enum Scope<'a> {
Binder {
bound_vars: FxIndexMap<LocalDefId, ResolvedArg>,
scope_type: BinderScopeType,
hir_id: HirId,
s: &'a Scope<'a>,
where_bound_origin: Option<PredicateOrigin>,
},
Body {
id: BodyId,
s: &'a Scope<'a>,
},
ObjectLifetimeDefault {
lifetime: Option<ResolvedArg>,
s: &'a Scope<'a>,
},
Supertrait {
bound_vars: Vec<BoundVariableKind>,
s: &'a Scope<'a>,
},
TraitRefBoundary {
s: &'a Scope<'a>,
},
LateBoundary {
s: &'a Scope<'a>,
what: &'static str,
},
Root {
opt_parent_item: Option<LocalDefId>,
},
}
Variants§
Binder
Declares lifetimes, and each can be early-bound or late-bound.
The DebruijnIndex
of late-bound lifetimes starts at 1
and
it should be shifted by the number of Binder
s in between the
declaration Binder
and the location it’s referenced from.
Fields
bound_vars: FxIndexMap<LocalDefId, ResolvedArg>
We use an IndexMap here because we want these lifetimes in order for diagnostics.
scope_type: BinderScopeType
hir_id: HirId
The late bound vars for a given item are stored by HirId
to be
queried later. However, if we enter an elision scope, we have to
later append the elided bound vars to the list and need to know what
to append to.
where_bound_origin: Option<PredicateOrigin>
If this binder comes from a where clause, specify how it was created. This is used to diagnose inaccessible lifetimes in APIT:
fn foo(x: impl for<'a> Trait<'a, Assoc = impl Copy + 'a>) {}
Body
Lifetimes introduced by a fn are scoped to the call-site for that fn,
if this is a fn body, otherwise the original definitions are used.
Unspecified lifetimes are inferred, unless an elision scope is nested,
e.g., (&T, fn(&T) -> &T);
becomes (&'_ T, for<'a> fn(&'a T) -> &'a T)
.
ObjectLifetimeDefault
Use a specific lifetime (if Some
) or leave it unset (to be
inferred in a function body or potentially error outside one),
for the default choice of lifetime in a trait object type.
Supertrait
When we have nested trait refs, we concatenate late bound vars for inner trait refs from outer ones. But we also need to include any HRTB lifetimes encountered when identifying the trait that an associated type is declared on.
TraitRefBoundary
LateBoundary
Disallows capturing late-bound vars from parent scopes.
This is necessary for something like for<T> [(); { /* references T */ }]:
,
since we don’t do something more correct like replacing any captured
late-bound vars with early-bound params in the const’s own generics.
Root
Fields
opt_parent_item: Option<LocalDefId>
Trait Implementations§
Auto Trait Implementations§
impl<'a> Freeze for Scope<'a>
impl<'a> RefUnwindSafe for Scope<'a>
impl<'a> Send for Scope<'a>
impl<'a> Sync for Scope<'a>
impl<'a> Unpin for Scope<'a>
impl<'a> UnwindSafe for Scope<'a>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T, R> CollectAndApply<T, R> for T
impl<T, R> CollectAndApply<T, R> for T
source§impl<T> Filterable for T
impl<T> Filterable for T
source§fn filterable(
self,
filter_name: &'static str,
) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>
fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>
source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§impl<P> IntoQueryParam<P> for P
impl<P> IntoQueryParam<P> for P
fn into_query_param(self) -> P
source§impl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
source§impl<I, T, U> Upcast<I, U> for Twhere
U: UpcastFrom<I, T>,
impl<I, T, U> Upcast<I, U> for Twhere
U: UpcastFrom<I, T>,
source§impl<I, T> UpcastFrom<I, T> for T
impl<I, T> UpcastFrom<I, T> for T
fn upcast_from(from: T, _tcx: I) -> T
source§impl<Tcx, T> Value<Tcx> for Twhere
Tcx: DepContext,
impl<Tcx, T> Value<Tcx> for Twhere
Tcx: DepContext,
default fn from_cycle_error( tcx: Tcx, cycle_error: &CycleError, _guar: ErrorGuaranteed, ) -> T
source§impl<T> WithSubscriber for T
impl<T> WithSubscriber for T
source§fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
source§fn with_current_subscriber(self) -> WithDispatch<Self>
fn with_current_subscriber(self) -> WithDispatch<Self>
impl<'a, T> Captures<'a> for Twhere
T: ?Sized,
impl<T> ErasedDestructor for Twhere
T: 'static,
impl<T> MaybeSendSync for T
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: 80 bytes
Size for each variant:
Binder
: 80 bytesBody
: 24 bytesObjectLifetimeDefault
: 32 bytesSupertrait
: 40 bytesTraitRefBoundary
: 16 bytesLateBoundary
: 32 bytesRoot
: 12 bytes