1 //! Borrow checker diagnostics.
3 use rustc_errors::DiagnosticBuilder;
5 use rustc_hir::def::Namespace;
6 use rustc_hir::def_id::DefId;
7 use rustc_hir::lang_items::LangItemGroup;
8 use rustc_hir::GeneratorKind;
9 use rustc_middle::mir::{
10 AggregateKind, Constant, FakeReadCause, Field, Local, LocalInfo, LocalKind, Location, Operand,
11 Place, PlaceRef, ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind,
13 use rustc_middle::ty::print::Print;
14 use rustc_middle::ty::{self, DefIdTree, Instance, Ty, TyCtxt};
15 use rustc_mir_dataflow::move_paths::{InitLocation, LookupResult};
16 use rustc_span::{hygiene::DesugaringKind, symbol::sym, Span};
17 use rustc_target::abi::VariantIdx;
19 use super::borrow_set::BorrowData;
20 use super::MirBorrowckCtxt;
22 mod find_all_local_uses;
24 mod outlives_suggestion;
28 mod bound_region_errors;
32 mod mutability_errors;
35 crate use bound_region_errors::{ToUniverseInfo, UniverseInfo};
36 crate use mutability_errors::AccessKind;
37 crate use outlives_suggestion::OutlivesSuggestionBuilder;
38 crate use region_errors::{ErrorConstraintInfo, RegionErrorKind, RegionErrors};
39 crate use region_name::{RegionName, RegionNameSource};
40 use rustc_span::symbol::Ident;
42 pub(super) struct IncludingDowncast(pub(super) bool);
44 impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
45 /// Adds a suggestion when a closure is invoked twice with a moved variable or when a closure
46 /// is moved after being invoked.
49 /// note: closure cannot be invoked more than once because it moves the variable `dict` out of
51 /// --> $DIR/issue-42065.rs:16:29
53 /// LL | for (key, value) in dict {
56 pub(super) fn add_moved_or_invoked_closure_note(
59 place: PlaceRef<'tcx>,
60 diag: &mut DiagnosticBuilder<'_>,
62 debug!("add_moved_or_invoked_closure_note: location={:?} place={:?}", location, place);
63 let mut target = place.local_or_deref_local();
64 for stmt in &self.body[location.block].statements[location.statement_index..] {
65 debug!("add_moved_or_invoked_closure_note: stmt={:?} target={:?}", stmt, target);
66 if let StatementKind::Assign(box (into, Rvalue::Use(from))) = &stmt.kind {
67 debug!("add_fnonce_closure_note: into={:?} from={:?}", into, from);
69 Operand::Copy(ref place) | Operand::Move(ref place)
70 if target == place.local_or_deref_local() =>
72 target = into.local_or_deref_local()
79 // Check if we are attempting to call a closure after it has been invoked.
80 let terminator = self.body[location.block].terminator();
81 debug!("add_moved_or_invoked_closure_note: terminator={:?}", terminator);
82 if let TerminatorKind::Call {
83 func: Operand::Constant(box Constant { literal, .. }),
88 if let ty::FnDef(id, _) = *literal.ty().kind() {
89 debug!("add_moved_or_invoked_closure_note: id={:?}", id);
90 if self.infcx.tcx.parent(id) == self.infcx.tcx.lang_items().fn_once_trait() {
91 let closure = match args.first() {
92 Some(Operand::Copy(ref place)) | Some(Operand::Move(ref place))
93 if target == place.local_or_deref_local() =>
95 place.local_or_deref_local().unwrap()
100 debug!("add_moved_or_invoked_closure_note: closure={:?}", closure);
101 if let ty::Closure(did, _) = self.body.local_decls[closure].ty.kind() {
102 let did = did.expect_local();
103 let hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(did);
105 if let Some((span, hir_place)) =
106 self.infcx.tcx.typeck(did).closure_kind_origins().get(hir_id)
111 "closure cannot be invoked more than once because it moves the \
112 variable `{}` out of its environment",
113 ty::place_to_string_for_capture(self.infcx.tcx, hir_place)
123 // Check if we are just moving a closure after it has been invoked.
124 if let Some(target) = target {
125 if let ty::Closure(did, _) = self.body.local_decls[target].ty.kind() {
126 let did = did.expect_local();
127 let hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(did);
129 if let Some((span, hir_place)) =
130 self.infcx.tcx.typeck(did).closure_kind_origins().get(hir_id)
135 "closure cannot be moved more than once as it is not `Copy` due to \
136 moving the variable `{}` out of its environment",
137 ty::place_to_string_for_capture(self.infcx.tcx, hir_place)
145 /// End-user visible description of `place` if one can be found.
146 /// If the place is a temporary for instance, `"value"` will be returned.
147 pub(super) fn describe_any_place(&self, place_ref: PlaceRef<'tcx>) -> String {
148 match self.describe_place(place_ref) {
150 // Surround descr with `backticks`.
152 descr.insert(0, '`');
156 None => "value".to_string(),
160 /// End-user visible description of `place` if one can be found.
161 /// If the place is a temporary for instance, None will be returned.
162 pub(super) fn describe_place(&self, place_ref: PlaceRef<'tcx>) -> Option<String> {
163 self.describe_place_with_options(place_ref, IncludingDowncast(false))
166 /// End-user visible description of `place` if one can be found. If the
167 /// place is a temporary for instance, None will be returned.
168 /// `IncludingDowncast` parameter makes the function return `Err` if `ProjectionElem` is
169 /// `Downcast` and `IncludingDowncast` is true
170 pub(super) fn describe_place_with_options(
172 place: PlaceRef<'tcx>,
173 including_downcast: IncludingDowncast,
174 ) -> Option<String> {
175 let mut buf = String::new();
176 match self.append_place_to_string(place, &mut buf, false, &including_downcast) {
182 /// Appends end-user visible description of `place` to `buf`.
183 fn append_place_to_string(
185 place: PlaceRef<'tcx>,
188 including_downcast: &IncludingDowncast,
189 ) -> Result<(), ()> {
191 PlaceRef { local, projection: [] } => {
192 self.append_local_to_string(local, buf)?;
194 PlaceRef { local, projection: [ProjectionElem::Deref] }
195 if self.body.local_decls[local].is_ref_for_guard() =>
197 self.append_place_to_string(
198 PlaceRef { local, projection: &[] },
204 PlaceRef { local, projection: [ProjectionElem::Deref] }
205 if self.body.local_decls[local].is_ref_to_static() =>
207 let local_info = &self.body.local_decls[local].local_info;
208 if let Some(box LocalInfo::StaticRef { def_id, .. }) = *local_info {
209 buf.push_str(&self.infcx.tcx.item_name(def_id).as_str());
214 PlaceRef { local, projection: [proj_base @ .., elem] } => {
216 ProjectionElem::Deref => {
217 let upvar_field_projection = self.is_upvar_field_projection(place);
218 if let Some(field) = upvar_field_projection {
219 let var_index = field.index();
220 let name = self.upvars[var_index].place.to_string(self.infcx.tcx);
221 if self.upvars[var_index].by_ref {
229 // FIXME turn this recursion into iteration
230 self.append_place_to_string(
231 PlaceRef { local, projection: proj_base },
238 self.append_place_to_string(
239 PlaceRef { local, projection: proj_base },
247 ProjectionElem::Downcast(..) => {
248 self.append_place_to_string(
249 PlaceRef { local, projection: proj_base },
254 if including_downcast.0 {
258 ProjectionElem::Field(field, _ty) => {
261 // FIXME(project-rfc_2229#36): print capture precisely here.
262 let upvar_field_projection = self.is_upvar_field_projection(place);
263 if let Some(field) = upvar_field_projection {
264 let var_index = field.index();
265 let name = self.upvars[var_index].place.to_string(self.infcx.tcx);
268 let field_name = self
269 .describe_field(PlaceRef { local, projection: proj_base }, *field);
270 self.append_place_to_string(
271 PlaceRef { local, projection: proj_base },
277 buf.push_str(&field_name);
280 ProjectionElem::Index(index) => {
283 self.append_place_to_string(
284 PlaceRef { local, projection: proj_base },
290 if self.append_local_to_string(*index, buf).is_err() {
295 ProjectionElem::ConstantIndex { .. } | ProjectionElem::Subslice { .. } => {
297 // Since it isn't possible to borrow an element on a particular index and
298 // then use another while the borrow is held, don't output indices details
299 // to avoid confusing the end-user
300 self.append_place_to_string(
301 PlaceRef { local, projection: proj_base },
306 buf.push_str("[..]");
315 /// Appends end-user visible description of the `local` place to `buf`. If `local` doesn't have
316 /// a name, or its name was generated by the compiler, then `Err` is returned
317 fn append_local_to_string(&self, local: Local, buf: &mut String) -> Result<(), ()> {
318 let decl = &self.body.local_decls[local];
319 match self.local_names[local] {
320 Some(name) if !decl.from_compiler_desugaring() => {
321 buf.push_str(&name.as_str());
328 /// End-user visible description of the `field`nth field of `base`
329 fn describe_field(&self, place: PlaceRef<'tcx>, field: Field) -> String {
330 // FIXME Place2 Make this work iteratively
332 PlaceRef { local, projection: [] } => {
333 let local = &self.body.local_decls[local];
334 self.describe_field_from_ty(&local.ty, field, None)
336 PlaceRef { local, projection: [proj_base @ .., elem] } => match elem {
337 ProjectionElem::Deref => {
338 self.describe_field(PlaceRef { local, projection: proj_base }, field)
340 ProjectionElem::Downcast(_, variant_index) => {
341 let base_ty = place.ty(self.body, self.infcx.tcx).ty;
342 self.describe_field_from_ty(&base_ty, field, Some(*variant_index))
344 ProjectionElem::Field(_, field_type) => {
345 self.describe_field_from_ty(&field_type, field, None)
347 ProjectionElem::Index(..)
348 | ProjectionElem::ConstantIndex { .. }
349 | ProjectionElem::Subslice { .. } => {
350 self.describe_field(PlaceRef { local, projection: proj_base }, field)
356 /// End-user visible description of the `field_index`nth field of `ty`
357 fn describe_field_from_ty(
361 variant_index: Option<VariantIdx>,
364 // If the type is a box, the field is described from the boxed type
365 self.describe_field_from_ty(&ty.boxed_ty(), field, variant_index)
369 let variant = if let Some(idx) = variant_index {
370 assert!(def.is_enum());
373 def.non_enum_variant()
375 variant.fields[field.index()].ident.to_string()
377 ty::Tuple(_) => field.index().to_string(),
378 ty::Ref(_, ty, _) | ty::RawPtr(ty::TypeAndMut { ty, .. }) => {
379 self.describe_field_from_ty(&ty, field, variant_index)
381 ty::Array(ty, _) | ty::Slice(ty) => {
382 self.describe_field_from_ty(&ty, field, variant_index)
384 ty::Closure(def_id, _) | ty::Generator(def_id, _, _) => {
385 // We won't be borrowck'ing here if the closure came from another crate,
386 // so it's safe to call `expect_local`.
388 // We know the field exists so it's safe to call operator[] and `unwrap` here.
392 .typeck(def_id.expect_local())
393 .closure_min_captures_flattened(def_id)
396 .get_root_variable();
398 self.infcx.tcx.hir().name(var_id).to_string()
401 // Might need a revision when the fields in trait RFC is implemented
402 // (https://github.com/rust-lang/rfcs/pull/1546)
403 bug!("End-user description not implemented for field access on `{:?}`", ty);
409 /// Add a note that a type does not implement `Copy`
410 pub(super) fn note_type_does_not_implement_copy(
412 err: &mut DiagnosticBuilder<'a>,
418 let message = format!(
419 "{}move occurs because {} has type `{}`, which does not implement the `Copy` trait",
420 move_prefix, place_desc, ty,
422 if let Some(span) = span {
423 err.span_label(span, message);
429 pub(super) fn borrowed_content_source(
431 deref_base: PlaceRef<'tcx>,
432 ) -> BorrowedContentSource<'tcx> {
433 let tcx = self.infcx.tcx;
435 // Look up the provided place and work out the move path index for it,
436 // we'll use this to check whether it was originally from an overloaded
438 match self.move_data.rev_lookup.find(deref_base) {
439 LookupResult::Exact(mpi) | LookupResult::Parent(Some(mpi)) => {
440 debug!("borrowed_content_source: mpi={:?}", mpi);
442 for i in &self.move_data.init_path_map[mpi] {
443 let init = &self.move_data.inits[*i];
444 debug!("borrowed_content_source: init={:?}", init);
445 // We're only interested in statements that initialized a value, not the
446 // initializations from arguments.
447 let loc = match init.location {
448 InitLocation::Statement(stmt) => stmt,
452 let bbd = &self.body[loc.block];
453 let is_terminator = bbd.statements.len() == loc.statement_index;
455 "borrowed_content_source: loc={:?} is_terminator={:?}",
460 } else if let Some(Terminator {
461 kind: TerminatorKind::Call { ref func, from_hir_call: false, .. },
465 if let Some(source) =
466 BorrowedContentSource::from_call(func.ty(self.body, tcx), tcx)
473 // Base is a `static` so won't be from an overloaded operator
477 // If we didn't find an overloaded deref or index, then assume it's a
478 // built in deref and check the type of the base.
479 let base_ty = deref_base.ty(self.body, tcx).ty;
480 if base_ty.is_unsafe_ptr() {
481 BorrowedContentSource::DerefRawPointer
482 } else if base_ty.is_mutable_ptr() {
483 BorrowedContentSource::DerefMutableRef
485 BorrowedContentSource::DerefSharedRef
490 impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
491 /// Return the name of the provided `Ty` (that must be a reference) with a synthesized lifetime
492 /// name where required.
493 pub(super) fn get_name_for_ty(&self, ty: Ty<'tcx>, counter: usize) -> String {
494 let mut s = String::new();
495 let mut printer = ty::print::FmtPrinter::new(self.infcx.tcx, &mut s, Namespace::TypeNS);
497 // We need to add synthesized lifetimes where appropriate. We do
498 // this by hooking into the pretty printer and telling it to label the
499 // lifetimes without names with the value `'0`.
502 ty::RegionKind::ReLateBound(_, ty::BoundRegion { kind: br, .. })
503 | ty::RegionKind::RePlaceholder(ty::PlaceholderRegion { name: br, .. }),
506 ) => printer.region_highlight_mode.highlighting_bound_region(*br, counter),
510 let _ = ty.print(printer);
514 /// Returns the name of the provided `Ty` (that must be a reference)'s region with a
515 /// synthesized lifetime name where required.
516 pub(super) fn get_region_name_for_ty(&self, ty: Ty<'tcx>, counter: usize) -> String {
517 let mut s = String::new();
518 let mut printer = ty::print::FmtPrinter::new(self.infcx.tcx, &mut s, Namespace::TypeNS);
520 let region = match ty.kind() {
521 ty::Ref(region, _, _) => {
523 ty::RegionKind::ReLateBound(_, ty::BoundRegion { kind: br, .. })
524 | ty::RegionKind::RePlaceholder(ty::PlaceholderRegion { name: br, .. }) => {
525 printer.region_highlight_mode.highlighting_bound_region(*br, counter)
532 _ => bug!("ty for annotation of borrow region is not a reference"),
535 let _ = region.print(printer);
540 /// The span(s) associated to a use of a place.
541 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
542 pub(super) enum UseSpans<'tcx> {
543 /// The access is caused by capturing a variable for a closure.
545 /// This is true if the captured variable was from a generator.
546 generator_kind: Option<GeneratorKind>,
547 /// The span of the args of the closure, including the `move` keyword if
550 /// The span of the use resulting in capture kind
551 /// Check `ty::CaptureInfo` for more details
552 capture_kind_span: Span,
553 /// The span of the use resulting in the captured path
554 /// Check `ty::CaptureInfo` for more details
557 /// The access is caused by using a variable as the receiver of a method
558 /// that takes 'self'
560 /// The span of the variable being moved
562 /// The span of the method call on the variable
564 /// The definition span of the method being called
566 kind: FnSelfUseKind<'tcx>,
568 /// This access is caused by a `match` or `if let` pattern.
570 /// This access has a single span associated to it: common case.
574 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
575 pub(super) enum FnSelfUseKind<'tcx> {
576 /// A normal method call of the form `receiver.foo(a, b, c)`
579 implicit_into_iter: bool,
580 /// Whether the self type of the method call has an `.as_ref()` method.
581 /// Used for better diagnostics.
582 is_option_or_result: bool,
584 /// A call to `FnOnce::call_once`, desugared from `my_closure(a, b, c)`
586 /// A call to an operator trait, desuraged from operator syntax (e.g. `a << b`)
587 Operator { self_arg: Ident },
589 /// The `Span` of the `Target` associated type
590 /// in the `Deref` impl we are using.
592 /// The type `T::Deref` we are dereferencing to
593 deref_target_ty: Ty<'tcx>,
598 pub(super) fn args_or_use(self) -> Span {
600 UseSpans::ClosureUse { args_span: span, .. }
601 | UseSpans::PatUse(span)
602 | UseSpans::OtherUse(span) => span,
603 UseSpans::FnSelfUse {
604 fn_call_span, kind: FnSelfUseKind::DerefCoercion { .. }, ..
606 UseSpans::FnSelfUse { var_span, .. } => var_span,
610 /// Returns the span of `self`, in the case of a `ClosureUse` returns the `path_span`
611 pub(super) fn var_or_use_path_span(self) -> Span {
613 UseSpans::ClosureUse { path_span: span, .. }
614 | UseSpans::PatUse(span)
615 | UseSpans::OtherUse(span) => span,
616 UseSpans::FnSelfUse {
617 fn_call_span, kind: FnSelfUseKind::DerefCoercion { .. }, ..
619 UseSpans::FnSelfUse { var_span, .. } => var_span,
623 /// Returns the span of `self`, in the case of a `ClosureUse` returns the `capture_kind_span`
624 pub(super) fn var_or_use(self) -> Span {
626 UseSpans::ClosureUse { capture_kind_span: span, .. }
627 | UseSpans::PatUse(span)
628 | UseSpans::OtherUse(span) => span,
629 UseSpans::FnSelfUse {
630 fn_call_span, kind: FnSelfUseKind::DerefCoercion { .. }, ..
632 UseSpans::FnSelfUse { var_span, .. } => var_span,
636 pub(super) fn generator_kind(self) -> Option<GeneratorKind> {
638 UseSpans::ClosureUse { generator_kind, .. } => generator_kind,
643 // Add a span label to the arguments of the closure, if it exists.
644 pub(super) fn args_span_label(
646 err: &mut DiagnosticBuilder<'_>,
647 message: impl Into<String>,
649 if let UseSpans::ClosureUse { args_span, .. } = self {
650 err.span_label(args_span, message);
654 // Add a span label to the use of the captured variable, if it exists.
655 // only adds label to the `path_span`
656 pub(super) fn var_span_label_path_only(
658 err: &mut DiagnosticBuilder<'_>,
659 message: impl Into<String>,
661 if let UseSpans::ClosureUse { path_span, .. } = self {
662 err.span_label(path_span, message);
666 // Add a span label to the use of the captured variable, if it exists.
667 pub(super) fn var_span_label(
669 err: &mut DiagnosticBuilder<'_>,
670 message: impl Into<String>,
671 kind_desc: impl Into<String>,
673 if let UseSpans::ClosureUse { capture_kind_span, path_span, .. } = self {
674 if capture_kind_span == path_span {
675 err.span_label(capture_kind_span, message);
677 let capture_kind_label =
678 format!("capture is {} because of use here", kind_desc.into());
679 let path_label = message;
680 err.span_label(capture_kind_span, capture_kind_label);
681 err.span_label(path_span, path_label);
686 /// Returns `false` if this place is not used in a closure.
687 pub(super) fn for_closure(&self) -> bool {
689 UseSpans::ClosureUse { generator_kind, .. } => generator_kind.is_none(),
694 /// Returns `false` if this place is not used in a generator.
695 pub(super) fn for_generator(&self) -> bool {
697 UseSpans::ClosureUse { generator_kind, .. } => generator_kind.is_some(),
702 /// Describe the span associated with a use of a place.
703 pub(super) fn describe(&self) -> String {
705 UseSpans::ClosureUse { generator_kind, .. } => {
706 if generator_kind.is_some() {
707 " in generator".to_string()
709 " in closure".to_string()
716 pub(super) fn or_else<F>(self, if_other: F) -> Self
721 closure @ UseSpans::ClosureUse { .. } => closure,
722 UseSpans::PatUse(_) | UseSpans::OtherUse(_) => if_other(),
723 fn_self @ UseSpans::FnSelfUse { .. } => fn_self,
728 pub(super) enum BorrowedContentSource<'tcx> {
732 OverloadedDeref(Ty<'tcx>),
733 OverloadedIndex(Ty<'tcx>),
736 impl BorrowedContentSource<'tcx> {
737 pub(super) fn describe_for_unnamed_place(&self, tcx: TyCtxt<'_>) -> String {
739 BorrowedContentSource::DerefRawPointer => "a raw pointer".to_string(),
740 BorrowedContentSource::DerefSharedRef => "a shared reference".to_string(),
741 BorrowedContentSource::DerefMutableRef => "a mutable reference".to_string(),
742 BorrowedContentSource::OverloadedDeref(ty) => ty
744 .and_then(|adt| match tcx.get_diagnostic_name(adt.did)? {
745 name @ (sym::Rc | sym::Arc) => Some(format!("an `{}`", name)),
748 .unwrap_or_else(|| format!("dereference of `{}`", ty)),
749 BorrowedContentSource::OverloadedIndex(ty) => format!("index of `{}`", ty),
753 pub(super) fn describe_for_named_place(&self) -> Option<&'static str> {
755 BorrowedContentSource::DerefRawPointer => Some("raw pointer"),
756 BorrowedContentSource::DerefSharedRef => Some("shared reference"),
757 BorrowedContentSource::DerefMutableRef => Some("mutable reference"),
758 // Overloaded deref and index operators should be evaluated into a
759 // temporary. So we don't need a description here.
760 BorrowedContentSource::OverloadedDeref(_)
761 | BorrowedContentSource::OverloadedIndex(_) => None,
765 pub(super) fn describe_for_immutable_place(&self, tcx: TyCtxt<'_>) -> String {
767 BorrowedContentSource::DerefRawPointer => "a `*const` pointer".to_string(),
768 BorrowedContentSource::DerefSharedRef => "a `&` reference".to_string(),
769 BorrowedContentSource::DerefMutableRef => {
770 bug!("describe_for_immutable_place: DerefMutableRef isn't immutable")
772 BorrowedContentSource::OverloadedDeref(ty) => ty
774 .and_then(|adt| match tcx.get_diagnostic_name(adt.did)? {
775 name @ (sym::Rc | sym::Arc) => Some(format!("an `{}`", name)),
778 .unwrap_or_else(|| format!("dereference of `{}`", ty)),
779 BorrowedContentSource::OverloadedIndex(ty) => format!("an index of `{}`", ty),
783 fn from_call(func: Ty<'tcx>, tcx: TyCtxt<'tcx>) -> Option<Self> {
785 ty::FnDef(def_id, substs) => {
786 let trait_id = tcx.trait_of_item(def_id)?;
788 let lang_items = tcx.lang_items();
789 if Some(trait_id) == lang_items.deref_trait()
790 || Some(trait_id) == lang_items.deref_mut_trait()
792 Some(BorrowedContentSource::OverloadedDeref(substs.type_at(0)))
793 } else if Some(trait_id) == lang_items.index_trait()
794 || Some(trait_id) == lang_items.index_mut_trait()
796 Some(BorrowedContentSource::OverloadedIndex(substs.type_at(0)))
806 impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
807 /// Finds the spans associated to a move or copy of move_place at location.
808 pub(super) fn move_spans(
810 moved_place: PlaceRef<'tcx>, // Could also be an upvar.
812 ) -> UseSpans<'tcx> {
813 use self::UseSpans::*;
815 let stmt = match self.body[location.block].statements.get(location.statement_index) {
817 None => return OtherUse(self.body.source_info(location).span),
820 debug!("move_spans: moved_place={:?} location={:?} stmt={:?}", moved_place, location, stmt);
821 if let StatementKind::Assign(box (_, Rvalue::Aggregate(ref kind, ref places))) = stmt.kind {
823 box AggregateKind::Closure(def_id, _)
824 | box AggregateKind::Generator(def_id, _, _) => {
825 debug!("move_spans: def_id={:?} places={:?}", def_id, places);
826 if let Some((args_span, generator_kind, capture_kind_span, path_span)) =
827 self.closure_span(*def_id, moved_place, places)
841 // StatementKind::FakeRead only contains a def_id if they are introduced as a result
842 // of pattern matching within a closure.
843 if let StatementKind::FakeRead(box (cause, ref place)) = stmt.kind {
845 FakeReadCause::ForMatchedPlace(Some(closure_def_id))
846 | FakeReadCause::ForLet(Some(closure_def_id)) => {
847 debug!("move_spans: def_id={:?} place={:?}", closure_def_id, place);
848 let places = &[Operand::Move(*place)];
849 if let Some((args_span, generator_kind, capture_kind_span, path_span)) =
850 self.closure_span(closure_def_id, moved_place, places)
865 if moved_place.projection.iter().any(|p| matches!(p, ProjectionElem::Downcast(..))) {
866 PatUse(stmt.source_info.span)
868 OtherUse(stmt.source_info.span)
871 // We are trying to find MIR of the form:
873 // _temp = _moved_val;
875 // FnSelfCall(_temp, ...)
878 // where `_moved_val` is the place we generated the move error for,
879 // `_temp` is some other local, and `FnSelfCall` is a function
880 // that has a `self` parameter.
882 let target_temp = match stmt.kind {
883 StatementKind::Assign(box (temp, _)) if temp.as_local().is_some() => {
884 temp.as_local().unwrap()
886 _ => return normal_ret,
889 debug!("move_spans: target_temp = {:?}", target_temp);
891 if let Some(Terminator {
892 kind: TerminatorKind::Call { fn_span, from_hir_call, .. }, ..
893 }) = &self.body[location.block].terminator
895 let (method_did, method_substs) = if let Some(info) =
896 rustc_const_eval::util::find_self_call(
907 let tcx = self.infcx.tcx;
908 let parent = tcx.parent(method_did);
909 let is_fn_once = parent == tcx.lang_items().fn_once_trait();
910 let is_operator = !from_hir_call
911 && parent.map_or(false, |p| tcx.lang_items().group(LangItemGroup::Op).contains(&p));
912 let is_deref = !from_hir_call && tcx.is_diagnostic_item(sym::deref_method, method_did);
913 let fn_call_span = *fn_span;
915 let self_arg = tcx.fn_arg_names(method_did)[0];
918 "terminator = {:?} from_hir_call={:?}",
919 self.body[location.block].terminator, from_hir_call
922 // Check for a 'special' use of 'self' -
923 // an FnOnce call, an operator (e.g. `<<`), or a
925 let kind = if is_fn_once {
926 Some(FnSelfUseKind::FnOnceCall)
927 } else if is_operator {
928 Some(FnSelfUseKind::Operator { self_arg })
931 tcx.get_diagnostic_item(sym::deref_target).and_then(|deref_target| {
932 Instance::resolve(tcx, self.param_env, deref_target, method_substs)
935 if let Some(Ok(instance)) = deref_target {
936 let deref_target_ty = instance.ty(tcx, self.param_env);
937 Some(FnSelfUseKind::DerefCoercion {
938 deref_target: tcx.def_span(instance.def_id()),
948 let kind = kind.unwrap_or_else(|| {
949 // This isn't a 'special' use of `self`
950 debug!("move_spans: method_did={:?}, fn_call_span={:?}", method_did, fn_call_span);
951 let implicit_into_iter = Some(method_did) == tcx.lang_items().into_iter_fn()
952 && fn_call_span.desugaring_kind() == Some(DesugaringKind::ForLoop);
953 let parent_self_ty = parent
954 .filter(|did| tcx.def_kind(*did) == rustc_hir::def::DefKind::Impl)
955 .and_then(|did| match tcx.type_of(did).kind() {
956 ty::Adt(def, ..) => Some(def.did),
959 let is_option_or_result = parent_self_ty.map_or(false, |def_id| {
960 matches!(tcx.get_diagnostic_name(def_id), Some(sym::Option | sym::Result))
962 FnSelfUseKind::Normal { self_arg, implicit_into_iter, is_option_or_result }
966 var_span: stmt.source_info.span,
973 .guess_head_span(self.infcx.tcx.def_span(method_did)),
980 /// Finds the span of arguments of a closure (within `maybe_closure_span`)
981 /// and its usage of the local assigned at `location`.
982 /// This is done by searching in statements succeeding `location`
983 /// and originating from `maybe_closure_span`.
984 pub(super) fn borrow_spans(&self, use_span: Span, location: Location) -> UseSpans<'tcx> {
985 use self::UseSpans::*;
986 debug!("borrow_spans: use_span={:?} location={:?}", use_span, location);
988 let target = match self.body[location.block].statements.get(location.statement_index) {
989 Some(&Statement { kind: StatementKind::Assign(box (ref place, _)), .. }) => {
990 if let Some(local) = place.as_local() {
993 return OtherUse(use_span);
996 _ => return OtherUse(use_span),
999 if self.body.local_kind(target) != LocalKind::Temp {
1000 // operands are always temporaries.
1001 return OtherUse(use_span);
1004 for stmt in &self.body[location.block].statements[location.statement_index + 1..] {
1005 if let StatementKind::Assign(box (_, Rvalue::Aggregate(ref kind, ref places))) =
1008 let (def_id, is_generator) = match kind {
1009 box AggregateKind::Closure(def_id, _) => (def_id, false),
1010 box AggregateKind::Generator(def_id, _, _) => (def_id, true),
1015 "borrow_spans: def_id={:?} is_generator={:?} places={:?}",
1016 def_id, is_generator, places
1018 if let Some((args_span, generator_kind, capture_kind_span, path_span)) =
1019 self.closure_span(*def_id, Place::from(target).as_ref(), places)
1021 return ClosureUse { generator_kind, args_span, capture_kind_span, path_span };
1023 return OtherUse(use_span);
1027 if use_span != stmt.source_info.span {
1035 /// Finds the spans of a captured place within a closure or generator.
1036 /// The first span is the location of the use resulting in the capture kind of the capture
1037 /// The second span is the location the use resulting in the captured path of the capture
1041 target_place: PlaceRef<'tcx>,
1042 places: &[Operand<'tcx>],
1043 ) -> Option<(Span, Option<GeneratorKind>, Span, Span)> {
1045 "closure_span: def_id={:?} target_place={:?} places={:?}",
1046 def_id, target_place, places
1048 let local_did = def_id.as_local()?;
1049 let hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(local_did);
1050 let expr = &self.infcx.tcx.hir().expect_expr(hir_id).kind;
1051 debug!("closure_span: hir_id={:?} expr={:?}", hir_id, expr);
1052 if let hir::ExprKind::Closure(.., body_id, args_span, _) = expr {
1053 for (captured_place, place) in self
1056 .typeck(def_id.expect_local())
1057 .closure_min_captures_flattened(def_id)
1061 Operand::Copy(place) | Operand::Move(place)
1062 if target_place == place.as_ref() =>
1064 debug!("closure_span: found captured local {:?}", place);
1065 let body = self.infcx.tcx.hir().body(*body_id);
1066 let generator_kind = body.generator_kind();
1071 captured_place.get_capture_kind_span(self.infcx.tcx),
1072 captured_place.get_path_span(self.infcx.tcx),
1082 /// Helper to retrieve span(s) of given borrow from the current MIR
1084 pub(super) fn retrieve_borrow_spans(&self, borrow: &BorrowData<'_>) -> UseSpans<'tcx> {
1085 let span = self.body.source_info(borrow.reserve_location).span;
1086 self.borrow_spans(span, borrow.reserve_location)