Enum rustc_middle::traits::ImplSource

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

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

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.

Closure(ImplSourceClosureData<'tcx, N>)

ImplSource automatically generated for a closure. The DefId is the ID of the closure expression. This is a 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.

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, 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, N, __D: TyDecoder<'tcx>> Decodable<__D> for ImplSource<'tcx, N> where
    N: Decodable<__D>, 

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

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

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

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::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: &ImplSource<'tcx, N>) -> bool

This method tests for !=.

impl<'tcx, N> TypeFoldable<'tcx> for ImplSource<'tcx, N> where
    N: 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<__F::BreakTy>

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

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

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.

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>