Struct rustc_middle::ty::WithOptConstParam

pub struct WithOptConstParam<T> {
    pub did: T,
    pub const_param_did: Option<DefId>,
}

A DefId which is potentially bundled with its corresponding generic parameter in case did is a const argument.

This is used to prevent cycle errors during typeck as type_of(const_arg) depends on typeck(owning_body) which once again requires the type of its generic arguments.

Luckily we only need to deal with const arguments once we know their corresponding parameters. We (ab)use this by calling type_of(param_did) for these arguments.

#![feature(const_generics)]

struct A;
impl A {
    fn foo<const N: usize>(&self) -> usize { N }
}
struct B;
impl B {
    fn foo<const N: u8>(&self) -> usize { 42 }
}

fn main() {
    let a = A;
    a.foo::<7>();
}

Fields

did: T

const_param_did: Option<DefId>

The DefId of the corresponding generic parameter in case did is a const argument.

Note that even if did is a const argument, this may still be None. All queries taking WithOptConstParam start by calling tcx.opt_const_param_of(def.did) to potentially update param_did in case it None.

Implementations

impl<T> WithOptConstParam<T>

pub fn unknown(did: T) -> WithOptConstParam<T>

Creates a new WithOptConstParam setting const_param_did to None.

impl WithOptConstParam<LocalDefId>

pub fn try_lookup(
    did: LocalDefId,
    tcx: TyCtxt<'_>
) -> Option<(LocalDefId, DefId)>

Returns Some((did, param_did)) if def_id is a const argument, None otherwise.

pub fn try_upgrade(
    self,
    tcx: TyCtxt<'_>
) -> Option<WithOptConstParam<LocalDefId>>

In case self is unknown but self.did is a const argument, this returns a WithOptConstParam with the correct const_param_did.

pub fn to_global(self) -> WithOptConstParam<DefId>

pub fn def_id_for_type_of(self) -> DefId

impl WithOptConstParam<DefId>

pub fn as_local(self) -> Option<WithOptConstParam<LocalDefId>>

pub fn as_const_arg(self) -> Option<(LocalDefId, DefId)>

pub fn expect_local(self) -> WithOptConstParam<LocalDefId>

pub fn is_local(self) -> bool

pub fn def_id_for_type_of(self) -> DefId

Trait Implementations

impl<T: Clone> Clone for WithOptConstParam<T>

fn clone(&self) -> WithOptConstParam<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Copy> Copy for WithOptConstParam<T>

impl<T: Debug> Debug for WithOptConstParam<T>

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

Formats the value using the given formatter.

impl<'tcx, T, __D: TyDecoder<'tcx>> Decodable<__D> for WithOptConstParam<T> where
    T: Decodable<__D>, 

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

impl<'tcx, T, __E: TyEncoder<'tcx>> Encodable<__E> for WithOptConstParam<T> where
    T: Encodable<__E>, 

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

impl<T: Eq> Eq for WithOptConstParam<T>

impl<T: Hash> Hash for WithOptConstParam<T>

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, 

Feeds a slice of this type into the given Hasher.

impl<'__ctx, T> HashStable<StableHashingContext<'__ctx>> for WithOptConstParam<T> where
    T: HashStable<StableHashingContext<'__ctx>>, 

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

impl Key for WithOptConstParam<LocalDefId>

type CacheSelector = DefaultCacheSelector

fn query_crate(&self) -> CrateNum

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?

impl<'__lifted, T> Lift<'__lifted> for WithOptConstParam<T> where
    T: Lift<'__lifted>, 

type Lifted = WithOptConstParam<T::Lifted>

fn lift_to_tcx(
    self,
    __tcx: TyCtxt<'__lifted>
) -> Option<WithOptConstParam<T::Lifted>>

impl<T: Ord> Ord for WithOptConstParam<T>

fn cmp(&self, other: &WithOptConstParam<T>) -> Ordering

This method returns an Ordering between self and other.

#[must_use]fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]fn clamp(self, min: Self, max: Self) -> Self

🔬 This is a nightly-only experimental API. (clamp)

Restrict a value to a certain interval.

impl<T: PartialEq> PartialEq<WithOptConstParam<T>> for WithOptConstParam<T>

fn eq(&self, other: &WithOptConstParam<T>) -> bool

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

fn ne(&self, other: &WithOptConstParam<T>) -> bool

This method tests for !=.

impl<T: PartialOrd> PartialOrd<WithOptConstParam<T>> for WithOptConstParam<T>

fn partial_cmp(&self, other: &WithOptConstParam<T>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &WithOptConstParam<T>) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &WithOptConstParam<T>) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &WithOptConstParam<T>) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &WithOptConstParam<T>) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T: SpecIntoSelfProfilingString> SpecIntoSelfProfilingString for WithOptConstParam<T>

fn spec_to_self_profile_string(
    &self,
    builder: &mut QueryKeyStringBuilder<'_, '_, '_>
) -> StringId

impl<T> StructuralEq for WithOptConstParam<T>

impl<T> StructuralPartialEq for WithOptConstParam<T>

impl<T, 'tcx> TypeFoldable<'tcx> for WithOptConstParam<T> where
    T: TypeFoldable<'tcx>, 

fn super_fold_with<__F: TypeFolder<'tcx>>(&self, __folder: &mut __F) -> Self

fn super_visit_with<__F: TypeVisitor<'tcx>>(
    &self,
    __folder: &mut __F
) -> ControlFlow<()>

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

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

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

fn has_escaping_bound_vars(&self) -> bool

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 has_param_types_or_consts(&self) -> bool

fn has_infer_regions(&self) -> bool

fn has_infer_types(&self) -> bool

fn has_infer_types_or_consts(&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.

fn visit_tys_shallow(
    &self,
    visit: impl FnMut(Ty<'tcx>) -> ControlFlow<()>
) -> ControlFlow<()>

A visitor that does not recurse into types, works like fn walk_shallow in Ty.