Struct rustc_middle::middle::region::Scope

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pub struct Scope {
    pub id: ItemLocalId,
    pub data: ScopeData,
}
Expand description

Represents a statically-describable scope that can be used to bound the lifetime/region for values.

Node(node_id): Any AST node that has any scope at all has the Node(node_id) scope. Other variants represent special cases not immediately derivable from the abstract syntax tree structure.

DestructionScope(node_id) represents the scope of destructors implicitly-attached to node_id that run immediately after the expression for node_id itself. Not every AST node carries a DestructionScope, but those that are terminating_scopes do; see discussion with ScopeTree.

Remainder { block, statement_index } represents the scope of user code running immediately after the initializer expression for the indexed statement, until the end of the block.

So: the following code can be broken down into the scopes beneath:

let a = f().g( 'b: { let x = d(); let y = d(); x.h(y)  }   ) ;

                                                             +-+ (D12.)
                                                       +-+       (D11.)
                                             +---------+         (R10.)
                                             +-+                  (D9.)
                                  +----------+                    (M8.)
                                +----------------------+          (R7.)
                                +-+                               (D6.)
                     +----------+                                 (M5.)
                   +-----------------------------------+          (M4.)
        +--------------------------------------------------+      (M3.)
        +--+                                                      (M2.)
+-----------------------------------------------------------+     (M1.)

 (M1.): Node scope of the whole `let a = ...;` statement.
 (M2.): Node scope of the `f()` expression.
 (M3.): Node scope of the `f().g(..)` expression.
 (M4.): Node scope of the block labeled `'b:`.
 (M5.): Node scope of the `let x = d();` statement
 (D6.): DestructionScope for temporaries created during M5.
 (R7.): Remainder scope for block `'b:`, stmt 0 (let x = ...).
 (M8.): Node scope of the `let y = d();` statement.
 (D9.): DestructionScope for temporaries created during M8.
(R10.): Remainder scope for block `'b:`, stmt 1 (let y = ...).
(D11.): DestructionScope for temporaries and bindings from block `'b:`.
(D12.): DestructionScope for temporaries created during M1 (e.g., f()).

Note that while the above picture shows the destruction scopes as following their corresponding node scopes, in the internal data structures of the compiler the destruction scopes are represented as enclosing parents. This is sound because we use the enclosing parent relationship just to ensure that referenced values live long enough; phrased another way, the starting point of each range is not really the important thing in the above picture, but rather the ending point.

Fields§

§id: ItemLocalId§data: ScopeData

Implementations§

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impl Scope

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pub fn item_local_id(&self) -> ItemLocalId

Returns an item-local ID associated with this scope.

N.B., likely to be replaced as API is refined; e.g., pnkfelix anticipates fn entry_node_id and fn each_exit_node_id.

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pub fn hir_id(&self, scope_tree: &ScopeTree) -> Option<HirId>

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pub fn span(&self, tcx: TyCtxt<'_>, scope_tree: &ScopeTree) -> Span

Returns the span of this Scope. Note that in general the returned span may not correspond to the span of any NodeId in the AST.

Trait Implementations§

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impl Clone for Scope

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fn clone(&self) -> Scope

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for Scope

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

Formats the value using the given formatter. Read more
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impl<__D: TyDecoder> Decodable<__D> for Scope

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

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impl<__E: TyEncoder> Encodable<__E> for Scope

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

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impl Hash for Scope

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<'__ctx> HashStable<StableHashingContext<'__ctx>> for Scope

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

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impl Ord for Scope

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fn cmp(&self, other: &Scope) -> Ordering

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
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impl PartialEq for Scope

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fn eq(&self, other: &Scope) -> bool

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

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

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl<'a> ToStableHashKey<StableHashingContext<'a>> for Scope

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impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Scope

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fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &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). Read more
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fn fold_with<F: TypeFolder<TyCtxt<'tcx>>>(self, _: &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.
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impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for Scope

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fn visit_with<F: TypeVisitor<TyCtxt<'tcx>>>(&self, _: &mut F) -> F::Result

The entry point for visiting. To visit a value t with a visitor v call: t.visit_with(v). Read more
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impl Copy for Scope

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impl Eq for Scope

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impl StructuralPartialEq for Scope

Auto Trait Implementations§

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impl Freeze for Scope

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impl RefUnwindSafe for Scope

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impl Send for Scope

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impl Sync for Scope

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impl Unpin for Scope

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impl UnwindSafe for Scope

Blanket Implementations§

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impl<T> Aligned for T

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const ALIGN: Alignment = _

Alignment of Self.
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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> AnyEq for T
where T: Any + PartialEq,

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fn equals(&self, other: &(dyn Any + 'static)) -> bool

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fn as_any(&self) -> &(dyn Any + 'static)

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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T
where T: Copy,

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T

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fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T>, ) -> &'a mut [T]

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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T
where T: Copy,

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T

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fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T>, ) -> &'a mut [T]

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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, R> CollectAndApply<T, R> for T

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fn collect_and_apply<I, F>(iter: I, f: F) -> R
where I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

Equivalent to f(&iter.collect::<Vec<_>>()).

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type Output = R

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impl<Q, K> Comparable<K> for Q
where Q: Ord + ?Sized, K: Borrow<Q> + ?Sized,

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fn compare(&self, key: &K) -> Ordering

Compare self to key and return their ordering.
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impl<Tcx, T> DepNodeParams<Tcx> for T
where Tcx: DepContext, T: for<'a> HashStable<StableHashingContext<'a>> + Debug,

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default fn fingerprint_style() -> FingerprintStyle

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default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint

This method turns the parameters of a DepNodeConstructor into an opaque Fingerprint to be used in DepNode. Not all DepNodeParams support being turned into a Fingerprint (they don’t need to if the corresponding DepNode is anonymous).
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default fn to_debug_str(&self, _: Tcx) -> String

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default fn recover(_: Tcx, _: &DepNode) -> Option<T>

This method tries to recover the query key from the given DepNode, something which is needed when forcing DepNodes during red-green evaluation. The query system will only call this method if fingerprint_style() is not FingerprintStyle::Opaque. It is always valid to return None here, in which case incremental compilation will treat the query as having changed instead of forcing it.
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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impl<T> Filterable for T

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fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

Creates a filterable data provider with the given name for debugging. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts 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 more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts 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 more
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impl<P> IntoQueryParam<P> for P

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impl<'tcx, T> IsSuggestable<'tcx> for T
where T: TypeVisitable<TyCtxt<'tcx>> + TypeFoldable<TyCtxt<'tcx>>,

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fn is_suggestable(self, tcx: TyCtxt<'tcx>, infer_suggestable: bool) -> bool

Whether this makes sense to suggest in a diagnostic. Read more
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fn make_suggestable( self, tcx: TyCtxt<'tcx>, infer_suggestable: bool, placeholder: Option<Ty<'tcx>>, ) -> Option<T>

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impl<T> MaybeResult<T> for T

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type Error = !

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fn from(_: Result<T, <T as MaybeResult<T>>::Error>) -> T

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fn to_result(self) -> Result<T, <T as MaybeResult<T>>::Error>

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<I, T> TypeVisitableExt<I> for T
where I: Interner, T: TypeVisitable<I>,

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fn has_type_flags(&self, flags: TypeFlags) -> bool

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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.
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fn error_reported(&self) -> Result<(), <I as Interner>::ErrorGuaranteed>

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fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool

Returns true if this type has any regions that escape binder (and hence are not bound by it).
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fn has_escaping_bound_vars(&self) -> bool

Return true if this type has regions that are not a part of the type. For example, for<'a> fn(&'a i32) return false, while fn(&'a i32) would return true. The latter can occur when traversing through the former. Read more
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fn has_aliases(&self) -> bool

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fn has_inherent_projections(&self) -> bool

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fn has_opaque_types(&self) -> bool

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fn has_coroutines(&self) -> bool

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fn references_error(&self) -> bool

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fn has_non_region_param(&self) -> bool

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fn has_infer_regions(&self) -> bool

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fn has_infer_types(&self) -> bool

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fn has_non_region_infer(&self) -> bool

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fn has_infer(&self) -> bool

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fn has_placeholders(&self) -> bool

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fn has_non_region_placeholders(&self) -> bool

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fn has_param(&self) -> bool

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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.
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fn has_erased_regions(&self) -> bool

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fn has_erasable_regions(&self) -> bool

True if there are any un-erased free regions.
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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.
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fn has_bound_regions(&self) -> bool

True if there are any late-bound regions
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fn has_non_region_bound_vars(&self) -> bool

True if there are any late-bound non-region variables
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fn has_bound_vars(&self) -> bool

True if there are any bound variables
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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.
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impl<I, T, U> Upcast<I, U> for T
where U: UpcastFrom<I, T>,

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fn upcast(self, interner: I) -> U

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impl<I, T> UpcastFrom<I, T> for T

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fn upcast_from(from: T, _tcx: I) -> T

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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<Tcx, T> Value<Tcx> for T
where Tcx: DepContext,

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default fn from_cycle_error( tcx: Tcx, cycle_error: &CycleError, _guar: ErrorGuaranteed, ) -> T

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
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impl<'a, T> Captures<'a> for T
where T: ?Sized,

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impl<T> ErasedDestructor for T
where T: 'static,

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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: 8 bytes