Trait QueryKey 

pub trait QueryKey: Sized + QueryKeyBounds {
    type Cache<V> = DefaultCache<Self, V>;

    // Required method
    fn default_span(&self, tcx: TyCtxt<'_>) -> Span;

    // Provided methods
    fn key_as_def_id(&self) -> Option<DefId> { ... }
    fn def_id_for_ty_in_cycle(&self) -> Option<DefId> { ... }
}

Controls what types can legally be used as the key for a query.

Provided Associated Types

type Cache<V> = DefaultCache<Self, V>

The type of in-memory cache to use for queries with this key type.

In practice the cache type must implement QueryCache, though that constraint is not enforced here.

Required Methods

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?

Provided Methods

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

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

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

Used to detect when ADT def ids are used as keys in a cycle for better error reporting.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl QueryKey for (CrateNum, DefId)

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

impl QueryKey for (CrateNum, SimplifiedType)

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

impl QueryKey for (DefId, SizedTraitKind)

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

impl QueryKey for (DefId, DefId)

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

impl QueryKey for (DefId, Ident)

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

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

impl QueryKey for (LocalDefId, LocalDefId, Ident)

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

impl QueryKey for Option<Symbol>

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

impl QueryKey for ()

type Cache<V> = SingleCache<V>

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

impl QueryKey for OwnerId

type Cache<V> = VecCache<OwnerId, V, DepNodeIndex>

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

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

impl QueryKey for CrateNum

type Cache<V> = VecCache<CrateNum, V, DepNodeIndex>

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

impl QueryKey for DefId

type Cache<V> = DefIdCache<V>

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

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

impl QueryKey for LocalDefId

type Cache<V> = VecCache<LocalDefId, V, DepNodeIndex>

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

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

impl QueryKey for LocalModDefId

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

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

impl QueryKey for Symbol

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

impl<'tcx> QueryKey for &'tcx OsStr

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

impl<'tcx> QueryKey for (ValidityRequirement, PseudoCanonicalInput<'tcx, Ty<'tcx>>)

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

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

impl<'tcx> QueryKey for (DefId, GenericArgsRef<'tcx>)

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

impl<'tcx> QueryKey for (LocalExpnId, &'tcx TokenStream)

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

impl<'tcx> QueryKey for (Instance<'tcx>, &'tcx List<Ty<'tcx>>)

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

impl<'tcx> QueryKey for (Instance<'tcx>, CollectionMode)

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

impl<'tcx> QueryKey for (Predicate<'tcx>, WellFormedLoc)

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

impl<'tcx> QueryKey for (Ty<'tcx>, Option<ExistentialTraitRef<'tcx>>)

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

impl<'tcx> QueryKey for (Ty<'tcx>, VariantIdx)

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

impl<'tcx> QueryKey for (Ty<'tcx>, Ty<'tcx>)

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

impl<'tcx> QueryKey for (PolyFnSig<'tcx>, &'tcx List<Ty<'tcx>>)

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

impl<'tcx, T: QueryKeyBounds> QueryKey for (CanonicalQueryInput<'tcx, T>, bool)

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

Implementors

impl QueryKey for SimplifiedType

impl<'tcx> QueryKey for InstanceKind<'tcx>

impl<'tcx> QueryKey for GlobalId<'tcx>

impl<'tcx> QueryKey for GenericArg<'tcx>

impl<'tcx> QueryKey for Instance<'tcx>

impl<'tcx> QueryKey for LitToConstInput<'tcx>

impl<'tcx> QueryKey for Ty<'tcx>

impl<'tcx> QueryKey for Value<'tcx>

impl<'tcx> QueryKey for Clauses<'tcx>

impl<'tcx> QueryKey for GenericArgsRef<'tcx>

impl<'tcx> QueryKey for TraitRef<'tcx>

impl<'tcx, T: QueryKey> QueryKey for PseudoCanonicalInput<'tcx, T>

impl<'tcx, T: QueryKeyBounds> QueryKey for CanonicalQueryInput<'tcx, T>

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