Enum ImplSource 

pub(crate) enum ImplSource<'db, N> {
    UserDefined(ImplSourceUserDefinedData<'db, N>),
    Param(Vec<N>),
    Builtin(BuiltinImplSource, Vec<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: 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<'db, N>)

ImplSource identifying a particular impl.

Param(Vec<N>)

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).

Builtin(BuiltinImplSource, Vec<N>)

Successful resolution for a builtin impl.

Implementations

impl<'db, N> ImplSource<'db, N>

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

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

pub(crate) fn borrow_nested_obligations_mut(&mut self) -> &mut [N]

pub(crate) fn map<M, F>(self, f: F) -> ImplSource<'db, M>

where F: FnMut(N) -> M,

Trait Implementations

impl<'db, N: Clone> Clone for ImplSource<'db, N>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

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

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

Formats the value using the given formatter.

impl<'db, N: Hash> Hash for ImplSource<'db, N>

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<'db, N: PartialEq> PartialEq for ImplSource<'db, N>

fn eq(&self, other: &ImplSource<'db, N>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'db, N> TypeFoldable<DbInterner<'db>> for ImplSource<'db, N>

where N: TypeFoldable<DbInterner<'db>>,

fn try_fold_with<__F: FallibleTypeFolder<DbInterner<'db>>>( 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<DbInterner<'db>>>(self, __folder: &mut __F) -> Self

The entry point for folding. To fold a value t with a folder f call: t.fold_with(f).

impl<'db, N> TypeVisitable<DbInterner<'db>> for ImplSource<'db, N>

where N: TypeVisitable<DbInterner<'db>>,

fn visit_with<__V: TypeVisitor<DbInterner<'db>>>( &self, __visitor: &mut __V, ) -> __V::Result

The entry point for visiting. To visit a value t with a visitor v call: t.visit_with(v).

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

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