Enum rustc_infer::infer::region_constraints::VerifyBound [−][src]
Describes the things that some GenericKind
value G
is known to
outlive. Each variant of VerifyBound
can be thought of as a
function:
fn(min: Region) -> bool { .. }
where true
means that the region min
meets that G: min
.
(False means nothing.)
So, for example, if we have the type T
and we have in scope that
T: 'a
and T: 'b
, then the verify bound might be:
fn(min: Region) -> bool { ('a: min) || ('b: min) }
This is described with a AnyRegion('a, 'b)
node.
Variants
IfEq(Ty<'tcx>, Box<VerifyBound<'tcx>>)
Given a kind K and a bound B, expands to a function like the
following, where G
is the generic for which this verify
bound was created:
fn(min) -> bool { if G == K { B(min) } else { false } }
In other words, if the generic G
that we are checking is
equal to K
, then check the associated verify bound
(otherwise, false).
This is used when we have something in the environment that
may or may not be relevant, depending on the region inference
results. For example, we may have where <T as Trait<'a>>::Item: 'b
in our where-clauses. If we are
generating the verify-bound for <T as Trait<'0>>::Item
, then
this where-clause is only relevant if '0
winds up inferred
to 'a
.
So we would compile to a verify-bound like
IfEq(<T as Trait<'a>>::Item, AnyRegion('a))
meaning, if the subject G is equal to <T as Trait<'a>>::Item
(after inference), and 'a: min
, then G: min
.
OutlivedBy(Region<'tcx>)
Given a region R
, expands to the function:
fn(min) -> bool { R: min }
This is used when we can establish that G: R
– therefore,
if R: min
, then by transitivity G: min
.
Given a region R
, true if it is 'empty
.
AnyBound(Vec<VerifyBound<'tcx>>)
Given a set of bounds B
, expands to the function:
fn(min) -> bool { exists (b in B) { b(min) } }
In other words, if we meet some bound in B
, that suffices.
This is used when all the bounds in B
are known to apply to G
.
AllBounds(Vec<VerifyBound<'tcx>>)
Given a set of bounds B
, expands to the function:
fn(min) -> bool { forall (b in B) { b(min) } }
In other words, if we meet all bounds in B
, that suffices.
This is used when some bound in B
is known to suffice, but
we don’t know which.
Implementations
impl<'tcx> VerifyBound<'tcx>
[src]
pub fn must_hold(&self) -> bool
[src]
pub fn cannot_hold(&self) -> bool
[src]
pub fn or(self, vb: VerifyBound<'tcx>) -> VerifyBound<'tcx>
[src]
pub fn and(self, vb: VerifyBound<'tcx>) -> VerifyBound<'tcx>
[src]
Trait Implementations
impl<'tcx> Clone for VerifyBound<'tcx>
[src]
fn clone(&self) -> VerifyBound<'tcx>
[src]
pub fn clone_from(&mut self, source: &Self)
1.0.0[src]
impl<'tcx> Debug for VerifyBound<'tcx>
[src]
Auto Trait Implementations
impl<'tcx> !RefUnwindSafe for VerifyBound<'tcx>
impl<'tcx> !Send for VerifyBound<'tcx>
impl<'tcx> !Sync for VerifyBound<'tcx>
impl<'tcx> Unpin for VerifyBound<'tcx>
impl<'tcx> !UnwindSafe for VerifyBound<'tcx>
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
[src]
impl<'a, T> Captures<'a> for T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> From<T> for T
[src]
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T> ToOwned for T where
T: Clone,
[src]
T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
[src]
pub fn clone_into(&self, target: &mut T)
[src]
impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
[src]
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.