diff --git a/compiler/rustc_typeck/src/check/upvar.rs b/compiler/rustc_typeck/src/check/upvar.rs
index 53b99a14f37..917bf4ecd8c 100644
--- a/compiler/rustc_typeck/src/check/upvar.rs
+++ b/compiler/rustc_typeck/src/check/upvar.rs
@@ -602,7 +602,78 @@ 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) {
+ // We do not need to look at the `Projection.ty` fields here because at each
+ // step of the iteration, the projections will either be the same and therefore
+ // the types must be as well or the current projection will be different and
+ // we will return the result of comparing the field indexes.
+ 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);
+ }
+
+ // We should have either a pair of `Deref`s or a pair of `Field`s.
+ // Anything else is a bug.
+ (
+ l @ (ProjectionKind::Deref | ProjectionKind::Field(..)),
+ r @ (ProjectionKind::Deref | ProjectionKind::Field(..)),
+ ) => bug!(
+ "ProjectionKinds Deref and Field were mismatched: ({:?}, {:?})",
+ l,
+ r
+ ),
+ (
+ l
+ @
+ (ProjectionKind::Index
+ | ProjectionKind::Subslice
+ | ProjectionKind::Deref
+ | ProjectionKind::Field(..)),
+ r
+ @
+ (ProjectionKind::Index
+ | ProjectionKind::Subslice
+ | ProjectionKind::Deref
+ | ProjectionKind::Field(..)),
+ ) => bug!(
+ "ProjectionKinds Index or Subslice were unexpected: ({:?}, {:?})",
+ 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.rs b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order.rs
new file mode 100644
index 00000000000..2f8cddc06ba
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order.rs
@@ -0,0 +1,101 @@
+// edition:2021
+
+// Tests that in cases where we individually capture all the fields of a type,
+// we still drop them in the order they would have been dropped in the 2018 edition.
+
+// NOTE: It is *critical* that the order of the min capture NOTES in the stderr output
+// does *not* change!
+
+#![feature(rustc_attrs)]
+
+#[derive(Debug)]
+struct HasDrop;
+impl Drop for HasDrop {
+ fn drop(&mut self) {
+ println!("dropped");
+ }
+}
+
+fn test_one() {
+ let a = (HasDrop, HasDrop);
+ let b = (HasDrop, HasDrop);
+
+ let c = #[rustc_capture_analysis]
+ //~^ ERROR: attributes on expressions are experimental
+ //~| NOTE: see issue #15701 <https://github.com/rust-lang/rust/issues/15701>
+ || {
+ //~^ ERROR: Min Capture analysis includes:
+ //~| ERROR
+ println!("{:?}", a.0);
+ //~^ NOTE: Min Capture a[(0, 0)] -> ImmBorrow
+ //~| NOTE
+ println!("{:?}", a.1);
+ //~^ NOTE: Min Capture a[(1, 0)] -> ImmBorrow
+ //~| NOTE
+
+ println!("{:?}", b.0);
+ //~^ NOTE: Min Capture b[(0, 0)] -> ImmBorrow
+ //~| NOTE
+ println!("{:?}", b.1);
+ //~^ NOTE: Min Capture b[(1, 0)] -> ImmBorrow
+ //~| NOTE
+ };
+}
+
+fn test_two() {
+ let a = (HasDrop, HasDrop);
+ let b = (HasDrop, HasDrop);
+
+ let c = #[rustc_capture_analysis]
+ //~^ ERROR: attributes on expressions are experimental
+ //~| NOTE: see issue #15701 <https://github.com/rust-lang/rust/issues/15701>
+ || {
+ //~^ ERROR: Min Capture analysis includes:
+ //~| ERROR
+ println!("{:?}", a.1);
+ //~^ NOTE: Min Capture a[(1, 0)] -> ImmBorrow
+ //~| NOTE
+ println!("{:?}", a.0);
+ //~^ NOTE: Min Capture a[(0, 0)] -> ImmBorrow
+ //~| NOTE
+
+ println!("{:?}", b.1);
+ //~^ NOTE: Min Capture b[(1, 0)] -> ImmBorrow
+ //~| NOTE
+ println!("{:?}", b.0);
+ //~^ NOTE: Min Capture b[(0, 0)] -> ImmBorrow
+ //~| NOTE
+ };
+}
+
+fn test_three() {
+ let a = (HasDrop, HasDrop);
+ let b = (HasDrop, HasDrop);
+
+ let c = #[rustc_capture_analysis]
+ //~^ ERROR: attributes on expressions are experimental
+ //~| NOTE: see issue #15701 <https://github.com/rust-lang/rust/issues/15701>
+ || {
+ //~^ ERROR: Min Capture analysis includes:
+ //~| ERROR
+ println!("{:?}", b.1);
+ //~^ NOTE: Min Capture b[(1, 0)] -> ImmBorrow
+ //~| NOTE
+ println!("{:?}", a.1);
+ //~^ NOTE: Min Capture a[(1, 0)] -> ImmBorrow
+ //~| NOTE
+ println!("{:?}", a.0);
+ //~^ NOTE: Min Capture a[(0, 0)] -> ImmBorrow
+ //~| NOTE
+
+ println!("{:?}", b.0);
+ //~^ NOTE: Min Capture b[(0, 0)] -> ImmBorrow
+ //~| NOTE
+ };
+}
+
+fn main() {
+ test_one();
+ test_two();
+ test_three();
+}
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
new file mode 100644
index 00000000000..2d1dc8727c2
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order.stderr
@@ -0,0 +1,228 @@
+error[E0658]: attributes on expressions are experimental
+ --> $DIR/preserve_field_drop_order.rs:23:13
+ |
+LL | let c = #[rustc_capture_analysis]
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+ = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+error[E0658]: attributes on expressions are experimental
+ --> $DIR/preserve_field_drop_order.rs:49:13
+ |
+LL | let c = #[rustc_capture_analysis]
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+ = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+error[E0658]: attributes on expressions are experimental
+ --> $DIR/preserve_field_drop_order.rs:75:13
+ |
+LL | let c = #[rustc_capture_analysis]
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+ = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+error: First Pass analysis includes:
+ --> $DIR/preserve_field_drop_order.rs:26:5
+ |
+LL | / || {
+LL | |
+LL | |
+LL | | println!("{:?}", a.0);
+... |
+LL | |
+LL | | };
+ | |_____^
+ |
+note: Capturing a[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:29:26
+ |
+LL | println!("{:?}", a.0);
+ | ^^^
+note: Capturing a[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:32:26
+ |
+LL | println!("{:?}", a.1);
+ | ^^^
+note: Capturing b[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:36:26
+ |
+LL | println!("{:?}", b.0);
+ | ^^^
+note: Capturing b[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:39:26
+ |
+LL | println!("{:?}", b.1);
+ | ^^^
+
+error: Min Capture analysis includes:
+ --> $DIR/preserve_field_drop_order.rs:26:5
+ |
+LL | / || {
+LL | |
+LL | |
+LL | | println!("{:?}", a.0);
+... |
+LL | |
+LL | | };
+ | |_____^
+ |
+note: Min Capture a[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:29:26
+ |
+LL | println!("{:?}", a.0);
+ | ^^^
+note: Min Capture a[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:32:26
+ |
+LL | println!("{:?}", a.1);
+ | ^^^
+note: Min Capture b[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:36:26
+ |
+LL | println!("{:?}", b.0);
+ | ^^^
+note: Min Capture b[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:39:26
+ |
+LL | println!("{:?}", b.1);
+ | ^^^
+
+error: First Pass analysis includes:
+ --> $DIR/preserve_field_drop_order.rs:52:5
+ |
+LL | / || {
+LL | |
+LL | |
+LL | | println!("{:?}", a.1);
+... |
+LL | |
+LL | | };
+ | |_____^
+ |
+note: Capturing a[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:55:26
+ |
+LL | println!("{:?}", a.1);
+ | ^^^
+note: Capturing a[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:58:26
+ |
+LL | println!("{:?}", a.0);
+ | ^^^
+note: Capturing b[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:62:26
+ |
+LL | println!("{:?}", b.1);
+ | ^^^
+note: Capturing b[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:65:26
+ |
+LL | println!("{:?}", b.0);
+ | ^^^
+
+error: Min Capture analysis includes:
+ --> $DIR/preserve_field_drop_order.rs:52:5
+ |
+LL | / || {
+LL | |
+LL | |
+LL | | println!("{:?}", a.1);
+... |
+LL | |
+LL | | };
+ | |_____^
+ |
+note: Min Capture a[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:58:26
+ |
+LL | println!("{:?}", a.0);
+ | ^^^
+note: Min Capture a[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:55:26
+ |
+LL | println!("{:?}", a.1);
+ | ^^^
+note: Min Capture b[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:65:26
+ |
+LL | println!("{:?}", b.0);
+ | ^^^
+note: Min Capture b[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:62:26
+ |
+LL | println!("{:?}", b.1);
+ | ^^^
+
+error: First Pass analysis includes:
+ --> $DIR/preserve_field_drop_order.rs:78:5
+ |
+LL | / || {
+LL | |
+LL | |
+LL | | println!("{:?}", b.1);
+... |
+LL | |
+LL | | };
+ | |_____^
+ |
+note: Capturing b[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:81:26
+ |
+LL | println!("{:?}", b.1);
+ | ^^^
+note: Capturing a[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:84:26
+ |
+LL | println!("{:?}", a.1);
+ | ^^^
+note: Capturing a[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:87:26
+ |
+LL | println!("{:?}", a.0);
+ | ^^^
+note: Capturing b[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:91:26
+ |
+LL | println!("{:?}", b.0);
+ | ^^^
+
+error: Min Capture analysis includes:
+ --> $DIR/preserve_field_drop_order.rs:78:5
+ |
+LL | / || {
+LL | |
+LL | |
+LL | | println!("{:?}", b.1);
+... |
+LL | |
+LL | | };
+ | |_____^
+ |
+note: Min Capture b[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:91:26
+ |
+LL | println!("{:?}", b.0);
+ | ^^^
+note: Min Capture b[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:81:26
+ |
+LL | println!("{:?}", b.1);
+ | ^^^
+note: Min Capture a[(0, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:87:26
+ |
+LL | println!("{:?}", a.0);
+ | ^^^
+note: Min Capture a[(1, 0)] -> ImmBorrow
+ --> $DIR/preserve_field_drop_order.rs:84:26
+ |
+LL | println!("{:?}", a.1);
+ | ^^^
+
+error: aborting due to 9 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.rs b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.rs
new file mode 100644
index 00000000000..1cae776dd68
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.rs
@@ -0,0 +1,58 @@
+// run-pass
+// check-run-results
+// revisions: twenty_eighteen twenty_twentyone
+// [twenty_eighteen]compile-flags: --edition 2018
+// [twenty_twentyone]compile-flags: --edition 2021
+
+#[derive(Debug)]
+struct Dropable(&'static str);
+
+impl Drop for Dropable {
+ fn drop(&mut self) {
+ println!("Dropping {}", self.0)
+ }
+}
+
+#[derive(Debug)]
+struct A {
+ x: Dropable,
+ y: Dropable,
+}
+
+#[derive(Debug)]
+struct B {
+ c: A,
+ d: A,
+}
+
+#[derive(Debug)]
+struct R<'a> {
+ c: &'a A,
+ d: &'a A,
+}
+
+fn main() {
+ let a = A { x: Dropable("x"), y: Dropable("y") };
+
+ let c = move || println!("{:?} {:?}", a.y, a.x);
+
+ c();
+
+ let b = B {
+ c: A { x: Dropable("b.c.x"), y: Dropable("b.c.y") },
+ d: A { x: Dropable("b.d.x"), y: Dropable("b.d.y") },
+ };
+
+ let d = move || println!("{:?} {:?} {:?} {:?}", b.d.y, b.d.x, b.c.y, b.c.x);
+
+ d();
+
+ let r = R {
+ c: &A { x: Dropable("r.c.x"), y: Dropable("r.c.y") },
+ d: &A { x: Dropable("r.d.x"), y: Dropable("r.d.y") },
+ };
+
+ let e = move || println!("{:?} {:?} {:?} {:?}", r.d.y, r.d.x, r.c.y, r.c.x);
+
+ e();
+}
diff --git a/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.twenty_eighteen.run.stdout b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.twenty_eighteen.run.stdout
new file mode 100644
index 00000000000..557d047c1d5
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.twenty_eighteen.run.stdout
@@ -0,0 +1,13 @@
+Dropable("y") Dropable("x")
+Dropable("b.d.y") Dropable("b.d.x") Dropable("b.c.y") Dropable("b.c.x")
+Dropable("r.d.y") Dropable("r.d.x") Dropable("r.c.y") Dropable("r.c.x")
+Dropping r.d.x
+Dropping r.d.y
+Dropping r.c.x
+Dropping r.c.y
+Dropping b.c.x
+Dropping b.c.y
+Dropping b.d.x
+Dropping b.d.y
+Dropping x
+Dropping y
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
new file mode 100644
index 00000000000..557d047c1d5
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/preserve_field_drop_order2.twenty_twentyone.run.stdout
@@ -0,0 +1,13 @@
+Dropable("y") Dropable("x")
+Dropable("b.d.y") Dropable("b.d.x") Dropable("b.c.y") Dropable("b.c.x")
+Dropable("r.d.y") Dropable("r.d.x") Dropable("r.c.y") Dropable("r.c.x")
+Dropping r.d.x
+Dropping r.d.y
+Dropping r.c.x
+Dropping r.c.y
+Dropping b.c.x
+Dropping b.c.y
+Dropping b.d.x
+Dropping b.d.y
+Dropping x
+Dropping y