compiler/rustc_borrowck/src/diagnostics/mod.rs

   1 //! Borrow checker diagnostics.
   2
   3 use crate::session_diagnostics::{
   4     CaptureArgLabel, CaptureReasonLabel, CaptureReasonNote, CaptureReasonSuggest, CaptureVarCause,
   5     CaptureVarKind, CaptureVarPathUseCause, OnClosureNote,
   6 };
   7 use itertools::Itertools;
   8 use rustc_errors::{Applicability, Diagnostic};
   9 use rustc_hir as hir;
  10 use rustc_hir::def::{CtorKind, Namespace};
  11 use rustc_hir::GeneratorKind;
  12 use rustc_index::IndexSlice;
  13 use rustc_infer::infer::LateBoundRegionConversionTime;
  14 use rustc_middle::mir::tcx::PlaceTy;
  15 use rustc_middle::mir::{
  16     AggregateKind, CallSource, ConstOperand, FakeReadCause, Local, LocalInfo, LocalKind, Location,
  17     Operand, Place, PlaceRef, ProjectionElem, Rvalue, Statement, StatementKind, Terminator,
  18     TerminatorKind,
  19 };
  20 use rustc_middle::ty::print::Print;
  21 use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
  22 use rustc_middle::util::{call_kind, CallDesugaringKind};
  23 use rustc_mir_dataflow::move_paths::{InitLocation, LookupResult};
  24 use rustc_span::def_id::LocalDefId;
  25 use rustc_span::{symbol::sym, Span, Symbol, DUMMY_SP};
  26 use rustc_target::abi::{FieldIdx, VariantIdx};
  27 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
  28 use rustc_trait_selection::traits::{
  29     type_known_to_meet_bound_modulo_regions, Obligation, ObligationCause,
  30 };
  31
  32 use super::borrow_set::BorrowData;
  33 use super::MirBorrowckCtxt;
  34
  35 mod find_all_local_uses;
  36 mod find_use;
  37 mod outlives_suggestion;
  38 mod region_name;
  39 mod var_name;
  40
  41 mod bound_region_errors;
  42 mod conflict_errors;
  43 mod explain_borrow;
  44 mod move_errors;
  45 mod mutability_errors;
  46 mod region_errors;
  47
  48 pub(crate) use bound_region_errors::{ToUniverseInfo, UniverseInfo};
  49 pub(crate) use mutability_errors::AccessKind;
  50 pub(crate) use outlives_suggestion::OutlivesSuggestionBuilder;
  51 pub(crate) use region_errors::{ErrorConstraintInfo, RegionErrorKind, RegionErrors};
  52 pub(crate) use region_name::{RegionName, RegionNameSource};
  53 pub(crate) use rustc_middle::util::CallKind;
  54
  55 pub(super) struct DescribePlaceOpt {
  56     pub including_downcast: bool,
  57
  58     /// Enable/Disable tuple fields.
  59     /// For example `x` tuple. if it's `true` `x.0`. Otherwise `x`
  60     pub including_tuple_field: bool,
  61 }
  62
  63 pub(super) struct IncludingTupleField(pub(super) bool);
  64
  65 impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
  66     /// Adds a suggestion when a closure is invoked twice with a moved variable or when a closure
  67     /// is moved after being invoked.
  68     ///
  69     /// ```text
  70     /// note: closure cannot be invoked more than once because it moves the variable `dict` out of
  71     ///       its environment
  72     ///   --> $DIR/issue-42065.rs:16:29
  73     ///    |
  74     /// LL |         for (key, value) in dict {
  75     ///    |                             ^^^^
  76     /// ```
  77     pub(super) fn add_moved_or_invoked_closure_note(
  78         &self,
  79         location: Location,
  80         place: PlaceRef<'tcx>,
  81         diag: &mut Diagnostic,
  82     ) -> bool {
  83         debug!("add_moved_or_invoked_closure_note: location={:?} place={:?}", location, place);
  84         let mut target = place.local_or_deref_local();
  85         for stmt in &self.body[location.block].statements[location.statement_index..] {
  86             debug!("add_moved_or_invoked_closure_note: stmt={:?} target={:?}", stmt, target);
  87             if let StatementKind::Assign(box (into, Rvalue::Use(from))) = &stmt.kind {
  88                 debug!("add_fnonce_closure_note: into={:?} from={:?}", into, from);
  89                 match from {
  90                     Operand::Copy(place) | Operand::Move(place)
  91                         if target == place.local_or_deref_local() =>
  92                     {
  93                         target = into.local_or_deref_local()
  94                     }
  95                     _ => {}
  96                 }
  97             }
  98         }
  99
 100         // Check if we are attempting to call a closure after it has been invoked.
 101         let terminator = self.body[location.block].terminator();
 102         debug!("add_moved_or_invoked_closure_note: terminator={:?}", terminator);
 103         if let TerminatorKind::Call {
 104             func: Operand::Constant(box ConstOperand { const_, .. }),
 105             args,
 106             ..
 107         } = &terminator.kind
 108         {
 109             if let ty::FnDef(id, _) = *const_.ty().kind() {
 110                 debug!("add_moved_or_invoked_closure_note: id={:?}", id);
 111                 if Some(self.infcx.tcx.parent(id)) == self.infcx.tcx.lang_items().fn_once_trait() {
 112                     let closure = match args.first() {
 113                         Some(Operand::Copy(place) | Operand::Move(place))
 114                             if target == place.local_or_deref_local() =>
 115                         {
 116                             place.local_or_deref_local().unwrap()
 117                         }
 118                         _ => return false,
 119                     };
 120
 121                     debug!("add_moved_or_invoked_closure_note: closure={:?}", closure);
 122                     if let ty::Closure(did, _) = self.body.local_decls[closure].ty.kind() {
 123                         let did = did.expect_local();
 124                         if let Some((span, hir_place)) = self.infcx.tcx.closure_kind_origin(did) {
 125                             diag.eager_subdiagnostic(
 126                                 &self.infcx.tcx.sess.parse_sess.span_diagnostic,
 127                                 OnClosureNote::InvokedTwice {
 128                                     place_name: &ty::place_to_string_for_capture(
 129                                         self.infcx.tcx,
 130                                         hir_place,
 131                                     ),
 132                                     span: *span,
 133                                 },
 134                             );
 135                             return true;
 136                         }
 137                     }
 138                 }
 139             }
 140         }
 141
 142         // Check if we are just moving a closure after it has been invoked.
 143         if let Some(target) = target {
 144             if let ty::Closure(did, _) = self.body.local_decls[target].ty.kind() {
 145                 let did = did.expect_local();
 146                 if let Some((span, hir_place)) = self.infcx.tcx.closure_kind_origin(did) {
 147                     diag.eager_subdiagnostic(
 148                         &self.infcx.tcx.sess.parse_sess.span_diagnostic,
 149                         OnClosureNote::MovedTwice {
 150                             place_name: &ty::place_to_string_for_capture(self.infcx.tcx, hir_place),
 151                             span: *span,
 152                         },
 153                     );
 154                     return true;
 155                 }
 156             }
 157         }
 158         false
 159     }
 160
 161     /// End-user visible description of `place` if one can be found.
 162     /// If the place is a temporary for instance, `"value"` will be returned.
 163     pub(super) fn describe_any_place(&self, place_ref: PlaceRef<'tcx>) -> String {
 164         match self.describe_place(place_ref) {
 165             Some(mut descr) => {
 166                 // Surround descr with `backticks`.
 167                 descr.reserve(2);
 168                 descr.insert(0, '`');
 169                 descr.push('`');
 170                 descr
 171             }
 172             None => "value".to_string(),
 173         }
 174     }
 175
 176     /// End-user visible description of `place` if one can be found.
 177     /// If the place is a temporary for instance, `None` will be returned.
 178     pub(super) fn describe_place(&self, place_ref: PlaceRef<'tcx>) -> Option<String> {
 179         self.describe_place_with_options(
 180             place_ref,
 181             DescribePlaceOpt { including_downcast: false, including_tuple_field: true },
 182         )
 183     }
 184
 185     /// End-user visible description of `place` if one can be found. If the place is a temporary
 186     /// for instance, `None` will be returned.
 187     /// `IncludingDowncast` parameter makes the function return `None` if `ProjectionElem` is
 188     /// `Downcast` and `IncludingDowncast` is true
 189     pub(super) fn describe_place_with_options(
 190         &self,
 191         place: PlaceRef<'tcx>,
 192         opt: DescribePlaceOpt,
 193     ) -> Option<String> {
 194         let local = place.local;
 195         let mut autoderef_index = None;
 196         let mut buf = String::new();
 197         let mut ok = self.append_local_to_string(local, &mut buf);
 198
 199         for (index, elem) in place.projection.into_iter().enumerate() {
 200             match elem {
 201                 ProjectionElem::Deref => {
 202                     if index == 0 {
 203                         if self.body.local_decls[local].is_ref_for_guard() {
 204                             continue;
 205                         }
 206                         if let LocalInfo::StaticRef { def_id, .. } =
 207                             *self.body.local_decls[local].local_info()
 208                         {
 209                             buf.push_str(self.infcx.tcx.item_name(def_id).as_str());
 210                             ok = Ok(());
 211                             continue;
 212                         }
 213                     }
 214                     if let Some(field) = self.is_upvar_field_projection(PlaceRef {
 215                         local,
 216                         projection: place.projection.split_at(index + 1).0,
 217                     }) {
 218                         let var_index = field.index();
 219                         buf = self.upvars[var_index].place.to_string(self.infcx.tcx);
 220                         ok = Ok(());
 221                         if !self.upvars[var_index].by_ref {
 222                             buf.insert(0, '*');
 223                         }
 224                     } else {
 225                         if autoderef_index.is_none() {
 226                             autoderef_index =
 227                                 match place.projection.into_iter().rev().find_position(|elem| {
 228                                     !matches!(
 229                                         elem,
 230                                         ProjectionElem::Deref | ProjectionElem::Downcast(..)
 231                                     )
 232                                 }) {
 233                                     Some((index, _)) => Some(place.projection.len() - index),
 234                                     None => Some(0),
 235                                 };
 236                         }
 237                         if index >= autoderef_index.unwrap() {
 238                             buf.insert(0, '*');
 239                         }
 240                     }
 241                 }
 242                 ProjectionElem::Downcast(..) if opt.including_downcast => return None,
 243                 ProjectionElem::Downcast(..) => (),
 244                 ProjectionElem::OpaqueCast(..) => (),
 245                 ProjectionElem::Subtype(..) => (),
 246                 ProjectionElem::Field(field, _ty) => {
 247                     // FIXME(project-rfc_2229#36): print capture precisely here.
 248                     if let Some(field) = self.is_upvar_field_projection(PlaceRef {
 249                         local,
 250                         projection: place.projection.split_at(index + 1).0,
 251                     }) {
 252                         buf = self.upvars[field.index()].place.to_string(self.infcx.tcx);
 253                         ok = Ok(());
 254                     } else {
 255                         let field_name = self.describe_field(
 256                             PlaceRef { local, projection: place.projection.split_at(index).0 },
 257                             *field,
 258                             IncludingTupleField(opt.including_tuple_field),
 259                         );
 260                         if let Some(field_name_str) = field_name {
 261                             buf.push('.');
 262                             buf.push_str(&field_name_str);
 263                         }
 264                     }
 265                 }
 266                 ProjectionElem::Index(index) => {
 267                     buf.push('[');
 268                     if self.append_local_to_string(*index, &mut buf).is_err() {
 269                         buf.push('_');
 270                     }
 271                     buf.push(']');
 272                 }
 273                 ProjectionElem::ConstantIndex { .. } | ProjectionElem::Subslice { .. } => {
 274                     // Since it isn't possible to borrow an element on a particular index and
 275                     // then use another while the borrow is held, don't output indices details
 276                     // to avoid confusing the end-user
 277                     buf.push_str("[..]");
 278                 }
 279             }
 280         }
 281         ok.ok().map(|_| buf)
 282     }
 283
 284     fn describe_name(&self, place: PlaceRef<'tcx>) -> Option<Symbol> {
 285         for elem in place.projection.into_iter() {
 286             match elem {
 287                 ProjectionElem::Downcast(Some(name), _) => {
 288                     return Some(*name);
 289                 }
 290                 _ => {}
 291             }
 292         }
 293         None
 294     }
 295
 296     /// Appends end-user visible description of the `local` place to `buf`. If `local` doesn't have
 297     /// a name, or its name was generated by the compiler, then `Err` is returned
 298     fn append_local_to_string(&self, local: Local, buf: &mut String) -> Result<(), ()> {
 299         let decl = &self.body.local_decls[local];
 300         match self.local_names[local] {
 301             Some(name) if !decl.from_compiler_desugaring() => {
 302                 buf.push_str(name.as_str());
 303                 Ok(())
 304             }
 305             _ => Err(()),
 306         }
 307     }
 308
 309     /// End-user visible description of the `field`nth field of `base`
 310     fn describe_field(
 311         &self,
 312         place: PlaceRef<'tcx>,
 313         field: FieldIdx,
 314         including_tuple_field: IncludingTupleField,
 315     ) -> Option<String> {
 316         let place_ty = match place {
 317             PlaceRef { local, projection: [] } => PlaceTy::from_ty(self.body.local_decls[local].ty),
 318             PlaceRef { local, projection: [proj_base @ .., elem] } => match elem {
 319                 ProjectionElem::Deref
 320                 | ProjectionElem::Index(..)
 321                 | ProjectionElem::ConstantIndex { .. }
 322                 | ProjectionElem::Subslice { .. } => {
 323                     PlaceRef { local, projection: proj_base }.ty(self.body, self.infcx.tcx)
 324                 }
 325                 ProjectionElem::Downcast(..) => place.ty(self.body, self.infcx.tcx),
 326                 ProjectionElem::Subtype(ty) | ProjectionElem::OpaqueCast(ty) => {
 327                     PlaceTy::from_ty(*ty)
 328                 }
 329                 ProjectionElem::Field(_, field_type) => PlaceTy::from_ty(*field_type),
 330             },
 331         };
 332         self.describe_field_from_ty(
 333             place_ty.ty,
 334             field,
 335             place_ty.variant_index,
 336             including_tuple_field,
 337         )
 338     }
 339
 340     /// End-user visible description of the `field_index`nth field of `ty`
 341     fn describe_field_from_ty(
 342         &self,
 343         ty: Ty<'_>,
 344         field: FieldIdx,
 345         variant_index: Option<VariantIdx>,
 346         including_tuple_field: IncludingTupleField,
 347     ) -> Option<String> {
 348         if ty.is_box() {
 349             // If the type is a box, the field is described from the boxed type
 350             self.describe_field_from_ty(ty.boxed_ty(), field, variant_index, including_tuple_field)
 351         } else {
 352             match *ty.kind() {
 353                 ty::Adt(def, _) => {
 354                     let variant = if let Some(idx) = variant_index {
 355                         assert!(def.is_enum());
 356                         &def.variant(idx)
 357                     } else {
 358                         def.non_enum_variant()
 359                     };
 360                     if !including_tuple_field.0 && variant.ctor_kind() == Some(CtorKind::Fn) {
 361                         return None;
 362                     }
 363                     Some(variant.fields[field].name.to_string())
 364                 }
 365                 ty::Tuple(_) => Some(field.index().to_string()),
 366                 ty::Ref(_, ty, _) | ty::RawPtr(ty::TypeAndMut { ty, .. }) => {
 367                     self.describe_field_from_ty(ty, field, variant_index, including_tuple_field)
 368                 }
 369                 ty::Array(ty, _) | ty::Slice(ty) => {
 370                     self.describe_field_from_ty(ty, field, variant_index, including_tuple_field)
 371                 }
 372                 ty::Closure(def_id, _) | ty::Generator(def_id, _, _) => {
 373                     // We won't be borrowck'ing here if the closure came from another crate,
 374                     // so it's safe to call `expect_local`.
 375                     //
 376                     // We know the field exists so it's safe to call operator[] and `unwrap` here.
 377                     let def_id = def_id.expect_local();
 378                     let var_id =
 379                         self.infcx.tcx.closure_captures(def_id)[field.index()].get_root_variable();
 380
 381                     Some(self.infcx.tcx.hir().name(var_id).to_string())
 382                 }
 383                 _ => {
 384                     // Might need a revision when the fields in trait RFC is implemented
 385                     // (https://github.com/rust-lang/rfcs/pull/1546)
 386                     bug!("End-user description not implemented for field access on `{:?}`", ty);
 387                 }
 388             }
 389         }
 390     }
 391
 392     pub(super) fn borrowed_content_source(
 393         &self,
 394         deref_base: PlaceRef<'tcx>,
 395     ) -> BorrowedContentSource<'tcx> {
 396         let tcx = self.infcx.tcx;
 397
 398         // Look up the provided place and work out the move path index for it,
 399         // we'll use this to check whether it was originally from an overloaded
 400         // operator.
 401         match self.move_data.rev_lookup.find(deref_base) {
 402             LookupResult::Exact(mpi) | LookupResult::Parent(Some(mpi)) => {
 403                 debug!("borrowed_content_source: mpi={:?}", mpi);
 404
 405                 for i in &self.move_data.init_path_map[mpi] {
 406                     let init = &self.move_data.inits[*i];
 407                     debug!("borrowed_content_source: init={:?}", init);
 408                     // We're only interested in statements that initialized a value, not the
 409                     // initializations from arguments.
 410                     let InitLocation::Statement(loc) = init.location else { continue };
 411
 412                     let bbd = &self.body[loc.block];
 413                     let is_terminator = bbd.statements.len() == loc.statement_index;
 414                     debug!(
 415                         "borrowed_content_source: loc={:?} is_terminator={:?}",
 416                         loc, is_terminator,
 417                     );
 418                     if !is_terminator {
 419                         continue;
 420                     } else if let Some(Terminator {
 421                         kind:
 422                             TerminatorKind::Call {
 423                                 func,
 424                                 call_source: CallSource::OverloadedOperator,
 425                                 ..
 426                             },
 427                         ..
 428                     }) = &bbd.terminator
 429                     {
 430                         if let Some(source) =
 431                             BorrowedContentSource::from_call(func.ty(self.body, tcx), tcx)
 432                         {
 433                             return source;
 434                         }
 435                     }
 436                 }
 437             }
 438             // Base is a `static` so won't be from an overloaded operator
 439             _ => (),
 440         };
 441
 442         // If we didn't find an overloaded deref or index, then assume it's a
 443         // built in deref and check the type of the base.
 444         let base_ty = deref_base.ty(self.body, tcx).ty;
 445         if base_ty.is_unsafe_ptr() {
 446             BorrowedContentSource::DerefRawPointer
 447         } else if base_ty.is_mutable_ptr() {
 448             BorrowedContentSource::DerefMutableRef
 449         } else {
 450             BorrowedContentSource::DerefSharedRef
 451         }
 452     }
 453
 454     /// Return the name of the provided `Ty` (that must be a reference) with a synthesized lifetime
 455     /// name where required.
 456     pub(super) fn get_name_for_ty(&self, ty: Ty<'tcx>, counter: usize) -> String {
 457         let mut printer = ty::print::FmtPrinter::new(self.infcx.tcx, Namespace::TypeNS);
 458
 459         // We need to add synthesized lifetimes where appropriate. We do
 460         // this by hooking into the pretty printer and telling it to label the
 461         // lifetimes without names with the value `'0`.
 462         if let ty::Ref(region, ..) = ty.kind() {
 463             match **region {
 464                 ty::ReLateBound(_, ty::BoundRegion { kind: br, .. })
 465                 | ty::RePlaceholder(ty::PlaceholderRegion {
 466                     bound: ty::BoundRegion { kind: br, .. },
 467                     ..
 468                 }) => printer.region_highlight_mode.highlighting_bound_region(br, counter),
 469                 _ => {}
 470             }
 471         }
 472
 473         ty.print(printer).unwrap().into_buffer()
 474     }
 475
 476     /// Returns the name of the provided `Ty` (that must be a reference)'s region with a
 477     /// synthesized lifetime name where required.
 478     pub(super) fn get_region_name_for_ty(&self, ty: Ty<'tcx>, counter: usize) -> String {
 479         let mut printer = ty::print::FmtPrinter::new(self.infcx.tcx, Namespace::TypeNS);
 480
 481         let region = if let ty::Ref(region, ..) = ty.kind() {
 482             match **region {
 483                 ty::ReLateBound(_, ty::BoundRegion { kind: br, .. })
 484                 | ty::RePlaceholder(ty::PlaceholderRegion {
 485                     bound: ty::BoundRegion { kind: br, .. },
 486                     ..
 487                 }) => printer.region_highlight_mode.highlighting_bound_region(br, counter),
 488                 _ => {}
 489             }
 490             region
 491         } else {
 492             bug!("ty for annotation of borrow region is not a reference");
 493         };
 494
 495         region.print(printer).unwrap().into_buffer()
 496     }
 497 }
 498
 499 /// The span(s) associated to a use of a place.
 500 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 501 pub(super) enum UseSpans<'tcx> {
 502     /// The access is caused by capturing a variable for a closure.
 503     ClosureUse {
 504         /// This is true if the captured variable was from a generator.
 505         generator_kind: Option<GeneratorKind>,
 506         /// The span of the args of the closure, including the `move` keyword if
 507         /// it's present.
 508         args_span: Span,
 509         /// The span of the use resulting in capture kind
 510         /// Check `ty::CaptureInfo` for more details
 511         capture_kind_span: Span,
 512         /// The span of the use resulting in the captured path
 513         /// Check `ty::CaptureInfo` for more details
 514         path_span: Span,
 515     },
 516     /// The access is caused by using a variable as the receiver of a method
 517     /// that takes 'self'
 518     FnSelfUse {
 519         /// The span of the variable being moved
 520         var_span: Span,
 521         /// The span of the method call on the variable
 522         fn_call_span: Span,
 523         /// The definition span of the method being called
 524         fn_span: Span,
 525         kind: CallKind<'tcx>,
 526     },
 527     /// This access is caused by a `match` or `if let` pattern.
 528     PatUse(Span),
 529     /// This access has a single span associated to it: common case.
 530     OtherUse(Span),
 531 }
 532
 533 impl UseSpans<'_> {
 534     pub(super) fn args_or_use(self) -> Span {
 535         match self {
 536             UseSpans::ClosureUse { args_span: span, .. }
 537             | UseSpans::PatUse(span)
 538             | UseSpans::OtherUse(span) => span,
 539             UseSpans::FnSelfUse { fn_call_span, kind: CallKind::DerefCoercion { .. }, .. } => {
 540                 fn_call_span
 541             }
 542             UseSpans::FnSelfUse { var_span, .. } => var_span,
 543         }
 544     }
 545
 546     /// Returns the span of `self`, in the case of a `ClosureUse` returns the `path_span`
 547     pub(super) fn var_or_use_path_span(self) -> Span {
 548         match self {
 549             UseSpans::ClosureUse { path_span: span, .. }
 550             | UseSpans::PatUse(span)
 551             | UseSpans::OtherUse(span) => span,
 552             UseSpans::FnSelfUse { fn_call_span, kind: CallKind::DerefCoercion { .. }, .. } => {
 553                 fn_call_span
 554             }
 555             UseSpans::FnSelfUse { var_span, .. } => var_span,
 556         }
 557     }
 558
 559     /// Returns the span of `self`, in the case of a `ClosureUse` returns the `capture_kind_span`
 560     pub(super) fn var_or_use(self) -> Span {
 561         match self {
 562             UseSpans::ClosureUse { capture_kind_span: span, .. }
 563             | UseSpans::PatUse(span)
 564             | UseSpans::OtherUse(span) => span,
 565             UseSpans::FnSelfUse { fn_call_span, kind: CallKind::DerefCoercion { .. }, .. } => {
 566                 fn_call_span
 567             }
 568             UseSpans::FnSelfUse { var_span, .. } => var_span,
 569         }
 570     }
 571
 572     pub(super) fn generator_kind(self) -> Option<GeneratorKind> {
 573         match self {
 574             UseSpans::ClosureUse { generator_kind, .. } => generator_kind,
 575             _ => None,
 576         }
 577     }
 578
 579     /// Add a span label to the arguments of the closure, if it exists.
 580     pub(super) fn args_subdiag(
 581         self,
 582         err: &mut Diagnostic,
 583         f: impl FnOnce(Span) -> CaptureArgLabel,
 584     ) {
 585         if let UseSpans::ClosureUse { args_span, .. } = self {
 586             err.subdiagnostic(f(args_span));
 587         }
 588     }
 589
 590     /// Add a span label to the use of the captured variable, if it exists.
 591     /// only adds label to the `path_span`
 592     pub(super) fn var_path_only_subdiag(
 593         self,
 594         err: &mut Diagnostic,
 595         action: crate::InitializationRequiringAction,
 596     ) {
 597         use crate::InitializationRequiringAction::*;
 598         use CaptureVarPathUseCause::*;
 599         if let UseSpans::ClosureUse { generator_kind, path_span, .. } = self {
 600             match generator_kind {
 601                 Some(_) => {
 602                     err.subdiagnostic(match action {
 603                         Borrow => BorrowInGenerator { path_span },
 604                         MatchOn | Use => UseInGenerator { path_span },
 605                         Assignment => AssignInGenerator { path_span },
 606                         PartialAssignment => AssignPartInGenerator { path_span },
 607                     });
 608                 }
 609                 None => {
 610                     err.subdiagnostic(match action {
 611                         Borrow => BorrowInClosure { path_span },
 612                         MatchOn | Use => UseInClosure { path_span },
 613                         Assignment => AssignInClosure { path_span },
 614                         PartialAssignment => AssignPartInClosure { path_span },
 615                     });
 616                 }
 617             }
 618         }
 619     }
 620
 621     /// Add a subdiagnostic to the use of the captured variable, if it exists.
 622     pub(super) fn var_subdiag(
 623         self,
 624         handler: Option<&rustc_errors::Handler>,
 625         err: &mut Diagnostic,
 626         kind: Option<rustc_middle::mir::BorrowKind>,
 627         f: impl FnOnce(Option<GeneratorKind>, Span) -> CaptureVarCause,
 628     ) {
 629         if let UseSpans::ClosureUse { generator_kind, capture_kind_span, path_span, .. } = self {
 630             if capture_kind_span != path_span {
 631                 err.subdiagnostic(match kind {
 632                     Some(kd) => match kd {
 633                         rustc_middle::mir::BorrowKind::Shared
 634                         | rustc_middle::mir::BorrowKind::Fake => {
 635                             CaptureVarKind::Immut { kind_span: capture_kind_span }
 636                         }
 637
 638                         rustc_middle::mir::BorrowKind::Mut { .. } => {
 639                             CaptureVarKind::Mut { kind_span: capture_kind_span }
 640                         }
 641                     },
 642                     None => CaptureVarKind::Move { kind_span: capture_kind_span },
 643                 });
 644             };
 645             let diag = f(generator_kind, path_span);
 646             match handler {
 647                 Some(hd) => err.eager_subdiagnostic(hd, diag),
 648                 None => err.subdiagnostic(diag),
 649             };
 650         }
 651     }
 652
 653     /// Returns `false` if this place is not used in a closure.
 654     pub(super) fn for_closure(&self) -> bool {
 655         match *self {
 656             UseSpans::ClosureUse { generator_kind, .. } => generator_kind.is_none(),
 657             _ => false,
 658         }
 659     }
 660
 661     /// Returns `false` if this place is not used in a generator.
 662     pub(super) fn for_generator(&self) -> bool {
 663         match *self {
 664             UseSpans::ClosureUse { generator_kind, .. } => generator_kind.is_some(),
 665             _ => false,
 666         }
 667     }
 668
 669     pub(super) fn or_else<F>(self, if_other: F) -> Self
 670     where
 671         F: FnOnce() -> Self,
 672     {
 673         match self {
 674             closure @ UseSpans::ClosureUse { .. } => closure,
 675             UseSpans::PatUse(_) | UseSpans::OtherUse(_) => if_other(),
 676             fn_self @ UseSpans::FnSelfUse { .. } => fn_self,
 677         }
 678     }
 679 }
 680
 681 pub(super) enum BorrowedContentSource<'tcx> {
 682     DerefRawPointer,
 683     DerefMutableRef,
 684     DerefSharedRef,
 685     OverloadedDeref(Ty<'tcx>),
 686     OverloadedIndex(Ty<'tcx>),
 687 }
 688
 689 impl<'tcx> BorrowedContentSource<'tcx> {
 690     pub(super) fn describe_for_unnamed_place(&self, tcx: TyCtxt<'_>) -> String {
 691         match *self {
 692             BorrowedContentSource::DerefRawPointer => "a raw pointer".to_string(),
 693             BorrowedContentSource::DerefSharedRef => "a shared reference".to_string(),
 694             BorrowedContentSource::DerefMutableRef => "a mutable reference".to_string(),
 695             BorrowedContentSource::OverloadedDeref(ty) => ty
 696                 .ty_adt_def()
 697                 .and_then(|adt| match tcx.get_diagnostic_name(adt.did())? {
 698                     name @ (sym::Rc | sym::Arc) => Some(format!("an `{name}`")),
 699                     _ => None,
 700                 })
 701                 .unwrap_or_else(|| format!("dereference of `{ty}`")),
 702             BorrowedContentSource::OverloadedIndex(ty) => format!("index of `{ty}`"),
 703         }
 704     }
 705
 706     pub(super) fn describe_for_named_place(&self) -> Option<&'static str> {
 707         match *self {
 708             BorrowedContentSource::DerefRawPointer => Some("raw pointer"),
 709             BorrowedContentSource::DerefSharedRef => Some("shared reference"),
 710             BorrowedContentSource::DerefMutableRef => Some("mutable reference"),
 711             // Overloaded deref and index operators should be evaluated into a
 712             // temporary. So we don't need a description here.
 713             BorrowedContentSource::OverloadedDeref(_)
 714             | BorrowedContentSource::OverloadedIndex(_) => None,
 715         }
 716     }
 717
 718     pub(super) fn describe_for_immutable_place(&self, tcx: TyCtxt<'_>) -> String {
 719         match *self {
 720             BorrowedContentSource::DerefRawPointer => "a `*const` pointer".to_string(),
 721             BorrowedContentSource::DerefSharedRef => "a `&` reference".to_string(),
 722             BorrowedContentSource::DerefMutableRef => {
 723                 bug!("describe_for_immutable_place: DerefMutableRef isn't immutable")
 724             }
 725             BorrowedContentSource::OverloadedDeref(ty) => ty
 726                 .ty_adt_def()
 727                 .and_then(|adt| match tcx.get_diagnostic_name(adt.did())? {
 728                     name @ (sym::Rc | sym::Arc) => Some(format!("an `{name}`")),
 729                     _ => None,
 730                 })
 731                 .unwrap_or_else(|| format!("dereference of `{ty}`")),
 732             BorrowedContentSource::OverloadedIndex(ty) => format!("an index of `{ty}`"),
 733         }
 734     }
 735
 736     fn from_call(func: Ty<'tcx>, tcx: TyCtxt<'tcx>) -> Option<Self> {
 737         match *func.kind() {
 738             ty::FnDef(def_id, args) => {
 739                 let trait_id = tcx.trait_of_item(def_id)?;
 740
 741                 let lang_items = tcx.lang_items();
 742                 if Some(trait_id) == lang_items.deref_trait()
 743                     || Some(trait_id) == lang_items.deref_mut_trait()
 744                 {
 745                     Some(BorrowedContentSource::OverloadedDeref(args.type_at(0)))
 746                 } else if Some(trait_id) == lang_items.index_trait()
 747                     || Some(trait_id) == lang_items.index_mut_trait()
 748                 {
 749                     Some(BorrowedContentSource::OverloadedIndex(args.type_at(0)))
 750                 } else {
 751                     None
 752                 }
 753             }
 754             _ => None,
 755         }
 756     }
 757 }
 758
 759 ///helper struct for explain_captures()
 760 struct CapturedMessageOpt {
 761     is_partial_move: bool,
 762     is_loop_message: bool,
 763     is_move_msg: bool,
 764     is_loop_move: bool,
 765     maybe_reinitialized_locations_is_empty: bool,
 766 }
 767
 768 impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 769     /// Finds the spans associated to a move or copy of move_place at location.
 770     pub(super) fn move_spans(
 771         &self,
 772         moved_place: PlaceRef<'tcx>, // Could also be an upvar.
 773         location: Location,
 774     ) -> UseSpans<'tcx> {
 775         use self::UseSpans::*;
 776
 777         let Some(stmt) = self.body[location.block].statements.get(location.statement_index) else {
 778             return OtherUse(self.body.source_info(location).span);
 779         };
 780
 781         debug!("move_spans: moved_place={:?} location={:?} stmt={:?}", moved_place, location, stmt);
 782         if let StatementKind::Assign(box (_, Rvalue::Aggregate(kind, places))) = &stmt.kind
 783             && let AggregateKind::Closure(def_id, _) | AggregateKind::Generator(def_id, _, _) = **kind
 784         {
 785             debug!("move_spans: def_id={:?} places={:?}", def_id, places);
 786             let def_id = def_id.expect_local();
 787             if let Some((args_span, generator_kind, capture_kind_span, path_span)) =
 788                 self.closure_span(def_id, moved_place, places)
 789             {
 790                 return ClosureUse {
 791                     generator_kind,
 792                     args_span,
 793                     capture_kind_span,
 794                     path_span,
 795                 };
 796             }
 797         }
 798
 799         // StatementKind::FakeRead only contains a def_id if they are introduced as a result
 800         // of pattern matching within a closure.
 801         if let StatementKind::FakeRead(box (cause, place)) = stmt.kind {
 802             match cause {
 803                 FakeReadCause::ForMatchedPlace(Some(closure_def_id))
 804                 | FakeReadCause::ForLet(Some(closure_def_id)) => {
 805                     debug!("move_spans: def_id={:?} place={:?}", closure_def_id, place);
 806                     let places = &[Operand::Move(place)];
 807                     if let Some((args_span, generator_kind, capture_kind_span, path_span)) =
 808                         self.closure_span(closure_def_id, moved_place, IndexSlice::from_raw(places))
 809                     {
 810                         return ClosureUse {
 811                             generator_kind,
 812                             args_span,
 813                             capture_kind_span,
 814                             path_span,
 815                         };
 816                     }
 817                 }
 818                 _ => {}
 819             }
 820         }
 821
 822         let normal_ret =
 823             if moved_place.projection.iter().any(|p| matches!(p, ProjectionElem::Downcast(..))) {
 824                 PatUse(stmt.source_info.span)
 825             } else {
 826                 OtherUse(stmt.source_info.span)
 827             };
 828
 829         // We are trying to find MIR of the form:
 830         // ```
 831         // _temp = _moved_val;
 832         // ...
 833         // FnSelfCall(_temp, ...)
 834         // ```
 835         //
 836         // where `_moved_val` is the place we generated the move error for,
 837         // `_temp` is some other local, and `FnSelfCall` is a function
 838         // that has a `self` parameter.
 839
 840         let target_temp = match stmt.kind {
 841             StatementKind::Assign(box (temp, _)) if temp.as_local().is_some() => {
 842                 temp.as_local().unwrap()
 843             }
 844             _ => return normal_ret,
 845         };
 846
 847         debug!("move_spans: target_temp = {:?}", target_temp);
 848
 849         if let Some(Terminator {
 850             kind: TerminatorKind::Call { fn_span, call_source, .. }, ..
 851         }) = &self.body[location.block].terminator
 852         {
 853             let Some((method_did, method_args)) = rustc_middle::util::find_self_call(
 854                 self.infcx.tcx,
 855                 &self.body,
 856                 target_temp,
 857                 location.block,
 858             ) else {
 859                 return normal_ret;
 860             };
 861
 862             let kind = call_kind(
 863                 self.infcx.tcx,
 864                 self.param_env,
 865                 method_did,
 866                 method_args,
 867                 *fn_span,
 868                 call_source.from_hir_call(),
 869                 Some(self.infcx.tcx.fn_arg_names(method_did)[0]),
 870             );
 871
 872             return FnSelfUse {
 873                 var_span: stmt.source_info.span,
 874                 fn_call_span: *fn_span,
 875                 fn_span: self.infcx.tcx.def_span(method_did),
 876                 kind,
 877             };
 878         }
 879         normal_ret
 880     }
 881
 882     /// Finds the span of arguments of a closure (within `maybe_closure_span`)
 883     /// and its usage of the local assigned at `location`.
 884     /// This is done by searching in statements succeeding `location`
 885     /// and originating from `maybe_closure_span`.
 886     pub(super) fn borrow_spans(&self, use_span: Span, location: Location) -> UseSpans<'tcx> {
 887         use self::UseSpans::*;
 888         debug!("borrow_spans: use_span={:?} location={:?}", use_span, location);
 889
 890         let target = match self.body[location.block].statements.get(location.statement_index) {
 891             Some(Statement { kind: StatementKind::Assign(box (place, _)), .. }) => {
 892                 if let Some(local) = place.as_local() {
 893                     local
 894                 } else {
 895                     return OtherUse(use_span);
 896                 }
 897             }
 898             _ => return OtherUse(use_span),
 899         };
 900
 901         if self.body.local_kind(target) != LocalKind::Temp {
 902             // operands are always temporaries.
 903             return OtherUse(use_span);
 904         }
 905
 906         // drop and replace might have moved the assignment to the next block
 907         let maybe_additional_statement =
 908             if let TerminatorKind::Drop { target: drop_target, .. } =
 909                 self.body[location.block].terminator().kind
 910             {
 911                 self.body[drop_target].statements.first()
 912             } else {
 913                 None
 914             };
 915
 916         let statements =
 917             self.body[location.block].statements[location.statement_index + 1..].iter();
 918
 919         for stmt in statements.chain(maybe_additional_statement) {
 920             if let StatementKind::Assign(box (_, Rvalue::Aggregate(kind, places))) = &stmt.kind {
 921                 let (&def_id, is_generator) = match kind {
 922                     box AggregateKind::Closure(def_id, _) => (def_id, false),
 923                     box AggregateKind::Generator(def_id, _, _) => (def_id, true),
 924                     _ => continue,
 925                 };
 926                 let def_id = def_id.expect_local();
 927
 928                 debug!(
 929                     "borrow_spans: def_id={:?} is_generator={:?} places={:?}",
 930                     def_id, is_generator, places
 931                 );
 932                 if let Some((args_span, generator_kind, capture_kind_span, path_span)) =
 933                     self.closure_span(def_id, Place::from(target).as_ref(), places)
 934                 {
 935                     return ClosureUse { generator_kind, args_span, capture_kind_span, path_span };
 936                 } else {
 937                     return OtherUse(use_span);
 938                 }
 939             }
 940
 941             if use_span != stmt.source_info.span {
 942                 break;
 943             }
 944         }
 945
 946         OtherUse(use_span)
 947     }
 948
 949     /// Finds the spans of a captured place within a closure or generator.
 950     /// The first span is the location of the use resulting in the capture kind of the capture
 951     /// The second span is the location the use resulting in the captured path of the capture
 952     fn closure_span(
 953         &self,
 954         def_id: LocalDefId,
 955         target_place: PlaceRef<'tcx>,
 956         places: &IndexSlice<FieldIdx, Operand<'tcx>>,
 957     ) -> Option<(Span, Option<GeneratorKind>, Span, Span)> {
 958         debug!(
 959             "closure_span: def_id={:?} target_place={:?} places={:?}",
 960             def_id, target_place, places
 961         );
 962         let hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(def_id);
 963         let expr = &self.infcx.tcx.hir().expect_expr(hir_id).kind;
 964         debug!("closure_span: hir_id={:?} expr={:?}", hir_id, expr);
 965         if let hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, .. }) = expr {
 966             for (captured_place, place) in
 967                 self.infcx.tcx.closure_captures(def_id).iter().zip(places)
 968             {
 969                 match place {
 970                     Operand::Copy(place) | Operand::Move(place)
 971                         if target_place == place.as_ref() =>
 972                     {
 973                         debug!("closure_span: found captured local {:?}", place);
 974                         let body = self.infcx.tcx.hir().body(body);
 975                         let generator_kind = body.generator_kind();
 976
 977                         return Some((
 978                             fn_decl_span,
 979                             generator_kind,
 980                             captured_place.get_capture_kind_span(self.infcx.tcx),
 981                             captured_place.get_path_span(self.infcx.tcx),
 982                         ));
 983                     }
 984                     _ => {}
 985                 }
 986             }
 987         }
 988         None
 989     }
 990
 991     /// Helper to retrieve span(s) of given borrow from the current MIR
 992     /// representation
 993     pub(super) fn retrieve_borrow_spans(&self, borrow: &BorrowData<'_>) -> UseSpans<'tcx> {
 994         let span = self.body.source_info(borrow.reserve_location).span;
 995         self.borrow_spans(span, borrow.reserve_location)
 996     }
 997
 998     fn explain_captures(
 999         &mut self,
1000         err: &mut Diagnostic,
1001         span: Span,
1002         move_span: Span,
1003         move_spans: UseSpans<'tcx>,
1004         moved_place: Place<'tcx>,
1005         msg_opt: CapturedMessageOpt,
1006     ) {
1007         let CapturedMessageOpt {
1008             is_partial_move: is_partial,
1009             is_loop_message,
1010             is_move_msg,
1011             is_loop_move,
1012             maybe_reinitialized_locations_is_empty,
1013         } = msg_opt;
1014         if let UseSpans::FnSelfUse { var_span, fn_call_span, fn_span, kind } = move_spans {
1015             let place_name = self
1016                 .describe_place(moved_place.as_ref())
1017                 .map(|n| format!("`{n}`"))
1018                 .unwrap_or_else(|| "value".to_owned());
1019             match kind {
1020                 CallKind::FnCall { fn_trait_id, .. }
1021                     if Some(fn_trait_id) == self.infcx.tcx.lang_items().fn_once_trait() =>
1022                 {
1023                     err.subdiagnostic(CaptureReasonLabel::Call {
1024                         fn_call_span,
1025                         place_name: &place_name,
1026                         is_partial,
1027                         is_loop_message,
1028                     });
1029                     err.subdiagnostic(CaptureReasonNote::FnOnceMoveInCall { var_span });
1030                 }
1031                 CallKind::Operator { self_arg, .. } => {
1032                     let self_arg = self_arg.unwrap();
1033                     err.subdiagnostic(CaptureReasonLabel::OperatorUse {
1034                         fn_call_span,
1035                         place_name: &place_name,
1036                         is_partial,
1037                         is_loop_message,
1038                     });
1039                     if self.fn_self_span_reported.insert(fn_span) {
1040                         err.subdiagnostic(CaptureReasonNote::LhsMoveByOperator {
1041                             span: self_arg.span,
1042                         });
1043                     }
1044                 }
1045                 CallKind::Normal { self_arg, desugaring, method_did, method_args } => {
1046                     let self_arg = self_arg.unwrap();
1047                     let tcx = self.infcx.tcx;
1048                     if let Some((CallDesugaringKind::ForLoopIntoIter, _)) = desugaring {
1049                         let ty = moved_place.ty(self.body, tcx).ty;
1050                         let suggest = match tcx.get_diagnostic_item(sym::IntoIterator) {
1051                             Some(def_id) => type_known_to_meet_bound_modulo_regions(
1052                                 &self.infcx,
1053                                 self.param_env,
1054                                 Ty::new_imm_ref(tcx, tcx.lifetimes.re_erased, ty),
1055                                 def_id,
1056                             ),
1057                             _ => false,
1058                         };
1059                         if suggest {
1060                             err.subdiagnostic(CaptureReasonSuggest::IterateSlice {
1061                                 ty,
1062                                 span: move_span.shrink_to_lo(),
1063                             });
1064                         }
1065
1066                         err.subdiagnostic(CaptureReasonLabel::ImplicitCall {
1067                             fn_call_span,
1068                             place_name: &place_name,
1069                             is_partial,
1070                             is_loop_message,
1071                         });
1072                         // If the moved place was a `&mut` ref, then we can
1073                         // suggest to reborrow it where it was moved, so it
1074                         // will still be valid by the time we get to the usage.
1075                         if let ty::Ref(_, _, hir::Mutability::Mut) =
1076                             moved_place.ty(self.body, self.infcx.tcx).ty.kind()
1077                         {
1078                             // If we are in a loop this will be suggested later.
1079                             if !is_loop_move {
1080                                 err.span_suggestion_verbose(
1081                                     move_span.shrink_to_lo(),
1082                                     format!(
1083                                         "consider creating a fresh reborrow of {} here",
1084                                         self.describe_place(moved_place.as_ref())
1085                                             .map(|n| format!("`{n}`"))
1086                                             .unwrap_or_else(|| "the mutable reference".to_string()),
1087                                     ),
1088                                     "&mut *",
1089                                     Applicability::MachineApplicable,
1090                                 );
1091                             }
1092                         }
1093                     } else {
1094                         if let Some((CallDesugaringKind::Await, _)) = desugaring {
1095                             err.subdiagnostic(CaptureReasonLabel::Await {
1096                                 fn_call_span,
1097                                 place_name: &place_name,
1098                                 is_partial,
1099                                 is_loop_message,
1100                             });
1101                         } else {
1102                             err.subdiagnostic(CaptureReasonLabel::MethodCall {
1103                                 fn_call_span,
1104                                 place_name: &place_name,
1105                                 is_partial,
1106                                 is_loop_message,
1107                             });
1108                         }
1109                         // Erase and shadow everything that could be passed to the new infcx.
1110                         let ty = moved_place.ty(self.body, tcx).ty;
1111
1112                         if let ty::Adt(def, args) = ty.kind()
1113                             && Some(def.did()) == tcx.lang_items().pin_type()
1114                             && let ty::Ref(_, _, hir::Mutability::Mut) = args.type_at(0).kind()
1115                             && let self_ty = self.infcx.instantiate_binder_with_fresh_vars(
1116                                 fn_call_span,
1117                                 LateBoundRegionConversionTime::FnCall,
1118                                 tcx.fn_sig(method_did).instantiate(tcx, method_args).input(0),
1119                             )
1120                             && self.infcx.can_eq(self.param_env, ty, self_ty)
1121                         {
1122                             err.eager_subdiagnostic(
1123                                 &self.infcx.tcx.sess.parse_sess.span_diagnostic,
1124                                 CaptureReasonSuggest::FreshReborrow {
1125                                     span: move_span.shrink_to_hi(),
1126                                 });
1127                         }
1128                         if let Some(clone_trait) = tcx.lang_items().clone_trait()
1129                             && let trait_ref = ty::TraitRef::new(tcx, clone_trait, [ty])
1130                             && let o = Obligation::new(
1131                                 tcx,
1132                                 ObligationCause::dummy(),
1133                                 self.param_env,
1134                                 ty::Binder::dummy(trait_ref),
1135                             )
1136                             && self.infcx.predicate_must_hold_modulo_regions(&o)
1137                         {
1138                             err.span_suggestion_verbose(
1139                                 move_span.shrink_to_hi(),
1140                                 "you can `clone` the value and consume it, but this might not be \
1141                                  your desired behavior",
1142                                 ".clone()".to_string(),
1143                                 Applicability::MaybeIncorrect,
1144                             );
1145                         }
1146                     }
1147                     // Avoid pointing to the same function in multiple different
1148                     // error messages.
1149                     if span != DUMMY_SP && self.fn_self_span_reported.insert(self_arg.span) {
1150                         self.explain_iterator_advancement_in_for_loop_if_applicable(
1151                             err,
1152                             span,
1153                             &move_spans,
1154                         );
1155
1156                         let func = tcx.def_path_str(method_did);
1157                         err.subdiagnostic(CaptureReasonNote::FuncTakeSelf {
1158                             func,
1159                             place_name,
1160                             span: self_arg.span,
1161                         });
1162                     }
1163                     let parent_did = tcx.parent(method_did);
1164                     let parent_self_ty =
1165                         matches!(tcx.def_kind(parent_did), rustc_hir::def::DefKind::Impl { .. })
1166                             .then_some(parent_did)
1167                             .and_then(|did| match tcx.type_of(did).instantiate_identity().kind() {
1168                                 ty::Adt(def, ..) => Some(def.did()),
1169                                 _ => None,
1170                             });
1171                     let is_option_or_result = parent_self_ty.is_some_and(|def_id| {
1172                         matches!(tcx.get_diagnostic_name(def_id), Some(sym::Option | sym::Result))
1173                     });
1174                     if is_option_or_result && maybe_reinitialized_locations_is_empty {
1175                         err.subdiagnostic(CaptureReasonLabel::BorrowContent { var_span });
1176                     }
1177                 }
1178                 // Other desugarings takes &self, which cannot cause a move
1179                 _ => {}
1180             }
1181         } else {
1182             if move_span != span || is_loop_message {
1183                 err.subdiagnostic(CaptureReasonLabel::MovedHere {
1184                     move_span,
1185                     is_partial,
1186                     is_move_msg,
1187                     is_loop_message,
1188                 });
1189             }
1190             // If the move error occurs due to a loop, don't show
1191             // another message for the same span
1192             if !is_loop_message {
1193                 move_spans.var_subdiag(None, err, None, |kind, var_span| match kind {
1194                     Some(_) => CaptureVarCause::PartialMoveUseInGenerator { var_span, is_partial },
1195                     None => CaptureVarCause::PartialMoveUseInClosure { var_span, is_partial },
1196                 })
1197             }
1198         }
1199     }
1200 }