Struct Scope

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

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

impl Scope

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.

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

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

impl Clone for Scope

fn clone(&self) -> Scope

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Scope

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

Formats the value using the given formatter.

impl<__D: TyDecoder> Decodable<__D> for Scope

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

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

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

impl Hash for Scope

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<'__ctx> HashStable<StableHashingContext<'__ctx>> for Scope

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

impl Ord for Scope

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

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Scope

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

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

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'a> ToStableHashKey<StableHashingContext<'a>> for Scope

type KeyType = Scope

fn to_stable_hash_key(&self, _: &StableHashingContext<'a>) -> Scope

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

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).

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.

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

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).

impl Copy for Scope

impl Eq for Scope

impl StructuralPartialEq for Scope

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