crates/ide_completion/src/context.rs

   1 //! See `CompletionContext` structure.
   2
   3 use std::iter;
   4
   5 use base_db::SourceDatabaseExt;
   6 use hir::{HasAttrs, Local, Name, ScopeDef, Semantics, SemanticsScope, Type, TypeInfo};
   7 use ide_db::{
   8     active_parameter::ActiveParameter,
   9     base_db::{FilePosition, SourceDatabase},
  10     helpers::FamousDefs,
  11     RootDatabase,
  12 };
  13 use syntax::{
  14     algo::find_node_at_offset,
  15     ast::{self, HasName, NameOrNameRef},
  16     match_ast, AstNode, NodeOrToken,
  17     SyntaxKind::{self, *},
  18     SyntaxNode, SyntaxToken, TextRange, TextSize, T,
  19 };
  20 use text_edit::Indel;
  21
  22 use crate::{
  23     patterns::{
  24         determine_location, determine_prev_sibling, for_is_prev2, inside_impl_trait_block,
  25         is_in_loop_body, previous_token, ImmediateLocation, ImmediatePrevSibling,
  26     },
  27     CompletionConfig,
  28 };
  29
  30 const COMPLETION_MARKER: &str = "intellijRulezz";
  31
  32 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
  33 pub(crate) enum PatternRefutability {
  34     Refutable,
  35     Irrefutable,
  36 }
  37
  38 #[derive(Copy, Clone, Debug)]
  39 pub(super) enum PathKind {
  40     Expr,
  41     Type,
  42     Attr,
  43     Mac,
  44     Pat,
  45     Vis { has_in_token: bool },
  46     Use,
  47 }
  48
  49 #[derive(Debug)]
  50 pub(crate) struct PathCompletionContext {
  51     /// If this is a call with () already there
  52     has_call_parens: 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) qualifier: Option<ast::Path>,
  57     #[allow(dead_code)]
  58     /// If not a trivial path, the suffix (parent).
  59     pub(super) parent: Option<ast::Path>,
  60     /// Whether the qualifier comes from a use tree parent or not
  61     pub(super) use_tree_parent: bool,
  62     pub(super) kind: Option<PathKind>,
  63     /// Whether the path segment has type args or not.
  64     pub(super) has_type_args: bool,
  65     /// `true` if we are a statement or a last expr in the block.
  66     pub(super) can_be_stmt: bool,
  67     pub(super) in_loop_body: bool,
  68 }
  69
  70 #[derive(Debug)]
  71 pub(super) struct PatternContext {
  72     pub(super) refutability: PatternRefutability,
  73     pub(super) param_ctx: Option<(ast::ParamList, ast::Param, ParamKind)>,
  74     pub(super) has_type_ascription: bool,
  75 }
  76
  77 #[derive(Debug)]
  78 pub(super) enum LifetimeContext {
  79     LifetimeParam(Option<ast::LifetimeParam>),
  80     Lifetime,
  81     LabelRef,
  82     LabelDef,
  83 }
  84
  85 #[derive(Clone, Debug, PartialEq, Eq)]
  86 pub(crate) enum ParamKind {
  87     Function(ast::Fn),
  88     Closure(ast::ClosureExpr),
  89 }
  90
  91 /// `CompletionContext` is created early during completion to figure out, where
  92 /// exactly is the cursor, syntax-wise.
  93 #[derive(Debug)]
  94 pub(crate) struct CompletionContext<'a> {
  95     pub(super) sema: Semantics<'a, RootDatabase>,
  96     pub(super) scope: SemanticsScope<'a>,
  97     pub(super) db: &'a RootDatabase,
  98     pub(super) config: &'a CompletionConfig,
  99     pub(super) position: FilePosition,
 100     /// The token before the cursor, in the original file.
 101     pub(super) original_token: SyntaxToken,
 102     /// The token before the cursor, in the macro-expanded file.
 103     pub(super) token: SyntaxToken,
 104     /// The crate of the current file.
 105     pub(super) krate: Option<hir::Crate>,
 106     pub(super) expected_name: Option<NameOrNameRef>,
 107     pub(super) expected_type: Option<Type>,
 108
 109     /// The parent function of the cursor position if it exists.
 110     pub(super) function_def: Option<ast::Fn>,
 111     pub(super) attr: Option<ast::Attr>,
 112     /// The parent impl of the cursor position if it exists.
 113     pub(super) impl_def: Option<ast::Impl>,
 114     /// The NameLike under the cursor in the original file if it exists.
 115     pub(super) name_syntax: Option<ast::NameLike>,
 116     pub(super) incomplete_let: bool,
 117
 118     pub(super) completion_location: Option<ImmediateLocation>,
 119     pub(super) prev_sibling: Option<ImmediatePrevSibling>,
 120     pub(super) fake_attribute_under_caret: Option<ast::Attr>,
 121     pub(super) previous_token: Option<SyntaxToken>,
 122
 123     pub(super) lifetime_ctx: Option<LifetimeContext>,
 124     pub(super) pattern_ctx: Option<PatternContext>,
 125     pub(super) path_context: Option<PathCompletionContext>,
 126
 127     pub(super) locals: Vec<(Name, Local)>,
 128
 129     no_completion_required: bool,
 130 }
 131
 132 impl<'a> CompletionContext<'a> {
 133     /// Checks whether completions in that particular case don't make much sense.
 134     /// Examples:
 135     /// - `fn $0` -- we expect function name, it's unlikely that "hint" will be helpful.
 136     ///   Exception for this case is `impl Trait for Foo`, where we would like to hint trait method names.
 137     /// - `for _ i$0` -- obviously, it'll be "in" keyword.
 138     pub(crate) fn no_completion_required(&self) -> bool {
 139         self.no_completion_required
 140     }
 141
 142     /// The range of the identifier that is being completed.
 143     pub(crate) fn source_range(&self) -> TextRange {
 144         // check kind of macro-expanded token, but use range of original token
 145         let kind = self.token.kind();
 146         if kind == IDENT || kind == LIFETIME_IDENT || kind == UNDERSCORE || kind.is_keyword() {
 147             self.original_token.text_range()
 148         } else if kind == CHAR {
 149             // assume we are completing a lifetime but the user has only typed the '
 150             cov_mark::hit!(completes_if_lifetime_without_idents);
 151             TextRange::at(self.original_token.text_range().start(), TextSize::from(1))
 152         } else {
 153             TextRange::empty(self.position.offset)
 154         }
 155     }
 156
 157     pub(crate) fn previous_token_is(&self, kind: SyntaxKind) -> bool {
 158         self.previous_token.as_ref().map_or(false, |tok| tok.kind() == kind)
 159     }
 160
 161     pub(crate) fn famous_defs(&self) -> FamousDefs {
 162         FamousDefs(&self.sema, self.krate)
 163     }
 164
 165     pub(crate) fn dot_receiver(&self) -> Option<&ast::Expr> {
 166         match &self.completion_location {
 167             Some(
 168                 ImmediateLocation::MethodCall { receiver, .. }
 169                 | ImmediateLocation::FieldAccess { receiver, .. },
 170             ) => receiver.as_ref(),
 171             _ => None,
 172         }
 173     }
 174
 175     pub(crate) fn has_dot_receiver(&self) -> bool {
 176         matches!(
 177             &self.completion_location,
 178             Some(ImmediateLocation::FieldAccess { receiver, .. } | ImmediateLocation::MethodCall { receiver,.. })
 179                 if receiver.is_some()
 180         )
 181     }
 182
 183     pub(crate) fn expects_assoc_item(&self) -> bool {
 184         matches!(self.completion_location, Some(ImmediateLocation::Trait | ImmediateLocation::Impl))
 185     }
 186
 187     pub(crate) fn expects_variant(&self) -> bool {
 188         matches!(self.completion_location, Some(ImmediateLocation::Variant))
 189     }
 190
 191     pub(crate) fn expects_non_trait_assoc_item(&self) -> bool {
 192         matches!(self.completion_location, Some(ImmediateLocation::Impl))
 193     }
 194
 195     pub(crate) fn expects_item(&self) -> bool {
 196         matches!(self.completion_location, Some(ImmediateLocation::ItemList))
 197     }
 198
 199     pub(crate) fn expects_generic_arg(&self) -> bool {
 200         matches!(self.completion_location, Some(ImmediateLocation::GenericArgList(_)))
 201     }
 202
 203     pub(crate) fn has_block_expr_parent(&self) -> bool {
 204         matches!(self.completion_location, Some(ImmediateLocation::StmtList))
 205     }
 206
 207     pub(crate) fn expects_ident_pat_or_ref_expr(&self) -> bool {
 208         matches!(
 209             self.completion_location,
 210             Some(ImmediateLocation::IdentPat | ImmediateLocation::RefExpr)
 211         )
 212     }
 213
 214     pub(crate) fn expect_field(&self) -> bool {
 215         matches!(
 216             self.completion_location,
 217             Some(ImmediateLocation::RecordField | ImmediateLocation::TupleField)
 218         )
 219     }
 220
 221     pub(crate) fn has_impl_or_trait_prev_sibling(&self) -> bool {
 222         matches!(
 223             self.prev_sibling,
 224             Some(ImmediatePrevSibling::ImplDefType | ImmediatePrevSibling::TraitDefName)
 225         )
 226     }
 227
 228     pub(crate) fn has_impl_prev_sibling(&self) -> bool {
 229         matches!(self.prev_sibling, Some(ImmediatePrevSibling::ImplDefType))
 230     }
 231
 232     pub(crate) fn has_visibility_prev_sibling(&self) -> bool {
 233         matches!(self.prev_sibling, Some(ImmediatePrevSibling::Visibility))
 234     }
 235
 236     pub(crate) fn after_if(&self) -> bool {
 237         matches!(self.prev_sibling, Some(ImmediatePrevSibling::IfExpr))
 238     }
 239
 240     pub(crate) fn is_path_disallowed(&self) -> bool {
 241         self.previous_token_is(T![unsafe])
 242             || matches!(
 243                 self.prev_sibling,
 244                 Some(ImmediatePrevSibling::Attribute | ImmediatePrevSibling::Visibility)
 245             )
 246             || matches!(
 247                 self.completion_location,
 248                 Some(
 249                     ImmediateLocation::ModDeclaration(_)
 250                         | ImmediateLocation::RecordPat(_)
 251                         | ImmediateLocation::RecordExpr(_)
 252                         | ImmediateLocation::Rename
 253                 )
 254             )
 255     }
 256
 257     pub(crate) fn expects_expression(&self) -> bool {
 258         matches!(self.path_context, Some(PathCompletionContext { kind: Some(PathKind::Expr), .. }))
 259     }
 260
 261     pub(crate) fn expects_type(&self) -> bool {
 262         matches!(self.path_context, Some(PathCompletionContext { kind: Some(PathKind::Type), .. }))
 263     }
 264
 265     pub(crate) fn path_is_call(&self) -> bool {
 266         self.path_context.as_ref().map_or(false, |it| it.has_call_parens)
 267     }
 268
 269     pub(crate) fn is_trivial_path(&self) -> bool {
 270         matches!(self.path_context, Some(PathCompletionContext { is_trivial_path: true, .. }))
 271     }
 272
 273     pub(crate) fn is_non_trivial_path(&self) -> bool {
 274         matches!(self.path_context, Some(PathCompletionContext { is_trivial_path: false, .. }))
 275     }
 276
 277     pub(crate) fn path_qual(&self) -> Option<&ast::Path> {
 278         self.path_context.as_ref().and_then(|it| it.qualifier.as_ref())
 279     }
 280
 281     pub(crate) fn path_kind(&self) -> Option<PathKind> {
 282         self.path_context.as_ref().and_then(|it| it.kind)
 283     }
 284
 285     /// Checks if an item is visible and not `doc(hidden)` at the completion site.
 286     pub(crate) fn is_visible<I>(&self, item: &I) -> bool
 287     where
 288         I: hir::HasVisibility + hir::HasAttrs + hir::HasCrate + Copy,
 289     {
 290         self.is_visible_impl(&item.visibility(self.db), &item.attrs(self.db), item.krate(self.db))
 291     }
 292
 293     pub(crate) fn is_scope_def_hidden(&self, scope_def: ScopeDef) -> bool {
 294         if let (Some(attrs), Some(krate)) = (scope_def.attrs(self.db), scope_def.krate(self.db)) {
 295             return self.is_doc_hidden(&attrs, krate);
 296         }
 297
 298         false
 299     }
 300
 301     /// Check if an item is `#[doc(hidden)]`.
 302     pub(crate) fn is_item_hidden(&self, item: &hir::ItemInNs) -> bool {
 303         let attrs = item.attrs(self.db);
 304         let krate = item.krate(self.db);
 305         match (attrs, krate) {
 306             (Some(attrs), Some(krate)) => self.is_doc_hidden(&attrs, krate),
 307             _ => false,
 308         }
 309     }
 310
 311     pub(crate) fn is_immediately_after_macro_bang(&self) -> bool {
 312         self.token.kind() == BANG && self.token.parent().map_or(false, |it| it.kind() == MACRO_CALL)
 313     }
 314
 315     /// Whether the given trait is an operator trait or not.
 316     pub(crate) fn is_ops_trait(&self, trait_: hir::Trait) -> bool {
 317         match trait_.attrs(self.db).lang() {
 318             Some(lang) => OP_TRAIT_LANG_NAMES.contains(&lang.as_str()),
 319             None => false,
 320         }
 321     }
 322
 323     /// A version of [`SemanticsScope::process_all_names`] that filters out `#[doc(hidden)]` items.
 324     pub(crate) fn process_all_names(&self, f: &mut dyn FnMut(Name, ScopeDef)) {
 325         let _p = profile::span("CompletionContext::process_all_names");
 326         self.scope.process_all_names(&mut |name, def| {
 327             if self.is_scope_def_hidden(def) {
 328                 return;
 329             }
 330
 331             f(name, def);
 332         })
 333     }
 334
 335     fn is_visible_impl(
 336         &self,
 337         vis: &hir::Visibility,
 338         attrs: &hir::Attrs,
 339         defining_crate: hir::Crate,
 340     ) -> bool {
 341         let module = match self.scope.module() {
 342             Some(it) => it,
 343             None => return false,
 344         };
 345         if !vis.is_visible_from(self.db, module.into()) {
 346             // If the definition location is editable, also show private items
 347             let root_file = defining_crate.root_file(self.db);
 348             let source_root_id = self.db.file_source_root(root_file);
 349             let is_editable = !self.db.source_root(source_root_id).is_library;
 350             return is_editable;
 351         }
 352
 353         !self.is_doc_hidden(attrs, defining_crate)
 354     }
 355
 356     fn is_doc_hidden(&self, attrs: &hir::Attrs, defining_crate: hir::Crate) -> bool {
 357         let krate = match self.krate {
 358             Some(it) => it,
 359             None => return true,
 360         };
 361         if krate != defining_crate && attrs.has_doc_hidden() {
 362             // `doc(hidden)` items are only completed within the defining crate.
 363             return true;
 364         }
 365
 366         false
 367     }
 368 }
 369
 370 // CompletionContext construction
 371 impl<'a> CompletionContext<'a> {
 372     pub(super) fn new(
 373         db: &'a RootDatabase,
 374         position @ FilePosition { file_id, offset }: FilePosition,
 375         config: &'a CompletionConfig,
 376     ) -> Option<CompletionContext<'a>> {
 377         let _p = profile::span("CompletionContext::new");
 378         let sema = Semantics::new(db);
 379
 380         let original_file = sema.parse(file_id);
 381
 382         // Insert a fake ident to get a valid parse tree. We will use this file
 383         // to determine context, though the original_file will be used for
 384         // actual completion.
 385         let file_with_fake_ident = {
 386             let parse = db.parse(file_id);
 387             let edit = Indel::insert(offset, COMPLETION_MARKER.to_string());
 388             parse.reparse(&edit).tree()
 389         };
 390         let fake_ident_token =
 391             file_with_fake_ident.syntax().token_at_offset(offset).right_biased()?;
 392
 393         let original_token = original_file.syntax().token_at_offset(offset).left_biased()?;
 394         let token = sema.descend_into_macros_single(original_token.clone());
 395         let scope = sema.scope_at_offset(&token.parent()?, offset);
 396         let krate = scope.krate();
 397         let mut locals = vec![];
 398         scope.process_all_names(&mut |name, scope| {
 399             if let ScopeDef::Local(local) = scope {
 400                 locals.push((name, local));
 401             }
 402         });
 403
 404         let mut ctx = CompletionContext {
 405             sema,
 406             scope,
 407             db,
 408             config,
 409             position,
 410             original_token,
 411             token,
 412             krate,
 413             expected_name: None,
 414             expected_type: None,
 415             function_def: None,
 416             attr: None,
 417             impl_def: None,
 418             name_syntax: None,
 419             lifetime_ctx: None,
 420             pattern_ctx: None,
 421             completion_location: None,
 422             prev_sibling: None,
 423             fake_attribute_under_caret: None,
 424             previous_token: None,
 425             path_context: None,
 426             locals,
 427             incomplete_let: false,
 428             no_completion_required: false,
 429         };
 430         ctx.expand_and_fill(
 431             original_file.syntax().clone(),
 432             file_with_fake_ident.syntax().clone(),
 433             offset,
 434             fake_ident_token,
 435         );
 436         Some(ctx)
 437     }
 438
 439     /// Do the attribute expansion at the current cursor position for both original file and fake file
 440     /// as long as possible. As soon as one of the two expansions fail we stop to stay in sync.
 441     fn expand_and_fill(
 442         &mut self,
 443         mut original_file: SyntaxNode,
 444         mut speculative_file: SyntaxNode,
 445         mut offset: TextSize,
 446         mut fake_ident_token: SyntaxToken,
 447     ) {
 448         let _p = profile::span("CompletionContext::expand_and_fill");
 449         'expansion: loop {
 450             let parent_item =
 451                 |item: &ast::Item| item.syntax().ancestors().skip(1).find_map(ast::Item::cast);
 452             let ancestor_items = iter::successors(
 453                 Option::zip(
 454                     find_node_at_offset::<ast::Item>(&original_file, offset),
 455                     find_node_at_offset::<ast::Item>(&speculative_file, offset),
 456                 ),
 457                 |(a, b)| parent_item(a).zip(parent_item(b)),
 458             );
 459             for (actual_item, item_with_fake_ident) in ancestor_items {
 460                 match (
 461                     self.sema.expand_attr_macro(&actual_item),
 462                     self.sema.speculative_expand_attr_macro(
 463                         &actual_item,
 464                         &item_with_fake_ident,
 465                         fake_ident_token.clone(),
 466                     ),
 467                 ) {
 468                     // maybe parent items have attributes
 469                     (None, None) => (),
 470                     // successful expansions
 471                     (Some(actual_expansion), Some((fake_expansion, fake_mapped_token))) => {
 472                         let new_offset = fake_mapped_token.text_range().start();
 473                         if new_offset > actual_expansion.text_range().end() {
 474                             break 'expansion;
 475                         }
 476                         original_file = actual_expansion;
 477                         speculative_file = fake_expansion;
 478                         fake_ident_token = fake_mapped_token;
 479                         offset = new_offset;
 480                         continue 'expansion;
 481                     }
 482                     // exactly one expansion failed, inconsistent state so stop expanding completely
 483                     _ => break 'expansion,
 484                 }
 485             }
 486
 487             // Expand fn-like macro calls
 488             if let (Some(actual_macro_call), Some(macro_call_with_fake_ident)) = (
 489                 find_node_at_offset::<ast::MacroCall>(&original_file, offset),
 490                 find_node_at_offset::<ast::MacroCall>(&speculative_file, offset),
 491             ) {
 492                 let mac_call_path0 = actual_macro_call.path().as_ref().map(|s| s.syntax().text());
 493                 let mac_call_path1 =
 494                     macro_call_with_fake_ident.path().as_ref().map(|s| s.syntax().text());
 495                 if mac_call_path0 != mac_call_path1 {
 496                     break;
 497                 }
 498                 let speculative_args = match macro_call_with_fake_ident.token_tree() {
 499                     Some(tt) => tt,
 500                     None => break,
 501                 };
 502
 503                 match (
 504                     self.sema.expand(&actual_macro_call),
 505                     self.sema.speculative_expand(
 506                         &actual_macro_call,
 507                         &speculative_args,
 508                         fake_ident_token.clone(),
 509                     ),
 510                 ) {
 511                     // successful expansions
 512                     (Some(actual_expansion), Some((fake_expansion, fake_mapped_token))) => {
 513                         let new_offset = fake_mapped_token.text_range().start();
 514                         if new_offset > actual_expansion.text_range().end() {
 515                             break;
 516                         }
 517                         original_file = actual_expansion;
 518                         speculative_file = fake_expansion;
 519                         fake_ident_token = fake_mapped_token;
 520                         offset = new_offset;
 521                         continue;
 522                     }
 523                     _ => break,
 524                 }
 525             }
 526
 527             break;
 528         }
 529
 530         self.fill(&original_file, speculative_file, offset);
 531     }
 532
 533     fn expected_type_and_name(&self) -> (Option<Type>, Option<NameOrNameRef>) {
 534         let mut node = match self.token.parent() {
 535             Some(it) => it,
 536             None => return (None, None),
 537         };
 538         loop {
 539             break match_ast! {
 540                 match node {
 541                     ast::LetStmt(it) => {
 542                         cov_mark::hit!(expected_type_let_with_leading_char);
 543                         cov_mark::hit!(expected_type_let_without_leading_char);
 544                         let ty = it.pat()
 545                             .and_then(|pat| self.sema.type_of_pat(&pat))
 546                             .or_else(|| it.initializer().and_then(|it| self.sema.type_of_expr(&it)))
 547                             .map(TypeInfo::original);
 548                         let name = match it.pat() {
 549                             Some(ast::Pat::IdentPat(ident)) => ident.name().map(NameOrNameRef::Name),
 550                             Some(_) | None => None,
 551                         };
 552
 553                         (ty, name)
 554                     },
 555                     ast::ArgList(_) => {
 556                         cov_mark::hit!(expected_type_fn_param);
 557                         ActiveParameter::at_token(
 558                             &self.sema,
 559                             self.token.clone(),
 560                         ).map(|ap| {
 561                             let name = ap.ident().map(NameOrNameRef::Name);
 562                             let ty = if has_ref(&self.token) {
 563                                 cov_mark::hit!(expected_type_fn_param_ref);
 564                                 ap.ty.remove_ref()
 565                             } else {
 566                                 Some(ap.ty)
 567                             };
 568                             (ty, name)
 569                         })
 570                         .unwrap_or((None, None))
 571                     },
 572                     ast::RecordExprFieldList(it) => {
 573                         // wouldn't try {} be nice...
 574                         (|| {
 575                             if self.token.kind() == T![..]
 576                                 || self.token.prev_token().map(|t| t.kind()) == Some(T![..])
 577                             {
 578                                 cov_mark::hit!(expected_type_struct_func_update);
 579                                 let record_expr = it.syntax().parent().and_then(ast::RecordExpr::cast)?;
 580                                 let ty = self.sema.type_of_expr(&record_expr.into())?;
 581                                 Some((
 582                                     Some(ty.original),
 583                                     None
 584                                 ))
 585                             } else {
 586                                 cov_mark::hit!(expected_type_struct_field_without_leading_char);
 587                                 let expr_field = self.token.prev_sibling_or_token()?
 588                                     .into_node()
 589                                     .and_then(ast::RecordExprField::cast)?;
 590                                 let (_, _, ty) = self.sema.resolve_record_field(&expr_field)?;
 591                                 Some((
 592                                     Some(ty),
 593                                     expr_field.field_name().map(NameOrNameRef::NameRef),
 594                                 ))
 595                             }
 596                         })().unwrap_or((None, None))
 597                     },
 598                     ast::RecordExprField(it) => {
 599                         if let Some(expr) = it.expr() {
 600                             cov_mark::hit!(expected_type_struct_field_with_leading_char);
 601                             (
 602                                 self.sema.type_of_expr(&expr).map(TypeInfo::original),
 603                                 it.field_name().map(NameOrNameRef::NameRef),
 604                             )
 605                         } else {
 606                             cov_mark::hit!(expected_type_struct_field_followed_by_comma);
 607                             let ty = self.sema.resolve_record_field(&it)
 608                                 .map(|(_, _, ty)| ty);
 609                             (
 610                                 ty,
 611                                 it.field_name().map(NameOrNameRef::NameRef),
 612                             )
 613                         }
 614                     },
 615                     ast::MatchExpr(it) => {
 616                         cov_mark::hit!(expected_type_match_arm_without_leading_char);
 617                         let ty = it.expr().and_then(|e| self.sema.type_of_expr(&e)).map(TypeInfo::original);
 618                         (ty, None)
 619                     },
 620                     ast::IfExpr(it) => {
 621                         cov_mark::hit!(expected_type_if_let_without_leading_char);
 622                         let ty = it.condition()
 623                             .and_then(|cond| cond.expr())
 624                             .and_then(|e| self.sema.type_of_expr(&e))
 625                             .map(TypeInfo::original);
 626                         (ty, None)
 627                     },
 628                     ast::IdentPat(it) => {
 629                         cov_mark::hit!(expected_type_if_let_with_leading_char);
 630                         cov_mark::hit!(expected_type_match_arm_with_leading_char);
 631                         let ty = self.sema.type_of_pat(&ast::Pat::from(it)).map(TypeInfo::original);
 632                         (ty, None)
 633                     },
 634                     ast::Fn(it) => {
 635                         cov_mark::hit!(expected_type_fn_ret_with_leading_char);
 636                         cov_mark::hit!(expected_type_fn_ret_without_leading_char);
 637                         let def = self.sema.to_def(&it);
 638                         (def.map(|def| def.ret_type(self.db)), None)
 639                     },
 640                     ast::ClosureExpr(it) => {
 641                         let ty = self.sema.type_of_expr(&it.into());
 642                         ty.and_then(|ty| ty.original.as_callable(self.db))
 643                             .map(|c| (Some(c.return_type()), None))
 644                             .unwrap_or((None, None))
 645                     },
 646                     ast::ParamList(_) => (None, None),
 647                     ast::Stmt(_) => (None, None),
 648                     ast::Item(_) => (None, None),
 649                     _ => {
 650                         match node.parent() {
 651                             Some(n) => {
 652                                 node = n;
 653                                 continue;
 654                             },
 655                             None => (None, None),
 656                         }
 657                     },
 658                 }
 659             };
 660         }
 661     }
 662
 663     fn fill(
 664         &mut self,
 665         original_file: &SyntaxNode,
 666         file_with_fake_ident: SyntaxNode,
 667         offset: TextSize,
 668     ) {
 669         let fake_ident_token = file_with_fake_ident.token_at_offset(offset).right_biased().unwrap();
 670         let syntax_element = NodeOrToken::Token(fake_ident_token);
 671         self.previous_token = previous_token(syntax_element.clone());
 672         self.no_completion_required = {
 673             let inside_impl_trait_block = inside_impl_trait_block(syntax_element.clone());
 674             let fn_is_prev = self.previous_token_is(T![fn]);
 675             let for_is_prev2 = for_is_prev2(syntax_element.clone());
 676             (fn_is_prev && !inside_impl_trait_block) || for_is_prev2
 677         };
 678
 679         self.attr = self
 680             .sema
 681             .token_ancestors_with_macros(self.token.clone())
 682             .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
 683             .find_map(ast::Attr::cast);
 684         self.fake_attribute_under_caret = syntax_element.ancestors().find_map(ast::Attr::cast);
 685
 686         self.incomplete_let =
 687             syntax_element.ancestors().take(6).find_map(ast::LetStmt::cast).map_or(false, |it| {
 688                 it.syntax().text_range().end() == syntax_element.text_range().end()
 689             });
 690
 691         let (expected_type, expected_name) = self.expected_type_and_name();
 692         self.expected_type = expected_type;
 693         self.expected_name = expected_name;
 694
 695         let name_like = match find_node_at_offset(&file_with_fake_ident, offset) {
 696             Some(it) => it,
 697             None => return,
 698         };
 699         self.completion_location =
 700             determine_location(&self.sema, original_file, offset, &name_like);
 701         self.prev_sibling = determine_prev_sibling(&name_like);
 702         self.name_syntax =
 703             find_node_at_offset(original_file, name_like.syntax().text_range().start());
 704         self.impl_def = self
 705             .sema
 706             .token_ancestors_with_macros(self.token.clone())
 707             .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
 708             .find_map(ast::Impl::cast);
 709         self.function_def = self
 710             .sema
 711             .token_ancestors_with_macros(self.token.clone())
 712             .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
 713             .find_map(ast::Fn::cast);
 714         match name_like {
 715             ast::NameLike::Lifetime(lifetime) => {
 716                 self.lifetime_ctx =
 717                     Self::classify_lifetime(&self.sema, original_file, lifetime, offset);
 718             }
 719             ast::NameLike::NameRef(name_ref) => {
 720                 if let Some((path_ctx, pat_ctx)) =
 721                     Self::classify_name_ref(&self.sema, original_file, name_ref)
 722                 {
 723                     self.path_context = Some(path_ctx);
 724                     self.pattern_ctx = pat_ctx;
 725                 }
 726             }
 727             ast::NameLike::Name(name) => {
 728                 self.pattern_ctx = Self::classify_name(&self.sema, original_file, name);
 729             }
 730         }
 731     }
 732
 733     fn classify_lifetime(
 734         sema: &Semantics<RootDatabase>,
 735         original_file: &SyntaxNode,
 736         lifetime: ast::Lifetime,
 737         offset: TextSize,
 738     ) -> Option<LifetimeContext> {
 739         let parent = lifetime.syntax().parent()?;
 740         if parent.kind() == ERROR {
 741             return None;
 742         }
 743
 744         Some(match_ast! {
 745             match parent {
 746                 ast::LifetimeParam(_) => LifetimeContext::LifetimeParam(sema.find_node_at_offset_with_macros(original_file, offset)),
 747                 ast::BreakExpr(_) => LifetimeContext::LabelRef,
 748                 ast::ContinueExpr(_) => LifetimeContext::LabelRef,
 749                 ast::Label(_) => LifetimeContext::LabelDef,
 750                 _ => LifetimeContext::Lifetime,
 751             }
 752         })
 753     }
 754
 755     fn classify_name(
 756         _sema: &Semantics<RootDatabase>,
 757         original_file: &SyntaxNode,
 758         name: ast::Name,
 759     ) -> Option<PatternContext> {
 760         let bind_pat = name.syntax().parent().and_then(ast::IdentPat::cast)?;
 761         let is_name_in_field_pat = bind_pat
 762             .syntax()
 763             .parent()
 764             .and_then(ast::RecordPatField::cast)
 765             .map_or(false, |pat_field| pat_field.name_ref().is_none());
 766         if is_name_in_field_pat {
 767             return None;
 768         }
 769         if !bind_pat.is_simple_ident() {
 770             return None;
 771         }
 772         Some(pattern_context_for(original_file, bind_pat.into()))
 773     }
 774
 775     fn classify_name_ref(
 776         _sema: &Semantics<RootDatabase>,
 777         original_file: &SyntaxNode,
 778         name_ref: ast::NameRef,
 779     ) -> Option<(PathCompletionContext, Option<PatternContext>)> {
 780         let parent = name_ref.syntax().parent()?;
 781         let segment = ast::PathSegment::cast(parent)?;
 782         let path = segment.parent_path();
 783
 784         let mut path_ctx = PathCompletionContext {
 785             has_call_parens: false,
 786             is_trivial_path: false,
 787             qualifier: None,
 788             parent: None,
 789             has_type_args: false,
 790             can_be_stmt: false,
 791             in_loop_body: false,
 792             use_tree_parent: false,
 793             kind: None,
 794         };
 795         let mut pat_ctx = None;
 796         path_ctx.in_loop_body = is_in_loop_body(name_ref.syntax());
 797
 798         path_ctx.kind  = path.syntax().ancestors().find_map(|it| {
 799             match_ast! {
 800                 match it {
 801                     ast::PathType(_) => Some(PathKind::Type),
 802                     ast::PathExpr(it) => {
 803                         path_ctx.has_call_parens = it.syntax().parent().map_or(false, |it| ast::CallExpr::can_cast(it.kind()));
 804                         Some(PathKind::Expr)
 805                     },
 806                     ast::TupleStructPat(it) => {
 807                         path_ctx.has_call_parens = true;
 808                         pat_ctx = Some(pattern_context_for(original_file, it.into()));
 809                         Some(PathKind::Pat)
 810                     },
 811                     ast::RecordPat(it) => {
 812                         pat_ctx = Some(pattern_context_for(original_file, it.into()));
 813                         Some(PathKind::Pat)
 814                     },
 815                     ast::PathPat(it) => {
 816                         pat_ctx = Some(pattern_context_for(original_file, it.into()));
 817                         Some(PathKind::Pat)
 818                     },
 819                     ast::MacroCall(it) => it.excl_token().and(Some(PathKind::Mac)),
 820                     ast::Meta(_) => Some(PathKind::Attr),
 821                     ast::Visibility(it) => Some(PathKind::Vis { has_in_token: it.in_token().is_some() }),
 822                     ast::UseTree(_) => Some(PathKind::Use),
 823                     _ => None,
 824                 }
 825             }
 826         });
 827         path_ctx.has_type_args = segment.generic_arg_list().is_some();
 828
 829         if let Some((path, use_tree_parent)) = path_or_use_tree_qualifier(&path) {
 830             path_ctx.use_tree_parent = use_tree_parent;
 831             path_ctx.qualifier = path
 832                 .segment()
 833                 .and_then(|it| find_node_in_file(original_file, &it))
 834                 .map(|it| it.parent_path());
 835             return Some((path_ctx, pat_ctx));
 836         }
 837
 838         if let Some(segment) = path.segment() {
 839             if segment.coloncolon_token().is_some() {
 840                 return Some((path_ctx, pat_ctx));
 841             }
 842         }
 843
 844         path_ctx.is_trivial_path = true;
 845
 846         // Find either enclosing expr statement (thing with `;`) or a
 847         // block. If block, check that we are the last expr.
 848         path_ctx.can_be_stmt = name_ref
 849             .syntax()
 850             .ancestors()
 851             .find_map(|node| {
 852                 if let Some(stmt) = ast::ExprStmt::cast(node.clone()) {
 853                     return Some(stmt.syntax().text_range() == name_ref.syntax().text_range());
 854                 }
 855                 if let Some(stmt_list) = ast::StmtList::cast(node) {
 856                     return Some(
 857                         stmt_list.tail_expr().map(|e| e.syntax().text_range())
 858                             == Some(name_ref.syntax().text_range()),
 859                     );
 860                 }
 861                 None
 862             })
 863             .unwrap_or(false);
 864         Some((path_ctx, pat_ctx))
 865     }
 866 }
 867
 868 fn pattern_context_for(original_file: &SyntaxNode, pat: ast::Pat) -> PatternContext {
 869     let mut is_param = None;
 870     let (refutability, has_type_ascription) =
 871     pat
 872         .syntax()
 873         .ancestors()
 874         .skip_while(|it| ast::Pat::can_cast(it.kind()))
 875         .next()
 876         .map_or((PatternRefutability::Irrefutable, false), |node| {
 877             let refutability = match_ast! {
 878                 match node {
 879                     ast::LetStmt(let_) => return (PatternRefutability::Irrefutable, let_.ty().is_some()),
 880                     ast::Param(param) => {
 881                         let has_type_ascription = param.ty().is_some();
 882                         is_param = (|| {
 883                             let fake_param_list = param.syntax().parent().and_then(ast::ParamList::cast)?;
 884                             let param_list = find_node_in_file_compensated(original_file, &fake_param_list)?;
 885                             let param_list_owner = param_list.syntax().parent()?;
 886                             let kind = match_ast! {
 887                                 match param_list_owner {
 888                                     ast::ClosureExpr(closure) => ParamKind::Closure(closure),
 889                                     ast::Fn(fn_) => ParamKind::Function(fn_),
 890                                     _ => return None,
 891                                 }
 892                             };
 893                             Some((param_list, param, kind))
 894                         })();
 895                         return (PatternRefutability::Irrefutable, has_type_ascription)
 896                     },
 897                     ast::MatchArm(_) => PatternRefutability::Refutable,
 898                     ast::Condition(_) => PatternRefutability::Refutable,
 899                     ast::ForExpr(_) => PatternRefutability::Irrefutable,
 900                     _ => PatternRefutability::Irrefutable,
 901                 }
 902             };
 903             (refutability, false)
 904         });
 905     PatternContext { refutability, param_ctx: is_param, has_type_ascription }
 906 }
 907
 908 fn find_node_in_file<N: AstNode>(syntax: &SyntaxNode, node: &N) -> Option<N> {
 909     let syntax_range = syntax.text_range();
 910     let range = node.syntax().text_range();
 911     let intersection = range.intersect(syntax_range)?;
 912     syntax.covering_element(intersection).ancestors().find_map(N::cast)
 913 }
 914
 915 /// Compensates for the offset introduced by the fake ident
 916 /// This is wrong if `node` comes before the insertion point! Use `find_node_in_file` instead.
 917 fn find_node_in_file_compensated<N: AstNode>(syntax: &SyntaxNode, node: &N) -> Option<N> {
 918     let syntax_range = syntax.text_range();
 919     let range = node.syntax().text_range();
 920     let end = range.end().checked_sub(TextSize::try_from(COMPLETION_MARKER.len()).ok()?)?;
 921     if end < range.start() {
 922         return None;
 923     }
 924     let range = TextRange::new(range.start(), end);
 925     // our inserted ident could cause `range` to be go outside of the original syntax, so cap it
 926     let intersection = range.intersect(syntax_range)?;
 927     syntax.covering_element(intersection).ancestors().find_map(N::cast)
 928 }
 929
 930 fn path_or_use_tree_qualifier(path: &ast::Path) -> Option<(ast::Path, bool)> {
 931     if let Some(qual) = path.qualifier() {
 932         return Some((qual, false));
 933     }
 934     let use_tree_list = path.syntax().ancestors().find_map(ast::UseTreeList::cast)?;
 935     let use_tree = use_tree_list.syntax().parent().and_then(ast::UseTree::cast)?;
 936     use_tree.path().zip(Some(true))
 937 }
 938
 939 fn has_ref(token: &SyntaxToken) -> bool {
 940     let mut token = token.clone();
 941     for skip in [IDENT, WHITESPACE, T![mut]] {
 942         if token.kind() == skip {
 943             token = match token.prev_token() {
 944                 Some(it) => it,
 945                 None => return false,
 946             }
 947         }
 948     }
 949     token.kind() == T![&]
 950 }
 951
 952 const OP_TRAIT_LANG_NAMES: &[&str] = &[
 953     "add_assign",
 954     "add",
 955     "bitand_assign",
 956     "bitand",
 957     "bitor_assign",
 958     "bitor",
 959     "bitxor_assign",
 960     "bitxor",
 961     "deref_mut",
 962     "deref",
 963     "div_assign",
 964     "div",
 965     "eq",
 966     "fn_mut",
 967     "fn_once",
 968     "fn",
 969     "index_mut",
 970     "index",
 971     "mul_assign",
 972     "mul",
 973     "neg",
 974     "not",
 975     "partial_ord",
 976     "rem_assign",
 977     "rem",
 978     "shl_assign",
 979     "shl",
 980     "shr_assign",
 981     "shr",
 982     "sub",
 983 ];
 984 #[cfg(test)]
 985 mod tests {
 986     use expect_test::{expect, Expect};
 987     use hir::HirDisplay;
 988
 989     use crate::tests::{position, TEST_CONFIG};
 990
 991     use super::CompletionContext;
 992
 993     fn check_expected_type_and_name(ra_fixture: &str, expect: Expect) {
 994         let (db, pos) = position(ra_fixture);
 995         let config = TEST_CONFIG;
 996         let completion_context = CompletionContext::new(&db, pos, &config).unwrap();
 997
 998         let ty = completion_context
 999             .expected_type
1000             .map(|t| t.display_test(&db).to_string())
1001             .unwrap_or("?".to_owned());
1002
1003         let name = completion_context
1004             .expected_name
1005             .map_or_else(|| "?".to_owned(), |name| name.to_string());
1006
1007         expect.assert_eq(&format!("ty: {}, name: {}", ty, name));
1008     }
1009
1010     #[test]
1011     fn expected_type_let_without_leading_char() {
1012         cov_mark::check!(expected_type_let_without_leading_char);
1013         check_expected_type_and_name(
1014             r#"
1015 fn foo() {
1016     let x: u32 = $0;
1017 }
1018 "#,
1019             expect![[r#"ty: u32, name: x"#]],
1020         );
1021     }
1022
1023     #[test]
1024     fn expected_type_let_with_leading_char() {
1025         cov_mark::check!(expected_type_let_with_leading_char);
1026         check_expected_type_and_name(
1027             r#"
1028 fn foo() {
1029     let x: u32 = c$0;
1030 }
1031 "#,
1032             expect![[r#"ty: u32, name: x"#]],
1033         );
1034     }
1035
1036     #[test]
1037     fn expected_type_let_pat() {
1038         check_expected_type_and_name(
1039             r#"
1040 fn foo() {
1041     let x$0 = 0u32;
1042 }
1043 "#,
1044             expect![[r#"ty: u32, name: ?"#]],
1045         );
1046         check_expected_type_and_name(
1047             r#"
1048 fn foo() {
1049     let $0 = 0u32;
1050 }
1051 "#,
1052             expect![[r#"ty: u32, name: ?"#]],
1053         );
1054     }
1055
1056     #[test]
1057     fn expected_type_fn_param() {
1058         cov_mark::check!(expected_type_fn_param);
1059         check_expected_type_and_name(
1060             r#"
1061 fn foo() { bar($0); }
1062 fn bar(x: u32) {}
1063 "#,
1064             expect![[r#"ty: u32, name: x"#]],
1065         );
1066         check_expected_type_and_name(
1067             r#"
1068 fn foo() { bar(c$0); }
1069 fn bar(x: u32) {}
1070 "#,
1071             expect![[r#"ty: u32, name: x"#]],
1072         );
1073     }
1074
1075     #[test]
1076     fn expected_type_fn_param_ref() {
1077         cov_mark::check!(expected_type_fn_param_ref);
1078         check_expected_type_and_name(
1079             r#"
1080 fn foo() { bar(&$0); }
1081 fn bar(x: &u32) {}
1082 "#,
1083             expect![[r#"ty: u32, name: x"#]],
1084         );
1085         check_expected_type_and_name(
1086             r#"
1087 fn foo() { bar(&mut $0); }
1088 fn bar(x: &mut u32) {}
1089 "#,
1090             expect![[r#"ty: u32, name: x"#]],
1091         );
1092         check_expected_type_and_name(
1093             r#"
1094 fn foo() { bar(& c$0); }
1095 fn bar(x: &u32) {}
1096         "#,
1097             expect![[r#"ty: u32, name: x"#]],
1098         );
1099         check_expected_type_and_name(
1100             r#"
1101 fn foo() { bar(&mut c$0); }
1102 fn bar(x: &mut u32) {}
1103 "#,
1104             expect![[r#"ty: u32, name: x"#]],
1105         );
1106         check_expected_type_and_name(
1107             r#"
1108 fn foo() { bar(&c$0); }
1109 fn bar(x: &u32) {}
1110         "#,
1111             expect![[r#"ty: u32, name: x"#]],
1112         );
1113     }
1114
1115     #[test]
1116     fn expected_type_struct_field_without_leading_char() {
1117         cov_mark::check!(expected_type_struct_field_without_leading_char);
1118         check_expected_type_and_name(
1119             r#"
1120 struct Foo { a: u32 }
1121 fn foo() {
1122     Foo { a: $0 };
1123 }
1124 "#,
1125             expect![[r#"ty: u32, name: a"#]],
1126         )
1127     }
1128
1129     #[test]
1130     fn expected_type_struct_field_followed_by_comma() {
1131         cov_mark::check!(expected_type_struct_field_followed_by_comma);
1132         check_expected_type_and_name(
1133             r#"
1134 struct Foo { a: u32 }
1135 fn foo() {
1136     Foo { a: $0, };
1137 }
1138 "#,
1139             expect![[r#"ty: u32, name: a"#]],
1140         )
1141     }
1142
1143     #[test]
1144     fn expected_type_generic_struct_field() {
1145         check_expected_type_and_name(
1146             r#"
1147 struct Foo<T> { a: T }
1148 fn foo() -> Foo<u32> {
1149     Foo { a: $0 }
1150 }
1151 "#,
1152             expect![[r#"ty: u32, name: a"#]],
1153         )
1154     }
1155
1156     #[test]
1157     fn expected_type_struct_field_with_leading_char() {
1158         cov_mark::check!(expected_type_struct_field_with_leading_char);
1159         check_expected_type_and_name(
1160             r#"
1161 struct Foo { a: u32 }
1162 fn foo() {
1163     Foo { a: c$0 };
1164 }
1165 "#,
1166             expect![[r#"ty: u32, name: a"#]],
1167         );
1168     }
1169
1170     #[test]
1171     fn expected_type_match_arm_without_leading_char() {
1172         cov_mark::check!(expected_type_match_arm_without_leading_char);
1173         check_expected_type_and_name(
1174             r#"
1175 enum E { X }
1176 fn foo() {
1177    match E::X { $0 }
1178 }
1179 "#,
1180             expect![[r#"ty: E, name: ?"#]],
1181         );
1182     }
1183
1184     #[test]
1185     fn expected_type_match_arm_with_leading_char() {
1186         cov_mark::check!(expected_type_match_arm_with_leading_char);
1187         check_expected_type_and_name(
1188             r#"
1189 enum E { X }
1190 fn foo() {
1191    match E::X { c$0 }
1192 }
1193 "#,
1194             expect![[r#"ty: E, name: ?"#]],
1195         );
1196     }
1197
1198     #[test]
1199     fn expected_type_if_let_without_leading_char() {
1200         cov_mark::check!(expected_type_if_let_without_leading_char);
1201         check_expected_type_and_name(
1202             r#"
1203 enum Foo { Bar, Baz, Quux }
1204
1205 fn foo() {
1206     let f = Foo::Quux;
1207     if let $0 = f { }
1208 }
1209 "#,
1210             expect![[r#"ty: Foo, name: ?"#]],
1211         )
1212     }
1213
1214     #[test]
1215     fn expected_type_if_let_with_leading_char() {
1216         cov_mark::check!(expected_type_if_let_with_leading_char);
1217         check_expected_type_and_name(
1218             r#"
1219 enum Foo { Bar, Baz, Quux }
1220
1221 fn foo() {
1222     let f = Foo::Quux;
1223     if let c$0 = f { }
1224 }
1225 "#,
1226             expect![[r#"ty: Foo, name: ?"#]],
1227         )
1228     }
1229
1230     #[test]
1231     fn expected_type_fn_ret_without_leading_char() {
1232         cov_mark::check!(expected_type_fn_ret_without_leading_char);
1233         check_expected_type_and_name(
1234             r#"
1235 fn foo() -> u32 {
1236     $0
1237 }
1238 "#,
1239             expect![[r#"ty: u32, name: ?"#]],
1240         )
1241     }
1242
1243     #[test]
1244     fn expected_type_fn_ret_with_leading_char() {
1245         cov_mark::check!(expected_type_fn_ret_with_leading_char);
1246         check_expected_type_and_name(
1247             r#"
1248 fn foo() -> u32 {
1249     c$0
1250 }
1251 "#,
1252             expect![[r#"ty: u32, name: ?"#]],
1253         )
1254     }
1255
1256     #[test]
1257     fn expected_type_fn_ret_fn_ref_fully_typed() {
1258         check_expected_type_and_name(
1259             r#"
1260 fn foo() -> u32 {
1261     foo$0
1262 }
1263 "#,
1264             expect![[r#"ty: u32, name: ?"#]],
1265         )
1266     }
1267
1268     #[test]
1269     fn expected_type_closure_param_return() {
1270         // FIXME: make this work with `|| $0`
1271         check_expected_type_and_name(
1272             r#"
1273 //- minicore: fn
1274 fn foo() {
1275     bar(|| a$0);
1276 }
1277
1278 fn bar(f: impl FnOnce() -> u32) {}
1279 "#,
1280             expect![[r#"ty: u32, name: ?"#]],
1281         );
1282     }
1283
1284     #[test]
1285     fn expected_type_generic_function() {
1286         check_expected_type_and_name(
1287             r#"
1288 fn foo() {
1289     bar::<u32>($0);
1290 }
1291
1292 fn bar<T>(t: T) {}
1293 "#,
1294             expect![[r#"ty: u32, name: t"#]],
1295         );
1296     }
1297
1298     #[test]
1299     fn expected_type_generic_method() {
1300         check_expected_type_and_name(
1301             r#"
1302 fn foo() {
1303     S(1u32).bar($0);
1304 }
1305
1306 struct S<T>(T);
1307 impl<T> S<T> {
1308     fn bar(self, t: T) {}
1309 }
1310 "#,
1311             expect![[r#"ty: u32, name: t"#]],
1312         );
1313     }
1314
1315     #[test]
1316     fn expected_type_functional_update() {
1317         cov_mark::check!(expected_type_struct_func_update);
1318         check_expected_type_and_name(
1319             r#"
1320 struct Foo { field: u32 }
1321 fn foo() {
1322     Foo {
1323         ..$0
1324     }
1325 }
1326 "#,
1327             expect![[r#"ty: Foo, name: ?"#]],
1328         );
1329     }
1330
1331     #[test]
1332     fn expected_type_param_pat() {
1333         check_expected_type_and_name(
1334             r#"
1335 struct Foo { field: u32 }
1336 fn foo(a$0: Foo) {}
1337 "#,
1338             expect![[r#"ty: Foo, name: ?"#]],
1339         );
1340         check_expected_type_and_name(
1341             r#"
1342 struct Foo { field: u32 }
1343 fn foo($0: Foo) {}
1344 "#,
1345             // FIXME make this work, currently fails due to pattern recovery eating the `:`
1346             expect![[r#"ty: ?, name: ?"#]],
1347         );
1348     }
1349 }