| //! Borrow checker diagnostics. | |
| use std::collections::BTreeMap; | |
| use rustc_abi::{FieldIdx, VariantIdx}; | |
| use rustc_data_structures::fx::FxIndexMap; | |
| use rustc_errors::formatting::DiagMessageAddArg; | |
| use rustc_errors::{Applicability, Diag, DiagMessage, EmissionGuarantee, MultiSpan, listify, msg}; | |
| use rustc_hir::def::{CtorKind, Namespace}; | |
| use rustc_hir::{ | |
| self as hir, CoroutineKind, GenericBound, LangItem, WhereBoundPredicate, WherePredicateKind, | |
| }; | |
| use rustc_index::{IndexSlice, IndexVec}; | |
| use rustc_infer::infer::{BoundRegionConversionTime, NllRegionVariableOrigin}; | |
| use rustc_infer::traits::SelectionError; | |
| use rustc_middle::mir::{ | |
| AggregateKind, CallSource, ConstOperand, ConstraintCategory, FakeReadCause, Local, LocalInfo, | |
| LocalKind, Location, Operand, Place, PlaceRef, PlaceTy, ProjectionElem, Rvalue, Statement, | |
| StatementKind, Terminator, TerminatorKind, VarDebugInfoContents, find_self_call, | |
| }; | |
| use rustc_middle::ty::print::Print; | |
| use rustc_middle::ty::{self, Ty, TyCtxt}; | |
| use rustc_middle::{bug, span_bug}; | |
| use rustc_mir_dataflow::move_paths::{InitLocation, LookupResult, MoveOutIndex}; | |
| use rustc_span::def_id::LocalDefId; | |
| use rustc_span::{DUMMY_SP, ErrorGuaranteed, Span, Spanned, Symbol, sym}; | |
| use rustc_trait_selection::error_reporting::InferCtxtErrorExt; | |
| use rustc_trait_selection::error_reporting::traits::call_kind::{CallDesugaringKind, call_kind}; | |
| use rustc_trait_selection::infer::InferCtxtExt; | |
| use rustc_trait_selection::traits::{ | |
| FulfillmentError, FulfillmentErrorCode, type_known_to_meet_bound_modulo_regions, | |
| }; | |
| use tracing::debug; | |
| use super::MirBorrowckCtxt; | |
| use super::borrow_set::BorrowData; | |
| use crate::constraints::OutlivesConstraint; | |
| use crate::nll::ConstraintDescription; | |
| use crate::session_diagnostics::{ | |
| CaptureArgLabel, CaptureReasonLabel, CaptureReasonNote, CaptureReasonSuggest, CaptureVarCause, | |
| CaptureVarKind, CaptureVarPathUseCause, OnClosureNote, | |
| }; | |
| mod find_all_local_uses; | |
| mod find_use; | |
| mod outlives_suggestion; | |
| mod region_name; | |
| mod var_name; | |
| mod bound_region_errors; | |
| mod conflict_errors; | |
| mod explain_borrow; | |
| mod move_errors; | |
| mod mutability_errors; | |
| mod opaque_types; | |
| mod region_errors; | |
| pub(crate) use bound_region_errors::{ToUniverseInfo, UniverseInfo}; | |
| pub(crate) use move_errors::{IllegalMoveOriginKind, MoveError}; | |
| pub(crate) use mutability_errors::AccessKind; | |
| pub(crate) use outlives_suggestion::OutlivesSuggestionBuilder; | |
| pub(crate) use region_errors::{ErrorConstraintInfo, RegionErrorKind, RegionErrors}; | |
| pub(crate) use region_name::{RegionName, RegionNameSource}; | |
| pub(crate) use rustc_trait_selection::error_reporting::traits::call_kind::CallKind; | |
| pub(super) struct DescribePlaceOpt { | |
| including_downcast: bool, | |
| /// Enable/Disable tuple fields. | |
| /// For example `x` tuple. if it's `true` `x.0`. Otherwise `x` | |
| including_tuple_field: bool, | |
| } | |
| pub(super) struct IncludingTupleField(pub(super) bool); | |
| enum BufferedDiag<'infcx> { | |
| Error(Diag<'infcx>), | |
| NonError(Diag<'infcx, ()>), | |
| } | |
| impl<'infcx> BufferedDiag<'infcx> { | |
| fn sort_span(&self) -> Span { | |
| match self { | |
| BufferedDiag::Error(diag) => diag.sort_span, | |
| BufferedDiag::NonError(diag) => diag.sort_span, | |
| } | |
| } | |
| } | |
| #[derive(Default)] | |
| pub(crate) struct BorrowckDiagnosticsBuffer<'infcx, 'tcx> { | |
| /// This field keeps track of move errors that are to be reported for given move indices. | |
| /// | |
| /// There are situations where many errors can be reported for a single move out (see | |
| /// #53807) and we want only the best of those errors. | |
| /// | |
| /// The `report_use_of_moved_or_uninitialized` function checks this map and replaces the | |
| /// diagnostic (if there is one) if the `Place` of the error being reported is a prefix of | |
| /// the `Place` of the previous most diagnostic. This happens instead of buffering the | |
| /// error. Once all move errors have been reported, any diagnostics in this map are added | |
| /// to the buffer to be emitted. | |
| /// | |
| /// `BTreeMap` is used to preserve the order of insertions when iterating. This is necessary | |
| /// when errors in the map are being re-added to the error buffer so that errors with the | |
| /// same primary span come out in a consistent order. | |
| buffered_move_errors: BTreeMap<Vec<MoveOutIndex>, (PlaceRef<'tcx>, Diag<'infcx>)>, | |
| buffered_mut_errors: FxIndexMap<Span, (Diag<'infcx>, usize)>, | |
| /// Buffer of diagnostics to be reported. A mixture of error and non-error diagnostics. | |
| buffered_diags: Vec<BufferedDiag<'infcx>>, | |
| } | |
| impl<'infcx, 'tcx> BorrowckDiagnosticsBuffer<'infcx, 'tcx> { | |
| pub(crate) fn buffer_non_error(&mut self, diag: Diag<'infcx, ()>) { | |
| self.buffered_diags.push(BufferedDiag::NonError(diag)); | |
| } | |
| } | |
| impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { | |
| pub(crate) fn buffer_error(&mut self, diag: Diag<'infcx>) { | |
| self.diags_buffer.buffered_diags.push(BufferedDiag::Error(diag)); | |
| } | |
| pub(crate) fn buffer_non_error(&mut self, diag: Diag<'infcx, ()>) { | |
| self.diags_buffer.buffer_non_error(diag); | |
| } | |
| pub(crate) fn buffer_move_error( | |
| &mut self, | |
| move_out_indices: Vec<MoveOutIndex>, | |
| place_and_err: (PlaceRef<'tcx>, Diag<'infcx>), | |
| ) -> bool { | |
| if let Some((_, diag)) = | |
| self.diags_buffer.buffered_move_errors.insert(move_out_indices, place_and_err) | |
| { | |
| // Cancel the old diagnostic so we don't ICE | |
| diag.cancel(); | |
| false | |
| } else { | |
| true | |
| } | |
| } | |
| pub(crate) fn get_buffered_mut_error(&mut self, span: Span) -> Option<(Diag<'infcx>, usize)> { | |
| // FIXME(#120456) - is `swap_remove` correct? | |
| self.diags_buffer.buffered_mut_errors.swap_remove(&span) | |
| } | |
| pub(crate) fn buffer_mut_error(&mut self, span: Span, diag: Diag<'infcx>, count: usize) { | |
| self.diags_buffer.buffered_mut_errors.insert(span, (diag, count)); | |
| } | |
| pub(crate) fn emit_errors(&mut self) -> Option<ErrorGuaranteed> { | |
| let mut res = self.infcx.tainted_by_errors(); | |
| // Buffer any move errors that we collected and de-duplicated. | |
| for (_, (_, diag)) in std::mem::take(&mut self.diags_buffer.buffered_move_errors) { | |
| // We have already set tainted for this error, so just buffer it. | |
| self.buffer_error(diag); | |
| } | |
| for (_, (mut diag, count)) in std::mem::take(&mut self.diags_buffer.buffered_mut_errors) { | |
| if count > 10 { | |
| diag.note(format!("...and {} other attempted mutable borrows", count - 10)); | |
| } | |
| self.buffer_error(diag); | |
| } | |
| if !self.diags_buffer.buffered_diags.is_empty() { | |
| self.diags_buffer.buffered_diags.sort_by_key(|buffered_diag| buffered_diag.sort_span()); | |
| for buffered_diag in self.diags_buffer.buffered_diags.drain(..) { | |
| match buffered_diag { | |
| BufferedDiag::Error(diag) => res = Some(diag.emit()), | |
| BufferedDiag::NonError(diag) => diag.emit(), | |
| } | |
| } | |
| } | |
| res | |
| } | |
| pub(crate) fn has_buffered_diags(&self) -> bool { | |
| self.diags_buffer.buffered_diags.is_empty() | |
| } | |
| pub(crate) fn has_move_error( | |
| &self, | |
| move_out_indices: &[MoveOutIndex], | |
| ) -> Option<&(PlaceRef<'tcx>, Diag<'infcx>)> { | |
| self.diags_buffer.buffered_move_errors.get(move_out_indices) | |
| } | |
| /// Uses `body.var_debug_info` to find the symbol | |
| fn local_name(&self, index: Local) -> Option<Symbol> { | |
| *self.local_names().get(index)? | |
| } | |
| fn local_names(&self) -> &IndexSlice<Local, Option<Symbol>> { | |
| self.local_names.get_or_init(|| { | |
| let mut local_names = IndexVec::from_elem(None, &self.body.local_decls); | |
| for var_debug_info in &self.body.var_debug_info { | |
| if let VarDebugInfoContents::Place(place) = var_debug_info.value { | |
| if let Some(local) = place.as_local() { | |
| if let Some(prev_name) = local_names[local] | |
| && var_debug_info.name != prev_name | |
| { | |
| span_bug!( | |
| var_debug_info.source_info.span, | |
| "local {:?} has many names (`{}` vs `{}`)", | |
| local, | |
| prev_name, | |
| var_debug_info.name | |
| ); | |
| } | |
| local_names[local] = Some(var_debug_info.name); | |
| } | |
| } | |
| } | |
| local_names | |
| }) | |
| } | |
| } | |
| impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { | |
| /// Adds a suggestion when a closure is invoked twice with a moved variable or when a closure | |
| /// is moved after being invoked. | |
| /// | |
| /// ```text | |
| /// note: closure cannot be invoked more than once because it moves the variable `dict` out of | |
| /// its environment | |
| /// --> $DIR/issue-42065.rs:16:29 | |
| /// | | |
| /// LL | for (key, value) in dict { | |
| /// | ^^^^ | |
| /// ``` | |
| pub(super) fn add_moved_or_invoked_closure_note( | |
| &self, | |
| location: Location, | |
| place: PlaceRef<'tcx>, | |
| diag: &mut Diag<'infcx>, | |
| ) -> bool { | |
| debug!("add_moved_or_invoked_closure_note: location={:?} place={:?}", location, place); | |
| let mut target = place.local_or_deref_local(); | |
| for stmt in &self.body[location.block].statements[location.statement_index..] { | |
| debug!("add_moved_or_invoked_closure_note: stmt={:?} target={:?}", stmt, target); | |
| if let StatementKind::Assign(box (into, Rvalue::Use(from))) = &stmt.kind { | |
| debug!("add_fnonce_closure_note: into={:?} from={:?}", into, from); | |
| match from { | |
| Operand::Copy(place) | Operand::Move(place) | |
| if target == place.local_or_deref_local() => | |
| { | |
| target = into.local_or_deref_local() | |
| } | |
| _ => {} | |
| } | |
| } | |
| } | |
| // Check if we are attempting to call a closure after it has been invoked. | |
| let terminator = self.body[location.block].terminator(); | |
| debug!("add_moved_or_invoked_closure_note: terminator={:?}", terminator); | |
| if let TerminatorKind::Call { | |
| func: Operand::Constant(box ConstOperand { const_, .. }), | |
| args, | |
| .. | |
| } = &terminator.kind | |
| && let ty::FnDef(id, _) = *const_.ty().kind() | |
| { | |
| debug!("add_moved_or_invoked_closure_note: id={:?}", id); | |
| if self.infcx.tcx.is_lang_item(self.infcx.tcx.parent(id), LangItem::FnOnce) { | |
| let closure = match args.first() { | |
| Some(Spanned { node: Operand::Copy(place) | Operand::Move(place), .. }) | |
| if target == place.local_or_deref_local() => | |
| { | |
| place.local_or_deref_local().unwrap() | |
| } | |
| _ => return false, | |
| }; | |
| debug!("add_moved_or_invoked_closure_note: closure={:?}", closure); | |
| if let ty::Closure(did, _) = self.body.local_decls[closure].ty.kind() { | |
| let did = did.expect_local(); | |
| if let Some((span, hir_place)) = self.infcx.tcx.closure_kind_origin(did) { | |
| diag.subdiagnostic(OnClosureNote::InvokedTwice { | |
| place_name: &ty::place_to_string_for_capture(self.infcx.tcx, hir_place), | |
| span: *span, | |
| }); | |
| return true; | |
| } | |
| } | |
| } | |
| } | |
| // Check if we are just moving a closure after it has been invoked. | |
| if let Some(target) = target | |
| && let ty::Closure(did, _) = self.body.local_decls[target].ty.kind() | |
| { | |
| let did = did.expect_local(); | |
| if let Some((span, hir_place)) = self.infcx.tcx.closure_kind_origin(did) { | |
| diag.subdiagnostic(OnClosureNote::MovedTwice { | |
| place_name: &ty::place_to_string_for_capture(self.infcx.tcx, hir_place), | |
| span: *span, | |
| }); | |
| return true; | |
| } | |
| } | |
| false | |
| } | |
| /// End-user visible description of `place` if one can be found. | |
| /// If the place is a temporary for instance, `"value"` will be returned. | |
| pub(super) fn describe_any_place(&self, place_ref: PlaceRef<'tcx>) -> String { | |
| match self.describe_place(place_ref) { | |
| Some(mut descr) => { | |
| // Surround descr with `backticks`. | |
| descr.reserve(2); | |
| descr.insert(0, '`'); | |
| descr.push('`'); | |
| descr | |
| } | |
| None => "value".to_string(), | |
| } | |
| } | |
| /// End-user visible description of `place` if one can be found. | |
| /// If the place is a temporary for instance, `None` will be returned. | |
| pub(super) fn describe_place(&self, place_ref: PlaceRef<'tcx>) -> Option<String> { | |
| self.describe_place_with_options( | |
| place_ref, | |
| DescribePlaceOpt { including_downcast: false, including_tuple_field: true }, | |
| ) | |
| } | |
| /// End-user visible description of `place` if one can be found. If the place is a temporary | |
| /// for instance, `None` will be returned. | |
| /// `IncludingDowncast` parameter makes the function return `None` if `ProjectionElem` is | |
| /// `Downcast` and `IncludingDowncast` is true | |
| pub(super) fn describe_place_with_options( | |
| &self, | |
| place: PlaceRef<'tcx>, | |
| opt: DescribePlaceOpt, | |
| ) -> Option<String> { | |
| let local = place.local; | |
| if self.body.local_decls[local] | |
| .source_info | |
| .span | |
| .in_external_macro(self.infcx.tcx.sess.source_map()) | |
| { | |
| return None; | |
| } | |
| let mut autoderef_index = None; | |
| let mut buf = String::new(); | |
| let mut ok = self.append_local_to_string(local, &mut buf); | |
| for (index, elem) in place.projection.into_iter().enumerate() { | |
| match elem { | |
| ProjectionElem::Deref => { | |
| if index == 0 { | |
| if self.body.local_decls[local].is_ref_for_guard() { | |
| continue; | |
| } | |
| if let LocalInfo::StaticRef { def_id, .. } = | |
| *self.body.local_decls[local].local_info() | |
| { | |
| buf.push_str(self.infcx.tcx.item_name(def_id).as_str()); | |
| ok = Ok(()); | |
| continue; | |
| } | |
| } | |
| if let Some(field) = self.is_upvar_field_projection(PlaceRef { | |
| local, | |
| projection: place.projection.split_at(index + 1).0, | |
| }) { | |
| let var_index = field.index(); | |
| buf = self.upvars[var_index].to_string(self.infcx.tcx); | |
| ok = Ok(()); | |
| if !self.upvars[var_index].is_by_ref() { | |
| buf.insert(0, '*'); | |
| } | |
| } else { | |
| if autoderef_index.is_none() { | |
| autoderef_index = match place.projection.iter().rposition(|elem| { | |
| !matches!( | |
| elem, | |
| ProjectionElem::Deref | ProjectionElem::Downcast(..) | |
| ) | |
| }) { | |
| Some(index) => Some(index + 1), | |
| None => Some(0), | |
| }; | |
| } | |
| if index >= autoderef_index.unwrap() { | |
| buf.insert(0, '*'); | |
| } | |
| } | |
| } | |
| ProjectionElem::Downcast(..) if opt.including_downcast => return None, | |
| ProjectionElem::Downcast(..) => (), | |
| ProjectionElem::OpaqueCast(..) => (), | |
| ProjectionElem::UnwrapUnsafeBinder(_) => (), | |
| ProjectionElem::Field(field, _ty) => { | |
| // FIXME(project-rfc_2229#36): print capture precisely here. | |
| if let Some(field) = self.is_upvar_field_projection(PlaceRef { | |
| local, | |
| projection: place.projection.split_at(index + 1).0, | |
| }) { | |
| buf = self.upvars[field.index()].to_string(self.infcx.tcx); | |
| ok = Ok(()); | |
| } else { | |
| let field_name = self.describe_field( | |
| PlaceRef { local, projection: place.projection.split_at(index).0 }, | |
| *field, | |
| IncludingTupleField(opt.including_tuple_field), | |
| ); | |
| if let Some(field_name_str) = field_name { | |
| buf.push('.'); | |
| buf.push_str(&field_name_str); | |
| } | |
| } | |
| } | |
| ProjectionElem::Index(index) => { | |
| buf.push('['); | |
| if self.append_local_to_string(*index, &mut buf).is_err() { | |
| buf.push('_'); | |
| } | |
| buf.push(']'); | |
| } | |
| ProjectionElem::ConstantIndex { .. } | ProjectionElem::Subslice { .. } => { | |
| // Since it isn't possible to borrow an element on a particular index and | |
| // then use another while the borrow is held, don't output indices details | |
| // to avoid confusing the end-user | |
| buf.push_str("[..]"); | |
| } | |
| } | |
| } | |
| ok.ok().map(|_| buf) | |
| } | |
| fn describe_name(&self, place: PlaceRef<'tcx>) -> Option<Symbol> { | |
| for elem in place.projection.into_iter() { | |
| match elem { | |
| ProjectionElem::Downcast(Some(name), _) => { | |
| return Some(*name); | |
| } | |
| _ => {} | |
| } | |
| } | |
| None | |
| } | |
| /// Appends end-user visible description of the `local` place to `buf`. If `local` doesn't have | |
| /// a name, or its name was generated by the compiler, then `Err` is returned | |
| fn append_local_to_string(&self, local: Local, buf: &mut String) -> Result<(), ()> { | |
| let decl = &self.body.local_decls[local]; | |
| match self.local_name(local) { | |
| Some(name) if !decl.from_compiler_desugaring() => { | |
| buf.push_str(name.as_str()); | |
| Ok(()) | |
| } | |
| _ => Err(()), | |
| } | |
| } | |
| /// End-user visible description of the `field`nth field of `base` | |
| fn describe_field( | |
| &self, | |
| place: PlaceRef<'tcx>, | |
| field: FieldIdx, | |
| including_tuple_field: IncludingTupleField, | |
| ) -> Option<String> { | |
| let place_ty = match place { | |
| PlaceRef { local, projection: [] } => PlaceTy::from_ty(self.body.local_decls[local].ty), | |
| PlaceRef { local, projection: [proj_base @ .., elem] } => match elem { | |
| ProjectionElem::Deref | |
| | ProjectionElem::Index(..) | |
| | ProjectionElem::ConstantIndex { .. } | |
| | ProjectionElem::Subslice { .. } => { | |
| PlaceRef { local, projection: proj_base }.ty(self.body, self.infcx.tcx) | |
| } | |
| ProjectionElem::Downcast(..) => place.ty(self.body, self.infcx.tcx), | |
| ProjectionElem::OpaqueCast(ty) | ProjectionElem::UnwrapUnsafeBinder(ty) => { | |
| PlaceTy::from_ty(*ty) | |
| } | |
| ProjectionElem::Field(_, field_type) => PlaceTy::from_ty(*field_type), | |
| }, | |
| }; | |
| self.describe_field_from_ty( | |
| place_ty.ty, | |
| field, | |
| place_ty.variant_index, | |
| including_tuple_field, | |
| ) | |
| } | |
| /// End-user visible description of the `field_index`nth field of `ty` | |
| fn describe_field_from_ty( | |
| &self, | |
| ty: Ty<'_>, | |
| field: FieldIdx, | |
| variant_index: Option<VariantIdx>, | |
| including_tuple_field: IncludingTupleField, | |
| ) -> Option<String> { | |
| if let Some(boxed_ty) = ty.boxed_ty() { | |
| // If the type is a box, the field is described from the boxed type | |
| self.describe_field_from_ty(boxed_ty, field, variant_index, including_tuple_field) | |
| } else { | |
| match *ty.kind() { | |
| ty::Adt(def, _) => { | |
| let variant = if let Some(idx) = variant_index { | |
| assert!(def.is_enum()); | |
| def.variant(idx) | |
| } else { | |
| def.non_enum_variant() | |
| }; | |
| if !including_tuple_field.0 && variant.ctor_kind() == Some(CtorKind::Fn) { | |
| return None; | |
| } | |
| Some(variant.fields[field].name.to_string()) | |
| } | |
| ty::Tuple(_) => Some(field.index().to_string()), | |
| ty::Ref(_, ty, _) | ty::RawPtr(ty, _) => { | |
| self.describe_field_from_ty(ty, field, variant_index, including_tuple_field) | |
| } | |
| ty::Array(ty, _) | ty::Slice(ty) => { | |
| self.describe_field_from_ty(ty, field, variant_index, including_tuple_field) | |
| } | |
| ty::Closure(def_id, _) | ty::Coroutine(def_id, _) => { | |
| // We won't be borrowck'ing here if the closure came from another crate, | |
| // so it's safe to call `expect_local`. | |
| // | |
| // We know the field exists so it's safe to call operator[] and `unwrap` here. | |
| let def_id = def_id.expect_local(); | |
| let var_id = | |
| self.infcx.tcx.closure_captures(def_id)[field.index()].get_root_variable(); | |
| Some(self.infcx.tcx.hir_name(var_id).to_string()) | |
| } | |
| _ => { | |
| // Might need a revision when the fields in trait RFC is implemented | |
| // (https://github.com/rust-lang/rfcs/pull/1546) | |
| bug!("End-user description not implemented for field access on `{:?}`", ty); | |
| } | |
| } | |
| } | |
| } | |
| pub(super) fn borrowed_content_source( | |
| &self, | |
| deref_base: PlaceRef<'tcx>, | |
| ) -> BorrowedContentSource<'tcx> { | |
| let tcx = self.infcx.tcx; | |
| // Look up the provided place and work out the move path index for it, | |
| // we'll use this to check whether it was originally from an overloaded | |
| // operator. | |
| match self.move_data.rev_lookup.find(deref_base) { | |
| LookupResult::Exact(mpi) | LookupResult::Parent(Some(mpi)) => { | |
| debug!("borrowed_content_source: mpi={:?}", mpi); | |
| for i in &self.move_data.init_path_map[mpi] { | |
| let init = &self.move_data.inits[*i]; | |
| debug!("borrowed_content_source: init={:?}", init); | |
| // We're only interested in statements that initialized a value, not the | |
| // initializations from arguments. | |
| let InitLocation::Statement(loc) = init.location else { continue }; | |
| let bbd = &self.body[loc.block]; | |
| let is_terminator = bbd.statements.len() == loc.statement_index; | |
| debug!( | |
| "borrowed_content_source: loc={:?} is_terminator={:?}", | |
| loc, is_terminator, | |
| ); | |
| if !is_terminator { | |
| continue; | |
| } else if let Some(Terminator { | |
| kind: | |
| TerminatorKind::Call { | |
| func, | |
| call_source: CallSource::OverloadedOperator, | |
| .. | |
| }, | |
| .. | |
| }) = &bbd.terminator | |
| { | |
| if let Some(source) = | |
| BorrowedContentSource::from_call(func.ty(self.body, tcx), tcx) | |
| { | |
| return source; | |
| } | |
| } | |
| } | |
| } | |
| // Base is a `static` so won't be from an overloaded operator | |
| _ => (), | |
| }; | |
| // If we didn't find an overloaded deref or index, then assume it's a | |
| // built in deref and check the type of the base. | |
| let base_ty = deref_base.ty(self.body, tcx).ty; | |
| if base_ty.is_raw_ptr() { | |
| BorrowedContentSource::DerefRawPointer | |
| } else if base_ty.is_mutable_ptr() { | |
| BorrowedContentSource::DerefMutableRef | |
| } else { | |
| BorrowedContentSource::DerefSharedRef | |
| } | |
| } | |
| /// Return the name of the provided `Ty` (that must be a reference) with a synthesized lifetime | |
| /// name where required. | |
| pub(super) fn get_name_for_ty(&self, ty: Ty<'tcx>, counter: usize) -> String { | |
| let mut p = ty::print::FmtPrinter::new(self.infcx.tcx, Namespace::TypeNS); | |
| // We need to add synthesized lifetimes where appropriate. We do | |
| // this by hooking into the pretty printer and telling it to label the | |
| // lifetimes without names with the value `'0`. | |
| if let ty::Ref(region, ..) = ty.kind() { | |
| match region.kind() { | |
| ty::ReBound(_, ty::BoundRegion { kind: br, .. }) | |
| | ty::RePlaceholder(ty::PlaceholderRegion { | |
| bound: ty::BoundRegion { kind: br, .. }, | |
| .. | |
| }) => p.region_highlight_mode.highlighting_bound_region(br, counter), | |
| _ => {} | |
| } | |
| } | |
| ty.print(&mut p).unwrap(); | |
| p.into_buffer() | |
| } | |
| /// Returns the name of the provided `Ty` (that must be a reference)'s region with a | |
| /// synthesized lifetime name where required. | |
| pub(super) fn get_region_name_for_ty(&self, ty: Ty<'tcx>, counter: usize) -> String { | |
| let mut p = ty::print::FmtPrinter::new(self.infcx.tcx, Namespace::TypeNS); | |
| let region = if let ty::Ref(region, ..) = ty.kind() { | |
| match region.kind() { | |
| ty::ReBound(_, ty::BoundRegion { kind: br, .. }) | |
| | ty::RePlaceholder(ty::PlaceholderRegion { | |
| bound: ty::BoundRegion { kind: br, .. }, | |
| .. | |
| }) => p.region_highlight_mode.highlighting_bound_region(br, counter), | |
| _ => {} | |
| } | |
| region | |
| } else { | |
| bug!("ty for annotation of borrow region is not a reference"); | |
| }; | |
| region.print(&mut p).unwrap(); | |
| p.into_buffer() | |
| } | |
| /// Add a note to region errors and borrow explanations when higher-ranked regions in predicates | |
| /// implicitly introduce an "outlives `'static`" constraint. | |
| /// | |
| /// This is very similar to `fn suggest_static_lifetime_for_gat_from_hrtb` which handles this | |
| /// note for failed type tests instead of outlives errors. | |
| fn add_placeholder_from_predicate_note<G: EmissionGuarantee>( | |
| &self, | |
| diag: &mut Diag<'_, G>, | |
| path: &[OutlivesConstraint<'tcx>], | |
| ) { | |
| let tcx = self.infcx.tcx; | |
| let Some((gat_hir_id, generics)) = path.iter().find_map(|constraint| { | |
| let outlived = constraint.sub; | |
| if let Some(origin) = self.regioncx.definitions.get(outlived) | |
| && let NllRegionVariableOrigin::Placeholder(placeholder) = origin.origin | |
| && let Some(id) = placeholder.bound.kind.get_id() | |
| && let Some(placeholder_id) = id.as_local() | |
| && let gat_hir_id = tcx.local_def_id_to_hir_id(placeholder_id) | |
| && let Some(generics_impl) = | |
| tcx.parent_hir_node(tcx.parent_hir_id(gat_hir_id)).generics() | |
| { | |
| Some((gat_hir_id, generics_impl)) | |
| } else { | |
| None | |
| } | |
| }) else { | |
| return; | |
| }; | |
| // Look for the where-bound which introduces the placeholder. | |
| // As we're using the HIR, we need to handle both `for<'a> T: Trait<'a>` | |
| // and `T: for<'a> Trait`<'a>. | |
| for pred in generics.predicates { | |
| let WherePredicateKind::BoundPredicate(WhereBoundPredicate { | |
| bound_generic_params, | |
| bounds, | |
| .. | |
| }) = pred.kind | |
| else { | |
| continue; | |
| }; | |
| if bound_generic_params | |
| .iter() | |
| .rfind(|bgp| tcx.local_def_id_to_hir_id(bgp.def_id) == gat_hir_id) | |
| .is_some() | |
| { | |
| diag.span_note(pred.span, LIMITATION_NOTE); | |
| return; | |
| } | |
| for bound in bounds.iter() { | |
| if let GenericBound::Trait(bound) = bound { | |
| if bound | |
| .bound_generic_params | |
| .iter() | |
| .rfind(|bgp| tcx.local_def_id_to_hir_id(bgp.def_id) == gat_hir_id) | |
| .is_some() | |
| { | |
| diag.span_note(bound.span, LIMITATION_NOTE); | |
| return; | |
| } | |
| } | |
| } | |
| } | |
| } | |
| /// Add a label to region errors and borrow explanations when outlives constraints arise from | |
| /// proving a type implements `Sized` or `Copy`. | |
| fn add_sized_or_copy_bound_info<G: EmissionGuarantee>( | |
| &self, | |
| err: &mut Diag<'_, G>, | |
| blamed_category: ConstraintCategory<'tcx>, | |
| path: &[OutlivesConstraint<'tcx>], | |
| ) { | |
| for sought_category in [ConstraintCategory::SizedBound, ConstraintCategory::CopyBound] { | |
| if sought_category != blamed_category | |
| && let Some(sought_constraint) = path.iter().find(|c| c.category == sought_category) | |
| { | |
| let label = format!( | |
| "requirement occurs due to {}", | |
| sought_category.description().trim_end() | |
| ); | |
| err.span_label(sought_constraint.span, label); | |
| } | |
| } | |
| } | |
| } | |
| /// The span(s) associated to a use of a place. | |
| #[derive(Copy, Clone, PartialEq, Eq, Debug)] | |
| pub(super) enum UseSpans<'tcx> { | |
| /// The access is caused by capturing a variable for a closure. | |
| ClosureUse { | |
| /// This is true if the captured variable was from a coroutine. | |
| closure_kind: hir::ClosureKind, | |
| /// The span of the args of the closure, including the `move` keyword if | |
| /// it's present. | |
| args_span: Span, | |
| /// The span of the use resulting in capture kind | |
| /// Check `ty::CaptureInfo` for more details | |
| capture_kind_span: Span, | |
| /// The span of the use resulting in the captured path | |
| /// Check `ty::CaptureInfo` for more details | |
| path_span: Span, | |
| }, | |
| /// The access is caused by using a variable as the receiver of a method | |
| /// that takes 'self' | |
| FnSelfUse { | |
| /// The span of the variable being moved | |
| var_span: Span, | |
| /// The span of the method call on the variable | |
| fn_call_span: Span, | |
| /// The definition span of the method being called | |
| fn_span: Span, | |
| kind: CallKind<'tcx>, | |
| }, | |
| /// This access is caused by a `match` or `if let` pattern. | |
| PatUse(Span), | |
| /// This access has a single span associated to it: common case. | |
| OtherUse(Span), | |
| } | |
| impl UseSpans<'_> { | |
| pub(super) fn args_or_use(self) -> Span { | |
| match self { | |
| UseSpans::ClosureUse { args_span: span, .. } | |
| | UseSpans::PatUse(span) | |
| | UseSpans::OtherUse(span) => span, | |
| UseSpans::FnSelfUse { var_span, .. } => var_span, | |
| } | |
| } | |
| /// Returns the span of `self`, in the case of a `ClosureUse` returns the `path_span` | |
| pub(super) fn var_or_use_path_span(self) -> Span { | |
| match self { | |
| UseSpans::ClosureUse { path_span: span, .. } | |
| | UseSpans::PatUse(span) | |
| | UseSpans::OtherUse(span) => span, | |
| UseSpans::FnSelfUse { var_span, .. } => var_span, | |
| } | |
| } | |
| /// Returns the span of `self`, in the case of a `ClosureUse` returns the `capture_kind_span` | |
| pub(super) fn var_or_use(self) -> Span { | |
| match self { | |
| UseSpans::ClosureUse { capture_kind_span: span, .. } | |
| | UseSpans::PatUse(span) | |
| | UseSpans::OtherUse(span) => span, | |
| UseSpans::FnSelfUse { var_span, .. } => var_span, | |
| } | |
| } | |
| // FIXME(coroutines): Make this just return the `ClosureKind` directly? | |
| pub(super) fn coroutine_kind(self) -> Option<CoroutineKind> { | |
| match self { | |
| UseSpans::ClosureUse { | |
| closure_kind: hir::ClosureKind::Coroutine(coroutine_kind), | |
| .. | |
| } => Some(coroutine_kind), | |
| _ => None, | |
| } | |
| } | |
| /// Add a span label to the arguments of the closure, if it exists. | |
| pub(super) fn args_subdiag(self, err: &mut Diag<'_>, f: impl FnOnce(Span) -> CaptureArgLabel) { | |
| if let UseSpans::ClosureUse { args_span, .. } = self { | |
| err.subdiagnostic(f(args_span)); | |
| } | |
| } | |
| /// Add a span label to the use of the captured variable, if it exists. | |
| /// only adds label to the `path_span` | |
| pub(super) fn var_path_only_subdiag( | |
| self, | |
| err: &mut Diag<'_>, | |
| action: crate::InitializationRequiringAction, | |
| ) { | |
| use CaptureVarPathUseCause::*; | |
| use crate::InitializationRequiringAction::*; | |
| if let UseSpans::ClosureUse { closure_kind, path_span, .. } = self { | |
| match closure_kind { | |
| hir::ClosureKind::Coroutine(_) => { | |
| err.subdiagnostic(match action { | |
| Borrow => BorrowInCoroutine { path_span }, | |
| MatchOn | Use => UseInCoroutine { path_span }, | |
| Assignment => AssignInCoroutine { path_span }, | |
| PartialAssignment => AssignPartInCoroutine { path_span }, | |
| }); | |
| } | |
| hir::ClosureKind::Closure | hir::ClosureKind::CoroutineClosure(_) => { | |
| err.subdiagnostic(match action { | |
| Borrow => BorrowInClosure { path_span }, | |
| MatchOn | Use => UseInClosure { path_span }, | |
| Assignment => AssignInClosure { path_span }, | |
| PartialAssignment => AssignPartInClosure { path_span }, | |
| }); | |
| } | |
| } | |
| } | |
| } | |
| /// Add a subdiagnostic to the use of the captured variable, if it exists. | |
| pub(super) fn var_subdiag( | |
| self, | |
| err: &mut Diag<'_>, | |
| kind: Option<rustc_middle::mir::BorrowKind>, | |
| f: impl FnOnce(hir::ClosureKind, Span) -> CaptureVarCause, | |
| ) { | |
| if let UseSpans::ClosureUse { closure_kind, capture_kind_span, path_span, .. } = self { | |
| if capture_kind_span != path_span { | |
| err.subdiagnostic(match kind { | |
| Some(kd) => match kd { | |
| rustc_middle::mir::BorrowKind::Shared | |
| | rustc_middle::mir::BorrowKind::Fake(_) => { | |
| CaptureVarKind::Immut { kind_span: capture_kind_span } | |
| } | |
| rustc_middle::mir::BorrowKind::Mut { .. } => { | |
| CaptureVarKind::Mut { kind_span: capture_kind_span } | |
| } | |
| }, | |
| None => CaptureVarKind::Move { kind_span: capture_kind_span }, | |
| }); | |
| }; | |
| let diag = f(closure_kind, path_span); | |
| err.subdiagnostic(diag); | |
| } | |
| } | |
| /// Returns `false` if this place is not used in a closure. | |
| pub(super) fn for_closure(&self) -> bool { | |
| match *self { | |
| UseSpans::ClosureUse { closure_kind, .. } => { | |
| matches!(closure_kind, hir::ClosureKind::Closure) | |
| } | |
| _ => false, | |
| } | |
| } | |
| /// Returns `false` if this place is not used in a coroutine. | |
| pub(super) fn for_coroutine(&self) -> bool { | |
| match *self { | |
| // FIXME(coroutines): Do we want this to apply to synthetic coroutines? | |
| UseSpans::ClosureUse { closure_kind, .. } => { | |
| matches!(closure_kind, hir::ClosureKind::Coroutine(..)) | |
| } | |
| _ => false, | |
| } | |
| } | |
| pub(super) fn or_else<F>(self, if_other: F) -> Self | |
| where | |
| F: FnOnce() -> Self, | |
| { | |
| match self { | |
| closure @ UseSpans::ClosureUse { .. } => closure, | |
| UseSpans::PatUse(_) | UseSpans::OtherUse(_) => if_other(), | |
| fn_self @ UseSpans::FnSelfUse { .. } => fn_self, | |
| } | |
| } | |
| } | |
| pub(super) enum BorrowedContentSource<'tcx> { | |
| DerefRawPointer, | |
| DerefMutableRef, | |
| DerefSharedRef, | |
| OverloadedDeref(Ty<'tcx>), | |
| OverloadedIndex(Ty<'tcx>), | |
| } | |
| impl<'tcx> BorrowedContentSource<'tcx> { | |
| pub(super) fn describe_for_unnamed_place(&self, tcx: TyCtxt<'_>) -> String { | |
| match *self { | |
| BorrowedContentSource::DerefRawPointer => "a raw pointer".to_string(), | |
| BorrowedContentSource::DerefSharedRef => "a shared reference".to_string(), | |
| BorrowedContentSource::DerefMutableRef => "a mutable reference".to_string(), | |
| BorrowedContentSource::OverloadedDeref(ty) => ty | |
| .ty_adt_def() | |
| .and_then(|adt| match tcx.get_diagnostic_name(adt.did())? { | |
| name @ (sym::Rc | sym::Arc) => Some(format!("an `{name}`")), | |
| _ => None, | |
| }) | |
| .unwrap_or_else(|| format!("dereference of `{ty}`")), | |
| BorrowedContentSource::OverloadedIndex(ty) => format!("index of `{ty}`"), | |
| } | |
| } | |
| pub(super) fn describe_for_named_place(&self) -> Option<&'static str> { | |
| match *self { | |
| BorrowedContentSource::DerefRawPointer => Some("raw pointer"), | |
| BorrowedContentSource::DerefSharedRef => Some("shared reference"), | |
| BorrowedContentSource::DerefMutableRef => Some("mutable reference"), | |
| // Overloaded deref and index operators should be evaluated into a | |
| // temporary. So we don't need a description here. | |
| BorrowedContentSource::OverloadedDeref(_) | |
| | BorrowedContentSource::OverloadedIndex(_) => None, | |
| } | |
| } | |
| pub(super) fn describe_for_immutable_place(&self, tcx: TyCtxt<'_>) -> String { | |
| match *self { | |
| BorrowedContentSource::DerefRawPointer => "a `*const` pointer".to_string(), | |
| BorrowedContentSource::DerefSharedRef => "a `&` reference".to_string(), | |
| BorrowedContentSource::DerefMutableRef => { | |
| bug!("describe_for_immutable_place: DerefMutableRef isn't immutable") | |
| } | |
| BorrowedContentSource::OverloadedDeref(ty) => ty | |
| .ty_adt_def() | |
| .and_then(|adt| match tcx.get_diagnostic_name(adt.did())? { | |
| name @ (sym::Rc | sym::Arc) => Some(format!("an `{name}`")), | |
| _ => None, | |
| }) | |
| .unwrap_or_else(|| format!("dereference of `{ty}`")), | |
| BorrowedContentSource::OverloadedIndex(ty) => format!("an index of `{ty}`"), | |
| } | |
| } | |
| fn from_call(func: Ty<'tcx>, tcx: TyCtxt<'tcx>) -> Option<Self> { | |
| match *func.kind() { | |
| ty::FnDef(def_id, args) => { | |
| let trait_id = tcx.trait_of_assoc(def_id)?; | |
| if tcx.is_lang_item(trait_id, LangItem::Deref) | |
| || tcx.is_lang_item(trait_id, LangItem::DerefMut) | |
| { | |
| Some(BorrowedContentSource::OverloadedDeref(args.type_at(0))) | |
| } else if tcx.is_lang_item(trait_id, LangItem::Index) | |
| || tcx.is_lang_item(trait_id, LangItem::IndexMut) | |
| { | |
| Some(BorrowedContentSource::OverloadedIndex(args.type_at(0))) | |
| } else { | |
| None | |
| } | |
| } | |
| _ => None, | |
| } | |
| } | |
| } | |
| /// Helper struct for `explain_captures`. | |
| struct CapturedMessageOpt { | |
| is_partial_move: bool, | |
| is_loop_message: bool, | |
| is_move_msg: bool, | |
| is_loop_move: bool, | |
| has_suggest_reborrow: bool, | |
| maybe_reinitialized_locations_is_empty: bool, | |
| } | |
| impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { | |
| /// Finds the spans associated to a move or copy of move_place at location. | |
| pub(super) fn move_spans( | |
| &self, | |
| moved_place: PlaceRef<'tcx>, // Could also be an upvar. | |
| location: Location, | |
| ) -> UseSpans<'tcx> { | |
| use self::UseSpans::*; | |
| let Some(stmt) = self.body[location.block].statements.get(location.statement_index) else { | |
| return OtherUse(self.body.source_info(location).span); | |
| }; | |
| debug!("move_spans: moved_place={:?} location={:?} stmt={:?}", moved_place, location, stmt); | |
| if let StatementKind::Assign(box (_, Rvalue::Aggregate(kind, places))) = &stmt.kind | |
| && let AggregateKind::Closure(def_id, _) | AggregateKind::Coroutine(def_id, _) = **kind | |
| { | |
| debug!("move_spans: def_id={:?} places={:?}", def_id, places); | |
| let def_id = def_id.expect_local(); | |
| if let Some((args_span, closure_kind, capture_kind_span, path_span)) = | |
| self.closure_span(def_id, moved_place, places) | |
| { | |
| return ClosureUse { closure_kind, args_span, capture_kind_span, path_span }; | |
| } | |
| } | |
| // StatementKind::FakeRead only contains a def_id if they are introduced as a result | |
| // of pattern matching within a closure. | |
| if let StatementKind::FakeRead(box (cause, place)) = stmt.kind { | |
| match cause { | |
| FakeReadCause::ForMatchedPlace(Some(closure_def_id)) | |
| | FakeReadCause::ForLet(Some(closure_def_id)) => { | |
| debug!("move_spans: def_id={:?} place={:?}", closure_def_id, place); | |
| let places = &[Operand::Move(place)]; | |
| if let Some((args_span, closure_kind, capture_kind_span, path_span)) = | |
| self.closure_span(closure_def_id, moved_place, IndexSlice::from_raw(places)) | |
| { | |
| return ClosureUse { | |
| closure_kind, | |
| args_span, | |
| capture_kind_span, | |
| path_span, | |
| }; | |
| } | |
| } | |
| _ => {} | |
| } | |
| } | |
| let normal_ret = | |
| if moved_place.projection.iter().any(|p| matches!(p, ProjectionElem::Downcast(..))) { | |
| PatUse(stmt.source_info.span) | |
| } else { | |
| OtherUse(stmt.source_info.span) | |
| }; | |
| // We are trying to find MIR of the form: | |
| // ``` | |
| // _temp = _moved_val; | |
| // ... | |
| // FnSelfCall(_temp, ...) | |
| // ``` | |
| // | |
| // where `_moved_val` is the place we generated the move error for, | |
| // `_temp` is some other local, and `FnSelfCall` is a function | |
| // that has a `self` parameter. | |
| let target_temp = match stmt.kind { | |
| StatementKind::Assign(box (temp, _)) if temp.as_local().is_some() => { | |
| temp.as_local().unwrap() | |
| } | |
| _ => return normal_ret, | |
| }; | |
| debug!("move_spans: target_temp = {:?}", target_temp); | |
| if let Some(Terminator { | |
| kind: TerminatorKind::Call { fn_span, call_source, .. }, .. | |
| }) = &self.body[location.block].terminator | |
| { | |
| let Some((method_did, method_args)) = | |
| find_self_call(self.infcx.tcx, self.body, target_temp, location.block) | |
| else { | |
| return normal_ret; | |
| }; | |
| let kind = call_kind( | |
| self.infcx.tcx, | |
| self.infcx.typing_env(self.infcx.param_env), | |
| method_did, | |
| method_args, | |
| *fn_span, | |
| call_source.from_hir_call(), | |
| self.infcx.tcx.fn_arg_idents(method_did)[0], | |
| ); | |
| return FnSelfUse { | |
| var_span: stmt.source_info.span, | |
| fn_call_span: *fn_span, | |
| fn_span: self.infcx.tcx.def_span(method_did), | |
| kind, | |
| }; | |
| } | |
| normal_ret | |
| } | |
| /// Finds the span of arguments of a closure (within `maybe_closure_span`) | |
| /// and its usage of the local assigned at `location`. | |
| /// This is done by searching in statements succeeding `location` | |
| /// and originating from `maybe_closure_span`. | |
| pub(super) fn borrow_spans(&self, use_span: Span, location: Location) -> UseSpans<'tcx> { | |
| use self::UseSpans::*; | |
| debug!("borrow_spans: use_span={:?} location={:?}", use_span, location); | |
| let Some(Statement { kind: StatementKind::Assign(box (place, _)), .. }) = | |
| self.body[location.block].statements.get(location.statement_index) | |
| else { | |
| return OtherUse(use_span); | |
| }; | |
| let Some(target) = place.as_local() else { return OtherUse(use_span) }; | |
| if self.body.local_kind(target) != LocalKind::Temp { | |
| // operands are always temporaries. | |
| return OtherUse(use_span); | |
| } | |
| // drop and replace might have moved the assignment to the next block | |
| let maybe_additional_statement = | |
| if let TerminatorKind::Drop { target: drop_target, .. } = | |
| self.body[location.block].terminator().kind | |
| { | |
| self.body[drop_target].statements.first() | |
| } else { | |
| None | |
| }; | |
| let statements = | |
| self.body[location.block].statements[location.statement_index + 1..].iter(); | |
| for stmt in statements.chain(maybe_additional_statement) { | |
| if let StatementKind::Assign(box (_, Rvalue::Aggregate(kind, places))) = &stmt.kind { | |
| let (&def_id, is_coroutine) = match kind { | |
| box AggregateKind::Closure(def_id, _) => (def_id, false), | |
| box AggregateKind::Coroutine(def_id, _) => (def_id, true), | |
| _ => continue, | |
| }; | |
| let def_id = def_id.expect_local(); | |
| debug!( | |
| "borrow_spans: def_id={:?} is_coroutine={:?} places={:?}", | |
| def_id, is_coroutine, places | |
| ); | |
| if let Some((args_span, closure_kind, capture_kind_span, path_span)) = | |
| self.closure_span(def_id, Place::from(target).as_ref(), places) | |
| { | |
| return ClosureUse { closure_kind, args_span, capture_kind_span, path_span }; | |
| } else { | |
| return OtherUse(use_span); | |
| } | |
| } | |
| if use_span != stmt.source_info.span { | |
| break; | |
| } | |
| } | |
| OtherUse(use_span) | |
| } | |
| /// Finds the spans of a captured place within a closure or coroutine. | |
| /// The first span is the location of the use resulting in the capture kind of the capture | |
| /// The second span is the location the use resulting in the captured path of the capture | |
| fn closure_span( | |
| &self, | |
| def_id: LocalDefId, | |
| target_place: PlaceRef<'tcx>, | |
| places: &IndexSlice<FieldIdx, Operand<'tcx>>, | |
| ) -> Option<(Span, hir::ClosureKind, Span, Span)> { | |
| debug!( | |
| "closure_span: def_id={:?} target_place={:?} places={:?}", | |
| def_id, target_place, places | |
| ); | |
| let hir_id = self.infcx.tcx.local_def_id_to_hir_id(def_id); | |
| let expr = &self.infcx.tcx.hir_expect_expr(hir_id).kind; | |
| debug!("closure_span: hir_id={:?} expr={:?}", hir_id, expr); | |
| if let &hir::ExprKind::Closure(&hir::Closure { kind, fn_decl_span, .. }) = expr { | |
| for (captured_place, place) in | |
| self.infcx.tcx.closure_captures(def_id).iter().zip(places) | |
| { | |
| match place { | |
| Operand::Copy(place) | Operand::Move(place) | |
| if target_place == place.as_ref() => | |
| { | |
| debug!("closure_span: found captured local {:?}", place); | |
| return Some(( | |
| fn_decl_span, | |
| kind, | |
| captured_place.get_capture_kind_span(self.infcx.tcx), | |
| captured_place.get_path_span(self.infcx.tcx), | |
| )); | |
| } | |
| _ => {} | |
| } | |
| } | |
| } | |
| None | |
| } | |
| /// Helper to retrieve span(s) of given borrow from the current MIR | |
| /// representation | |
| pub(super) fn retrieve_borrow_spans(&self, borrow: &BorrowData<'_>) -> UseSpans<'tcx> { | |
| let span = self.body.source_info(borrow.reserve_location).span; | |
| self.borrow_spans(span, borrow.reserve_location) | |
| } | |
| fn explain_captures( | |
| &mut self, | |
| err: &mut Diag<'infcx>, | |
| span: Span, | |
| move_span: Span, | |
| move_spans: UseSpans<'tcx>, | |
| moved_place: Place<'tcx>, | |
| msg_opt: CapturedMessageOpt, | |
| ) { | |
| let CapturedMessageOpt { | |
| is_partial_move: is_partial, | |
| is_loop_message, | |
| is_move_msg, | |
| is_loop_move, | |
| has_suggest_reborrow, | |
| maybe_reinitialized_locations_is_empty, | |
| } = msg_opt; | |
| if let UseSpans::FnSelfUse { var_span, fn_call_span, fn_span, kind } = move_spans { | |
| let place_name = self | |
| .describe_place(moved_place.as_ref()) | |
| .map(|n| format!("`{n}`")) | |
| .unwrap_or_else(|| "value".to_owned()); | |
| match kind { | |
| CallKind::FnCall { fn_trait_id, self_ty } | |
| if self.infcx.tcx.is_lang_item(fn_trait_id, LangItem::FnOnce) => | |
| { | |
| err.subdiagnostic(CaptureReasonLabel::Call { | |
| fn_call_span, | |
| place_name: &place_name, | |
| is_partial, | |
| is_loop_message, | |
| }); | |
| // Check if the move occurs on a value because of a call on a closure that comes | |
| // from a type parameter `F: FnOnce()`. If so, we provide a targeted `note`: | |
| // ``` | |
| // error[E0382]: use of moved value: `blk` | |
| // --> $DIR/once-cant-call-twice-on-heap.rs:8:5 | |
| // | | |
| // LL | fn foo<F:FnOnce()>(blk: F) { | |
| // | --- move occurs because `blk` has type `F`, which does not implement the `Copy` trait | |
| // LL | blk(); | |
| // | ----- `blk` moved due to this call | |
| // LL | blk(); | |
| // | ^^^ value used here after move | |
| // | | |
| // note: `FnOnce` closures can only be called once | |
| // --> $DIR/once-cant-call-twice-on-heap.rs:6:10 | |
| // | | |
| // LL | fn foo<F:FnOnce()>(blk: F) { | |
| // | ^^^^^^^^ `F` is made to be an `FnOnce` closure here | |
| // LL | blk(); | |
| // | ----- this value implements `FnOnce`, which causes it to be moved when called | |
| // ``` | |
| if let ty::Param(param_ty) = *self_ty.kind() | |
| && let generics = self.infcx.tcx.generics_of(self.mir_def_id()) | |
| && let param = generics.type_param(param_ty, self.infcx.tcx) | |
| && let Some(hir_generics) = self | |
| .infcx | |
| .tcx | |
| .typeck_root_def_id(self.mir_def_id().to_def_id()) | |
| .as_local() | |
| .and_then(|def_id| self.infcx.tcx.hir_get_generics(def_id)) | |
| && let spans = hir_generics | |
| .predicates | |
| .iter() | |
| .filter_map(|pred| match pred.kind { | |
| hir::WherePredicateKind::BoundPredicate(pred) => Some(pred), | |
| _ => None, | |
| }) | |
| .filter(|pred| { | |
| if let Some((id, _)) = pred.bounded_ty.as_generic_param() { | |
| id == param.def_id | |
| } else { | |
| false | |
| } | |
| }) | |
| .flat_map(|pred| pred.bounds) | |
| .filter_map(|bound| { | |
| if let Some(trait_ref) = bound.trait_ref() | |
| && let Some(trait_def_id) = trait_ref.trait_def_id() | |
| && trait_def_id == fn_trait_id | |
| { | |
| Some(bound.span()) | |
| } else { | |
| None | |
| } | |
| }) | |
| .collect::<Vec<Span>>() | |
| && !spans.is_empty() | |
| { | |
| let mut span: MultiSpan = spans.clone().into(); | |
| let msg = msg!("`{$ty}` is made to be an `FnOnce` closure here") | |
| .arg("ty", param_ty.to_string()) | |
| .format(); | |
| for sp in spans { | |
| span.push_span_label(sp, msg.clone()); | |
| } | |
| span.push_span_label( | |
| fn_call_span, | |
| msg!("this value implements `FnOnce`, which causes it to be moved when called"), | |
| ); | |
| err.span_note(span, msg!("`FnOnce` closures can only be called once")); | |
| } else { | |
| err.subdiagnostic(CaptureReasonNote::FnOnceMoveInCall { var_span }); | |
| } | |
| } | |
| CallKind::Operator { self_arg, trait_id, .. } => { | |
| let self_arg = self_arg.unwrap(); | |
| err.subdiagnostic(CaptureReasonLabel::OperatorUse { | |
| fn_call_span, | |
| place_name: &place_name, | |
| is_partial, | |
| is_loop_message, | |
| }); | |
| if self.fn_self_span_reported.insert(fn_span) { | |
| let lang = self.infcx.tcx.lang_items(); | |
| err.subdiagnostic( | |
| if [lang.not_trait(), lang.deref_trait(), lang.neg_trait()] | |
| .contains(&Some(trait_id)) | |
| { | |
| CaptureReasonNote::UnOpMoveByOperator { span: self_arg.span } | |
| } else { | |
| CaptureReasonNote::LhsMoveByOperator { span: self_arg.span } | |
| }, | |
| ); | |
| } | |
| } | |
| CallKind::Normal { self_arg, desugaring, method_did, method_args } => { | |
| let self_arg = self_arg.unwrap(); | |
| let mut has_sugg = false; | |
| let tcx = self.infcx.tcx; | |
| // Avoid pointing to the same function in multiple different | |
| // error messages. | |
| if span != DUMMY_SP && self.fn_self_span_reported.insert(self_arg.span) { | |
| self.explain_iterator_advancement_in_for_loop_if_applicable( | |
| err, | |
| span, | |
| &move_spans, | |
| ); | |
| let func = tcx.def_path_str(method_did); | |
| err.subdiagnostic(CaptureReasonNote::FuncTakeSelf { | |
| func, | |
| place_name: place_name.clone(), | |
| span: self_arg.span, | |
| }); | |
| } | |
| let parent_did = tcx.parent(method_did); | |
| let parent_self_ty = | |
| matches!(tcx.def_kind(parent_did), rustc_hir::def::DefKind::Impl { .. }) | |
| .then_some(parent_did) | |
| .and_then(|did| match tcx.type_of(did).instantiate_identity().kind() { | |
| ty::Adt(def, ..) => Some(def.did()), | |
| _ => None, | |
| }); | |
| let is_option_or_result = parent_self_ty.is_some_and(|def_id| { | |
| matches!(tcx.get_diagnostic_name(def_id), Some(sym::Option | sym::Result)) | |
| }); | |
| if is_option_or_result && maybe_reinitialized_locations_is_empty { | |
| err.subdiagnostic(CaptureReasonLabel::BorrowContent { | |
| var_span: var_span.shrink_to_hi(), | |
| }); | |
| } | |
| if let Some((CallDesugaringKind::ForLoopIntoIter, _)) = desugaring { | |
| let ty = moved_place.ty(self.body, tcx).ty; | |
| let suggest = match tcx.get_diagnostic_item(sym::IntoIterator) { | |
| Some(def_id) => type_known_to_meet_bound_modulo_regions( | |
| self.infcx, | |
| self.infcx.param_env, | |
| Ty::new_imm_ref(tcx, tcx.lifetimes.re_erased, ty), | |
| def_id, | |
| ), | |
| _ => false, | |
| }; | |
| if suggest { | |
| err.subdiagnostic(CaptureReasonSuggest::IterateSlice { | |
| ty, | |
| span: move_span.shrink_to_lo(), | |
| }); | |
| } | |
| err.subdiagnostic(CaptureReasonLabel::ImplicitCall { | |
| fn_call_span, | |
| place_name: &place_name, | |
| is_partial, | |
| is_loop_message, | |
| }); | |
| // If the moved place was a `&mut` ref, then we can | |
| // suggest to reborrow it where it was moved, so it | |
| // will still be valid by the time we get to the usage. | |
| if let ty::Ref(_, _, hir::Mutability::Mut) = | |
| moved_place.ty(self.body, self.infcx.tcx).ty.kind() | |
| { | |
| // Suggest `reborrow` in other place for following situations: | |
| // 1. If we are in a loop this will be suggested later. | |
| // 2. If the moved value is a mut reference, it is used in a | |
| // generic function and the corresponding arg's type is generic param. | |
| if !is_loop_move && !has_suggest_reborrow { | |
| self.suggest_reborrow( | |
| err, | |
| move_span.shrink_to_lo(), | |
| moved_place.as_ref(), | |
| ); | |
| } | |
| } | |
| } else { | |
| if let Some((CallDesugaringKind::Await, _)) = desugaring { | |
| err.subdiagnostic(CaptureReasonLabel::Await { | |
| fn_call_span, | |
| place_name: &place_name, | |
| is_partial, | |
| is_loop_message, | |
| }); | |
| } else { | |
| err.subdiagnostic(CaptureReasonLabel::MethodCall { | |
| fn_call_span, | |
| place_name: &place_name, | |
| is_partial, | |
| is_loop_message, | |
| }); | |
| } | |
| // Erase and shadow everything that could be passed to the new infcx. | |
| let ty = moved_place.ty(self.body, tcx).ty; | |
| if let ty::Adt(def, args) = ty.peel_refs().kind() | |
| && tcx.is_lang_item(def.did(), LangItem::Pin) | |
| && let ty::Ref(_, _, hir::Mutability::Mut) = args.type_at(0).kind() | |
| && let self_ty = self.infcx.instantiate_binder_with_fresh_vars( | |
| fn_call_span, | |
| BoundRegionConversionTime::FnCall, | |
| tcx.fn_sig(method_did).instantiate(tcx, method_args).input(0), | |
| ) | |
| && self.infcx.can_eq(self.infcx.param_env, ty, self_ty) | |
| { | |
| err.subdiagnostic(CaptureReasonSuggest::FreshReborrow { | |
| span: move_span.shrink_to_hi(), | |
| }); | |
| has_sugg = true; | |
| } | |
| if let Some(clone_trait) = tcx.lang_items().clone_trait() { | |
| let sugg = if moved_place | |
| .iter_projections() | |
| .any(|(_, elem)| matches!(elem, ProjectionElem::Deref)) | |
| { | |
| let (start, end) = if let Some(expr) = self.find_expr(move_span) | |
| && let Some(_) = self.clone_on_reference(expr) | |
| && let hir::ExprKind::MethodCall(_, rcvr, _, _) = expr.kind | |
| { | |
| (move_span.shrink_to_lo(), move_span.with_lo(rcvr.span.hi())) | |
| } else { | |
| (move_span.shrink_to_lo(), move_span.shrink_to_hi()) | |
| }; | |
| vec![ | |
| // We use the fully-qualified path because `.clone()` can | |
| // sometimes choose `<&T as Clone>` instead of `<T as Clone>` | |
| // when going through auto-deref, so this ensures that doesn't | |
| // happen, causing suggestions for `.clone().clone()`. | |
| (start, format!("<{ty} as Clone>::clone(&")), | |
| (end, ")".to_string()), | |
| ] | |
| } else { | |
| vec![(move_span.shrink_to_hi(), ".clone()".to_string())] | |
| }; | |
| if let Some(errors) = self.infcx.type_implements_trait_shallow( | |
| clone_trait, | |
| ty, | |
| self.infcx.param_env, | |
| ) && !has_sugg | |
| { | |
| let msg = match &errors[..] { | |
| [] => "you can `clone` the value and consume it, but this \ | |
| might not be your desired behavior" | |
| .to_string(), | |
| [error] => { | |
| format!( | |
| "you could `clone` the value and consume it, if the \ | |
| `{}` trait bound could be satisfied", | |
| error.obligation.predicate, | |
| ) | |
| } | |
| _ => { | |
| format!( | |
| "you could `clone` the value and consume it, if the \ | |
| following trait bounds could be satisfied: {}", | |
| listify(&errors, |e: &FulfillmentError<'tcx>| format!( | |
| "`{}`", | |
| e.obligation.predicate | |
| )) | |
| .unwrap(), | |
| ) | |
| } | |
| }; | |
| err.multipart_suggestion(msg, sugg, Applicability::MaybeIncorrect); | |
| for error in errors { | |
| if let FulfillmentErrorCode::Select( | |
| SelectionError::Unimplemented, | |
| ) = error.code | |
| && let ty::PredicateKind::Clause(ty::ClauseKind::Trait( | |
| pred, | |
| )) = error.obligation.predicate.kind().skip_binder() | |
| { | |
| self.infcx.err_ctxt().suggest_derive( | |
| &error.obligation, | |
| err, | |
| error.obligation.predicate.kind().rebind(pred), | |
| ); | |
| } | |
| } | |
| } | |
| } | |
| } | |
| } | |
| // Other desugarings takes &self, which cannot cause a move | |
| _ => {} | |
| } | |
| } else { | |
| if move_span != span || is_loop_message { | |
| err.subdiagnostic(CaptureReasonLabel::MovedHere { | |
| move_span, | |
| is_partial, | |
| is_move_msg, | |
| is_loop_message, | |
| }); | |
| } | |
| // If the move error occurs due to a loop, don't show | |
| // another message for the same span | |
| if !is_loop_message { | |
| move_spans.var_subdiag(err, None, |kind, var_span| match kind { | |
| hir::ClosureKind::Coroutine(_) => { | |
| CaptureVarCause::PartialMoveUseInCoroutine { var_span, is_partial } | |
| } | |
| hir::ClosureKind::Closure | hir::ClosureKind::CoroutineClosure(_) => { | |
| CaptureVarCause::PartialMoveUseInClosure { var_span, is_partial } | |
| } | |
| }) | |
| } | |
| } | |
| } | |
| /// Skip over locals that begin with an underscore or have no name | |
| pub(crate) fn local_excluded_from_unused_mut_lint(&self, index: Local) -> bool { | |
| self.local_name(index).is_none_or(|name| name.as_str().starts_with('_')) | |
| } | |
| } | |
| const LIMITATION_NOTE: DiagMessage = | |
| msg!("due to a current limitation of the type system, this implies a `'static` lifetime"); |