rustc_next_trait_solver::coherence

Struct OrphanChecker

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struct OrphanChecker<'a, Infcx, I: Interner, F> {
    infcx: &'a Infcx,
    in_crate: InCrate,
    in_self_ty: bool,
    lazily_normalize_ty: F,
    search_first_local_ty: bool,
    non_local_tys: Vec<(I::Ty, IsFirstInputType)>,
}

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§infcx: &'a Infcx§in_crate: InCrate§in_self_ty: bool§lazily_normalize_ty: F§search_first_local_ty: bool

Ignore orphan check failures and exclusively search for the first local type.

§non_local_tys: Vec<(I::Ty, IsFirstInputType)>

Implementations§

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impl<'a, Infcx, I, F, E> OrphanChecker<'a, Infcx, I, F>
where Infcx: InferCtxtLike<Interner = I>, I: Interner, F: FnOnce(I::Ty) -> Result<I::Ty, E>,

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fn new(infcx: &'a Infcx, in_crate: InCrate, lazily_normalize_ty: F) -> Self

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fn found_non_local_ty( &mut self, t: I::Ty, ) -> ControlFlow<OrphanCheckEarlyExit<I, E>>

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fn found_uncovered_ty_param( &mut self, ty: I::Ty, ) -> ControlFlow<OrphanCheckEarlyExit<I, E>>

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fn def_id_is_local(&mut self, def_id: I::DefId) -> bool

Trait Implementations§

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impl<'a, Infcx, I, F, E> TypeVisitor<I> for OrphanChecker<'a, Infcx, I, F>
where Infcx: InferCtxtLike<Interner = I>, I: Interner, F: FnMut(I::Ty) -> Result<I::Ty, E>,

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fn visit_const(&mut self, _c: I::Const) -> Self::Result

All possible values for a constant parameter already exist in the crate defining the trait, so they are always non-local1.

Because there’s no way to have an impl where the first local generic argument is a constant, we also don’t have to fail the orphan check when encountering a parameter or a generic constant.

This means that we can completely ignore constants during the orphan check.

See tests/ui/coherence/const-generics-orphan-check-ok.rs for examples.


  1. This might not hold for function pointers or trait objects in the future. As these should be quite rare as const arguments and especially rare as impl parameters, allowing uncovered const parameters in impls seems more useful than allowing impl<T> Trait<local_fn_ptr, T> for i32 to compile. 

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type Result = ControlFlow<OrphanCheckEarlyExit<I, E>>

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fn visit_region(&mut self, _r: I::Region) -> Self::Result

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fn visit_ty(&mut self, ty: I::Ty) -> Self::Result

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fn visit_binder<T>(&mut self, t: &Binder<I, T>) -> Self::Result
where T: TypeVisitable<I>,

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fn visit_predicate(&mut self, p: <I as Interner>::Predicate) -> Self::Result

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fn visit_clauses(&mut self, p: <I as Interner>::Clauses) -> Self::Result

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fn visit_error( &mut self, _guar: <I as Interner>::ErrorGuaranteed, ) -> Self::Result

Auto Trait Implementations§

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impl<'a, Infcx, I, F> Freeze for OrphanChecker<'a, Infcx, I, F>
where F: Freeze,

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impl<'a, Infcx, I, F> RefUnwindSafe for OrphanChecker<'a, Infcx, I, F>

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impl<'a, Infcx, I, F> Send for OrphanChecker<'a, Infcx, I, F>
where F: Send, Infcx: Sync, <I as Interner>::Ty: Send,

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impl<'a, Infcx, I, F> Sync for OrphanChecker<'a, Infcx, I, F>
where F: Sync, Infcx: Sync, <I as Interner>::Ty: Sync,

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impl<'a, Infcx, I, F> Unpin for OrphanChecker<'a, Infcx, I, F>
where F: Unpin, <I as Interner>::Ty: Unpin,

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impl<'a, Infcx, I, F> UnwindSafe for OrphanChecker<'a, Infcx, I, F>
where F: UnwindSafe, Infcx: RefUnwindSafe, <I as Interner>::Ty: UnwindSafe,

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> 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<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<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. 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, 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<I, T, U> Upcast<I, U> for T
where U: UpcastFrom<I, T>,

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fn upcast(self, interner: I) -> U

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impl<I, T> UpcastFrom<I, T> for T

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fn upcast_from(from: T, _tcx: I) -> 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,

Layout§

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.