Negative coverage: access_permitted_by_loan / write-indirect / premise if let TypedPlaceExpressionData::Deref(place_loaned_ref) = place_loaned.data()

Premise at line 947. Observed failure causes: if_let.

24 tests failed proving this premise:

Source location: src/test_util.rs:516 (all coverage from this test)

#[test]
fn rustc_expectation_is_independent_of_borrowck_modes() {
    let before = rustc_runs();
    FormalityTest::new(NLL_ONLY_ERROR)
        .rustc_err(expect_test::expect![[r#"
            error[E0499]: cannot borrow `*m` as mutable more than once at a time
             --> lib.rs
              |
            3 | pub fn foo<'a00>(mut m: &'a00 mut Map) -> &'a00 mut Map {
              |            ---- lifetime `'a00` defined here
            4 |     {
            5 |         let mut n: &'_ mut Map = &mut *m;
              |                                  ------- first mutable borrow occurs here
            6 |         if false {
            7 |             return n;
              |                    - returning this value requires that `*m` is borrowed for `'a00`
            8 |         } else {
            9 |             let mut o: &'_ mut Map = &mut *m;
              |                                      ^^^^^^^ second mutable borrow occurs here

            For more information about this error, try `rustc --explain E0499`.
            error: could not compile `Foo` (lib) due to 1 previous error
        "#]])
        .borrowck_err(BorrowCheckFailure::Nll, expect_test::expect![[r#"
            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 = *(m : &!lt_1 mut Map) : <&!lt_1 mut Map as Derefable>::Target
                &access.place = *(m : &!lt_1 mut Map) : <&!lt_1 mut Map as Derefable>::Target

            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 `m`

            the rule "write-indirect" at (nll.rs) failed because
              condition evaluated to false: `place_accessed.is_prefix_of(place_loaned_ref)`
                place_accessed = *(m : &!lt_1 mut Map) : <&!lt_1 mut Map as Derefable>::Target
                place_loaned_ref = m : &!lt_1 mut Map"#]]);
    assert_eq!(rustc_runs() - before, 1);
}

Source location: tests/borrowck.rs:2347 (all coverage from this test)

fn foo() -> i32 {
    exists<'r0, 'r1> {
        let v1: i32 = 0_i32;
        let v2: &'r0 mut i32 = &'r1 mut v1;
        // This should result in an error
        v1 = 1_i32;
        return *v2;
    }
}

Source location: tests/borrowck.rs:2385 (all coverage from this test)

fn foo() -> i32 {
    exists<'r0, 'r1> {
        let v1: i32 = 0_i32;
        let v2: &'r0 i32 = &'r1 v1;
        v1 = 1_i32;
        return *v2;
    }
}

Source location: tests/borrowck.rs:2419 (all coverage from this test)

fn foo() -> i32 {
    exists<'r> {
        let v3: i32 = 0_i32;
        let v4: &'r i32 = &'r v3;
    }
    exists<'r0, 'r1> {
        let v1: i32 = 0_i32;
        let v2: &'r0 i32 = &'r1 v1;
        v1 = 1_i32;
        return *v2;
    }
}

Source location: tests/borrowck.rs:2470 (all coverage from this test)

fn min_problem_case_3<'a>(m: &'a mut Map) -> &'a mut Map {
    exists<'r0, 'r1> {
        let n: &'r0 mut Map = &'r0 mut *m;
        if true {
            return n;
        } else {
            let o: &'r1 mut Map = &'r1 mut *m;
            return o;
        }
    }
}

Source location: tests/borrowck.rs:2531 (all coverage from this test)

fn foo() -> i32 {
    exists<'r0, 'r1> {
        let v2: &'r0 i32;
        {
            let v1: i32 = 0_i32;
            v2 = &'r1 v1;
        }
        return *v2;
    }
}

Source location: tests/borrowck.rs:2603 (all coverage from this test)

fn foo() -> i32 {
    exists<'r0, 'r1> {
        let v2: &'r0 mut i32;
        {
            let v1: i32 = 0_i32;
            v2 = &'r1 mut v1;
        }
        return *v2;
    }
}

Source location: tests/borrowck.rs:2645 (all coverage from this test)

fn foo() -> i32 {
    exists<'r0, 'r1> {
        let v2: &'r0 i32;
        'a: {
            let v1: i32 = 0_i32;
            v2 = &'r1 v1;
            break 'a;
        }
        return *v2;
    }
}

Source location: tests/borrowck.rs:2983 (all coverage from this test)

fn foo() -> i32 {
    exists<'r0, 'r1> {
        let r: &'r0 i32;
        'a: loop {
            let y: i32 = 0_i32;
            r = &'r1 y;
            continue 'a;
        }
        r; // only an error because of false edges, assumption that all loops terminate
    }
}

Source location: tests/borrowck.rs:3100 (all coverage from this test)

fn foo() -> i32 {
    exists<'r0, 'r1> {
        let r: &'r0 i32;
        'a: loop {
            let x: i32 = 0_i32;
            r = &'r1 x;
            break 'a;
        }
        return *r;
    }
}

Source location: tests/borrowck.rs:3227 (all coverage from this test)

fn foo() -> u32 {
    exists<'r0, 'r1> {
        let a: u32 = 22_u32;
        let p: &'r0 u32 = &'r1 a;
        'l: loop {
            if true {
                a = 23_u32;
                continue 'l;
            } else {
                break 'l;
            }
        }
        return *p;
    }
}

Proof trees omitted for the remaining 14 tests; each one is on its test’s page in Coverage by test.

Source location: tests/borrowck.rs:3288 (all coverage from this test)

fn foo<'a>(m: &'a mut Map) -> &'a mut Map {
    exists<'r0, 'r1> {
        let n: &'r0 mut Map = &'r0 mut *m;
        if false {
            return n;
        } else {
            let o: &'r1 mut Map = &'r1 mut *m;
            return o;
        }
    }
}

Source location: tests/borrowck.rs:3352 (all coverage from this test)

fn foo() -> u32 {
    exists<'r0, 'r1, 'r2> {
        let a: u32 = 22_u32;
        let b: u32 = 22_u32;
        let p: &'r0 u32 = &'r1 a;
        a = 23_u32;
        'l: loop {
            p = &'r2 b;
            break 'l;
        }
        return *p;
    }
}

Source location: tests/borrowck.rs:3536 (all coverage from this test)

fn bar() -> u32 {
    exists<'r0, 'r1, 'r2> {
        let v: u32 = 0_u32;
        let p: &'r0 u32 = &'r1 v;
        let _: u32 = foo::<'r2>(&'r2 mut v);
        return *p;
    }
}

Source location: tests/borrowck.rs:3584 (all coverage from this test)

fn foo() -> u32 {
    exists<'r0, 'r1> {
        let p: Point = Point { x: 0_u32, y: 0_u32 };
        let b1: &'r0 mut u32 = &'r1 mut p.x;
        p.x = 1_u32;
        return *b1;
    }
}

Source location: tests/borrowck.rs:3658 (all coverage from this test)

fn foo() -> u32 {
    exists<'r0> {
        let v1: u32 = 0_u32;
        let w: Wrapper<'r0> = Wrapper::<'r0> { value: &'r0 mut v1 };
        v1 = 1_u32;
        return *(w.value);
    }
}

Source location: tests/borrowck.rs:3715 (all coverage from this test)

fn reborrow<'a>(a: &'a mut u8) -> &'a mut u8 {
    exists<'r0, 'r1, 'r2, 'r3> {
        // This creates an outlives constraint
        let b: &'r1 mut u8 = &'r0 mut *a;
        if true {
            return b;
        } else {
            // this means the loan remains live
        }

        // If the outlives constraint propagated here,
        // we would get an error.
        let c: &'r3 mut u8 = &'r2 mut *a;
        return c;
    }
}

Source location: tests/borrowck.rs:3813 (all coverage from this test)

fn foo() -> u32 {
    exists<'r0, 'r1, 'r2> {
        let x: u32 = 22_u32;
        let p: &'r1 u32 = &'r0 x;
        let q: &'r2 u32 = p;
        x = 1_u32;
        q;
        return 0_u32;
    }
}

Source location: tests/borrowck.rs:4007 (all coverage from this test)

fn foo() -> u32 {
    exists<'r0, 'r1> {
        let x: u32 = 22_u32;
        let helper: &'r1 u32 = &'r0 x;
        x = 1_u32;
        helper;
        return 0_u32;
    }
}

Source location: tests/borrowck.rs:4214 (all coverage from this test)

fn remove_last_node_iterative<'a>(node: &'a mut List) -> u32 {
    exists<'r0, 'r1> {
        let cursor: &'r0 mut List = &'r0 mut *node;
        'l: loop {
            let next: &'r1 mut List = &'r1 mut *cursor;
            if true {
                cursor = next;
            } else {
                break 'l;
            }
        }
        *cursor = List { value: 0_u32 };
        return 0_u32;
    }
}

Source location: tests/borrowck.rs:4326 (all coverage from this test)

fn conditional() -> u32 {
    exists<'r0, 'r1, 'r2, 'r3> {
        let b: X = X { value: 0_u32 };
        let p: &'r0 mut X = &'r1 mut b;
        'l: loop {
            let now: &'r2 mut X = &'r2 mut *p;
            if true {
                if true {
                    let next: &'r3 mut X = next_of::<'r3>(&'r3 mut *now);
                    p = next;
                } else {
                }
            } else {
                break 'l;
            }
        }
        return 0_u32;
    }
}

Source location: tests/borrowck.rs:4592 (all coverage from this test)

fn next<'a>(d: &'a mut Decoder) -> &'a u32 {
    exists<'r0, 'r1> {
        'l: loop {
            let buf: &'r0 u32 = fill_buf::<'r0>(&'r0 mut (*d).buf_read);
            let s: &'r1 u32 = decode::<'r1>(buf);
            if true {
                return s;
            } else {
            }
        }
    }
}

Source location: tests/borrowck.rs:4715 (all coverage from this test)

fn next<'s>(f: &'s mut Filter) -> &'s mut u32 {
    exists<'r0, 'r1, 'r2> {
        'l: loop {
            let item: &'r0 mut u32 = iter_next::<'r0>(&'r0 mut (*f).iter);
            if true {
                let keep: bool = call_predicate::<'r1, 'r2>(&'r1 mut (*f).predicate, &'r2 *item);
                if keep {
                    return item;
                } else {
                }
            } else {
                break 'l;
            }
        }
        return no_item::<'s>();
    }
}

Source location: tests/borrowck.rs:5052 (all coverage from this test)

fn foo() -> () {
    let x: u32 = 1_u32;
    exists<'r0> {
        let r: &'r0 u32 = &'r0 x;
        x += 1_u32;
        let y: u32 = *r;
    }
}

How to read this page