Struct rustc_middle::infer::canonical::Canonical

pub struct Canonical<'tcx, V> {
    pub max_universe: UniverseIndex,
    pub variables: CanonicalVarInfos<'tcx>,
    pub value: V,
}

A “canonicalized” type V is one where all free inference variables have been rewritten to “canonical vars”. These are numbered starting from 0 in order of first appearance.

Fields

max_universe: UniverseIndex

variables: CanonicalVarInfos<'tcx>

value: V

Implementations

impl<'tcx, R> Canonical<'tcx, QueryResponse<'tcx, R>>

pub fn is_proven(&self) -> bool

pub fn is_ambiguous(&self) -> bool

impl<'tcx, R> Canonical<'tcx, ParamEnvAnd<'tcx, R>>

pub fn without_const(self) -> Self

impl<'tcx, V> Canonical<'tcx, V>

pub fn unchecked_map<W>(self, map_op: impl FnOnce(V) -> W) -> Canonical<'tcx, W>

Allows you to map the value of a canonical while keeping the same set of bound variables.

WARNING: This function is very easy to mis-use, hence the name! In particular, the new value W must use all the same type/region variables in precisely the same order as the original! (The ordering is defined by the TypeFoldable implementation of the type in question.)

An example of a correct use of this:

let a: Canonical<'_, T> = ...;
let b: Canonical<'_, (T,)> = a.unchecked_map(|v| (v, ));

An example of an incorrect use of this:

let a: Canonical<'tcx, T> = ...;
let ty: Ty<'tcx> = ...;
let b: Canonical<'tcx, (T, Ty<'tcx>)> = a.unchecked_map(|v| (v, ty));

impl<'tcx> Canonical<'tcx, UserType<'tcx>>

pub fn is_identity(&self) -> bool

Returns true if this represents a substitution of the form [?0, ?1, ?2], i.e., each thing is mapped to a canonical variable with the same index.

Trait Implementations

impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for Canonical<'tcx, QueryResponse<'tcx, ()>>

fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

fn allocate_from_iter<'a>(
    arena: &'a Arena<'tcx>,
    iter: impl IntoIterator<Item = Self>
) -> &'a mut [Self]

impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for Canonical<'tcx, QueryResponse<'tcx, DropckOutlivesResult<'tcx>>>

fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

fn allocate_from_iter<'a>(
    arena: &'a Arena<'tcx>,
    iter: impl IntoIterator<Item = Self>
) -> &'a mut [Self]

impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for Canonical<'tcx, QueryResponse<'tcx, FnSig<'tcx>>>

fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

fn allocate_from_iter<'a>(
    arena: &'a Arena<'tcx>,
    iter: impl IntoIterator<Item = Self>
) -> &'a mut [Self]

impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for Canonical<'tcx, QueryResponse<'tcx, NormalizationResult<'tcx>>>

fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

fn allocate_from_iter<'a>(
    arena: &'a Arena<'tcx>,
    iter: impl IntoIterator<Item = Self>
) -> &'a mut [Self]

impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for Canonical<'tcx, QueryResponse<'tcx, PolyFnSig<'tcx>>>

fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

fn allocate_from_iter<'a>(
    arena: &'a Arena<'tcx>,
    iter: impl IntoIterator<Item = Self>
) -> &'a mut [Self]

impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for Canonical<'tcx, QueryResponse<'tcx, Predicate<'tcx>>>

fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

fn allocate_from_iter<'a>(
    arena: &'a Arena<'tcx>,
    iter: impl IntoIterator<Item = Self>
) -> &'a mut [Self]

impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for Canonical<'tcx, QueryResponse<'tcx, Ty<'tcx>>>

fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

fn allocate_from_iter<'a>(
    arena: &'a Arena<'tcx>,
    iter: impl IntoIterator<Item = Self>
) -> &'a mut [Self]

impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for Canonical<'tcx, QueryResponse<'tcx, Vec<OutlivesBound<'tcx>>>>

fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

fn allocate_from_iter<'a>(
    arena: &'a Arena<'tcx>,
    iter: impl IntoIterator<Item = Self>
) -> &'a mut [Self]

impl<'tcx, V: Clone> Clone for Canonical<'tcx, V>

fn clone(&self) -> Canonical<'tcx, V>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'tcx, V: Debug> Debug for Canonical<'tcx, V>

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

Formats the value using the given formatter.

impl<'tcx, V, __D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<__D> for Canonical<'tcx, V>where
    V: Decodable<__D>,

fn decode(__decoder: &mut __D) -> Self

impl<'tcx, V, __E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<__E> for Canonical<'tcx, V>where
    V: Encodable<__E>,

fn encode(&self, __encoder: &mut __E)

impl<'tcx, V: Hash> Hash for Canonical<'tcx, V>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,
    Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'tcx, '__ctx, V> HashStable<StableHashingContext<'__ctx>> for Canonical<'tcx, V>where
    V: HashStable<StableHashingContext<'__ctx>>,

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

impl<'tcx, T> Key for Canonical<'tcx, T>

Canonical query goals correspond to abstract trait operations that are not tied to any crate in particular.

fn query_crate_is_local(&self) -> bool

Given an instance of this key, what crate is it referring to? This is used to find the provider.

fn default_span(&self, _tcx: TyCtxt<'_>) -> Span

In the event that a cycle occurs, if no explicit span has been given for a query with key self, what span should we use?

type CacheSelector = DefaultCacheSelector<Self>

fn key_as_def_id(&self) -> Option<DefId>

If the key is a DefId or DefId–equivalent, return that DefId. Otherwise, return None.

fn ty_adt_id(&self) -> Option<DefId>

impl<'tcx, '__lifted, V> Lift<'__lifted> for Canonical<'tcx, V>where
    V: Lift<'__lifted>,

type Lifted = Canonical<'__lifted, <V as Lift<'__lifted>>::Lifted>

fn lift_to_tcx(
    self,
    __tcx: TyCtxt<'__lifted>
) -> Option<Canonical<'__lifted, V::Lifted>>

impl<'tcx, V: PartialEq> PartialEq<Canonical<'tcx, V>> for Canonical<'tcx, V>

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

This method tests for self and other values to be equal, and is used by ==.

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.

impl<'tcx, V> TypeFoldable<'tcx> for Canonical<'tcx, V>where
    V: TypeFoldable<'tcx>,

fn try_fold_with<__F: FallibleTypeFolder<'tcx>>(
    self,
    __folder: &mut __F
) -> Result<Self, __F::Error>

The entry point for folding. To fold a value t with a folder f call: t.try_fold_with(f).

fn fold_with<F: TypeFolder<'tcx>>(self, folder: &mut F) -> Self

A convenient alternative to try_fold_with for use with infallible folders. Do not override this method, to ensure coherence with try_fold_with.

impl<'tcx, V> TypeVisitable<'tcx> for Canonical<'tcx, V>where
    V: TypeVisitable<'tcx>,

fn visit_with<__V: TypeVisitor<'tcx>>(
    &self,
    __visitor: &mut __V
) -> ControlFlow<__V::BreakTy>

The entry point for visiting. To visit a value t with a visitor v call: t.visit_with(v).

fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool

Returns true if self has any late-bound regions that are either bound by binder or bound by some binder outside of binder. If binder is ty::INNERMOST, this indicates whether there are any late-bound regions that appear free.

fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool

Returns true if this type has any regions that escape binder (and hence are not bound by it).

fn has_escaping_bound_vars(&self) -> bool

Return true if this type has regions that are not a part of the type. For example, for<'a> fn(&'a i32) return false, while fn(&'a i32) would return true. The latter can occur when traversing through the former.

fn has_type_flags(&self, flags: TypeFlags) -> bool

fn has_projections(&self) -> bool

fn has_opaque_types(&self) -> bool

fn references_error(&self) -> bool

fn error_reported(&self) -> Result<(), ErrorGuaranteed>

fn has_non_region_param(&self) -> bool

fn has_infer_regions(&self) -> bool

fn has_infer_types(&self) -> bool

fn has_non_region_infer(&self) -> bool

fn needs_infer(&self) -> bool

fn has_placeholders(&self) -> bool

fn needs_subst(&self) -> bool

fn has_free_regions(&self) -> bool

“Free” regions in this context means that it has any region that is not (a) erased or (b) late-bound.

fn has_erased_regions(&self) -> bool

fn has_erasable_regions(&self) -> bool

True if there are any un-erased free regions.

fn is_global(&self) -> bool

Indicates whether this value references only ‘global’ generic parameters that are the same regardless of what fn we are in. This is used for caching.

fn has_late_bound_regions(&self) -> bool

True if there are any late-bound regions

fn still_further_specializable(&self) -> bool

Indicates whether this value still has parameters/placeholders/inference variables which could be replaced later, in a way that would change the results of impl specialization.

impl<'tcx, V: Copy> Copy for Canonical<'tcx, V>

impl<'tcx, V: Eq> Eq for Canonical<'tcx, V>

impl<'tcx, V> StructuralEq for Canonical<'tcx, V>

impl<'tcx, V> StructuralPartialEq for Canonical<'tcx, V>

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.