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(in ty::layout) fn fn_sig_for_fn_abi(
    &self,
    tcx: TyCtxt<'tcx>
) -> PolyFnSig<'tcx>

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>>, ErrorReported>

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

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
) -> 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>
) -> Instance<'tcx>

pub(in ty::instance) 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) -> T where
    T: TypeFoldable<'tcx> + Copy, 

pub fn subst_mir_and_normalize_erasing_regions<T>(
    &self,
    tcx: TyCtxt<'tcx>,
    param_env: ParamEnv<'tcx>,
    v: T
) -> T 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 identify parameters if they are determined to be unused in instance.def.

Trait Implementations

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

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

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'tcx> Copy for Instance<'tcx>

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

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

Formats the value using the given formatter.

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

pub fn decode(__decoder: &mut __D) -> Result<Self, <__D as Decoder>::Error>

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

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

Formats the value using the given formatter.

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

pub fn encode(&self, __encoder: &mut __E) -> Result<(), <__E as Encoder>::Error>

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

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

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

Feeds this value into the given Hasher.

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

Feeds a slice of this type into the given Hasher.

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

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

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

type CacheSelector = DefaultCacheSelector

pub fn query_crate(&self) -> CrateNum

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

pub 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?

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

type Lifted = Instance<'__lifted>

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

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

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

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

pub fn ne(&self, other: &Instance<'tcx>) -> bool

This method tests for !=.

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

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

impl<'tcx> TypeFoldable<'tcx> for Instance<'tcx>

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

pub fn super_visit_with<V: TypeVisitor<'tcx>>(
    &self,
    visitor: &mut V
) -> ControlFlow<V::BreakTy>

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

pub fn visit_with<V: TypeVisitor<'tcx>>(
    &self,
    visitor: &mut V
) -> ControlFlow<V::BreakTy>

pub 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.

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

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

pub fn has_escaping_bound_vars(&self) -> bool

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

pub fn has_projections(&self) -> bool

pub fn has_opaque_types(&self) -> bool

pub fn references_error(&self) -> bool

pub fn has_param_types_or_consts(&self) -> bool

pub fn has_infer_regions(&self) -> bool

pub fn has_infer_types(&self) -> bool

pub fn has_infer_types_or_consts(&self) -> bool

pub fn needs_infer(&self) -> bool

pub fn has_placeholders(&self) -> bool

pub fn needs_subst(&self) -> bool

pub 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.

pub fn has_erased_regions(&self) -> bool

pub fn has_erasable_regions(&self) -> bool

True if there are any un-erased free regions.

pub 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.

pub fn has_late_bound_regions(&self) -> bool

True if there are any late-bound regions

pub 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.