diff options
3 files changed, 58 insertions, 18 deletions
diff --git a/compiler/rustc_typeck/src/check/upvar.rs b/compiler/rustc_typeck/src/check/upvar.rs index 53b99a14f37..036e1037383 100644 --- a/compiler/rustc_typeck/src/check/upvar.rs +++ b/compiler/rustc_typeck/src/check/upvar.rs @@ -602,7 +602,47 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { } } - debug!("For closure={:?}, min_captures={:#?}", closure_def_id, root_var_min_capture_list); + debug!( + "For closure={:?}, min_captures before sorting={:?}", + closure_def_id, root_var_min_capture_list + ); + + // Now that we have the minimized list of captures, sort the captures by field id. + // This causes the closure to capture the upvars in the same order as the fields are + // declared which is also the drop order. Thus, in situations where we capture all the + // fields of some type, the obserable drop order will remain the same as it previously + // was even though we're dropping each capture individually. + // See https://github.com/rust-lang/project-rfc-2229/issues/42 and + // `src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order.rs`. + for (_, captures) in &mut root_var_min_capture_list { + captures.sort_by(|capture1, capture2| { + for (p1, p2) in capture1.place.projections.iter().zip(&capture2.place.projections) { + match (p1.kind, p2.kind) { + // Paths are the same, continue to next loop. + (ProjectionKind::Deref, ProjectionKind::Deref) => {} + (ProjectionKind::Field(i1, _), ProjectionKind::Field(i2, _)) + if i1 == i2 => {} + + // Fields are different, compare them. + (ProjectionKind::Field(i1, _), ProjectionKind::Field(i2, _)) => { + return i1.cmp(&i2); + } + + (l, r) => bug!("ProjectionKinds were different: ({:?}, {:?})", l, r), + } + } + + unreachable!( + "we captured two identical projections: capture1 = {:?}, capture2 = {:?}", + capture1, capture2 + ); + }); + } + + debug!( + "For closure={:?}, min_captures after sorting={:#?}", + closure_def_id, root_var_min_capture_list + ); typeck_results.closure_min_captures.insert(closure_def_id, root_var_min_capture_list); } diff --git a/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order.stderr b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order.stderr index 7fdeab6a74d..559580ec059 100644 --- a/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order.stderr +++ b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order.stderr @@ -136,26 +136,26 @@ LL | | LL | | }; | |_____^ | -note: Min Capture a[(1, 0)] -> ImmBorrow - --> $DIR/preserve_field_drop_order.rs:52:26 - | -LL | println!("{:?}", a.1); - | ^^^ note: Min Capture a[(0, 0)] -> ImmBorrow --> $DIR/preserve_field_drop_order.rs:55:26 | LL | println!("{:?}", a.0); | ^^^ -note: Min Capture b[(1, 0)] -> ImmBorrow - --> $DIR/preserve_field_drop_order.rs:59:26 +note: Min Capture a[(1, 0)] -> ImmBorrow + --> $DIR/preserve_field_drop_order.rs:52:26 | -LL | println!("{:?}", b.1); +LL | println!("{:?}", a.1); | ^^^ note: Min Capture b[(0, 0)] -> ImmBorrow --> $DIR/preserve_field_drop_order.rs:62:26 | LL | println!("{:?}", b.0); | ^^^ +note: Min Capture b[(1, 0)] -> ImmBorrow + --> $DIR/preserve_field_drop_order.rs:59:26 + | +LL | println!("{:?}", b.1); + | ^^^ error: First Pass analysis includes: --> $DIR/preserve_field_drop_order.rs:75:5 @@ -202,26 +202,26 @@ LL | | LL | | }; | |_____^ | -note: Min Capture b[(1, 0)] -> ImmBorrow - --> $DIR/preserve_field_drop_order.rs:78:26 - | -LL | println!("{:?}", b.1); - | ^^^ note: Min Capture b[(0, 0)] -> ImmBorrow --> $DIR/preserve_field_drop_order.rs:88:26 | LL | println!("{:?}", b.0); | ^^^ -note: Min Capture a[(1, 0)] -> ImmBorrow - --> $DIR/preserve_field_drop_order.rs:81:26 +note: Min Capture b[(1, 0)] -> ImmBorrow + --> $DIR/preserve_field_drop_order.rs:78:26 | -LL | println!("{:?}", a.1); +LL | println!("{:?}", b.1); | ^^^ note: Min Capture a[(0, 0)] -> ImmBorrow --> $DIR/preserve_field_drop_order.rs:84:26 | LL | println!("{:?}", a.0); | ^^^ +note: Min Capture a[(1, 0)] -> ImmBorrow + --> $DIR/preserve_field_drop_order.rs:81:26 + | +LL | println!("{:?}", a.1); + | ^^^ error: aborting due to 9 previous errors diff --git a/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.twenty_twentyone.run.stdout b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.twenty_twentyone.run.stdout index 90b1200fd08..e3931696518 100644 --- a/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.twenty_twentyone.run.stdout +++ b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.twenty_twentyone.run.stdout @@ -1,3 +1,3 @@ Dropable("y") Dropable("x") -Dropping y Dropping x +Dropping y |