1 //! See `CompletionContext` structure.
3 use hir::{Local, ScopeDef, Semantics, SemanticsScope, Type};
4 use ide_db::base_db::{FilePosition, SourceDatabase};
5 use ide_db::{call_info::ActiveParameter, RootDatabase};
7 algo::find_node_at_offset, ast, match_ast, AstNode, NodeOrToken, SyntaxKind::*, SyntaxNode,
8 SyntaxToken, TextRange, TextSize,
15 fn_is_prev, for_is_prev2, has_bind_pat_parent, has_block_expr_parent,
16 has_field_list_parent, has_impl_as_prev_sibling, has_impl_parent,
17 has_item_list_or_source_file_parent, has_ref_parent, has_trait_as_prev_sibling,
18 has_trait_parent, if_is_prev, inside_impl_trait_block, is_in_loop_body, is_match_arm,
24 /// `CompletionContext` is created early during completion to figure out, where
25 /// exactly is the cursor, syntax-wise.
27 pub(crate) struct CompletionContext<'a> {
28 pub(super) sema: Semantics<'a, RootDatabase>,
29 pub(super) scope: SemanticsScope<'a>,
30 pub(super) db: &'a RootDatabase,
31 pub(super) config: &'a CompletionConfig,
32 pub(super) position: FilePosition,
33 /// The token before the cursor, in the original file.
34 pub(super) original_token: SyntaxToken,
35 /// The token before the cursor, in the macro-expanded file.
36 pub(super) token: SyntaxToken,
37 pub(super) krate: Option<hir::Crate>,
38 pub(super) expected_type: Option<Type>,
39 pub(super) name_ref_syntax: Option<ast::NameRef>,
40 pub(super) function_syntax: Option<ast::Fn>,
41 pub(super) use_item_syntax: Option<ast::Use>,
42 pub(super) record_lit_syntax: Option<ast::RecordExpr>,
43 pub(super) record_pat_syntax: Option<ast::RecordPat>,
44 pub(super) record_field_syntax: Option<ast::RecordExprField>,
45 pub(super) impl_def: Option<ast::Impl>,
46 /// FIXME: `ActiveParameter` is string-based, which is very very wrong
47 pub(super) active_parameter: Option<ActiveParameter>,
48 pub(super) is_param: bool,
49 /// If a name-binding or reference to a const in a pattern.
50 /// Irrefutable patterns (like let) are excluded.
51 pub(super) is_pat_binding_or_const: bool,
52 pub(super) is_irrefutable_pat_binding: bool,
53 /// A single-indent path, like `foo`. `::foo` should not be considered a trivial path.
54 pub(super) is_trivial_path: bool,
55 /// If not a trivial path, the prefix (qualifier).
56 pub(super) path_qual: Option<ast::Path>,
57 pub(super) after_if: bool,
58 /// `true` if we are a statement or a last expr in the block.
59 pub(super) can_be_stmt: bool,
60 /// `true` if we expect an expression at the cursor position.
61 pub(super) is_expr: bool,
62 /// Something is typed at the "top" level, in module or impl/trait.
63 pub(super) is_new_item: bool,
64 /// The receiver if this is a field or method access, i.e. writing something.$0
65 pub(super) dot_receiver: Option<ast::Expr>,
66 pub(super) dot_receiver_is_ambiguous_float_literal: bool,
67 /// If this is a call (method or function) in particular, i.e. the () are already there.
68 pub(super) is_call: bool,
69 /// Like `is_call`, but for tuple patterns.
70 pub(super) is_pattern_call: bool,
71 /// If this is a macro call, i.e. the () are already there.
72 pub(super) is_macro_call: bool,
73 pub(super) is_path_type: bool,
74 pub(super) has_type_args: bool,
75 pub(super) attribute_under_caret: Option<ast::Attr>,
76 pub(super) mod_declaration_under_caret: Option<ast::Module>,
77 pub(super) unsafe_is_prev: bool,
78 pub(super) if_is_prev: bool,
79 pub(super) block_expr_parent: bool,
80 pub(super) bind_pat_parent: bool,
81 pub(super) ref_pat_parent: bool,
82 pub(super) in_loop_body: bool,
83 pub(super) has_trait_parent: bool,
84 pub(super) has_impl_parent: bool,
85 pub(super) inside_impl_trait_block: bool,
86 pub(super) has_field_list_parent: bool,
87 pub(super) trait_as_prev_sibling: bool,
88 pub(super) impl_as_prev_sibling: bool,
89 pub(super) is_match_arm: bool,
90 pub(super) has_item_list_or_source_file_parent: bool,
91 pub(super) for_is_prev2: bool,
92 pub(super) fn_is_prev: bool,
93 pub(super) incomplete_let: bool,
94 pub(super) locals: Vec<(String, Local)>,
97 impl<'a> CompletionContext<'a> {
100 position: FilePosition,
101 config: &'a CompletionConfig,
102 ) -> Option<CompletionContext<'a>> {
103 let sema = Semantics::new(db);
105 let original_file = sema.parse(position.file_id);
107 // Insert a fake ident to get a valid parse tree. We will use this file
108 // to determine context, though the original_file will be used for
109 // actual completion.
110 let file_with_fake_ident = {
111 let parse = db.parse(position.file_id);
112 let edit = Indel::insert(position.offset, "intellijRulezz".to_string());
113 parse.reparse(&edit).tree()
115 let fake_ident_token =
116 file_with_fake_ident.syntax().token_at_offset(position.offset).right_biased().unwrap();
118 let krate = sema.to_module_def(position.file_id).map(|m| m.krate());
120 original_file.syntax().token_at_offset(position.offset).left_biased()?;
121 let token = sema.descend_into_macros(original_token.clone());
122 let scope = sema.scope_at_offset(&token.parent(), position.offset);
123 let mut locals = vec![];
124 scope.process_all_names(&mut |name, scope| {
125 if let ScopeDef::Local(local) = scope {
126 locals.push((name.to_string(), local));
129 let mut ctx = CompletionContext {
139 name_ref_syntax: None,
140 function_syntax: None,
141 use_item_syntax: None,
142 record_lit_syntax: None,
143 record_pat_syntax: None,
144 record_field_syntax: None,
146 active_parameter: ActiveParameter::at(db, position),
148 is_pat_binding_or_const: false,
149 is_irrefutable_pat_binding: false,
150 is_trivial_path: false,
157 dot_receiver_is_ambiguous_float_literal: false,
159 is_pattern_call: false,
160 is_macro_call: false,
162 has_type_args: false,
163 attribute_under_caret: None,
164 mod_declaration_under_caret: None,
165 unsafe_is_prev: false,
167 block_expr_parent: false,
168 bind_pat_parent: false,
169 ref_pat_parent: false,
171 has_trait_parent: false,
172 has_impl_parent: false,
173 inside_impl_trait_block: false,
174 has_field_list_parent: false,
175 trait_as_prev_sibling: false,
176 impl_as_prev_sibling: false,
178 has_item_list_or_source_file_parent: false,
181 incomplete_let: false,
185 let mut original_file = original_file.syntax().clone();
186 let mut hypothetical_file = file_with_fake_ident.syntax().clone();
187 let mut offset = position.offset;
188 let mut fake_ident_token = fake_ident_token;
190 // Are we inside a macro call?
191 while let (Some(actual_macro_call), Some(macro_call_with_fake_ident)) = (
192 find_node_at_offset::<ast::MacroCall>(&original_file, offset),
193 find_node_at_offset::<ast::MacroCall>(&hypothetical_file, offset),
195 if actual_macro_call.path().as_ref().map(|s| s.syntax().text())
196 != macro_call_with_fake_ident.path().as_ref().map(|s| s.syntax().text())
200 let hypothetical_args = match macro_call_with_fake_ident.token_tree() {
204 if let (Some(actual_expansion), Some(hypothetical_expansion)) = (
205 ctx.sema.expand(&actual_macro_call),
206 ctx.sema.speculative_expand(
212 let new_offset = hypothetical_expansion.1.text_range().start();
213 if new_offset > actual_expansion.text_range().end() {
216 original_file = actual_expansion;
217 hypothetical_file = hypothetical_expansion.0;
218 fake_ident_token = hypothetical_expansion.1;
224 ctx.fill_keyword_patterns(&hypothetical_file, offset);
225 ctx.fill(&original_file, hypothetical_file, offset);
229 /// Checks whether completions in that particular case don't make much sense.
231 /// - `fn $0` -- we expect function name, it's unlikely that "hint" will be helpful.
232 /// Exception for this case is `impl Trait for Foo`, where we would like to hint trait method names.
233 /// - `for _ i$0` -- obviously, it'll be "in" keyword.
234 pub(crate) fn no_completion_required(&self) -> bool {
235 (self.fn_is_prev && !self.inside_impl_trait_block) || self.for_is_prev2
238 /// The range of the identifier that is being completed.
239 pub(crate) fn source_range(&self) -> TextRange {
240 // check kind of macro-expanded token, but use range of original token
241 let kind = self.token.kind();
242 if kind == IDENT || kind == UNDERSCORE || kind.is_keyword() {
243 mark::hit!(completes_if_prefix_is_keyword);
244 self.original_token.text_range()
246 TextRange::empty(self.position.offset)
250 fn fill_keyword_patterns(&mut self, file_with_fake_ident: &SyntaxNode, offset: TextSize) {
251 let fake_ident_token = file_with_fake_ident.token_at_offset(offset).right_biased().unwrap();
252 let syntax_element = NodeOrToken::Token(fake_ident_token);
253 self.block_expr_parent = has_block_expr_parent(syntax_element.clone());
254 self.unsafe_is_prev = unsafe_is_prev(syntax_element.clone());
255 self.if_is_prev = if_is_prev(syntax_element.clone());
256 self.bind_pat_parent = has_bind_pat_parent(syntax_element.clone());
257 self.ref_pat_parent = has_ref_parent(syntax_element.clone());
258 self.in_loop_body = is_in_loop_body(syntax_element.clone());
259 self.has_trait_parent = has_trait_parent(syntax_element.clone());
260 self.has_impl_parent = has_impl_parent(syntax_element.clone());
261 self.inside_impl_trait_block = inside_impl_trait_block(syntax_element.clone());
262 self.has_field_list_parent = has_field_list_parent(syntax_element.clone());
263 self.impl_as_prev_sibling = has_impl_as_prev_sibling(syntax_element.clone());
264 self.trait_as_prev_sibling = has_trait_as_prev_sibling(syntax_element.clone());
265 self.is_match_arm = is_match_arm(syntax_element.clone());
266 self.has_item_list_or_source_file_parent =
267 has_item_list_or_source_file_parent(syntax_element.clone());
268 self.mod_declaration_under_caret =
269 find_node_at_offset::<ast::Module>(&file_with_fake_ident, offset)
270 .filter(|module| module.item_list().is_none());
271 self.for_is_prev2 = for_is_prev2(syntax_element.clone());
272 self.fn_is_prev = fn_is_prev(syntax_element.clone());
273 self.incomplete_let =
274 syntax_element.ancestors().take(6).find_map(ast::LetStmt::cast).map_or(false, |it| {
275 it.syntax().text_range().end() == syntax_element.text_range().end()
279 fn fill_impl_def(&mut self) {
282 .ancestors_with_macros(self.token.parent())
283 .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
284 .find_map(ast::Impl::cast);
289 original_file: &SyntaxNode,
290 file_with_fake_ident: SyntaxNode,
293 // FIXME: this is wrong in at least two cases:
294 // * when there's no token `foo($0)`
295 // * when there is a token, but it happens to have type of it's own
296 self.expected_type = self
300 let ty = match_ast! {
302 ast::Pat(it) => self.sema.type_of_pat(&it),
303 ast::Expr(it) => self.sema.type_of_expr(&it),
310 self.attribute_under_caret = find_node_at_offset(&file_with_fake_ident, offset);
312 // First, let's try to complete a reference to some declaration.
313 if let Some(name_ref) = find_node_at_offset::<ast::NameRef>(&file_with_fake_ident, offset) {
314 // Special case, `trait T { fn foo(i_am_a_name_ref) {} }`.
316 if is_node::<ast::Param>(name_ref.syntax()) {
317 self.is_param = true;
320 // FIXME: remove this (V) duplication and make the check more precise
321 if name_ref.syntax().ancestors().find_map(ast::RecordPatFieldList::cast).is_some() {
322 self.record_pat_syntax =
323 self.sema.find_node_at_offset_with_macros(&original_file, offset);
325 self.classify_name_ref(original_file, name_ref, offset);
328 // Otherwise, see if this is a declaration. We can use heuristics to
329 // suggest declaration names, see `CompletionKind::Magic`.
330 if let Some(name) = find_node_at_offset::<ast::Name>(&file_with_fake_ident, offset) {
331 if let Some(bind_pat) = name.syntax().ancestors().find_map(ast::IdentPat::cast) {
332 self.is_pat_binding_or_const = true;
333 if bind_pat.at_token().is_some()
334 || bind_pat.ref_token().is_some()
335 || bind_pat.mut_token().is_some()
337 self.is_pat_binding_or_const = false;
339 if bind_pat.syntax().parent().and_then(ast::RecordPatFieldList::cast).is_some() {
340 self.is_pat_binding_or_const = false;
342 if let Some(Some(pat)) = bind_pat.syntax().ancestors().find_map(|node| {
345 ast::LetStmt(it) => Some(it.pat()),
346 ast::Param(it) => Some(it.pat()),
351 if pat.syntax().text_range().contains_range(bind_pat.syntax().text_range()) {
352 self.is_pat_binding_or_const = false;
353 self.is_irrefutable_pat_binding = true;
357 self.fill_impl_def();
359 if is_node::<ast::Param>(name.syntax()) {
360 self.is_param = true;
363 // FIXME: remove this (^) duplication and make the check more precise
364 if name.syntax().ancestors().find_map(ast::RecordPatFieldList::cast).is_some() {
365 self.record_pat_syntax =
366 self.sema.find_node_at_offset_with_macros(&original_file, offset);
371 fn classify_name_ref(
373 original_file: &SyntaxNode,
374 name_ref: ast::NameRef,
377 self.name_ref_syntax =
378 find_node_at_offset(&original_file, name_ref.syntax().text_range().start());
379 let name_range = name_ref.syntax().text_range();
380 if ast::RecordExprField::for_field_name(&name_ref).is_some() {
381 self.record_lit_syntax =
382 self.sema.find_node_at_offset_with_macros(&original_file, offset);
385 self.fill_impl_def();
387 let top_node = name_ref
390 .take_while(|it| it.text_range() == name_range)
394 match top_node.parent().map(|it| it.kind()) {
395 Some(SOURCE_FILE) | Some(ITEM_LIST) => {
396 self.is_new_item = true;
402 self.use_item_syntax =
403 self.sema.ancestors_with_macros(self.token.parent()).find_map(ast::Use::cast);
405 self.function_syntax = self
407 .ancestors_with_macros(self.token.parent())
408 .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
409 .find_map(ast::Fn::cast);
411 self.record_field_syntax = self
413 .ancestors_with_macros(self.token.parent())
415 it.kind() != SOURCE_FILE && it.kind() != MODULE && it.kind() != CALL_EXPR
417 .find_map(ast::RecordExprField::cast);
419 let parent = match name_ref.syntax().parent() {
424 if let Some(segment) = ast::PathSegment::cast(parent.clone()) {
425 let path = segment.parent_path();
429 .and_then(ast::PathExpr::cast)
430 .and_then(|it| it.syntax().parent().and_then(ast::CallExpr::cast))
432 self.is_macro_call = path.syntax().parent().and_then(ast::MacroCall::cast).is_some();
433 self.is_pattern_call =
434 path.syntax().parent().and_then(ast::TupleStructPat::cast).is_some();
436 self.is_path_type = path.syntax().parent().and_then(ast::PathType::cast).is_some();
437 self.has_type_args = segment.generic_arg_list().is_some();
439 if let Some(path) = path_or_use_tree_qualifier(&path) {
440 self.path_qual = path
443 find_node_with_range::<ast::PathSegment>(
445 it.syntax().text_range(),
448 .map(|it| it.parent_path());
452 if let Some(segment) = path.segment() {
453 if segment.coloncolon_token().is_some() {
458 self.is_trivial_path = true;
460 // Find either enclosing expr statement (thing with `;`) or a
461 // block. If block, check that we are the last expr.
462 self.can_be_stmt = name_ref
466 if let Some(stmt) = ast::ExprStmt::cast(node.clone()) {
467 return Some(stmt.syntax().text_range() == name_ref.syntax().text_range());
469 if let Some(block) = ast::BlockExpr::cast(node) {
471 block.tail_expr().map(|e| e.syntax().text_range())
472 == Some(name_ref.syntax().text_range()),
478 self.is_expr = path.syntax().parent().and_then(ast::PathExpr::cast).is_some();
480 if let Some(off) = name_ref.syntax().text_range().start().checked_sub(2.into()) {
481 if let Some(if_expr) =
482 self.sema.find_node_at_offset_with_macros::<ast::IfExpr>(original_file, off)
484 if if_expr.syntax().text_range().end() < name_ref.syntax().text_range().start()
486 self.after_if = true;
491 if let Some(field_expr) = ast::FieldExpr::cast(parent.clone()) {
492 // The receiver comes before the point of insertion of the fake
493 // ident, so it should have the same range in the non-modified file
494 self.dot_receiver = field_expr
496 .map(|e| e.syntax().text_range())
497 .and_then(|r| find_node_with_range(original_file, r));
498 self.dot_receiver_is_ambiguous_float_literal =
499 if let Some(ast::Expr::Literal(l)) = &self.dot_receiver {
501 ast::LiteralKind::FloatNumber { .. } => l.token().text().ends_with('.'),
508 if let Some(method_call_expr) = ast::MethodCallExpr::cast(parent) {
510 self.dot_receiver = method_call_expr
512 .map(|e| e.syntax().text_range())
513 .and_then(|r| find_node_with_range(original_file, r));
519 fn find_node_with_range<N: AstNode>(syntax: &SyntaxNode, range: TextRange) -> Option<N> {
520 syntax.covering_element(range).ancestors().find_map(N::cast)
523 fn is_node<N: AstNode>(node: &SyntaxNode) -> bool {
524 match node.ancestors().find_map(N::cast) {
526 Some(n) => n.syntax().text_range() == node.text_range(),
530 fn path_or_use_tree_qualifier(path: &ast::Path) -> Option<ast::Path> {
531 if let Some(qual) = path.qualifier() {
534 let use_tree_list = path.syntax().ancestors().find_map(ast::UseTreeList::cast)?;
535 let use_tree = use_tree_list.syntax().parent().and_then(ast::UseTree::cast)?;