crates/ide_completion/src/context.rs

   1 //! See `CompletionContext` structure.
   2
   3 use hir::{Local, ScopeDef, Semantics, SemanticsScope, Type};
   4 use ide_db::base_db::{FilePosition, SourceDatabase};
   5 use ide_db::{call_info::ActiveParameter, RootDatabase};
   6 use syntax::{
   7     algo::find_node_at_offset, ast, match_ast, AstNode, NodeOrToken, SyntaxKind::*, SyntaxNode,
   8     SyntaxToken, TextRange, TextSize,
   9 };
  10
  11 use text_edit::Indel;
  12
  13 use crate::{
  14     patterns::{
  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,
  19         unsafe_is_prev,
  20     },
  21     CompletionConfig,
  22 };
  23
  24 /// `CompletionContext` is created early during completion to figure out, where
  25 /// exactly is the cursor, syntax-wise.
  26 #[derive(Debug)]
  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_name: Option<String>,
  39     pub(super) expected_type: Option<Type>,
  40     pub(super) name_ref_syntax: Option<ast::NameRef>,
  41     pub(super) function_syntax: Option<ast::Fn>,
  42     pub(super) use_item_syntax: Option<ast::Use>,
  43     pub(super) record_lit_syntax: Option<ast::RecordExpr>,
  44     pub(super) record_pat_syntax: Option<ast::RecordPat>,
  45     pub(super) record_field_syntax: Option<ast::RecordExprField>,
  46     pub(super) impl_def: Option<ast::Impl>,
  47     /// FIXME: `ActiveParameter` is string-based, which is very very wrong
  48     pub(super) active_parameter: Option<ActiveParameter>,
  49     pub(super) is_param: bool,
  50     /// If a name-binding or reference to a const in a pattern.
  51     /// Irrefutable patterns (like let) are excluded.
  52     pub(super) is_pat_binding_or_const: bool,
  53     pub(super) is_irrefutable_pat_binding: bool,
  54     /// A single-indent path, like `foo`. `::foo` should not be considered a trivial path.
  55     pub(super) is_trivial_path: bool,
  56     /// If not a trivial path, the prefix (qualifier).
  57     pub(super) path_qual: Option<ast::Path>,
  58     pub(super) after_if: bool,
  59     /// `true` if we are a statement or a last expr in the block.
  60     pub(super) can_be_stmt: bool,
  61     /// `true` if we expect an expression at the cursor position.
  62     pub(super) is_expr: bool,
  63     /// Something is typed at the "top" level, in module or impl/trait.
  64     pub(super) is_new_item: bool,
  65     /// The receiver if this is a field or method access, i.e. writing something.$0
  66     pub(super) dot_receiver: Option<ast::Expr>,
  67     pub(super) dot_receiver_is_ambiguous_float_literal: bool,
  68     /// If this is a call (method or function) in particular, i.e. the () are already there.
  69     pub(super) is_call: bool,
  70     /// Like `is_call`, but for tuple patterns.
  71     pub(super) is_pattern_call: bool,
  72     /// If this is a macro call, i.e. the () are already there.
  73     pub(super) is_macro_call: bool,
  74     pub(super) is_path_type: bool,
  75     pub(super) has_type_args: bool,
  76     pub(super) attribute_under_caret: Option<ast::Attr>,
  77     pub(super) mod_declaration_under_caret: Option<ast::Module>,
  78     pub(super) unsafe_is_prev: bool,
  79     pub(super) if_is_prev: bool,
  80     pub(super) block_expr_parent: bool,
  81     pub(super) bind_pat_parent: bool,
  82     pub(super) ref_pat_parent: bool,
  83     pub(super) in_loop_body: bool,
  84     pub(super) has_trait_parent: bool,
  85     pub(super) has_impl_parent: bool,
  86     pub(super) inside_impl_trait_block: bool,
  87     pub(super) has_field_list_parent: bool,
  88     pub(super) trait_as_prev_sibling: bool,
  89     pub(super) impl_as_prev_sibling: bool,
  90     pub(super) is_match_arm: bool,
  91     pub(super) has_item_list_or_source_file_parent: bool,
  92     pub(super) for_is_prev2: bool,
  93     pub(super) fn_is_prev: bool,
  94     pub(super) incomplete_let: bool,
  95     pub(super) locals: Vec<(String, Local)>,
  96 }
  97
  98 impl<'a> CompletionContext<'a> {
  99     pub(super) fn new(
 100         db: &'a RootDatabase,
 101         position: FilePosition,
 102         config: &'a CompletionConfig,
 103     ) -> Option<CompletionContext<'a>> {
 104         let sema = Semantics::new(db);
 105
 106         let original_file = sema.parse(position.file_id);
 107
 108         // Insert a fake ident to get a valid parse tree. We will use this file
 109         // to determine context, though the original_file will be used for
 110         // actual completion.
 111         let file_with_fake_ident = {
 112             let parse = db.parse(position.file_id);
 113             let edit = Indel::insert(position.offset, "intellijRulezz".to_string());
 114             parse.reparse(&edit).tree()
 115         };
 116         let fake_ident_token =
 117             file_with_fake_ident.syntax().token_at_offset(position.offset).right_biased().unwrap();
 118
 119         let krate = sema.to_module_def(position.file_id).map(|m| m.krate());
 120         let original_token =
 121             original_file.syntax().token_at_offset(position.offset).left_biased()?;
 122         let token = sema.descend_into_macros(original_token.clone());
 123         let scope = sema.scope_at_offset(&token, position.offset);
 124         let mut locals = vec![];
 125         scope.process_all_names(&mut |name, scope| {
 126             if let ScopeDef::Local(local) = scope {
 127                 locals.push((name.to_string(), local));
 128             }
 129         });
 130         let mut ctx = CompletionContext {
 131             sema,
 132             scope,
 133             db,
 134             config,
 135             position,
 136             original_token,
 137             token,
 138             krate,
 139             expected_name: None,
 140             expected_type: None,
 141             name_ref_syntax: None,
 142             function_syntax: None,
 143             use_item_syntax: None,
 144             record_lit_syntax: None,
 145             record_pat_syntax: None,
 146             record_field_syntax: None,
 147             impl_def: None,
 148             active_parameter: ActiveParameter::at(db, position),
 149             is_param: false,
 150             is_pat_binding_or_const: false,
 151             is_irrefutable_pat_binding: false,
 152             is_trivial_path: false,
 153             path_qual: None,
 154             after_if: false,
 155             can_be_stmt: false,
 156             is_expr: false,
 157             is_new_item: false,
 158             dot_receiver: None,
 159             dot_receiver_is_ambiguous_float_literal: false,
 160             is_call: false,
 161             is_pattern_call: false,
 162             is_macro_call: false,
 163             is_path_type: false,
 164             has_type_args: false,
 165             attribute_under_caret: None,
 166             mod_declaration_under_caret: None,
 167             unsafe_is_prev: false,
 168             if_is_prev: false,
 169             block_expr_parent: false,
 170             bind_pat_parent: false,
 171             ref_pat_parent: false,
 172             in_loop_body: false,
 173             has_trait_parent: false,
 174             has_impl_parent: false,
 175             inside_impl_trait_block: false,
 176             has_field_list_parent: false,
 177             trait_as_prev_sibling: false,
 178             impl_as_prev_sibling: false,
 179             is_match_arm: false,
 180             has_item_list_or_source_file_parent: false,
 181             for_is_prev2: false,
 182             fn_is_prev: false,
 183             incomplete_let: false,
 184             locals,
 185         };
 186
 187         let mut original_file = original_file.syntax().clone();
 188         let mut hypothetical_file = file_with_fake_ident.syntax().clone();
 189         let mut offset = position.offset;
 190         let mut fake_ident_token = fake_ident_token;
 191
 192         // Are we inside a macro call?
 193         while let (Some(actual_macro_call), Some(macro_call_with_fake_ident)) = (
 194             find_node_at_offset::<ast::MacroCall>(&original_file, offset),
 195             find_node_at_offset::<ast::MacroCall>(&hypothetical_file, offset),
 196         ) {
 197             if actual_macro_call.path().as_ref().map(|s| s.syntax().text())
 198                 != macro_call_with_fake_ident.path().as_ref().map(|s| s.syntax().text())
 199             {
 200                 break;
 201             }
 202             let hypothetical_args = match macro_call_with_fake_ident.token_tree() {
 203                 Some(tt) => tt,
 204                 None => break,
 205             };
 206             if let (Some(actual_expansion), Some(hypothetical_expansion)) = (
 207                 ctx.sema.expand(&actual_macro_call),
 208                 ctx.sema.speculative_expand(
 209                     &actual_macro_call,
 210                     &hypothetical_args,
 211                     fake_ident_token,
 212                 ),
 213             ) {
 214                 let new_offset = hypothetical_expansion.1.text_range().start();
 215                 if new_offset > actual_expansion.text_range().end() {
 216                     break;
 217                 }
 218                 original_file = actual_expansion;
 219                 hypothetical_file = hypothetical_expansion.0;
 220                 fake_ident_token = hypothetical_expansion.1;
 221                 offset = new_offset;
 222             } else {
 223                 break;
 224             }
 225         }
 226         ctx.fill_keyword_patterns(&hypothetical_file, offset);
 227         ctx.fill(&original_file, hypothetical_file, offset);
 228         Some(ctx)
 229     }
 230
 231     /// Checks whether completions in that particular case don't make much sense.
 232     /// Examples:
 233     /// - `fn $0` -- we expect function name, it's unlikely that "hint" will be helpful.
 234     ///   Exception for this case is `impl Trait for Foo`, where we would like to hint trait method names.
 235     /// - `for _ i$0` -- obviously, it'll be "in" keyword.
 236     pub(crate) fn no_completion_required(&self) -> bool {
 237         (self.fn_is_prev && !self.inside_impl_trait_block) || self.for_is_prev2
 238     }
 239
 240     /// The range of the identifier that is being completed.
 241     pub(crate) fn source_range(&self) -> TextRange {
 242         // check kind of macro-expanded token, but use range of original token
 243         let kind = self.token.kind();
 244         if kind == IDENT || kind == UNDERSCORE || kind.is_keyword() {
 245             cov_mark::hit!(completes_if_prefix_is_keyword);
 246             self.original_token.text_range()
 247         } else {
 248             TextRange::empty(self.position.offset)
 249         }
 250     }
 251
 252     fn fill_keyword_patterns(&mut self, file_with_fake_ident: &SyntaxNode, offset: TextSize) {
 253         let fake_ident_token = file_with_fake_ident.token_at_offset(offset).right_biased().unwrap();
 254         let syntax_element = NodeOrToken::Token(fake_ident_token);
 255         self.block_expr_parent = has_block_expr_parent(syntax_element.clone());
 256         self.unsafe_is_prev = unsafe_is_prev(syntax_element.clone());
 257         self.if_is_prev = if_is_prev(syntax_element.clone());
 258         self.bind_pat_parent = has_bind_pat_parent(syntax_element.clone());
 259         self.ref_pat_parent = has_ref_parent(syntax_element.clone());
 260         self.in_loop_body = is_in_loop_body(syntax_element.clone());
 261         self.has_trait_parent = has_trait_parent(syntax_element.clone());
 262         self.has_impl_parent = has_impl_parent(syntax_element.clone());
 263         self.inside_impl_trait_block = inside_impl_trait_block(syntax_element.clone());
 264         self.has_field_list_parent = has_field_list_parent(syntax_element.clone());
 265         self.impl_as_prev_sibling = has_impl_as_prev_sibling(syntax_element.clone());
 266         self.trait_as_prev_sibling = has_trait_as_prev_sibling(syntax_element.clone());
 267         self.is_match_arm = is_match_arm(syntax_element.clone());
 268         self.has_item_list_or_source_file_parent =
 269             has_item_list_or_source_file_parent(syntax_element.clone());
 270         self.mod_declaration_under_caret =
 271             find_node_at_offset::<ast::Module>(&file_with_fake_ident, offset)
 272                 .filter(|module| module.item_list().is_none());
 273         self.for_is_prev2 = for_is_prev2(syntax_element.clone());
 274         self.fn_is_prev = fn_is_prev(syntax_element.clone());
 275         self.incomplete_let =
 276             syntax_element.ancestors().take(6).find_map(ast::LetStmt::cast).map_or(false, |it| {
 277                 it.syntax().text_range().end() == syntax_element.text_range().end()
 278             });
 279     }
 280
 281     fn fill_impl_def(&mut self) {
 282         self.impl_def = self
 283             .sema
 284             .token_ancestors_with_macros(self.token.clone())
 285             .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
 286             .find_map(ast::Impl::cast);
 287     }
 288
 289     fn fill(
 290         &mut self,
 291         original_file: &SyntaxNode,
 292         file_with_fake_ident: SyntaxNode,
 293         offset: TextSize,
 294     ) {
 295         let expected = {
 296             let mut node = match self.token.parent() {
 297                 Some(it) => it,
 298                 None => return,
 299             };
 300             loop {
 301                 let ret = match_ast! {
 302                     match node {
 303                         ast::LetStmt(it) => {
 304                             cov_mark::hit!(expected_type_let_with_leading_char);
 305                             cov_mark::hit!(expected_type_let_without_leading_char);
 306                             let ty = it.pat()
 307                                 .and_then(|pat| self.sema.type_of_pat(&pat));
 308                             let name = if let Some(ast::Pat::IdentPat(ident)) = it.pat() {
 309                                 Some(ident.syntax().text().to_string())
 310                             } else {
 311                                 None
 312                             };
 313
 314                             (ty, name)
 315                         },
 316                         ast::ArgList(_it) => {
 317                             cov_mark::hit!(expected_type_fn_param_with_leading_char);
 318                             cov_mark::hit!(expected_type_fn_param_without_leading_char);
 319                             ActiveParameter::at_token(
 320                                 &self.sema,
 321                                 self.token.clone(),
 322                             ).map(|ap| (Some(ap.ty), Some(ap.name)))
 323                             .unwrap_or((None, None))
 324                         },
 325                         ast::RecordExprFieldList(_it) => {
 326                             cov_mark::hit!(expected_type_struct_field_without_leading_char);
 327                             self.token.prev_sibling_or_token()
 328                                 .and_then(|se| se.into_node())
 329                                 .and_then(|node| ast::RecordExprField::cast(node))
 330                                 .and_then(|rf| self.sema.resolve_record_field(&rf))
 331                                 .map(|f|(
 332                                     Some(f.0.signature_ty(self.db)),
 333                                     Some(f.0.name(self.db).to_string()),
 334                                 ))
 335                                 .unwrap_or((None, None))
 336                         },
 337                         ast::RecordExprField(it) => {
 338                             cov_mark::hit!(expected_type_struct_field_with_leading_char);
 339                             self.sema
 340                                 .resolve_record_field(&it)
 341                                 .map(|f|(
 342                                     Some(f.0.signature_ty(self.db)),
 343                                     Some(f.0.name(self.db).to_string()),
 344                                 ))
 345                                 .unwrap_or((None, None))
 346                         },
 347                         ast::MatchExpr(it) => {
 348                             cov_mark::hit!(expected_type_match_arm_without_leading_char);
 349                             let ty = it.expr()
 350                                 .and_then(|e| self.sema.type_of_expr(&e));
 351
 352                             (ty, None)
 353                         },
 354                         ast::IdentPat(it) => {
 355                             cov_mark::hit!(expected_type_if_let_with_leading_char);
 356                             cov_mark::hit!(expected_type_match_arm_with_leading_char);
 357                             let ty = self.sema.type_of_pat(&ast::Pat::from(it));
 358
 359                             (ty, None)
 360                         },
 361                         ast::Fn(_it) => {
 362                             cov_mark::hit!(expected_type_fn_ret_with_leading_char);
 363                             cov_mark::hit!(expected_type_fn_ret_without_leading_char);
 364                             let ty = self.token.ancestors()
 365                                 .find_map(|ancestor| ast::Expr::cast(ancestor))
 366                                 .and_then(|expr| self.sema.type_of_expr(&expr));
 367
 368                             (ty, None)
 369                         },
 370                         _ => {
 371                             match node.parent() {
 372                                 Some(n) => {
 373                                     node = n;
 374                                     continue;
 375                                 },
 376                                 None => (None, None),
 377                             }
 378                         },
 379                     }
 380                 };
 381
 382                 break ret;
 383             }
 384         };
 385         self.expected_type = expected.0;
 386         self.expected_name = expected.1;
 387         self.attribute_under_caret = find_node_at_offset(&file_with_fake_ident, offset);
 388
 389         // First, let's try to complete a reference to some declaration.
 390         if let Some(name_ref) = find_node_at_offset::<ast::NameRef>(&file_with_fake_ident, offset) {
 391             // Special case, `trait T { fn foo(i_am_a_name_ref) {} }`.
 392             // See RFC#1685.
 393             if is_node::<ast::Param>(name_ref.syntax()) {
 394                 self.is_param = true;
 395                 return;
 396             }
 397             // FIXME: remove this (V) duplication and make the check more precise
 398             if name_ref.syntax().ancestors().find_map(ast::RecordPatFieldList::cast).is_some() {
 399                 self.record_pat_syntax =
 400                     self.sema.find_node_at_offset_with_macros(&original_file, offset);
 401             }
 402             self.classify_name_ref(original_file, name_ref, offset);
 403         }
 404
 405         // Otherwise, see if this is a declaration. We can use heuristics to
 406         // suggest declaration names, see `CompletionKind::Magic`.
 407         if let Some(name) = find_node_at_offset::<ast::Name>(&file_with_fake_ident, offset) {
 408             if let Some(bind_pat) = name.syntax().ancestors().find_map(ast::IdentPat::cast) {
 409                 self.is_pat_binding_or_const = true;
 410                 if bind_pat.at_token().is_some()
 411                     || bind_pat.ref_token().is_some()
 412                     || bind_pat.mut_token().is_some()
 413                 {
 414                     self.is_pat_binding_or_const = false;
 415                 }
 416                 if bind_pat.syntax().parent().and_then(ast::RecordPatFieldList::cast).is_some() {
 417                     self.is_pat_binding_or_const = false;
 418                 }
 419                 if let Some(Some(pat)) = bind_pat.syntax().ancestors().find_map(|node| {
 420                     match_ast! {
 421                         match node {
 422                             ast::LetStmt(it) => Some(it.pat()),
 423                             ast::Param(it) => Some(it.pat()),
 424                             _ => None,
 425                         }
 426                     }
 427                 }) {
 428                     if pat.syntax().text_range().contains_range(bind_pat.syntax().text_range()) {
 429                         self.is_pat_binding_or_const = false;
 430                         self.is_irrefutable_pat_binding = true;
 431                     }
 432                 }
 433
 434                 self.fill_impl_def();
 435             }
 436             if is_node::<ast::Param>(name.syntax()) {
 437                 self.is_param = true;
 438                 return;
 439             }
 440             // FIXME: remove this (^) duplication and make the check more precise
 441             if name.syntax().ancestors().find_map(ast::RecordPatFieldList::cast).is_some() {
 442                 self.record_pat_syntax =
 443                     self.sema.find_node_at_offset_with_macros(&original_file, offset);
 444             }
 445         }
 446     }
 447
 448     fn classify_name_ref(
 449         &mut self,
 450         original_file: &SyntaxNode,
 451         name_ref: ast::NameRef,
 452         offset: TextSize,
 453     ) {
 454         self.name_ref_syntax =
 455             find_node_at_offset(&original_file, name_ref.syntax().text_range().start());
 456         let name_range = name_ref.syntax().text_range();
 457         if ast::RecordExprField::for_field_name(&name_ref).is_some() {
 458             self.record_lit_syntax =
 459                 self.sema.find_node_at_offset_with_macros(&original_file, offset);
 460         }
 461
 462         self.fill_impl_def();
 463
 464         let top_node = name_ref
 465             .syntax()
 466             .ancestors()
 467             .take_while(|it| it.text_range() == name_range)
 468             .last()
 469             .unwrap();
 470
 471         match top_node.parent().map(|it| it.kind()) {
 472             Some(SOURCE_FILE) | Some(ITEM_LIST) => {
 473                 self.is_new_item = true;
 474                 return;
 475             }
 476             _ => (),
 477         }
 478
 479         self.use_item_syntax =
 480             self.sema.token_ancestors_with_macros(self.token.clone()).find_map(ast::Use::cast);
 481
 482         self.function_syntax = self
 483             .sema
 484             .token_ancestors_with_macros(self.token.clone())
 485             .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
 486             .find_map(ast::Fn::cast);
 487
 488         self.record_field_syntax = self
 489             .sema
 490             .token_ancestors_with_macros(self.token.clone())
 491             .take_while(|it| {
 492                 it.kind() != SOURCE_FILE && it.kind() != MODULE && it.kind() != CALL_EXPR
 493             })
 494             .find_map(ast::RecordExprField::cast);
 495
 496         let parent = match name_ref.syntax().parent() {
 497             Some(it) => it,
 498             None => return,
 499         };
 500
 501         if let Some(segment) = ast::PathSegment::cast(parent.clone()) {
 502             let path = segment.parent_path();
 503             self.is_call = path
 504                 .syntax()
 505                 .parent()
 506                 .and_then(ast::PathExpr::cast)
 507                 .and_then(|it| it.syntax().parent().and_then(ast::CallExpr::cast))
 508                 .is_some();
 509             self.is_macro_call = path.syntax().parent().and_then(ast::MacroCall::cast).is_some();
 510             self.is_pattern_call =
 511                 path.syntax().parent().and_then(ast::TupleStructPat::cast).is_some();
 512
 513             self.is_path_type = path.syntax().parent().and_then(ast::PathType::cast).is_some();
 514             self.has_type_args = segment.generic_arg_list().is_some();
 515
 516             if let Some(path) = path_or_use_tree_qualifier(&path) {
 517                 self.path_qual = path
 518                     .segment()
 519                     .and_then(|it| {
 520                         find_node_with_range::<ast::PathSegment>(
 521                             original_file,
 522                             it.syntax().text_range(),
 523                         )
 524                     })
 525                     .map(|it| it.parent_path());
 526                 return;
 527             }
 528
 529             if let Some(segment) = path.segment() {
 530                 if segment.coloncolon_token().is_some() {
 531                     return;
 532                 }
 533             }
 534
 535             self.is_trivial_path = true;
 536
 537             // Find either enclosing expr statement (thing with `;`) or a
 538             // block. If block, check that we are the last expr.
 539             self.can_be_stmt = name_ref
 540                 .syntax()
 541                 .ancestors()
 542                 .find_map(|node| {
 543                     if let Some(stmt) = ast::ExprStmt::cast(node.clone()) {
 544                         return Some(stmt.syntax().text_range() == name_ref.syntax().text_range());
 545                     }
 546                     if let Some(block) = ast::BlockExpr::cast(node) {
 547                         return Some(
 548                             block.tail_expr().map(|e| e.syntax().text_range())
 549                                 == Some(name_ref.syntax().text_range()),
 550                         );
 551                     }
 552                     None
 553                 })
 554                 .unwrap_or(false);
 555             self.is_expr = path.syntax().parent().and_then(ast::PathExpr::cast).is_some();
 556
 557             if let Some(off) = name_ref.syntax().text_range().start().checked_sub(2.into()) {
 558                 if let Some(if_expr) =
 559                     self.sema.find_node_at_offset_with_macros::<ast::IfExpr>(original_file, off)
 560                 {
 561                     if if_expr.syntax().text_range().end() < name_ref.syntax().text_range().start()
 562                     {
 563                         self.after_if = true;
 564                     }
 565                 }
 566             }
 567         }
 568         if let Some(field_expr) = ast::FieldExpr::cast(parent.clone()) {
 569             // The receiver comes before the point of insertion of the fake
 570             // ident, so it should have the same range in the non-modified file
 571             self.dot_receiver = field_expr
 572                 .expr()
 573                 .map(|e| e.syntax().text_range())
 574                 .and_then(|r| find_node_with_range(original_file, r));
 575             self.dot_receiver_is_ambiguous_float_literal =
 576                 if let Some(ast::Expr::Literal(l)) = &self.dot_receiver {
 577                     match l.kind() {
 578                         ast::LiteralKind::FloatNumber { .. } => l.token().text().ends_with('.'),
 579                         _ => false,
 580                     }
 581                 } else {
 582                     false
 583                 };
 584         }
 585         if let Some(method_call_expr) = ast::MethodCallExpr::cast(parent) {
 586             // As above
 587             self.dot_receiver = method_call_expr
 588                 .receiver()
 589                 .map(|e| e.syntax().text_range())
 590                 .and_then(|r| find_node_with_range(original_file, r));
 591             self.is_call = true;
 592         }
 593     }
 594 }
 595
 596 fn find_node_with_range<N: AstNode>(syntax: &SyntaxNode, range: TextRange) -> Option<N> {
 597     syntax.covering_element(range).ancestors().find_map(N::cast)
 598 }
 599
 600 fn is_node<N: AstNode>(node: &SyntaxNode) -> bool {
 601     match node.ancestors().find_map(N::cast) {
 602         None => false,
 603         Some(n) => n.syntax().text_range() == node.text_range(),
 604     }
 605 }
 606
 607 fn path_or_use_tree_qualifier(path: &ast::Path) -> Option<ast::Path> {
 608     if let Some(qual) = path.qualifier() {
 609         return Some(qual);
 610     }
 611     let use_tree_list = path.syntax().ancestors().find_map(ast::UseTreeList::cast)?;
 612     let use_tree = use_tree_list.syntax().parent().and_then(ast::UseTree::cast)?;
 613     use_tree.path()
 614 }
 615
 616 #[cfg(test)]
 617 mod tests {
 618     use expect_test::{expect, Expect};
 619     use hir::HirDisplay;
 620
 621     use crate::test_utils::{position, TEST_CONFIG};
 622
 623     use super::CompletionContext;
 624
 625     fn check_expected_type_and_name(ra_fixture: &str, expect: Expect) {
 626         let (db, pos) = position(ra_fixture);
 627         let completion_context = CompletionContext::new(&db, pos, &TEST_CONFIG).unwrap();
 628
 629         let ty = completion_context
 630             .expected_type
 631             .map(|t| t.display_test(&db).to_string())
 632             .unwrap_or("?".to_owned());
 633
 634         let name = completion_context.expected_name.unwrap_or("?".to_owned());
 635
 636         expect.assert_eq(&format!("ty: {}, name: {}", ty, name));
 637     }
 638
 639     #[test]
 640     fn expected_type_let_without_leading_char() {
 641         cov_mark::check!(expected_type_let_without_leading_char);
 642         check_expected_type_and_name(
 643             r#"
 644 fn foo() {
 645     let x: u32 = $0;
 646 }
 647 "#,
 648             expect![[r#"ty: u32, name: x"#]],
 649         );
 650     }
 651
 652     #[test]
 653     fn expected_type_let_with_leading_char() {
 654         cov_mark::check!(expected_type_let_with_leading_char);
 655         check_expected_type_and_name(
 656             r#"
 657 fn foo() {
 658     let x: u32 = c$0;
 659 }
 660 "#,
 661             expect![[r#"ty: u32, name: x"#]],
 662         );
 663     }
 664
 665     #[test]
 666     fn expected_type_fn_param_without_leading_char() {
 667         cov_mark::check!(expected_type_fn_param_without_leading_char);
 668         check_expected_type_and_name(
 669             r#"
 670 fn foo() {
 671     bar($0);
 672 }
 673
 674 fn bar(x: u32) {}
 675 "#,
 676             expect![[r#"ty: u32, name: x"#]],
 677         );
 678     }
 679
 680     #[test]
 681     fn expected_type_fn_param_with_leading_char() {
 682         cov_mark::check!(expected_type_fn_param_with_leading_char);
 683         check_expected_type_and_name(
 684             r#"
 685 fn foo() {
 686     bar(c$0);
 687 }
 688
 689 fn bar(x: u32) {}
 690 "#,
 691             expect![[r#"ty: u32, name: x"#]],
 692         );
 693     }
 694
 695     #[test]
 696     fn expected_type_struct_field_without_leading_char() {
 697         cov_mark::check!(expected_type_struct_field_without_leading_char);
 698         check_expected_type_and_name(
 699             r#"
 700 struct Foo { a: u32 }
 701 fn foo() {
 702     Foo { a: $0 };
 703 }
 704 "#,
 705             expect![[r#"ty: u32, name: a"#]],
 706         )
 707     }
 708
 709     #[test]
 710     fn expected_type_struct_field_with_leading_char() {
 711         cov_mark::check!(expected_type_struct_field_with_leading_char);
 712         check_expected_type_and_name(
 713             r#"
 714 struct Foo { a: u32 }
 715 fn foo() {
 716     Foo { a: c$0 };
 717 }
 718 "#,
 719             expect![[r#"ty: u32, name: a"#]],
 720         );
 721     }
 722
 723     #[test]
 724     fn expected_type_match_arm_without_leading_char() {
 725         cov_mark::check!(expected_type_match_arm_without_leading_char);
 726         check_expected_type_and_name(
 727             r#"
 728 enum E { X }
 729 fn foo() {
 730    match E::X { $0 }
 731 }
 732 "#,
 733             expect![[r#"ty: E, name: ?"#]],
 734         );
 735     }
 736
 737     #[test]
 738     fn expected_type_match_arm_with_leading_char() {
 739         cov_mark::check!(expected_type_match_arm_with_leading_char);
 740         check_expected_type_and_name(
 741             r#"
 742 enum E { X }
 743 fn foo() {
 744    match E::X { c$0 }
 745 }
 746 "#,
 747             expect![[r#"ty: E, name: ?"#]],
 748         );
 749     }
 750
 751     #[test]
 752     fn expected_type_if_let_without_leading_char() {
 753         check_expected_type_and_name(
 754             r#"
 755 enum Foo { Bar, Baz, Quux }
 756
 757 fn foo() {
 758     let f = Foo::Quux;
 759     if let $0 = f { }
 760 }
 761 "#,
 762             expect![[r#"ty: (), name: ?"#]],
 763         ) // FIXME should be `ty: u32, name: ?`
 764     }
 765
 766     #[test]
 767     fn expected_type_if_let_with_leading_char() {
 768         cov_mark::check!(expected_type_if_let_with_leading_char);
 769         check_expected_type_and_name(
 770             r#"
 771 enum Foo { Bar, Baz, Quux }
 772
 773 fn foo() {
 774     let f = Foo::Quux;
 775     if let c$0 = f { }
 776 }
 777 "#,
 778             expect![[r#"ty: Foo, name: ?"#]],
 779         )
 780     }
 781
 782     #[test]
 783     fn expected_type_fn_ret_without_leading_char() {
 784         cov_mark::check!(expected_type_fn_ret_without_leading_char);
 785         check_expected_type_and_name(
 786             r#"
 787 fn foo() -> u32 {
 788     $0
 789 }
 790 "#,
 791             expect![[r#"ty: (), name: ?"#]],
 792         ) // FIXME this should be `ty: u32, name: ?`
 793     }
 794
 795     #[test]
 796     fn expected_type_fn_ret_with_leading_char() {
 797         cov_mark::check!(expected_type_fn_ret_with_leading_char);
 798         check_expected_type_and_name(
 799             r#"
 800 fn foo() -> u32 {
 801     c$0
 802 }
 803 "#,
 804             expect![[r#"ty: u32, name: ?"#]],
 805         )
 806     }
 807 }