Enum rustc_middle::mir::syntax::ProjectionElem
source · [−]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)
Index into a slice/array.
Note that this does not also dereference, and so it does not exactly correspond to slice indexing in Rust. In other words, in the below Rust code:
let x = &[1, 2, 3, 4];
let i = 2;
x[i];
The x[i]
is turned into a Deref
followed by an Index
, not just an Index
. The same
thing is true of the ConstantIndex
and Subslice
projections below.
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 PlaceElem
s 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 enum or a generator.
The included Symbol is the name of the variant, used for printing MIR.
Implementations
sourceimpl<V, T> ProjectionElem<V, T>
impl<V, T> ProjectionElem<V, T>
sourcefn is_indirect(&self) -> bool
fn is_indirect(&self) -> bool
Returns true
if the target of this projection may refer to a different region of memory
than the base.
sourcepub fn is_downcast_to(&self, v: VariantIdx) -> bool
pub fn is_downcast_to(&self, v: VariantIdx) -> bool
Returns true
if this is a Downcast
projection with the given VariantIdx
.
sourcepub fn is_field_to(&self, f: Field) -> bool
pub fn is_field_to(&self, f: Field) -> bool
Returns true
if this is a Field
projection with the given index.
Trait Implementations
sourceimpl<V: Clone, T: Clone> Clone for ProjectionElem<V, T>
impl<V: Clone, T: Clone> Clone for ProjectionElem<V, T>
sourcefn clone(&self) -> ProjectionElem<V, T>
fn clone(&self) -> ProjectionElem<V, T>
Returns a copy of the value. Read more
1.0.0 · sourcefn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
sourceimpl<V: Debug, T: Debug> Debug for ProjectionElem<V, T>
impl<V: Debug, T: Debug> Debug for ProjectionElem<V, T>
sourceimpl<'tcx, V, T, __D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<__D> for ProjectionElem<V, T> where
T: Decodable<__D>,
V: Decodable<__D>,
impl<'tcx, V, T, __D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<__D> for ProjectionElem<V, T> where
T: Decodable<__D>,
V: Decodable<__D>,
sourceimpl<'tcx, V, T, __E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<__E> for ProjectionElem<V, T> where
T: Encodable<__E>,
V: Encodable<__E>,
impl<'tcx, V, T, __E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<__E> for ProjectionElem<V, T> where
T: Encodable<__E>,
V: Encodable<__E>,
sourceimpl<V: Hash, T: Hash> Hash for ProjectionElem<V, T>
impl<V: Hash, T: Hash> Hash for ProjectionElem<V, T>
sourceimpl<'__ctx, V, T> HashStable<StableHashingContext<'__ctx>> for ProjectionElem<V, T> where
T: HashStable<StableHashingContext<'__ctx>>,
V: HashStable<StableHashingContext<'__ctx>>,
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
)
sourceimpl<V: Ord, T: Ord> Ord for ProjectionElem<V, T>
impl<V: Ord, T: Ord> Ord for ProjectionElem<V, T>
sourcefn cmp(&self, other: &ProjectionElem<V, T>) -> Ordering
fn cmp(&self, other: &ProjectionElem<V, T>) -> Ordering
1.21.0 · sourcefn max(self, other: Self) -> Self
fn max(self, other: Self) -> Self
Compares and returns the maximum of two values. Read more
1.21.0 · sourcefn min(self, other: Self) -> Self
fn min(self, other: Self) -> Self
Compares and returns the minimum of two values. Read more
1.50.0 · sourcefn clamp(self, min: Self, max: Self) -> Self where
Self: PartialOrd<Self>,
fn clamp(self, min: Self, max: Self) -> Self where
Self: PartialOrd<Self>,
Restrict a value to a certain interval. Read more
sourceimpl<V: PartialEq, T: PartialEq> PartialEq<ProjectionElem<V, T>> for ProjectionElem<V, T>
impl<V: PartialEq, T: PartialEq> PartialEq<ProjectionElem<V, T>> for ProjectionElem<V, T>
sourcefn eq(&self, other: &ProjectionElem<V, T>) -> bool
fn eq(&self, other: &ProjectionElem<V, T>) -> bool
This method tests for self
and other
values to be equal, and is used
by ==
. Read more
sourcefn ne(&self, other: &ProjectionElem<V, T>) -> bool
fn ne(&self, other: &ProjectionElem<V, T>) -> bool
This method tests for !=
.
sourceimpl<V: PartialOrd, T: PartialOrd> PartialOrd<ProjectionElem<V, T>> for ProjectionElem<V, T>
impl<V: PartialOrd, T: PartialOrd> PartialOrd<ProjectionElem<V, T>> for ProjectionElem<V, T>
sourcefn partial_cmp(&self, other: &ProjectionElem<V, T>) -> Option<Ordering>
fn partial_cmp(&self, other: &ProjectionElem<V, T>) -> Option<Ordering>
This method returns an ordering between self
and other
values if one exists. Read more
1.0.0 · sourcefn lt(&self, other: &Rhs) -> bool
fn lt(&self, other: &Rhs) -> bool
This method tests less than (for self
and other
) and is used by the <
operator. Read more
1.0.0 · sourcefn le(&self, other: &Rhs) -> bool
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
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>
Auto Trait Implementations
impl<V, T> RefUnwindSafe for ProjectionElem<V, T> where
T: RefUnwindSafe,
V: RefUnwindSafe,
impl<V, T> Send for ProjectionElem<V, T> where
T: Send,
V: Send,
impl<V, T> Sync for ProjectionElem<V, T> where
T: Sync,
V: Sync,
impl<V, T> Unpin for ProjectionElem<V, T> where
T: Unpin,
V: Unpin,
impl<V, T> UnwindSafe for ProjectionElem<V, T> where
T: UnwindSafe,
V: UnwindSafe,
Blanket Implementations
sourceimpl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T where
T: Copy,
impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T where
T: Copy,
fn allocate_on(self, arena: &'a Arena<'tcx>) -> &'a mut T
fn allocate_from_iter(
arena: &'a Arena<'tcx>,
iter: impl IntoIterator<Item = T>
) -> &'a mut [T]ⓘNotable traits for &[u8]impl Read for &[u8]impl Write for &mut [u8]
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<Ctxt, T> DepNodeParams<Ctxt> for T where
Ctxt: DepContext,
T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
impl<Ctxt, T> DepNodeParams<Ctxt> for T where
Ctxt: DepContext,
T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
default fn fingerprint_style() -> FingerprintStyle
sourcedefault fn to_fingerprint(&self, tcx: Ctxt) -> Fingerprint
default fn to_fingerprint(&self, tcx: Ctxt) -> 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). Read more
default fn to_debug_str(&self, Ctxt) -> String
sourcedefault fn recover(Ctxt, &DepNode<<Ctxt as DepContext>::DepKind>) -> Option<T>
default fn recover(Ctxt, &DepNode<<Ctxt as DepContext>::DepKind>) -> 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. Read more
sourceimpl<T, R> InternIteratorElement<T, R> for T
impl<T, R> InternIteratorElement<T, R> for T
type Output = R
fn intern_with<I, F>(iter: I, f: F) -> <T as InternIteratorElement<T, R>>::Output where
I: Iterator<Item = T>,
F: FnOnce(&[T]) -> R,
sourceimpl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
impl<'a, T> Captures<'a> for T where
T: ?Sized,
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.