Struct rustc_middle::ty::ParamEnv
source · pub struct ParamEnv<'tcx> {
packed: CopyTaggedPtr<&'tcx List<Predicate<'tcx>>, ParamTag, true>,
}
Expand description
When type checking, we use the ParamEnv
to track
details about the set of where-clauses that are in scope at this
particular point.
Fields
packed: CopyTaggedPtr<&'tcx List<Predicate<'tcx>>, ParamTag, true>
This packs both caller bounds and the reveal enum into one pointer.
Caller bounds are Obligation
s that the caller must satisfy. This is
basically the set of bounds on the in-scope type parameters, translated
into Obligation
s, and elaborated and normalized.
Use the caller_bounds()
method to access.
Typically, this is Reveal::UserFacing
, but during codegen we
want Reveal::All
.
Note: This is packed, use the reveal() method to access it.
Implementations
sourceimpl<'tcx> ParamEnv<'tcx>
impl<'tcx> ParamEnv<'tcx>
sourcepub fn empty() -> Self
pub fn empty() -> Self
Construct a trait environment suitable for contexts where
there are no where-clauses in scope. Hidden types (like impl Trait
) are left hidden, so this is suitable for ordinary
type-checking.
pub fn caller_bounds(self) -> &'tcx List<Predicate<'tcx>>
pub fn reveal(self) -> Reveal
pub fn constness(self) -> Constness
pub fn is_const(self) -> bool
sourcepub fn reveal_all() -> Self
pub fn reveal_all() -> Self
Construct a trait environment with no where-clauses in scope
where the values of all impl Trait
and other hidden types
are revealed. This is suitable for monomorphized, post-typeck
environments like codegen or doing optimizations.
N.B., if you want to have predicates in scope, use ParamEnv::new
,
or invoke param_env.with_reveal_all()
.
sourcepub fn new(
caller_bounds: &'tcx List<Predicate<'tcx>>,
reveal: Reveal,
constness: Constness
) -> Self
pub fn new(
caller_bounds: &'tcx List<Predicate<'tcx>>,
reveal: Reveal,
constness: Constness
) -> Self
Construct a trait environment with the given set of predicates.
pub fn with_user_facing(self) -> Self
pub fn with_constness(self, constness: Constness) -> Self
pub fn with_const(self) -> Self
pub fn without_const(self) -> Self
pub fn remap_constness_with(&mut self, constness: BoundConstness)
sourcepub fn with_reveal_all_normalized(self, tcx: TyCtxt<'tcx>) -> Self
pub fn with_reveal_all_normalized(self, tcx: TyCtxt<'tcx>) -> Self
Returns a new parameter environment with the same clauses, but
which “reveals” the true results of projections in all cases
(even for associated types that are specializable). This is
the desired behavior during codegen and certain other special
contexts; normally though we want to use Reveal::UserFacing
,
which is the default.
All opaque types in the caller_bounds of the ParamEnv
will be normalized to their underlying types.
See PR #65989 and issue #65918 for more details
sourcepub fn without_caller_bounds(self) -> Self
pub fn without_caller_bounds(self) -> Self
Returns this same environment but with no caller bounds.
sourcepub fn and<T: TypeVisitable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T>
pub fn and<T: TypeVisitable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T>
Creates a suitable environment in which to perform trait
queries on the given value. When type-checking, this is simply
the pair of the environment plus value. But when reveal is set to
All, then if value
does not reference any type parameters, we will
pair it with the empty environment. This improves caching and is generally
invisible.
N.B., we preserve the environment when type-checking because it
is possible for the user to have wacky where-clauses like
where Box<u32>: Copy
, which are clearly never
satisfiable. We generally want to behave as if they were true,
although the surrounding function is never reachable.
Trait Implementations
sourceimpl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ParamEnv<'tcx>
impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ParamEnv<'tcx>
fn hash_stable(
&self,
hcx: &mut StableHashingContext<'a>,
hasher: &mut StableHasher
)
sourceimpl<'tcx> PartialEq<ParamEnv<'tcx>> for ParamEnv<'tcx>
impl<'tcx> PartialEq<ParamEnv<'tcx>> for ParamEnv<'tcx>
sourceimpl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx>
impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx>
sourcefn try_fold_with<F: FallibleTypeFolder<'tcx>>(
self,
folder: &mut F
) -> Result<Self, F::Error>
fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
self,
folder: &mut F
) -> Result<Self, F::Error>
sourcefn fold_with<F: TypeFolder<'tcx>>(self, folder: &mut F) -> Self
fn fold_with<F: TypeFolder<'tcx>>(self, folder: &mut F) -> Self
try_fold_with
for use with infallible
folders. Do not override this method, to ensure coherence with
try_fold_with
. Read moresourceimpl<'tcx> TypeVisitable<'tcx> for ParamEnv<'tcx>
impl<'tcx> TypeVisitable<'tcx> for ParamEnv<'tcx>
sourcefn visit_with<V: TypeVisitor<'tcx>>(
&self,
visitor: &mut V
) -> ControlFlow<V::BreakTy>
fn visit_with<V: TypeVisitor<'tcx>>(
&self,
visitor: &mut V
) -> ControlFlow<V::BreakTy>
sourcefn 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. Read moresourcefn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
true
if this self
has any regions that escape binder
(and
hence are not bound by it). Read morefn has_escaping_bound_vars(&self) -> bool
fn has_type_flags(&self, flags: TypeFlags) -> bool
fn has_projections(&self) -> bool
fn has_opaque_types(&self) -> bool
fn references_error(&self) -> bool
fn error_reported(&self) -> Option<ErrorGuaranteed>
fn has_param_types_or_consts(&self) -> bool
fn has_infer_regions(&self) -> bool
fn has_infer_types(&self) -> bool
fn has_infer_types_or_consts(&self) -> bool
fn needs_infer(&self) -> bool
fn has_placeholders(&self) -> bool
fn needs_subst(&self) -> bool
sourcefn has_free_regions(&self) -> bool
fn has_free_regions(&self) -> bool
fn has_erased_regions(&self) -> bool
sourcefn has_erasable_regions(&self) -> bool
fn has_erasable_regions(&self) -> bool
sourcefn is_global(&self) -> bool
fn is_global(&self) -> bool
sourcefn has_late_bound_regions(&self) -> bool
fn has_late_bound_regions(&self) -> bool
sourcefn still_further_specializable(&self) -> bool
fn still_further_specializable(&self) -> bool
impl
specialization. Read moreimpl<'tcx> Copy for ParamEnv<'tcx>
impl<'tcx> Eq for ParamEnv<'tcx>
impl<'tcx> StructuralEq for ParamEnv<'tcx>
impl<'tcx> StructuralPartialEq for ParamEnv<'tcx>
Auto Trait Implementations
impl<'tcx> !RefUnwindSafe for ParamEnv<'tcx>
impl<'tcx> Send for ParamEnv<'tcx>
impl<'tcx> Sync for ParamEnv<'tcx>
impl<'tcx> Unpin for ParamEnv<'tcx>
impl<'tcx> !UnwindSafe for ParamEnv<'tcx>
Blanket Implementations
sourceimpl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
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 Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
sourceimpl<Ctxt, T> DepNodeParams<Ctxt> for Twhere
Ctxt: DepContext,
T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
impl<Ctxt, T> DepNodeParams<Ctxt> for Twhere
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
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>
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 moresourceimpl<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>>::Outputwhere
I: Iterator<Item = T>,
F: FnOnce(&[T]) -> R,
sourceimpl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
sourceimpl<CTX, T> Value<CTX> for Twhere
CTX: DepContext,
impl<CTX, T> Value<CTX> for Twhere
CTX: DepContext,
default fn from_cycle_error(tcx: CTX) -> T
impl<'a, T> Captures<'a> for Twhere
T: ?Sized,
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