Enum rustc_middle::mir::ProjectionElem
source · pub enum ProjectionElem<V, T> {
Deref,
Field(FieldIdx, T),
Index(V),
ConstantIndex {
offset: u64,
min_length: u64,
from_end: bool,
},
Subslice {
from: u64,
to: u64,
from_end: bool,
},
Downcast(Option<Symbol>, VariantIdx),
OpaqueCast(T),
}
Variants§
Deref
Field(FieldIdx, T)
A field (e.g., f
in _1.f
) is one variant of ProjectionElem
. Conceptually,
rustc can identify that a field projection refers to either two different regions of memory
or the same one between the base and the ‘projection element’.
Read more about projections in the rustc-dev-guide
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
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
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.
OpaqueCast(T)
Like an explicit cast from an opaque type to a concrete type, but without requiring an intermediate variable.
Implementations§
source§impl<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_stable_offset(&self) -> bool
pub fn is_stable_offset(&self) -> bool
Returns true
if the target of this projection always refers to the same memory region
whatever the state of the program.
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: FieldIdx) -> bool
pub fn is_field_to(&self, f: FieldIdx) -> bool
Returns true
if this is a Field
projection with the given index.
sourcepub fn can_use_in_debuginfo(&self) -> bool
pub fn can_use_in_debuginfo(&self) -> bool
Returns true
if this is accepted inside VarDebugInfoContents::Place
.
Trait Implementations§
source§impl<V: Clone, T: Clone> Clone for ProjectionElem<V, T>
impl<V: Clone, T: Clone> Clone for ProjectionElem<V, T>
source§fn clone(&self) -> ProjectionElem<V, T>
fn clone(&self) -> ProjectionElem<V, T>
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl<'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>,
source§impl<'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>,
source§impl<'__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 )
source§impl<V: Ord, T: Ord> Ord for ProjectionElem<V, T>
impl<V: Ord, T: Ord> Ord for ProjectionElem<V, T>
source§fn cmp(&self, other: &ProjectionElem<V, T>) -> Ordering
fn cmp(&self, other: &ProjectionElem<V, T>) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere Self: Sized,
source§impl<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>
source§fn eq(&self, other: &ProjectionElem<V, T>) -> bool
fn eq(&self, other: &ProjectionElem<V, T>) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl<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>
source§fn partial_cmp(&self, other: &ProjectionElem<V, T>) -> Option<Ordering>
fn partial_cmp(&self, other: &ProjectionElem<V, T>) -> Option<Ordering>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moresource§impl<'tcx, V, T> TypeFoldable<TyCtxt<'tcx>> for ProjectionElem<V, T>where
T: TypeFoldable<TyCtxt<'tcx>>,
V: TypeFoldable<TyCtxt<'tcx>>,
impl<'tcx, V, T> TypeFoldable<TyCtxt<'tcx>> for ProjectionElem<V, T>where T: TypeFoldable<TyCtxt<'tcx>>, V: TypeFoldable<TyCtxt<'tcx>>,
source§fn try_fold_with<__F: FallibleTypeFolder<TyCtxt<'tcx>>>(
self,
__folder: &mut __F
) -> Result<Self, __F::Error>
fn try_fold_with<__F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, __folder: &mut __F ) -> Result<Self, __F::Error>
source§fn fold_with<F>(self, folder: &mut F) -> Selfwhere
F: TypeFolder<I>,
fn fold_with<F>(self, folder: &mut F) -> Selfwhere F: TypeFolder<I>,
try_fold_with
for use with infallible
folders. Do not override this method, to ensure coherence with
try_fold_with
.source§impl<'tcx, V, T> TypeVisitable<TyCtxt<'tcx>> for ProjectionElem<V, T>where
T: TypeVisitable<TyCtxt<'tcx>>,
V: TypeVisitable<TyCtxt<'tcx>>,
impl<'tcx, V, T> TypeVisitable<TyCtxt<'tcx>> for ProjectionElem<V, T>where T: TypeVisitable<TyCtxt<'tcx>>, V: TypeVisitable<TyCtxt<'tcx>>,
source§fn visit_with<__V: TypeVisitor<TyCtxt<'tcx>>>(
&self,
__visitor: &mut __V
) -> ControlFlow<__V::BreakTy>
fn visit_with<__V: TypeVisitor<TyCtxt<'tcx>>>( &self, __visitor: &mut __V ) -> ControlFlow<__V::BreakTy>
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§
source§impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere T: Copy,
fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T
fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T> ) -> &'a mut [T]
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T, R> CollectAndApply<T, R> for T
impl<T, R> CollectAndApply<T, R> for T
source§impl<Tcx, T> DepNodeParams<Tcx> for Twhere
Tcx: DepContext,
T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
impl<Tcx, T> DepNodeParams<Tcx> for Twhere Tcx: DepContext, T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
default fn fingerprint_style() -> FingerprintStyle
source§default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint
default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint
default fn to_debug_str(&self, _: Tcx) -> String
source§default fn recover(_: Tcx, _: &DepNode) -> Option<T>
default fn recover(_: Tcx, _: &DepNode) -> Option<T>
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<P> IntoQueryParam<P> for P
impl<P> IntoQueryParam<P> for P
fn into_query_param(self) -> P
source§impl<'tcx, T> IsSuggestable<'tcx> for Twhere
T: TypeVisitable<TyCtxt<'tcx>> + TypeFoldable<TyCtxt<'tcx>>,
impl<'tcx, T> IsSuggestable<'tcx> for Twhere T: TypeVisitable<TyCtxt<'tcx>> + TypeFoldable<TyCtxt<'tcx>>,
source§impl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
source§impl<'tcx, T> ToPredicate<'tcx, T> for T
impl<'tcx, T> ToPredicate<'tcx, T> for T
fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T
source§impl<'tcx, T> TypeVisitableExt<'tcx> for Twhere
T: TypeVisitable<TyCtxt<'tcx>>,
impl<'tcx, T> TypeVisitableExt<'tcx> for Twhere T: TypeVisitable<TyCtxt<'tcx>>,
source§fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
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.source§fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
true
if this type has any regions that escape binder
(and
hence are not bound by it).source§fn has_escaping_bound_vars(&self) -> bool
fn has_escaping_bound_vars(&self) -> bool
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 morefn has_type_flags(&self, flags: TypeFlags) -> bool
fn has_projections(&self) -> bool
fn has_inherent_projections(&self) -> bool
fn has_opaque_types(&self) -> bool
fn has_generators(&self) -> bool
fn references_error(&self) -> bool
fn error_reported(&self) -> Result<(), ErrorGuaranteed>
fn has_non_region_param(&self) -> bool
fn has_infer_regions(&self) -> bool
fn has_infer_types(&self) -> bool
fn has_non_region_infer(&self) -> bool
fn has_infer(&self) -> bool
fn has_placeholders(&self) -> bool
fn has_non_region_placeholders(&self) -> bool
fn has_param(&self) -> bool
source§fn has_free_regions(&self) -> bool
fn has_free_regions(&self) -> bool
fn has_erased_regions(&self) -> bool
source§fn has_erasable_regions(&self) -> bool
fn has_erasable_regions(&self) -> bool
source§fn is_global(&self) -> bool
fn is_global(&self) -> bool
source§fn has_late_bound_regions(&self) -> bool
fn has_late_bound_regions(&self) -> bool
source§fn has_non_region_late_bound(&self) -> bool
fn has_non_region_late_bound(&self) -> bool
source§fn has_late_bound_vars(&self) -> bool
fn has_late_bound_vars(&self) -> bool
source§fn still_further_specializable(&self) -> bool
fn still_further_specializable(&self) -> bool
impl
specialization.source§impl<Tcx, T> Value<Tcx> for Twhere
Tcx: DepContext,
impl<Tcx, T> Value<Tcx> for Twhere Tcx: DepContext,
default fn from_cycle_error( tcx: Tcx, cycle: &[QueryInfo], _guar: ErrorGuaranteed ) -> 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.