try to fix issue 57017, but not quite there yet

Co-authored-by: Eric Holk <eric@theincredibleholk.org>

Author: nikomatsakis

compiler/rustc_typeck/src/check/generator_interior.rs

@@ -13,7 +13,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::hir_id::HirIdSet;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{Arm, Expr, ExprKind, Guard, HirId, Pat, PatKind};
-use rustc_middle::middle::region::{self, YieldData};
+use rustc_middle::middle::region::{self, Scope, ScopeData, YieldData};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::symbol::sym;
 use rustc_span::Span;
@@ -369,7 +369,17 @@ impl<'a, 'tcx> Visitor<'tcx> for InteriorVisitor<'a, 'tcx> {
 
  self.expr_count += 1;
 
- let scope = self.region_scope_tree.temporary_scope(expr.hir_id.local_id);
+ debug!("is_borrowed_temporary: {:?}", self.drop_ranges.is_borrowed_temporary(expr));
+
+ let scope = if self.drop_ranges.is_borrowed_temporary(expr) {
+ self.region_scope_tree.temporary_scope(expr.hir_id.local_id)
+ } else {
+ debug!("parent_node: {:?}", self.fcx.tcx.hir().find_parent_node(expr.hir_id));
+ match self.fcx.tcx.hir().find_parent_node(expr.hir_id) {
+ Some(parent) => Some(Scope { id: parent.local_id, data: ScopeData::Node }),
+ None => self.region_scope_tree.temporary_scope(expr.hir_id.local_id),
+ }
+ };
 
  // If there are adjustments, then record the final type --
  // this is the actual value that is being produced.

compiler/rustc_typeck/src/check/generator_interior/drop_ranges.rs

@@ -18,6 +18,7 @@ use crate::check::FnCtxt;
 use hir::def_id::DefId;
 use hir::{Body, HirId, HirIdMap, Node};
 use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::stable_set::FxHashSet;
 use rustc_hir as hir;
 use rustc_index::bit_set::BitSet;
 use rustc_index::vec::IndexVec;
@@ -41,7 +42,7 @@ pub fn compute_drop_ranges<'a, 'tcx>(
  let consumed_borrowed_places = find_consumed_and_borrowed(fcx, def_id, body);
 
  let num_exprs = fcx.tcx.region_scope_tree(def_id).body_expr_count(body.id()).unwrap_or(0);
- let mut drop_ranges = build_control_flow_graph(
+ let (mut drop_ranges, borrowed_temporaries) = build_control_flow_graph(
  fcx.tcx.hir(),
  fcx.tcx,
  &fcx.typeck_results.borrow(),
@@ -52,11 +53,20 @@ pub fn compute_drop_ranges<'a, 'tcx>(
 
  drop_ranges.propagate_to_fixpoint();
 
- DropRanges { tracked_value_map: drop_ranges.tracked_value_map, nodes: drop_ranges.nodes }
+ debug!("borrowed_temporaries = {borrowed_temporaries:?}");
+ DropRanges {
+ tracked_value_map: drop_ranges.tracked_value_map,
+ nodes: drop_ranges.nodes,
+ borrowed_temporaries: Some(borrowed_temporaries),
+ }
  } else {
  // If drop range tracking is not enabled, skip all the analysis and produce an
  // empty set of DropRanges.
- DropRanges { tracked_value_map: FxHashMap::default(), nodes: IndexVec::new() }
+ DropRanges {
+ tracked_value_map: FxHashMap::default(),
+ nodes: IndexVec::new(),
+ borrowed_temporaries: None,
+ }
  }
 }
 
@@ -161,6 +171,7 @@ impl TryFrom<&PlaceWithHirId<'_>> for TrackedValue {
 pub struct DropRanges {
  tracked_value_map: FxHashMap<TrackedValue, TrackedValueIndex>,
  nodes: IndexVec<PostOrderId, NodeInfo>,
+ borrowed_temporaries: Option<FxHashSet<HirId>>,
 }
 
 impl DropRanges {
@@ -174,6 +185,10 @@ impl DropRanges {
  })
  }
 
+ pub fn is_borrowed_temporary(&self, expr: &hir::Expr<'_>) -> bool {
+ if let Some(b) = &self.borrowed_temporaries { b.contains(&expr.hir_id) } else { true }
+ }
+
  /// Returns a reference to the NodeInfo for a node, panicking if it does not exist
  fn expect_node(&self, id: PostOrderId) -> &NodeInfo {
  &self.nodes[id]

compiler/rustc_typeck/src/check/generator_interior/drop_ranges/cfg_build.rs

@@ -6,7 +6,7 @@ use hir::{
  intravisit::{self, Visitor},
  Body, Expr, ExprKind, Guard, HirId, LoopIdError,
 };
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::{fx::FxHashMap, stable_set::FxHashSet};
 use rustc_hir as hir;
 use rustc_index::vec::IndexVec;
 use rustc_middle::{
@@ -27,14 +27,14 @@ pub(super) fn build_control_flow_graph<'tcx>(
  consumed_borrowed_places: ConsumedAndBorrowedPlaces,
  body: &'tcx Body<'tcx>,
  num_exprs: usize,
-) -> DropRangesBuilder {
+) -> (DropRangesBuilder, FxHashSet<HirId>) {
  let mut drop_range_visitor =
  DropRangeVisitor::new(hir, tcx, typeck_results, consumed_borrowed_places, num_exprs);
  intravisit::walk_body(&mut drop_range_visitor, body);
 
  drop_range_visitor.drop_ranges.process_deferred_edges();
 
- drop_range_visitor.drop_ranges
+ (drop_range_visitor.drop_ranges, drop_range_visitor.places.borrowed_temporaries)
 }
 
 /// This struct is used to gather the information for `DropRanges` to determine the regions of the

compiler/rustc_typeck/src/check/generator_interior/drop_ranges/record_consumed_borrow.rs

@@ -6,6 +6,7 @@ use crate::{
 use hir::{def_id::DefId, Body, HirId, HirIdMap};
 use rustc_data_structures::stable_set::FxHashSet;
 use rustc_hir as hir;
+use rustc_middle::hir::place::PlaceBase;
 use rustc_middle::ty::{ParamEnv, TyCtxt};
 
 pub(super) fn find_consumed_and_borrowed<'a, 'tcx>(
@@ -27,8 +28,12 @@ pub(super) struct ConsumedAndBorrowedPlaces {
  /// Note that this set excludes "partial drops" -- for example, a statement like `drop(x.y)` is
  /// not considered a drop of `x`, although it would be a drop of `x.y`.
  pub(super) consumed: HirIdMap<FxHashSet<TrackedValue>>,
+
  /// A set of hir-ids of values or variables that are borrowed at some point within the body.
  pub(super) borrowed: FxHashSet<TrackedValue>,
+
+ /// A set of hir-ids of values or variables that are borrowed at some point within the body.
+ pub(super) borrowed_temporaries: FxHashSet<HirId>,
 }
 
 /// Works with ExprUseVisitor to find interesting values for the drop range analysis.
@@ -49,6 +54,7 @@ impl<'tcx> ExprUseDelegate<'tcx> {
  places: ConsumedAndBorrowedPlaces {
  consumed: <_>::default(),
  borrowed: <_>::default(),
+ borrowed_temporaries: <_>::default(),
  },
  }
  }
@@ -98,10 +104,19 @@ impl<'tcx> expr_use_visitor::Delegate<'tcx> for ExprUseDelegate<'tcx> {
  diag_expr_id: HirId,
  _bk: rustc_middle::ty::BorrowKind,
  ) {
- debug!("borrow {:?}; diag_expr_id={:?}", place_with_id, diag_expr_id);
+ debug!("borrow: place_with_id = {place_with_id:?}, diag_expr_id={diag_expr_id:?}");
+
  self.places
  .borrowed
  .insert(TrackedValue::from_place_with_projections_allowed(place_with_id));
+
+ // XXX -- we need to distinguish "consuming a copy" from other borrows
+ //
+ // XXX -- we need to distinguish `&*E` where `E: &T` which is not creating a temporary
+ // even though the place-base E is an rvalue
+ if let PlaceBase::Rvalue = place_with_id.place.base {
+ self.places.borrowed_temporaries.insert(place_with_id.hir_id);
+ }
  }
 
  fn mutate(

foo.rs

@@ -0,0 +1,21 @@
+// check-pass
+#![feature(generators, negative_impls)]
+
+struct Client;
+
+impl !Sync for Client {}
+
+fn status(_client_status: &Client) -> i16 {
+ 200
+}
+
+fn assert_send<T: Send>(_thing: T) {}
+
+// This is the same bug as issue 57017, but using yield instead of await
+fn main() {
+ let client = Client;
+ let g = move || match status(&client) {
+ _status => yield,
+ };
+ assert_send(g);
+}