Struct rustc_middle::ty::Instance

pub struct Instance<'tcx> {
    pub def: InstanceDef<'tcx>,
    pub substs: SubstsRef<'tcx>,
}

A monomorphized InstanceDef.

Monomorphization happens on-the-fly and no monomorphized MIR is ever created. Instead, this type simply couples a potentially generic InstanceDef with some substs, and codegen and const eval will do all required substitution as they run.

Fields

def: InstanceDef<'tcx>

substs: SubstsRef<'tcx>

Implementations

impl<'tcx> Instance<'tcx>

pub fn ty(&self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Ty<'tcx>

Returns the Ty corresponding to this Instance, with generic substitutions applied and lifetimes erased, allowing a ParamEnv to be specified for use during normalization.

pub fn upstream_monomorphization(&self, tcx: TyCtxt<'tcx>) -> Option<CrateNum>

Finds a crate that contains a monomorphization of this instance that can be linked to from the local crate. A return value of None means no upstream crate provides such an exported monomorphization.

This method already takes into account the global -Zshare-generics setting, always returning None if share-generics is off.

impl<'tcx> Instance<'tcx>

pub fn new(def_id: DefId, substs: SubstsRef<'tcx>) -> Instance<'tcx>

pub fn mono(tcx: TyCtxt<'tcx>, def_id: DefId) -> Instance<'tcx>

pub fn def_id(&self) -> DefId

pub fn resolve(
    tcx: TyCtxt<'tcx>,
    param_env: ParamEnv<'tcx>,
    def_id: DefId,
    substs: SubstsRef<'tcx>
) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed>

Resolves a (def_id, substs) pair to an (optional) instance – most commonly, this is used to find the precise code that will run for a trait method invocation, if known.

Returns Ok(None) if we cannot resolve Instance to a specific instance. For example, in a context like this,

fn foo<T: Debug>(t: T) { ... }

trying to resolve Debug::fmt applied to T will yield Ok(None), because we do not know what code ought to run. (Note that this setting is also affected by the RevealMode in the parameter environment.)

Presuming that coherence and type-check have succeeded, if this method is invoked in a monomorphic context (i.e., like during codegen), then it is guaranteed to return Ok(Some(instance)).

Returns Err(ErrorGuaranteed) when the Instance resolution process couldn’t complete due to errors elsewhere - this is distinct from Ok(None) to avoid misleading diagnostics when an error has already been/will be emitted, for the original cause

pub fn expect_resolve(
    tcx: TyCtxt<'tcx>,
    param_env: ParamEnv<'tcx>,
    def_id: DefId,
    substs: SubstsRef<'tcx>
) -> Instance<'tcx>

pub fn resolve_opt_const_arg(
    tcx: TyCtxt<'tcx>,
    param_env: ParamEnv<'tcx>,
    def: WithOptConstParam<DefId>,
    substs: SubstsRef<'tcx>
) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed>

pub fn resolve_for_fn_ptr(
    tcx: TyCtxt<'tcx>,
    param_env: ParamEnv<'tcx>,
    def_id: DefId,
    substs: SubstsRef<'tcx>
) -> Option<Instance<'tcx>>

pub fn resolve_for_vtable(
    tcx: TyCtxt<'tcx>,
    param_env: ParamEnv<'tcx>,
    def_id: DefId,
    substs: SubstsRef<'tcx>
) -> Option<Instance<'tcx>>

pub fn resolve_closure(
    tcx: TyCtxt<'tcx>,
    def_id: DefId,
    substs: SubstsRef<'tcx>,
    requested_kind: ClosureKind
) -> Option<Instance<'tcx>>

pub fn resolve_drop_in_place(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Instance<'tcx>

pub fn fn_once_adapter_instance(
    tcx: TyCtxt<'tcx>,
    closure_did: DefId,
    substs: SubstsRef<'tcx>
) -> Option<Instance<'tcx>>

fn substs_for_mir_body(&self) -> Option<SubstsRef<'tcx>>

Depending on the kind of InstanceDef, the MIR body associated with an instance is expressed in terms of the generic parameters of self.def_id(), and in other cases the MIR body is expressed in terms of the types found in the substitution array. In the former case, we want to substitute those generic types and replace them with the values from the substs when monomorphizing the function body. But in the latter case, we don’t want to do that substitution, since it has already been done effectively.

This function returns Some(substs) in the former case and None otherwise – i.e., if this function returns None, then the MIR body does not require substitution during codegen.

pub fn subst_mir<T>(&self, tcx: TyCtxt<'tcx>, v: &T) -> Twhere
    T: TypeFoldable<'tcx> + Copy,

pub fn subst_mir_and_normalize_erasing_regions<T>(
    &self,
    tcx: TyCtxt<'tcx>,
    param_env: ParamEnv<'tcx>,
    v: T
) -> Twhere
    T: TypeFoldable<'tcx> + Clone,

pub fn try_subst_mir_and_normalize_erasing_regions<T>(
    &self,
    tcx: TyCtxt<'tcx>,
    param_env: ParamEnv<'tcx>,
    v: T
) -> Result<T, NormalizationError<'tcx>>where
    T: TypeFoldable<'tcx> + Clone,

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

Returns a new Instance where generic parameters in instance.substs are replaced by identity parameters if they are determined to be unused in instance.def.

Trait Implementations

impl<'tcx> Clone for Instance<'tcx>

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

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'tcx> Debug for Instance<'tcx>

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

Formats the value using the given formatter.

impl<'tcx, __D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<__D> for Instance<'tcx>

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

impl<'tcx> Display for Instance<'tcx>

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

Formats the value using the given formatter.

impl<'tcx, __E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<__E> for Instance<'tcx>

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

impl<'tcx> Hash for Instance<'tcx>

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> HashStable<StableHashingContext<'__ctx>> for Instance<'tcx>

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

impl<'tcx> Key for Instance<'tcx>

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> Lift<'__lifted> for Instance<'tcx>

type Lifted = Instance<'__lifted>

fn lift_to_tcx(self, __tcx: TyCtxt<'__lifted>) -> Option<Instance<'__lifted>>

impl<'tcx> PartialEq<Instance<'tcx>> for Instance<'tcx>

fn eq(&self, other: &Instance<'tcx>) -> 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> TypeFoldable<'tcx> for Instance<'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> TypeVisitable<'tcx> for Instance<'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> Copy for Instance<'tcx>

impl<'tcx> Eq for Instance<'tcx>

impl<'tcx> StructuralEq for Instance<'tcx>

impl<'tcx> StructuralPartialEq for Instance<'tcx>

Layout

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: 32 bytes