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Positive coverage: borrow_check_place_expr / parens

parens
LineCoverageSource
650✗(borrow_check_place_expr(env, assumptions, state, place) => (place_typed, state))
──────── ("parens")
65215(borrow_check_place_expr(env, assumptions, state, PlaceExpr::Parens(place)) => (place_typed, state))

15 tests exercised this rule:

Source location: tests/borrowck.rs:2341

fn min_problem_case_4<'a>(list: &'a mut Map, list2: &'a mut Map) -> u32 {
    exists<'r0> {
        let num: &'r0 mut u32 = &mut 'r0 (*list).value;
        list = &mut 'a *list2;
        num;
        return 0_u32;
    }
}
Proof tree
… (200 of 1518 nodes shown)

Source location: tests/borrowck.rs:4137

#[test]
fn issue_46859_to_refs() {
    // [nll]: rustc passes
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_TO_REFS))
        .skip_execute()
        .ok();

    // [polonius]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_TO_REFS,
    ))
    .skip_execute()
    .ok();

    // [legacy]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_TO_REFS,
    ))
    .skip_execute()
    .ok();
}
Proof tree
… (200 of 2380 nodes shown)

Source location: tests/borrowck.rs:4145

#[test]
fn issue_46859_to_refs() {
    // [nll]: rustc passes
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_TO_REFS))
        .skip_execute()
        .ok();

    // [polonius]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_TO_REFS,
    ))
    .skip_execute()
    .ok();

    // [legacy]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_TO_REFS,
    ))
    .skip_execute()
    .ok();
}
Proof tree
… (200 of 1746 nodes shown)

Source location: tests/borrowck.rs:4153

#[test]
fn issue_46859_to_refs() {
    // [nll]: rustc passes
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_TO_REFS))
        .skip_execute()
        .ok();

    // [polonius]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_TO_REFS,
    ))
    .skip_execute()
    .ok();

    // [legacy]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_TO_REFS,
    ))
    .skip_execute()
    .ok();
}
Proof tree
… (200 of 1733 nodes shown)

Source location: tests/borrowck.rs:4191

#[test]
fn issue_46859_to_refs2() {
    // [nll]: rustc passes.
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_TO_REFS2))
        .skip_execute()
        .ok();

    // [polonius]: rustc passes.
    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_TO_REFS2,
    ))
    .skip_execute()
    .ok();

    // [legacy]: rustc passes.
    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_TO_REFS2,
    ))
    .skip_execute()
    .ok();
}
Proof tree
… (200 of 2658 nodes shown)

Source location: tests/borrowck.rs:4199

#[test]
fn issue_46859_to_refs2() {
    // [nll]: rustc passes.
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_TO_REFS2))
        .skip_execute()
        .ok();

    // [polonius]: rustc passes.
    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_TO_REFS2,
    ))
    .skip_execute()
    .ok();

    // [legacy]: rustc passes.
    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_TO_REFS2,
    ))
    .skip_execute()
    .ok();
}
Proof tree
… (200 of 2034 nodes shown)

Source location: tests/borrowck.rs:4207

#[test]
fn issue_46859_to_refs2() {
    // [nll]: rustc passes.
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_TO_REFS2))
        .skip_execute()
        .ok();

    // [polonius]: rustc passes.
    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_TO_REFS2,
    ))
    .skip_execute()
    .ok();

    // [legacy]: rustc passes.
    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_TO_REFS2,
    ))
    .skip_execute()
    .ok();
}
Proof tree
… (200 of 2021 nodes shown)

Source location: tests/borrowck.rs:4256

#[test]
fn issue_46859_to_refs3() {
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_TO_REFS3))
        .skip_execute()
        .ok();

    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_TO_REFS3,
    ))
    .skip_execute()
    .ok();

    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_TO_REFS3,
    ))
    .skip_execute()
    .ok();
}
Proof tree
… (200 of 2695 nodes shown)

Source location: tests/borrowck.rs:4263

#[test]
fn issue_46859_to_refs3() {
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_TO_REFS3))
        .skip_execute()
        .ok();

    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_TO_REFS3,
    ))
    .skip_execute()
    .ok();

    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_TO_REFS3,
    ))
    .skip_execute()
    .ok();
}
Proof tree
… (200 of 1901 nodes shown)

Source location: tests/borrowck.rs:4270

#[test]
fn issue_46859_to_refs3() {
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_TO_REFS3))
        .skip_execute()
        .ok();

    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_TO_REFS3,
    ))
    .skip_execute()
    .ok();

    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_TO_REFS3,
    ))
    .skip_execute()
    .ok();
}
Proof tree
… (200 of 1888 nodes shown)

Source location: tests/borrowck.rs:4394

#[test]
fn issue_46859_decoder_next() {
    // [nll]: rustc errors
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_DECODER_NEXT))
        .skip_execute()
        .err(expect_test::expect![[r#"
            the rule "fixed-point" at (nll.rs) failed because
              condition evaluated to false: `state0 == state1`
                state0 = flow_state([scope(some(U(1)), None, {}, None, [(d, &!lt_1 mut Decoder)], [d : &!lt_1 mut Decoder]), scope(some(U(1)), None, {}, None, [], []), scope(some(U(3)), None, {}, None, [], []), scope(some(U(3)), Some('l), {}, Some({(* d) . buf_read}), [], [])], point_flow_state({pending_outlives(!lt_1, ?lt_2), pending_outlives(?lt_2, ?lt_3), pending_outlives(?lt_3, !lt_1)}, {}, {}), {}, {}, {pending_outlives(!lt_1, ?lt_2), pending_outlives(?lt_2, ?lt_3), pending_outlives(?lt_3, !lt_1)})
                state1 = flow_state([scope(some(U(1)), None, {}, None, [(d, &!lt_1 mut Decoder)], [d : &!lt_1 mut Decoder]), scope(some(U(1)), None, {}, None, [], []), scope(some(U(3)), None, {}, None, [], []), scope(some(U(3)), Some('l), {}, Some({(* d) . buf_read}), [], [])], point_flow_state({pending_outlives(!lt_1, ?lt_2), pending_outlives(?lt_2, ?lt_3), pending_outlives(?lt_3, !lt_1)}, {loan(?lt_2, *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32, mut)}, {}), {}, {}, {pending_outlives(!lt_1, ?lt_2), pending_outlives(?lt_2, ?lt_3), pending_outlives(?lt_3, !lt_1)})

            the rule "borrow of disjoint places" at (nll.rs) failed because
              condition evaluated to false: `place_disjoint_from_place(&loan.place, &access.place)`
                &loan.place = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32
                &access.place = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32

            the rule "loan_cannot_outlive" at (nll.rs) failed because
              condition evaluated to false: `!outlived_by_loan.contains(&lifetime.upcast())`
                outlived_by_loan = {!lt_1, ?lt_2, ?lt_3}
                &lifetime.upcast() = !lt_1

            the rule "loan_not_required_by_universal_regions" at (nll.rs) failed because
              condition evaluated to false: `outlived_by_loan.iter().all(|p| match p
              {
                  Parameter::Ty(_) => false, Parameter::Lt(lt) => match lt.as_ref()
                  {
                      Lt::Static => false, Lt::Variable(Variable::UniversalVar(_)) => false,
                      Lt::Variable(Variable::ExistentialVar(_)) => true,
                      Lt::Variable(Variable::BoundVar(_)) =>
                      panic!("cannot outlive a bound var"), Lt::Erased => true,
                  }, Parameter::Const(_) => panic!("cannot outlive a constant"),
              })`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `*(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct]`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `d`

            the rule "write-indirect" at (nll.rs) failed because
              condition evaluated to false: `place_accessed.is_prefix_of(place_loaned_ref)`
                place_accessed = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32
                place_loaned_ref = d : &!lt_1 mut Decoder

            the rule "borrow of disjoint places" at (nll.rs) failed because
              condition evaluated to false: `place_disjoint_from_place(&loan.place, &access.place)`
                &loan.place = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32
                &access.place = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32

            the rule "loan_cannot_outlive" at (nll.rs) failed because
              condition evaluated to false: `!outlived_by_loan.contains(&lifetime.upcast())`
                outlived_by_loan = {!lt_1, ?lt_2, ?lt_3}
                &lifetime.upcast() = !lt_1

            the rule "loan_not_required_by_universal_regions" at (nll.rs) failed because
              condition evaluated to false: `outlived_by_loan.iter().all(|p| match p
              {
                  Parameter::Ty(_) => false, Parameter::Lt(lt) => match lt.as_ref()
                  {
                      Lt::Static => false, Lt::Variable(Variable::UniversalVar(_)) => false,
                      Lt::Variable(Variable::ExistentialVar(_)) => true,
                      Lt::Variable(Variable::BoundVar(_)) =>
                      panic!("cannot outlive a bound var"), Lt::Erased => true,
                  }, Parameter::Const(_) => panic!("cannot outlive a constant"),
              })`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `*(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct]`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `d`

            the rule "write-indirect" at (nll.rs) failed because
              condition evaluated to false: `place_accessed.is_prefix_of(place_loaned_ref)`
                place_accessed = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32
                place_loaned_ref = d : &!lt_1 mut Decoder"#]]);

    // [polonius]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_DECODER_NEXT,
    ))
    .skip_execute()
    .ok();

    // [legacy]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_DECODER_NEXT,
    ))
    .skip_execute()
    .ok();
}

Proof trees omitted for the remaining 5 tests.

Source location: tests/borrowck.rs:4402

#[test]
fn issue_46859_decoder_next() {
    // [nll]: rustc errors
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_46859_DECODER_NEXT))
        .skip_execute()
        .err(expect_test::expect![[r#"
            the rule "fixed-point" at (nll.rs) failed because
              condition evaluated to false: `state0 == state1`
                state0 = flow_state([scope(some(U(1)), None, {}, None, [(d, &!lt_1 mut Decoder)], [d : &!lt_1 mut Decoder]), scope(some(U(1)), None, {}, None, [], []), scope(some(U(3)), None, {}, None, [], []), scope(some(U(3)), Some('l), {}, Some({(* d) . buf_read}), [], [])], point_flow_state({pending_outlives(!lt_1, ?lt_2), pending_outlives(?lt_2, ?lt_3), pending_outlives(?lt_3, !lt_1)}, {}, {}), {}, {}, {pending_outlives(!lt_1, ?lt_2), pending_outlives(?lt_2, ?lt_3), pending_outlives(?lt_3, !lt_1)})
                state1 = flow_state([scope(some(U(1)), None, {}, None, [(d, &!lt_1 mut Decoder)], [d : &!lt_1 mut Decoder]), scope(some(U(1)), None, {}, None, [], []), scope(some(U(3)), None, {}, None, [], []), scope(some(U(3)), Some('l), {}, Some({(* d) . buf_read}), [], [])], point_flow_state({pending_outlives(!lt_1, ?lt_2), pending_outlives(?lt_2, ?lt_3), pending_outlives(?lt_3, !lt_1)}, {loan(?lt_2, *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32, mut)}, {}), {}, {}, {pending_outlives(!lt_1, ?lt_2), pending_outlives(?lt_2, ?lt_3), pending_outlives(?lt_3, !lt_1)})

            the rule "borrow of disjoint places" at (nll.rs) failed because
              condition evaluated to false: `place_disjoint_from_place(&loan.place, &access.place)`
                &loan.place = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32
                &access.place = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32

            the rule "loan_cannot_outlive" at (nll.rs) failed because
              condition evaluated to false: `!outlived_by_loan.contains(&lifetime.upcast())`
                outlived_by_loan = {!lt_1, ?lt_2, ?lt_3}
                &lifetime.upcast() = !lt_1

            the rule "loan_not_required_by_universal_regions" at (nll.rs) failed because
              condition evaluated to false: `outlived_by_loan.iter().all(|p| match p
              {
                  Parameter::Ty(_) => false, Parameter::Lt(lt) => match lt.as_ref()
                  {
                      Lt::Static => false, Lt::Variable(Variable::UniversalVar(_)) => false,
                      Lt::Variable(Variable::ExistentialVar(_)) => true,
                      Lt::Variable(Variable::BoundVar(_)) =>
                      panic!("cannot outlive a bound var"), Lt::Erased => true,
                  }, Parameter::Const(_) => panic!("cannot outlive a constant"),
              })`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `*(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct]`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `d`

            the rule "write-indirect" at (nll.rs) failed because
              condition evaluated to false: `place_accessed.is_prefix_of(place_loaned_ref)`
                place_accessed = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32
                place_loaned_ref = d : &!lt_1 mut Decoder

            the rule "borrow of disjoint places" at (nll.rs) failed because
              condition evaluated to false: `place_disjoint_from_place(&loan.place, &access.place)`
                &loan.place = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32
                &access.place = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32

            the rule "loan_cannot_outlive" at (nll.rs) failed because
              condition evaluated to false: `!outlived_by_loan.contains(&lifetime.upcast())`
                outlived_by_loan = {!lt_1, ?lt_2, ?lt_3}
                &lifetime.upcast() = !lt_1

            the rule "loan_not_required_by_universal_regions" at (nll.rs) failed because
              condition evaluated to false: `outlived_by_loan.iter().all(|p| match p
              {
                  Parameter::Ty(_) => false, Parameter::Lt(lt) => match lt.as_ref()
                  {
                      Lt::Static => false, Lt::Variable(Variable::UniversalVar(_)) => false,
                      Lt::Variable(Variable::ExistentialVar(_)) => true,
                      Lt::Variable(Variable::BoundVar(_)) =>
                      panic!("cannot outlive a bound var"), Lt::Erased => true,
                  }, Parameter::Const(_) => panic!("cannot outlive a constant"),
              })`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `*(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct]`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `d`

            the rule "write-indirect" at (nll.rs) failed because
              condition evaluated to false: `place_accessed.is_prefix_of(place_loaned_ref)`
                place_accessed = *(d : &!lt_1 mut Decoder) : <&!lt_1 mut Decoder as Derefable>::Target . buf_read[Decoder , struct] : u32
                place_loaned_ref = d : &!lt_1 mut Decoder"#]]);

    // [polonius]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_46859_DECODER_NEXT,
    ))
    .skip_execute()
    .ok();

    // [legacy]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_46859_DECODER_NEXT,
    ))
    .skip_execute()
    .ok();
}

Source location: tests/borrowck.rs:4536

#[test]
fn issue_92985_filtering_lending_iterator() {
    // [nll]: rustc errors
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_92985_FILTER_NEXT))
        .skip_execute()
        .err(expect_test::expect![[r#"
            the rule "fixed-point" at (nll.rs) failed because
              condition evaluated to false: `state0 == state1`
                state0 = flow_state([scope(some(U(1)), None, {}, None, [(f, &!lt_1 mut Filter)], [f : &!lt_1 mut Filter]), scope(some(U(1)), None, {}, None, [], []), scope(some(U(4)), None, {}, None, [], []), scope(some(U(4)), Some('l), {}, Some({(* f) . iter, (* f) . predicate}), [], [])], point_flow_state({pending_outlives(!lt_1, ?lt_2), pending_outlives(!lt_1, ?lt_3), pending_outlives(?lt_2, !lt_1), pending_outlives(?lt_2, ?lt_4)}, {}, {}), {}, {}, {pending_outlives(!lt_1, ?lt_2), pending_outlives(!lt_1, ?lt_3), pending_outlives(?lt_2, !lt_1), pending_outlives(?lt_2, ?lt_4)})
                state1 = flow_state([scope(some(U(1)), None, {}, None, [(f, &!lt_1 mut Filter)], [f : &!lt_1 mut Filter]), scope(some(U(1)), None, {}, None, [], []), scope(some(U(4)), None, {}, None, [], []), scope(some(U(4)), Some('l), {}, Some({(* f) . iter, (* f) . predicate}), [], [])], point_flow_state({pending_outlives(!lt_1, ?lt_2), pending_outlives(!lt_1, ?lt_3), pending_outlives(?lt_2, !lt_1), pending_outlives(?lt_2, ?lt_4)}, {loan(?lt_2, *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32, mut), loan(?lt_3, *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . predicate[Filter , struct] : u32, mut)}, {}), {labeled_flow_state('l, point_flow_state({pending_outlives(!lt_1, ?lt_2), pending_outlives(!lt_1, ?lt_3), pending_outlives(?lt_2, !lt_1), pending_outlives(?lt_2, ?lt_4)}, {loan(?lt_2, *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32, mut)}, {}))}, {}, {pending_outlives(!lt_1, ?lt_2), pending_outlives(!lt_1, ?lt_3), pending_outlives(?lt_2, !lt_1), pending_outlives(?lt_2, ?lt_4)})

            the rule "borrow of disjoint places" at (nll.rs) failed because
              condition evaluated to false: `place_disjoint_from_place(&loan.place, &access.place)`
                &loan.place = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32
                &access.place = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32

            the rule "loan_cannot_outlive" at (nll.rs) failed because
              condition evaluated to false: `!outlived_by_loan.contains(&lifetime.upcast())`
                outlived_by_loan = {!lt_1, ?lt_2, ?lt_3, ?lt_4}
                &lifetime.upcast() = !lt_1

            the rule "loan_not_required_by_universal_regions" at (nll.rs) failed because
              condition evaluated to false: `outlived_by_loan.iter().all(|p| match p
              {
                  Parameter::Ty(_) => false, Parameter::Lt(lt) => match lt.as_ref()
                  {
                      Lt::Static => false, Lt::Variable(Variable::UniversalVar(_)) => false,
                      Lt::Variable(Variable::ExistentialVar(_)) => true,
                      Lt::Variable(Variable::BoundVar(_)) =>
                      panic!("cannot outlive a bound var"), Lt::Erased => true,
                  }, Parameter::Const(_) => panic!("cannot outlive a constant"),
              })`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `*(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct]`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `f`

            the rule "write-indirect" at (nll.rs) failed because
              condition evaluated to false: `place_accessed.is_prefix_of(place_loaned_ref)`
                place_accessed = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32
                place_loaned_ref = f : &!lt_1 mut Filter

            the rule "borrow of disjoint places" at (nll.rs) failed because
              condition evaluated to false: `place_disjoint_from_place(&loan.place, &access.place)`
                &loan.place = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32
                &access.place = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32

            the rule "loan_cannot_outlive" at (nll.rs) failed because
              condition evaluated to false: `!outlived_by_loan.contains(&lifetime.upcast())`
                outlived_by_loan = {!lt_1, ?lt_2, ?lt_3, ?lt_4}
                &lifetime.upcast() = !lt_1

            the rule "loan_not_required_by_universal_regions" at (nll.rs) failed because
              condition evaluated to false: `outlived_by_loan.iter().all(|p| match p
              {
                  Parameter::Ty(_) => false, Parameter::Lt(lt) => match lt.as_ref()
                  {
                      Lt::Static => false, Lt::Variable(Variable::UniversalVar(_)) => false,
                      Lt::Variable(Variable::ExistentialVar(_)) => true,
                      Lt::Variable(Variable::BoundVar(_)) =>
                      panic!("cannot outlive a bound var"), Lt::Erased => true,
                  }, Parameter::Const(_) => panic!("cannot outlive a constant"),
              })`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `*(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct]`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `f`

            the rule "write-indirect" at (nll.rs) failed because
              condition evaluated to false: `place_accessed.is_prefix_of(place_loaned_ref)`
                place_accessed = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32
                place_loaned_ref = f : &!lt_1 mut Filter"#]]);

    // [polonius]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_92985_FILTER_NEXT,
    ))
    .skip_execute()
    .ok();

    // [legacy]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_92985_FILTER_NEXT,
    ))
    .skip_execute()
    .ok();
}

Source location: tests/borrowck.rs:4544

#[test]
fn issue_92985_filtering_lending_iterator() {
    // [nll]: rustc errors
    FormalityTest::new(feature_gate_program(NLL_GATE, ISSUE_92985_FILTER_NEXT))
        .skip_execute()
        .err(expect_test::expect![[r#"
            the rule "fixed-point" at (nll.rs) failed because
              condition evaluated to false: `state0 == state1`
                state0 = flow_state([scope(some(U(1)), None, {}, None, [(f, &!lt_1 mut Filter)], [f : &!lt_1 mut Filter]), scope(some(U(1)), None, {}, None, [], []), scope(some(U(4)), None, {}, None, [], []), scope(some(U(4)), Some('l), {}, Some({(* f) . iter, (* f) . predicate}), [], [])], point_flow_state({pending_outlives(!lt_1, ?lt_2), pending_outlives(!lt_1, ?lt_3), pending_outlives(?lt_2, !lt_1), pending_outlives(?lt_2, ?lt_4)}, {}, {}), {}, {}, {pending_outlives(!lt_1, ?lt_2), pending_outlives(!lt_1, ?lt_3), pending_outlives(?lt_2, !lt_1), pending_outlives(?lt_2, ?lt_4)})
                state1 = flow_state([scope(some(U(1)), None, {}, None, [(f, &!lt_1 mut Filter)], [f : &!lt_1 mut Filter]), scope(some(U(1)), None, {}, None, [], []), scope(some(U(4)), None, {}, None, [], []), scope(some(U(4)), Some('l), {}, Some({(* f) . iter, (* f) . predicate}), [], [])], point_flow_state({pending_outlives(!lt_1, ?lt_2), pending_outlives(!lt_1, ?lt_3), pending_outlives(?lt_2, !lt_1), pending_outlives(?lt_2, ?lt_4)}, {loan(?lt_2, *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32, mut), loan(?lt_3, *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . predicate[Filter , struct] : u32, mut)}, {}), {labeled_flow_state('l, point_flow_state({pending_outlives(!lt_1, ?lt_2), pending_outlives(!lt_1, ?lt_3), pending_outlives(?lt_2, !lt_1), pending_outlives(?lt_2, ?lt_4)}, {loan(?lt_2, *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32, mut)}, {}))}, {}, {pending_outlives(!lt_1, ?lt_2), pending_outlives(!lt_1, ?lt_3), pending_outlives(?lt_2, !lt_1), pending_outlives(?lt_2, ?lt_4)})

            the rule "borrow of disjoint places" at (nll.rs) failed because
              condition evaluated to false: `place_disjoint_from_place(&loan.place, &access.place)`
                &loan.place = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32
                &access.place = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32

            the rule "loan_cannot_outlive" at (nll.rs) failed because
              condition evaluated to false: `!outlived_by_loan.contains(&lifetime.upcast())`
                outlived_by_loan = {!lt_1, ?lt_2, ?lt_3, ?lt_4}
                &lifetime.upcast() = !lt_1

            the rule "loan_not_required_by_universal_regions" at (nll.rs) failed because
              condition evaluated to false: `outlived_by_loan.iter().all(|p| match p
              {
                  Parameter::Ty(_) => false, Parameter::Lt(lt) => match lt.as_ref()
                  {
                      Lt::Static => false, Lt::Variable(Variable::UniversalVar(_)) => false,
                      Lt::Variable(Variable::ExistentialVar(_)) => true,
                      Lt::Variable(Variable::BoundVar(_)) =>
                      panic!("cannot outlive a bound var"), Lt::Erased => true,
                  }, Parameter::Const(_) => panic!("cannot outlive a constant"),
              })`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `*(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct]`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `f`

            the rule "write-indirect" at (nll.rs) failed because
              condition evaluated to false: `place_accessed.is_prefix_of(place_loaned_ref)`
                place_accessed = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32
                place_loaned_ref = f : &!lt_1 mut Filter

            the rule "borrow of disjoint places" at (nll.rs) failed because
              condition evaluated to false: `place_disjoint_from_place(&loan.place, &access.place)`
                &loan.place = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32
                &access.place = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32

            the rule "loan_cannot_outlive" at (nll.rs) failed because
              condition evaluated to false: `!outlived_by_loan.contains(&lifetime.upcast())`
                outlived_by_loan = {!lt_1, ?lt_2, ?lt_3, ?lt_4}
                &lifetime.upcast() = !lt_1

            the rule "loan_not_required_by_universal_regions" at (nll.rs) failed because
              condition evaluated to false: `outlived_by_loan.iter().all(|p| match p
              {
                  Parameter::Ty(_) => false, Parameter::Lt(lt) => match lt.as_ref()
                  {
                      Lt::Static => false, Lt::Variable(Variable::UniversalVar(_)) => false,
                      Lt::Variable(Variable::ExistentialVar(_)) => true,
                      Lt::Variable(Variable::BoundVar(_)) =>
                      panic!("cannot outlive a bound var"), Lt::Erased => true,
                  }, Parameter::Const(_) => panic!("cannot outlive a constant"),
              })`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `*(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct]`

            the rule "write-indirect" at (nll.rs) failed because
              pattern `TypedPlaceExpressionData::Deref(place_loaned_ref)` did not match value `f`

            the rule "write-indirect" at (nll.rs) failed because
              condition evaluated to false: `place_accessed.is_prefix_of(place_loaned_ref)`
                place_accessed = *(f : &!lt_1 mut Filter) : <&!lt_1 mut Filter as Derefable>::Target . iter[Filter , struct] : u32
                place_loaned_ref = f : &!lt_1 mut Filter"#]]);

    // [polonius]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_ALPHA_GATE,
        ISSUE_92985_FILTER_NEXT,
    ))
    .skip_execute()
    .ok();

    // [legacy]: rustc passes
    FormalityTest::new(feature_gate_program(
        POLONIUS_UNLOCKED_GATE,
        ISSUE_92985_FILTER_NEXT,
    ))
    .skip_execute()
    .ok();
}

Source location: tests/mir_typeck.rs:857

fn foo<'a>(v1: &'a Pair) -> u32 {
    exists<'r0> {
        let v2: u32 = (*v1).value;
        return v2;
    }
}