Enum rustc_middle::traits::ImplSource

pub enum ImplSource<'tcx, N> {
    UserDefined(ImplSourceUserDefinedData<'tcx, N>),
    AutoImpl(ImplSourceAutoImplData<N>),
    Param(Vec<N>, BoundConstness),
    Object(ImplSourceObjectData<'tcx, N>),
    Builtin(ImplSourceBuiltinData<N>),
    TraitUpcasting(ImplSourceTraitUpcastingData<'tcx, N>),
    Closure(ImplSourceClosureData<'tcx, N>),
    FnPointer(ImplSourceFnPointerData<'tcx, N>),
    DiscriminantKind(ImplSourceDiscriminantKindData),
    Pointee(ImplSourcePointeeData),
    Generator(ImplSourceGeneratorData<'tcx, N>),
    TraitAlias(ImplSourceTraitAliasData<'tcx, N>),
    ConstDestruct(ImplSourceConstDestructData<N>),
    Tuple,
}

Given the successful resolution of an obligation, the ImplSource indicates where the impl comes from.

For example, the obligation may be satisfied by a specific impl (case A), or it may be relative to some bound that is in scope (case B).

impl<T:Clone> Clone<T> for Option<T> { ... } // Impl_1
impl<T:Clone> Clone<T> for Box<T> { ... }    // Impl_2
impl Clone for i32 { ... }                   // Impl_3

fn foo<T: Clone>(concrete: Option<Box<i32>>, param: T, mixed: Option<T>) {
    // Case A: ImplSource points at a specific impl. Only possible when
    // type is concretely known. If the impl itself has bounded
    // type parameters, ImplSource will carry resolutions for those as well:
    concrete.clone(); // ImplSource(Impl_1, [ImplSource(Impl_2, [ImplSource(Impl_3)])])

    // Case A: ImplSource points at a specific impl. Only possible when
    // type is concretely known. If the impl itself has bounded
    // type parameters, ImplSource will carry resolutions for those as well:
    concrete.clone(); // ImplSource(Impl_1, [ImplSource(Impl_2, [ImplSource(Impl_3)])])

    // Case B: ImplSource must be provided by caller. This applies when
    // type is a type parameter.
    param.clone();    // ImplSource::Param

    // Case C: A mix of cases A and B.
    mixed.clone();    // ImplSource(Impl_1, [ImplSource::Param])
}

The type parameter N

See explanation on ImplSourceUserDefinedData.

Variants

UserDefined(ImplSourceUserDefinedData<'tcx, N>)

ImplSource identifying a particular impl.

AutoImpl(ImplSourceAutoImplData<N>)

ImplSource for auto trait implementations. This carries the information and nested obligations with regards to an auto implementation for a trait Trait. The nested obligations ensure the trait implementation holds for all the constituent types.

Param(Vec<N>, BoundConstness)

Successful resolution to an obligation provided by the caller for some type parameter. The Vec<N> represents the obligations incurred from normalizing the where-clause (if any).

Object(ImplSourceObjectData<'tcx, N>)

Virtual calls through an object.

Builtin(ImplSourceBuiltinData<N>)

Successful resolution for a builtin trait.

TraitUpcasting(ImplSourceTraitUpcastingData<'tcx, N>)

ImplSource for trait upcasting coercion

Closure(ImplSourceClosureData<'tcx, N>)

ImplSource automatically generated for a closure. The DefId is the ID of the closure expression. This is an ImplSource::UserDefined in spirit, but the impl is generated by the compiler and does not appear in the source.

FnPointer(ImplSourceFnPointerData<'tcx, N>)

Same as above, but for a function pointer type with the given signature.

DiscriminantKind(ImplSourceDiscriminantKindData)

ImplSource for a builtin DeterminantKind trait implementation.

Pointee(ImplSourcePointeeData)

ImplSource for a builtin Pointee trait implementation.

Generator(ImplSourceGeneratorData<'tcx, N>)

ImplSource automatically generated for a generator.

TraitAlias(ImplSourceTraitAliasData<'tcx, N>)

ImplSource for a trait alias.

ConstDestruct(ImplSourceConstDestructData<N>)

ImplSource for a const Drop implementation.

Tuple

ImplSource for a std::marker::Tuple implementation. This has no nested predicates ever, so no data.

Implementations

impl<'tcx, N> ImplSource<'tcx, N>

pub fn nested_obligations(self) -> Vec<N>

pub fn borrow_nested_obligations(&self) -> &[N]

pub fn map<M, F>(self, f: F) -> ImplSource<'tcx, M>where
    F: FnMut(N) -> M,

Trait Implementations

impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for ImplSource<'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, N: Clone> Clone for ImplSource<'tcx, N>

fn clone(&self) -> ImplSource<'tcx, N>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'tcx, N: Debug> Debug for ImplSource<'tcx, N>

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

Formats the value using the given formatter.

impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for &'tcx ImplSource<'tcx, ()>

fn decode(decoder: &mut D) -> Self

impl<'tcx, N, __D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<__D> for ImplSource<'tcx, N>where
    N: Decodable<__D>,

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

impl<'tcx, N, __E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<__E> for ImplSource<'tcx, N>where
    N: Encodable<__E>,

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

impl<'tcx, '__ctx, N> HashStable<StableHashingContext<'__ctx>> for ImplSource<'tcx, N>where
    N: HashStable<StableHashingContext<'__ctx>>,

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

impl<'tcx, '__lifted, N> Lift<'__lifted> for ImplSource<'tcx, N>where
    N: Lift<'__lifted>,

type Lifted = ImplSource<'__lifted, <N as Lift<'__lifted>>::Lifted>

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

impl<'tcx, N: PartialEq> PartialEq<ImplSource<'tcx, N>> for ImplSource<'tcx, N>

fn eq(&self, other: &ImplSource<'tcx, N>) -> 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, D: TyDecoder<I = TyCtxt<'tcx>>> RefDecodable<'tcx, D> for ImplSource<'tcx, ()>

fn decode(decoder: &mut D) -> &'tcx Self

impl<'tcx, N> TypeFoldable<'tcx> for ImplSource<'tcx, N>where
    N: 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, N> TypeVisitable<'tcx> for ImplSource<'tcx, N>where
    N: 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 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 error_reported(&self) -> Option<ErrorGuaranteed>

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.

impl<'tcx, N: Eq> Eq for ImplSource<'tcx, N>

impl<'tcx, N> StructuralEq for ImplSource<'tcx, N>

impl<'tcx, N> StructuralPartialEq for ImplSource<'tcx, N>

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: 72 bytes

Size for each variant:

• UserDefined: 47 bytes
• AutoImpl: 39 bytes
• Param: 31 bytes
• Object: 63 bytes
• Builtin: 31 bytes
• TraitUpcasting: 71 bytes
• Closure: 47 bytes
• FnPointer: 39 bytes
• DiscriminantKind: 0 bytes
• Pointee: 0 bytes
• Generator: 47 bytes
• TraitAlias: 47 bytes
• ConstDestruct: 31 bytes
• Tuple: 0 bytes