Scope in rustc_middle::middle::region - Rust
Description: Represents a statically-describable scope that can be used to bound the lifetime/region for values.

Skip to main content

## Scope

# Struct Scope

Source

    pub struct Scope {
        pub local_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§

§`local_id: ItemLocalId`§`data: ScopeData`

## Implementations§

Source§

### impl Scope

Source

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

Source

#### 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§

Source§

### impl Clone for Scope

Source§

#### fn clone(&self) -> Scope

Returns a duplicate of the value. Read more
1.0.0 (const: unstable) · Source§

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

Performs copy-assignment from `source`. Read more
Source§

### impl Debug for Scope

Source§

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

Formats the value using the given formatter. Read more
Source§

### impl<'tcx, __D: TyDecoder<'tcx>> Decodable<__D> for Scope

Source§

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

Source§

### impl<'tcx, __E: TyEncoder<'tcx>> Encodable<__E> for Scope

Source§

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

Source§

### impl Hash for Scope

Source§

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

Feeds this value into the given `Hasher`. Read more
1.3.0 · Source§

#### 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
Source§

### impl Ord for Scope

Source§

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

This method returns an `Ordering` between `self` and `other`. Read more
1.21.0 (const: unstable) · Source§

#### fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 (const: unstable) · Source§

#### fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 (const: unstable) · Source§

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

Restrict a value to a certain interval. Read more
Source§

### impl PartialEq for Scope

Source§

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

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 (const: unstable) · Source§

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

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

### impl PartialOrd for Scope

Source§

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

This method returns an ordering between `self` and `other` values if one exists. Read more
1.0.0 (const: unstable) · Source§

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

Tests less than (for `self` and `other`) and is used by the `<` operator. Read more
1.0.0 (const: unstable) · Source§

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

Tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
1.0.0 (const: unstable) · Source§

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

Tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
1.0.0 (const: unstable) · Source§

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

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

### impl StableHash for Scope

Source§

#### fn stable_hash<__Hcx: StableHashCtxt>( &self, __hcx: &mut __Hcx, __hasher: &mut StableHasher, )

Source§

### impl Copy for Scope

Source§

### impl Eq for Scope

Source§

### impl StructuralPartialEq for Scope

## Auto Trait Implementations§

§

### impl DynSend for Scope

§

### impl DynSync for Scope

§

### impl Freeze for Scope

§

### impl RefUnwindSafe for Scope

§

### impl Send for Scope

§

### impl Sync for Scope

§

### impl Unpin for Scope

§

### impl UnsafeUnpin for Scope

§

### impl UnwindSafe for Scope

## Blanket Implementations§

Source§

### impl<T> Aligned for T

Source§

#### const ALIGN: Alignment

Alignment of `Self`.
Source§

### impl<T> Any for T
where T: 'static + ?Sized,

Source§

#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
Source§

### impl<T> AnyEq for T
where T: Any + PartialEq,

Source§

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

Source§

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

Source§

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

Source§

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

Source§

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

Source§

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

Source§

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

Source§

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

Source§

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

Source§

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
Source§

### impl<T> BorrowMut<T> for T
where T: ?Sized,

Source§

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

Mutably borrows from an owned value. Read more
Source§

### impl<T> CloneToUninit for T
where T: Clone,

Source§

#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit`)
Performs copy-assignment from `self` to `dest`. Read more
Source§

### impl<T, R> CollectAndApply<T, R> for T

Source§

#### 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<_>>())`.

Source§

#### type Output = R

Source§

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

Source§

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

Compare self to `key` and return their ordering.
Source§

### impl<'tcx, T> DepNodeKey<'tcx> for T
where T: StableHash + Debug,

Source§

#### default fn key_fingerprint_style() -> KeyFingerprintStyle

Source§

#### default fn to_fingerprint(&self, tcx: TyCtxt<'tcx>) -> Fingerprint

This method turns a query key into an opaque `Fingerprint` to be used in `DepNode`.
Source§

#### default fn try_recover_key(_: TyCtxt<'tcx>, _: &DepNode) -> Option<T>

This method tries to recover the query key from the given `DepNode`, something which is needed when forcing `DepNode`s 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.
Source§

### impl<T> DynClone for T
where T: Clone,

Source§

#### fn __clone_box(&self, _: Private) -> *mut ()

Source§

### impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

Source§

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

Checks if this value is equivalent to the given key. Read more
Source§

### impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

Source§

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

Checks if this value is equivalent to the given key. Read more
Source§

### impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

Source§

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

Compare self to `key` and return `true` if they are equal.
Source§

### impl<T> From<T> for T

Source§

#### fn from(t: T) -> T

Returns the argument unchanged.

Source§

### impl<T> Instrument for T

Source§

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

Instruments this type with the provided `Span`, returning an `Instrumented` wrapper. Read more
Source§

#### fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current `Span`, returning an `Instrumented` wrapper. Read more
Source§

### impl<T, U> Into<U> for T
where U: From<T>,

Source§

#### fn into(self) -> U

Calls `U::from(self)`.

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

Source§

### impl<T> IntoEither for T

Source§

#### 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
Source§

#### 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
Source§

### impl<K> IntoQueryKey<K> for K

Source§

#### fn into_query_key(self) -> K

Argument conversion from `Self` to `K`. This should always be a very cheap conversion, e.g. `LocalDefId::to_def_id`.
Source§

### impl<T> MaybeResult<T> for T

Source§

#### type Error = !

Source§

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

Source§

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

Source§

### impl<T> Pointable for T

Source§

#### const ALIGN: usize

The alignment of pointer.
Source§

#### type Init = T

The type for initializers.
Source§

#### unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
Source§

#### unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
Source§

#### unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
Source§

#### unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
Source§

### impl<T> Same for T

Source§

#### type Output = T

Should always be `Self`
Source§

### impl<T> ToOwned for T
where T: Clone,

Source§

#### type Owned = T

The resulting type after obtaining ownership.
Source§

#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
Source§

#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
Source§

### impl<T, U> TryFrom<U> for T
where U: Into<T>,

Source§

#### type Error = Infallible

The type returned in the event of a conversion error.
Source§

#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
Source§

### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

Source§

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

The type returned in the event of a conversion error.
Source§

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
Source§

### impl<I, T, U> Upcast<I, U> for T
where U: UpcastFrom<I, T>,

Source§

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

Source§

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

Source§

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

Source§

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

Source§

#### fn vzip(self) -> V

Source§

### impl<T> WithSubscriber for T

Source§

#### 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
Source§

#### fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default `Subscriber` to this type, returning a `WithDispatch` wrapper. Read more
Source§

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

## 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