Enum rustc_middle::mir::ProjectionElem

pub enum ProjectionElem<V, T> {
    Deref,
    Field(Field, T),
    Index(V),
    ConstantIndex {
        offset: u64,
        min_length: u64,
        from_end: bool,
    },
    Subslice {
        from: u64,
        to: u64,
        from_end: bool,
    },
    Downcast(Option<Symbol>, VariantIdx),
}

Variants

Deref

Field(Field, T)

Index(V)

ConstantIndex

Fields

offset: u64

index or -index (in Python terms), depending on from_end

min_length: u64

The thing being indexed must be at least this long. For arrays this is always the exact length.

from_end: bool

Counting backwards from end? This is always false when indexing an array.

These indices are generated by slice patterns. Easiest to explain by example:

[X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
[_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
[_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
[_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },

Subslice

Fields

from: u64

to: u64

from_end: bool

Whether to counts from the start or end of the array/slice. For PlaceElems this is true if and only if the base is a slice. For ProjectionKind, this can also be true for arrays.

These indices are generated by slice patterns.

If from_end is true slice[from..slice.len() - to]. Otherwise array[from..to].

Downcast(Option<Symbol>, VariantIdx)

“Downcast” to a variant of an ADT. Currently, we only introduce this for ADTs with more than one variant. It may be better to just introduce it always, or always for enums.

The included Symbol is the name of the variant, used for printing MIR.

Implementations

impl<V, T> ProjectionElem<V, T>

fn is_indirect(&self) -> bool

Returns true if the target of this projection may refer to a different region of memory than the base.

pub fn is_downcast_to(&self, v: VariantIdx) -> bool

Returns true if this is a Downcast projection with the given VariantIdx.

pub fn is_field_to(&self, f: Field) -> bool

Returns true if this is a Field projection with the given index.

Trait Implementations

impl<V: Clone, T: Clone> Clone for ProjectionElem<V, T>

fn clone(&self) -> ProjectionElem<V, T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<V: Debug, T: Debug> Debug for ProjectionElem<V, T>

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

Formats the value using the given formatter.

impl<'tcx, V, T, __D: TyDecoder<'tcx>> Decodable<__D> for ProjectionElem<V, T> where
    T: Decodable<__D>,
    V: Decodable<__D>, 

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

impl<'tcx, V, T, __E: TyEncoder<'tcx>> Encodable<__E> for ProjectionElem<V, T> where
    T: Encodable<__E>,
    V: Encodable<__E>, 

fn encode(&self, __encoder: &mut __E) -> Result<(), <__E as Encoder>::Error>

impl<V: Hash, T: Hash> Hash for ProjectionElem<V, T>

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, 

Feeds a slice of this type into the given Hasher.

impl<'__ctx, V, T> HashStable<StableHashingContext<'__ctx>> for ProjectionElem<V, T> where
    T: HashStable<StableHashingContext<'__ctx>>,
    V: HashStable<StableHashingContext<'__ctx>>, 

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

impl<V: Ord, T: Ord> Ord for ProjectionElem<V, T>

fn cmp(&self, other: &ProjectionElem<V, T>) -> Ordering

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

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

Restrict a value to a certain interval.

impl<V: PartialEq, T: PartialEq> PartialEq<ProjectionElem<V, T>> for ProjectionElem<V, T>

fn eq(&self, other: &ProjectionElem<V, T>) -> bool

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

fn ne(&self, other: &ProjectionElem<V, T>) -> bool

This method tests for !=.

impl<V: PartialOrd, T: PartialOrd> PartialOrd<ProjectionElem<V, T>> for ProjectionElem<V, T>

fn partial_cmp(&self, other: &ProjectionElem<V, T>) -> Option<Ordering>

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

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

This method tests less than (for self and other) and is used by the < operator.

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

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

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

This method tests greater than (for self and other) and is used by the > operator.

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

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

impl<V: Copy, T: Copy> Copy for ProjectionElem<V, T>

impl<V: Eq, T: Eq> Eq for ProjectionElem<V, T>

impl<V, T> StructuralEq for ProjectionElem<V, T>

impl<V, T> StructuralPartialEq for ProjectionElem<V, T>

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.