pub enum InhabitedPredicate<'tcx> {
    True,
    False,
    ConstIsZero(Const<'tcx>),
    NotInModule(DefId),
    GenericType(Ty<'tcx>),
    OpaqueType(OpaqueTypeKey<'tcx>),
    And(&'tcx [InhabitedPredicate<'tcx>; 2]),
    Or(&'tcx [InhabitedPredicate<'tcx>; 2]),
}
Expand description

Represents whether some type is inhabited in a given context. Examples of uninhabited types are !, enum Void {}, or a struct containing either of those types. A type’s inhabitedness may depend on the ParamEnv as well as what types are visible in the current module.

Variants§

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True

Inhabited

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False

Uninhabited

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ConstIsZero(Const<'tcx>)

Uninhabited when a const value is non-zero. This occurs when there is an array of uninhabited items, but the array is inhabited if it is empty.

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NotInModule(DefId)

Uninhabited if within a certain module. This occurs when an uninhabited type has restricted visibility.

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GenericType(Ty<'tcx>)

Inhabited if some generic type is inhabited. These are replaced by calling Self::instantiate.

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OpaqueType(OpaqueTypeKey<'tcx>)

Inhabited if either we don’t know the hidden type or we know it and it is inhabited.

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And(&'tcx [InhabitedPredicate<'tcx>; 2])

A AND B

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Or(&'tcx [InhabitedPredicate<'tcx>; 2])

A OR B

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impl<'tcx> InhabitedPredicate<'tcx>

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pub fn apply( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, module_def_id: DefId ) -> bool

Returns true if the corresponding type is inhabited in the given ParamEnv and module.

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pub fn apply_revealing_opaque( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, module_def_id: DefId, reveal_opaque: &impl Fn(OpaqueTypeKey<'tcx>) -> Option<Ty<'tcx>> ) -> bool

Returns true if the corresponding type is inhabited in the given ParamEnv and module, revealing opaques when possible.

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pub fn apply_any_module( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx> ) -> Option<bool>

Same as apply, but returns None if self contains a module predicate

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pub fn apply_ignore_module( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx> ) -> bool

Same as apply, but NotInModule(_) predicates yield false. That is, privately uninhabited types are considered always uninhabited.

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fn apply_inner<E: Debug>( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, eval_stack: &mut SmallVec<[Ty<'tcx>; 1]>, in_module: &impl Fn(DefId) -> Result<bool, E>, reveal_opaque: &impl Fn(OpaqueTypeKey<'tcx>) -> Option<Ty<'tcx>> ) -> Result<bool, E>

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pub fn and(self, tcx: TyCtxt<'tcx>, other: Self) -> Self

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pub fn or(self, tcx: TyCtxt<'tcx>, other: Self) -> Self

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pub fn all(tcx: TyCtxt<'tcx>, iter: impl IntoIterator<Item = Self>) -> Self

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pub fn any(tcx: TyCtxt<'tcx>, iter: impl IntoIterator<Item = Self>) -> Self

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fn reduce_and(self, tcx: TyCtxt<'tcx>, other: Self) -> Option<Self>

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fn reduce_or(self, tcx: TyCtxt<'tcx>, other: Self) -> Option<Self>

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pub fn instantiate(self, tcx: TyCtxt<'tcx>, args: GenericArgsRef<'tcx>) -> Self

Replaces generic types with its corresponding predicate

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fn instantiate_opt( self, tcx: TyCtxt<'tcx>, args: GenericArgsRef<'tcx> ) -> Option<Self>

Trait Implementations§

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impl<'tcx> Clone for InhabitedPredicate<'tcx>

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fn clone(&self) -> InhabitedPredicate<'tcx>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<'tcx> Debug for InhabitedPredicate<'tcx>

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl<'tcx> EraseType for InhabitedPredicate<'tcx>

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type Result = [u8; 16]

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impl<'tcx, '__ctx> HashStable<StableHashingContext<'__ctx>> for InhabitedPredicate<'tcx>

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fn hash_stable( &self, __hcx: &mut StableHashingContext<'__ctx>, __hasher: &mut StableHasher )

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impl<'tcx> PartialEq for InhabitedPredicate<'tcx>

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fn eq(&self, other: &InhabitedPredicate<'tcx>) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<'tcx> Copy for InhabitedPredicate<'tcx>

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impl<'tcx> StructuralPartialEq for InhabitedPredicate<'tcx>

Auto Trait Implementations§

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impl<'tcx> DynSend for InhabitedPredicate<'tcx>

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impl<'tcx> DynSync for InhabitedPredicate<'tcx>

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impl<'tcx> !RefUnwindSafe for InhabitedPredicate<'tcx>

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impl<'tcx> Send for InhabitedPredicate<'tcx>

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impl<'tcx> Sync for InhabitedPredicate<'tcx>

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impl<'tcx> Unpin for InhabitedPredicate<'tcx>

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impl<'tcx> !UnwindSafe for InhabitedPredicate<'tcx>

Blanket Implementations§

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impl<T> Aligned for T

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const ALIGN: Alignment = _

Alignment of Self.
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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> AnyEq for T
where T: Any + PartialEq,

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fn equals(&self, other: &(dyn Any + 'static)) -> bool

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fn as_any(&self) -> &(dyn Any + 'static)

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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T
where T: Copy,

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T

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fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T> ) -> &'a mut [T]

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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T
where T: Copy,

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T

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fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T> ) -> &'a mut [T]

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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, R> CollectAndApply<T, R> for T

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fn collect_and_apply<I, F>(iter: I, f: F) -> R
where I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

Equivalent to f(&iter.collect::<Vec<_>>()).

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type Output = R

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impl<Tcx, T> DepNodeParams<Tcx> for T
where Tcx: DepContext, T: for<'a> HashStable<StableHashingContext<'a>> + Debug,

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default fn fingerprint_style() -> FingerprintStyle

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default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint

This method turns the parameters of a DepNodeConstructor into an opaque Fingerprint to be used in DepNode. Not all DepNodeParams support being turned into a Fingerprint (they don’t need to if the corresponding DepNode is anonymous).
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default fn to_debug_str(&self, _: Tcx) -> String

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default fn recover(_: Tcx, _: &DepNode) -> Option<T>

This method tries to recover the query key from the given DepNode, something which is needed when forcing DepNodes during red-green evaluation. The query system will only call this method if fingerprint_style() is not FingerprintStyle::Opaque. It is always valid to return None here, in which case incremental compilation will treat the query as having changed instead of forcing it.
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impl<T> Filterable for T

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fn filterable( self, filter_name: &'static str ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

Creates a filterable data provider with the given name for debugging. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<P> IntoQueryParam<P> for P

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impl<T> MaybeResult<T> for T

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type Error = !

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fn from(_: Result<T, <T as MaybeResult<T>>::Error>) -> T

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fn to_result(self) -> Result<T, <T as MaybeResult<T>>::Error>

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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<'tcx, T> ToPredicate<'tcx, T> for T

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fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<Tcx, T> Value<Tcx> for T
where Tcx: DepContext,

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default fn from_cycle_error( tcx: Tcx, cycle_error: &CycleError, _guar: ErrorGuaranteed ) -> T

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
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impl<'a, T> Captures<'a> for T
where T: ?Sized,

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impl<T> ErasedDestructor for T
where T: 'static,

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impl<T> MaybeSendSync for T
where T: Send + Sync,

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Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 16 bytes

Size for each variant:

  • True: 0 bytes
  • False: 0 bytes
  • ConstIsZero: 8 bytes
  • NotInModule: 8 bytes
  • GenericType: 8 bytes
  • OpaqueType: 16 bytes
  • And: 8 bytes
  • Or: 8 bytes