1 //! Name resolution for expressions.
4 use hir_expand::name::Name;
5 use la_arena::{Arena, Idx};
6 use rustc_hash::FxHashMap;
11 expr::{Expr, ExprId, LabelId, MatchGuard, Pat, PatId, Statement},
12 BlockId, DefWithBodyId,
15 pub type ScopeId = Idx<ScopeData>;
17 #[derive(Debug, PartialEq, Eq)]
18 pub struct ExprScopes {
19 scopes: Arena<ScopeData>,
20 scope_by_expr: FxHashMap<ExprId, ScopeId>,
23 #[derive(Debug, PartialEq, Eq)]
24 pub struct ScopeEntry {
30 pub fn name(&self) -> &Name {
34 pub fn pat(&self) -> PatId {
39 #[derive(Debug, PartialEq, Eq)]
40 pub struct ScopeData {
41 parent: Option<ScopeId>,
42 block: Option<BlockId>,
43 label: Option<(LabelId, Name)>,
44 entries: Vec<ScopeEntry>,
48 pub(crate) fn expr_scopes_query(db: &dyn DefDatabase, def: DefWithBodyId) -> Arc<ExprScopes> {
49 let body = db.body(def);
50 Arc::new(ExprScopes::new(&*body))
53 fn new(body: &Body) -> ExprScopes {
55 ExprScopes { scopes: Arena::default(), scope_by_expr: FxHashMap::default() };
56 let root = scopes.root_scope();
57 scopes.add_params_bindings(body, root, &body.params);
58 compute_expr_scopes(body.body_expr, body, &mut scopes, root);
62 pub fn entries(&self, scope: ScopeId) -> &[ScopeEntry] {
63 &self.scopes[scope].entries
66 /// If `scope` refers to a block expression scope, returns the corresponding `BlockId`.
67 pub fn block(&self, scope: ScopeId) -> Option<BlockId> {
68 self.scopes[scope].block
71 /// If `scope` refers to a labeled expression scope, returns the corresponding `Label`.
72 pub fn label(&self, scope: ScopeId) -> Option<(LabelId, Name)> {
73 self.scopes[scope].label.clone()
76 pub fn scope_chain(&self, scope: Option<ScopeId>) -> impl Iterator<Item = ScopeId> + '_ {
77 std::iter::successors(scope, move |&scope| self.scopes[scope].parent)
80 pub fn resolve_name_in_scope(&self, scope: ScopeId, name: &Name) -> Option<&ScopeEntry> {
81 self.scope_chain(Some(scope))
82 .find_map(|scope| self.entries(scope).iter().find(|it| it.name == *name))
85 pub fn scope_for(&self, expr: ExprId) -> Option<ScopeId> {
86 self.scope_by_expr.get(&expr).copied()
89 pub fn scope_by_expr(&self) -> &FxHashMap<ExprId, ScopeId> {
93 fn root_scope(&mut self) -> ScopeId {
94 self.scopes.alloc(ScopeData { parent: None, block: None, label: None, entries: vec![] })
97 fn new_scope(&mut self, parent: ScopeId) -> ScopeId {
98 self.scopes.alloc(ScopeData {
106 fn new_labeled_scope(&mut self, parent: ScopeId, label: Option<(LabelId, Name)>) -> ScopeId {
107 self.scopes.alloc(ScopeData { parent: Some(parent), block: None, label, entries: vec![] })
114 label: Option<(LabelId, Name)>,
116 self.scopes.alloc(ScopeData {
117 parent: Some(parent),
124 fn add_bindings(&mut self, body: &Body, scope: ScopeId, pat: PatId) {
125 let pattern = &body[pat];
126 if let Pat::Bind { name, .. } = pattern {
127 let entry = ScopeEntry { name: name.clone(), pat };
128 self.scopes[scope].entries.push(entry);
131 pattern.walk_child_pats(|pat| self.add_bindings(body, scope, pat));
134 fn add_params_bindings(&mut self, body: &Body, scope: ScopeId, params: &[PatId]) {
135 params.iter().for_each(|pat| self.add_bindings(body, scope, *pat));
138 fn set_scope(&mut self, node: ExprId, scope: ScopeId) {
139 self.scope_by_expr.insert(node, scope);
143 fn compute_block_scopes(
144 statements: &[Statement],
145 tail: Option<ExprId>,
147 scopes: &mut ExprScopes,
150 for stmt in statements {
152 Statement::Let { pat, initializer, else_branch, .. } => {
153 if let Some(expr) = initializer {
154 compute_expr_scopes(*expr, body, scopes, scope);
156 if let Some(expr) = else_branch {
157 compute_expr_scopes(*expr, body, scopes, scope);
159 scope = scopes.new_scope(scope);
160 scopes.add_bindings(body, scope, *pat);
162 Statement::Expr { expr, .. } => {
163 compute_expr_scopes(*expr, body, scopes, scope);
167 if let Some(expr) = tail {
168 compute_expr_scopes(expr, body, scopes, scope);
172 fn compute_expr_scopes(expr: ExprId, body: &Body, scopes: &mut ExprScopes, scope: ScopeId) {
174 |label: &Option<LabelId>| label.map(|label| (label, body.labels[label].name.clone()));
176 scopes.set_scope(expr, scope);
178 Expr::Block { statements, tail, id, label } => {
179 let scope = scopes.new_block_scope(scope, *id, make_label(label));
180 // Overwrite the old scope for the block expr, so that every block scope can be found
181 // via the block itself (important for blocks that only contain items, no expressions).
182 scopes.set_scope(expr, scope);
183 compute_block_scopes(statements, *tail, body, scopes, scope);
185 Expr::For { iterable, pat, body: body_expr, label } => {
186 compute_expr_scopes(*iterable, body, scopes, scope);
187 let scope = scopes.new_labeled_scope(scope, make_label(label));
188 scopes.add_bindings(body, scope, *pat);
189 compute_expr_scopes(*body_expr, body, scopes, scope);
191 Expr::While { condition, body: body_expr, label } => {
192 let scope = scopes.new_labeled_scope(scope, make_label(label));
193 compute_expr_scopes(*condition, body, scopes, scope);
194 compute_expr_scopes(*body_expr, body, scopes, scope);
196 Expr::Loop { body: body_expr, label } => {
197 let scope = scopes.new_labeled_scope(scope, make_label(label));
198 compute_expr_scopes(*body_expr, body, scopes, scope);
200 Expr::Lambda { args, body: body_expr, .. } => {
201 let scope = scopes.new_scope(scope);
202 scopes.add_params_bindings(body, scope, args);
203 compute_expr_scopes(*body_expr, body, scopes, scope);
205 Expr::Match { expr, arms } => {
206 compute_expr_scopes(*expr, body, scopes, scope);
207 for arm in arms.iter() {
208 let mut scope = scopes.new_scope(scope);
209 scopes.add_bindings(body, scope, arm.pat);
211 Some(MatchGuard::If { expr: guard }) => {
212 scopes.set_scope(guard, scope);
213 compute_expr_scopes(guard, body, scopes, scope);
215 Some(MatchGuard::IfLet { pat, expr: guard }) => {
216 scopes.set_scope(guard, scope);
217 compute_expr_scopes(guard, body, scopes, scope);
218 scope = scopes.new_scope(scope);
219 scopes.add_bindings(body, scope, pat);
223 scopes.set_scope(arm.expr, scope);
224 compute_expr_scopes(arm.expr, body, scopes, scope);
227 e => e.walk_child_exprs(|e| compute_expr_scopes(e, body, scopes, scope)),
233 use base_db::{fixture::WithFixture, FileId, SourceDatabase};
234 use hir_expand::{name::AsName, InFile};
235 use syntax::{algo::find_node_at_offset, ast, AstNode};
236 use test_utils::{assert_eq_text, extract_offset};
238 use crate::{db::DefDatabase, test_db::TestDB, FunctionId, ModuleDefId};
240 fn find_function(db: &TestDB, file_id: FileId) -> FunctionId {
241 let krate = db.test_crate();
242 let crate_def_map = db.crate_def_map(krate);
244 let module = crate_def_map.modules_for_file(file_id).next().unwrap();
245 let (_, def) = crate_def_map[module].scope.entries().next().unwrap();
246 match def.take_values().unwrap() {
247 ModuleDefId::FunctionId(it) => it,
252 fn do_check(ra_fixture: &str, expected: &[&str]) {
253 let (offset, code) = extract_offset(ra_fixture);
255 let mut buf = String::new();
256 let off: usize = offset.into();
257 buf.push_str(&code[..off]);
258 buf.push_str("$0marker");
259 buf.push_str(&code[off..]);
263 let (db, position) = TestDB::with_position(&code);
264 let file_id = position.file_id;
265 let offset = position.offset;
267 let file_syntax = db.parse(file_id).syntax_node();
268 let marker: ast::PathExpr = find_node_at_offset(&file_syntax, offset).unwrap();
269 let function = find_function(&db, file_id);
271 let scopes = db.expr_scopes(function.into());
272 let (_body, source_map) = db.body_with_source_map(function.into());
274 let expr_id = source_map
275 .node_expr(InFile { file_id: file_id.into(), value: &marker.into() })
277 let scope = scopes.scope_for(expr_id);
281 .flat_map(|scope| scopes.entries(scope))
282 .map(|it| it.name().to_smol_str())
285 let expected = expected.join("\n");
286 assert_eq_text!(&expected, &actual);
290 fn test_lambda_scope() {
294 let f = |bar, baz: i32| {
298 &["bar", "baz", "foo"],
303 fn test_call_scope() {
314 fn test_method_call_scope() {
325 fn test_loop_scope() {
354 fn test_shadow_variable() {
365 fn test_bindings_after_at() {
370 opt @ Some(unit) => {
382 fn macro_inner_item() {
402 fn broken_inner_item() {
414 fn do_check_local_name(ra_fixture: &str, expected_offset: u32) {
415 let (db, position) = TestDB::with_position(ra_fixture);
416 let file_id = position.file_id;
417 let offset = position.offset;
419 let file = db.parse(file_id).ok().unwrap();
420 let expected_name = find_node_at_offset::<ast::Name>(file.syntax(), expected_offset.into())
421 .expect("failed to find a name at the target offset");
422 let name_ref: ast::NameRef = find_node_at_offset(file.syntax(), offset).unwrap();
424 let function = find_function(&db, file_id);
426 let scopes = db.expr_scopes(function.into());
427 let (_body, source_map) = db.body_with_source_map(function.into());
430 let expr_ast = name_ref.syntax().ancestors().find_map(ast::Expr::cast).unwrap();
432 source_map.node_expr(InFile { file_id: file_id.into(), value: &expr_ast }).unwrap();
433 scopes.scope_for(expr_id).unwrap()
436 let resolved = scopes.resolve_name_in_scope(expr_scope, &name_ref.as_name()).unwrap();
437 let pat_src = source_map.pat_syntax(resolved.pat()).unwrap();
439 let local_name = pat_src.value.either(
440 |it| it.syntax_node_ptr().to_node(file.syntax()),
441 |it| it.syntax_node_ptr().to_node(file.syntax()),
443 assert_eq!(local_name.text_range(), expected_name.syntax().text_range());
447 fn test_resolve_local_name() {
450 fn foo(x: i32, y: u32) {
464 fn test_resolve_local_name_declaration() {
476 fn test_resolve_local_name_shadow() {
489 fn ref_patterns_contribute_bindings() {
493 if let Some(&from) = bar() {
503 fn while_let_desugaring() {
504 cov_mark::check!(infer_resolve_while_let);
508 let foo: Option<f32> = None;
509 while let Option::Some(spam) = foo {