]
39 pub enum HoverDocFormat {
44 #[derive(Debug, Clone)]
45 pub enum HoverAction {
47 Implementation(FilePosition),
48 Reference(FilePosition),
49 GoToType(Vec<HoverGotoTypeData>),
53 fn goto_type_from_targets(db: &RootDatabase, targets: Vec<hir::ModuleDef>) -> Self {
57 Some(HoverGotoTypeData {
58 mod_path: render::path(
61 it.name(db).map(|name| name.to_string()),
63 nav: it.try_to_nav(db)?,
67 HoverAction::GoToType(targets)
71 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
72 pub struct HoverGotoTypeData {
74 pub nav: NavigationTarget,
77 /// Contains the results when hovering over an item
78 #[derive(Debug, Default)]
79 pub struct HoverResult {
81 pub actions: Vec<HoverAction>,
86 // Shows additional information, like the type of an expression or the documentation for a definition when "focusing" code.
87 // Focusing is usually hovering with a mouse, but can also be triggered with a shortcut.
89 // image::https://user-images.githubusercontent.com/48062697/113020658-b5f98b80-917a-11eb-9f88-3dbc27320c95.gif[]
92 FileRange { file_id, range }: FileRange,
94 ) -> Option<RangeInfo<HoverResult>> {
95 let sema = &hir::Semantics::new(db);
96 let file = sema.parse(file_id).syntax().clone();
98 if !range.is_empty() {
99 return hover_ranged(&file, range, sema, config);
101 let offset = range.start();
103 let original_token = pick_best_token(file.token_at_offset(offset), |kind| match kind {
104 IDENT | INT_NUMBER | LIFETIME_IDENT | T![self] | T![super] | T![crate] => 3,
105 T!['('] | T![')'] => 2,
106 kind if kind.is_trivia() => 0,
110 if let Some(doc_comment) = token_as_doc_comment(&original_token) {
111 cov_mark::hit!(no_highlight_on_comment_hover);
112 return doc_comment.get_definition_with_descend_at(sema, offset, |def, node, range| {
113 let res = hover_for_definition(sema, file_id, def, &node, config)?;
114 Some(RangeInfo::new(range, res))
118 let descended = sema.descend_into_macros(original_token.clone());
120 // FIXME: Definition should include known lints and the like instead of having this special case here
121 if let Some(res) = descended.iter().find_map(|token| {
122 let attr = token.ancestors().find_map(ast::Attr::cast)?;
123 render::try_for_lint(&attr, token)
125 return Some(RangeInfo::new(original_token.text_range(), res));
128 let result = descended
130 .filter_map(|token| {
131 let node = token.parent()?;
132 let defs = Definition::from_token(sema, token);
133 Some(defs.into_iter().zip(iter::once(node).cycle()))
136 .unique_by(|&(def, _)| def)
137 .filter_map(|(def, node)| hover_for_definition(sema, file_id, def, &node, config))
138 .reduce(|mut acc: HoverResult, HoverResult { markup, actions }| {
139 acc.actions.extend(actions);
140 acc.markup = Markup::from(format!("{}\n---\n{}", acc.markup, markup));
144 if result.is_none() {
145 // fallbacks, show keywords or types
146 if let Some(res) = render::keyword(sema, config, &original_token) {
147 return Some(RangeInfo::new(original_token.text_range(), res));
149 if let res @ Some(_) =
150 descended.iter().find_map(|token| hover_type_fallback(sema, config, token))
155 result.map(|mut res: HoverResult| {
156 res.actions = dedupe_or_merge_hover_actions(res.actions);
157 RangeInfo::new(original_token.text_range(), res)
161 pub(crate) fn hover_for_definition(
162 sema: &Semantics<RootDatabase>,
164 definition: Definition,
166 config: &HoverConfig,
167 ) -> Option<HoverResult> {
168 let famous_defs = match &definition {
169 Definition::BuiltinType(_) => Some(FamousDefs(sema, sema.scope(node).krate())),
172 if let Some(markup) = render::definition(sema.db, definition, famous_defs.as_ref(), config) {
173 let mut res = HoverResult::default();
174 res.markup = render::process_markup(sema.db, definition, &markup, config);
175 if let Some(action) = show_implementations_action(sema.db, definition) {
176 res.actions.push(action);
179 if let Some(action) = show_fn_references_action(sema.db, definition) {
180 res.actions.push(action);
183 if let Some(action) = runnable_action(sema, definition, file_id) {
184 res.actions.push(action);
187 if let Some(action) = goto_type_action_for_def(sema.db, definition) {
188 res.actions.push(action);
197 range: syntax::TextRange,
198 sema: &Semantics<RootDatabase>,
199 config: &HoverConfig,
200 ) -> Option<RangeInfo<HoverResult>> {
201 let expr_or_pat = file.covering_element(range).ancestors().find_map(|it| {
204 ast::Expr(expr) => Some(Either::Left(expr)),
205 ast::Pat(pat) => Some(Either::Right(pat)),
210 let res = match &expr_or_pat {
211 Either::Left(ast::Expr::TryExpr(try_expr)) => render::try_expr(sema, config, try_expr),
212 Either::Left(ast::Expr::PrefixExpr(prefix_expr))
213 if prefix_expr.op_kind() == Some(ast::UnaryOp::Deref) =>
215 render::deref_expr(sema, config, prefix_expr)
219 let res = res.or_else(|| render::type_info(sema, config, &expr_or_pat));
221 let range = match expr_or_pat {
222 Either::Left(it) => it.syntax().text_range(),
223 Either::Right(it) => it.syntax().text_range(),
225 RangeInfo::new(range, it)
229 fn hover_type_fallback(
230 sema: &Semantics<RootDatabase>,
231 config: &HoverConfig,
233 ) -> Option<RangeInfo<HoverResult>> {
236 .take_while(|it| !ast::Item::can_cast(it.kind()))
237 .find(|n| ast::Expr::can_cast(n.kind()) || ast::Pat::can_cast(n.kind()))?;
239 let expr_or_pat = match_ast! {
241 ast::Expr(it) => Either::Left(it),
242 ast::Pat(it) => Either::Right(it),
243 // If this node is a MACRO_CALL, it means that `descend_into_macros_many` failed to resolve.
244 // (e.g expanding a builtin macro). So we give up here.
245 ast::MacroCall(_it) => return None,
250 let res = render::type_info(sema, config, &expr_or_pat)?;
251 let range = sema.original_range(&node).range;
252 Some(RangeInfo::new(range, res))
255 fn show_implementations_action(db: &RootDatabase, def: Definition) -> Option<HoverAction> {
256 fn to_action(nav_target: NavigationTarget) -> HoverAction {
257 HoverAction::Implementation(FilePosition {
258 file_id: nav_target.file_id,
259 offset: nav_target.focus_or_full_range().start(),
263 let adt = match def {
264 Definition::Trait(it) => return it.try_to_nav(db).map(to_action),
265 Definition::Adt(it) => Some(it),
266 Definition::SelfType(it) => it.self_ty(db).as_adt(),
269 adt.try_to_nav(db).map(to_action)
272 fn show_fn_references_action(db: &RootDatabase, def: Definition) -> Option<HoverAction> {
274 Definition::Function(it) => it.try_to_nav(db).map(|nav_target| {
275 HoverAction::Reference(FilePosition {
276 file_id: nav_target.file_id,
277 offset: nav_target.focus_or_full_range().start(),
285 sema: &hir::Semantics<RootDatabase>,
288 ) -> Option<HoverAction> {
290 Definition::Module(it) => runnable_mod(sema, it).map(HoverAction::Runnable),
291 Definition::Function(func) => {
292 let src = func.source(sema.db)?;
293 if src.file_id != file_id.into() {
294 cov_mark::hit!(hover_macro_generated_struct_fn_doc_comment);
295 cov_mark::hit!(hover_macro_generated_struct_fn_doc_attr);
299 runnable_fn(sema, func).map(HoverAction::Runnable)
305 fn goto_type_action_for_def(db: &RootDatabase, def: Definition) -> Option<HoverAction> {
306 let mut targets: Vec<hir::ModuleDef> = Vec::new();
307 let mut push_new_def = |item: hir::ModuleDef| {
308 if !targets.contains(&item) {
313 if let Definition::GenericParam(hir::GenericParam::TypeParam(it)) = def {
314 it.trait_bounds(db).into_iter().for_each(|it| push_new_def(it.into()));
317 Definition::Local(it) => it.ty(db),
318 Definition::GenericParam(hir::GenericParam::ConstParam(it)) => it.ty(db),
319 Definition::Field(field) => field.ty(db),
320 Definition::Function(function) => function.ret_type(db),
324 walk_and_push_ty(db, &ty, &mut push_new_def);
327 Some(HoverAction::goto_type_from_targets(db, targets))
333 push_new_def: &mut dyn FnMut(hir::ModuleDef),
336 if let Some(adt) = t.as_adt() {
337 push_new_def(adt.into());
338 } else if let Some(trait_) = t.as_dyn_trait() {
339 push_new_def(trait_.into());
340 } else if let Some(traits) = t.as_impl_traits(db) {
341 traits.into_iter().for_each(|it| push_new_def(it.into()));
342 } else if let Some(trait_) = t.as_associated_type_parent_trait(db) {
343 push_new_def(trait_.into());
348 fn dedupe_or_merge_hover_actions(actions: Vec<HoverAction>) -> Vec<HoverAction> {
349 let mut deduped_actions = Vec::with_capacity(actions.len());
350 let mut go_to_type_targets = FxIndexSet::default();
352 let mut seen_implementation = false;
353 let mut seen_reference = false;
354 let mut seen_runnable = false;
355 for action in actions {
357 HoverAction::GoToType(targets) => {
358 go_to_type_targets.extend(targets);
360 HoverAction::Implementation(..) => {
361 if !seen_implementation {
362 seen_implementation = true;
363 deduped_actions.push(action);
366 HoverAction::Reference(..) => {
368 seen_reference = true;
369 deduped_actions.push(action);
372 HoverAction::Runnable(..) => {
374 seen_runnable = true;
375 deduped_actions.push(action);
381 if !go_to_type_targets.is_empty() {
382 deduped_actions.push(HoverAction::GoToType(go_to_type_targets.into_iter().collect()));