Struct ParamEnv

pub struct ParamEnv<'tcx> {
    caller_bounds: Clauses<'tcx>,
}

When interacting with the type system we must provide information about the environment. ParamEnv is the type that represents this information. See the dev guide chapter for more information.

Fields

caller_bounds: Clauses<'tcx>

Caller bounds are Obligations that the caller must satisfy. This is basically the set of bounds on the in-scope type parameters, translated into Obligations, and elaborated and normalized.

Use the caller_bounds() method to access.

Implementations

impl<'tcx> ParamEnv<'tcx>

pub fn empty() -> Self

Construct a trait environment suitable for contexts where there are no where-clauses in scope. In the majority of cases it is incorrect to use an empty environment. See the dev guide section for information on what a ParamEnv is and how to acquire one.

pub fn caller_bounds(self) -> Clauses<'tcx>

pub fn new(caller_bounds: Clauses<'tcx>) -> Self

Construct a trait environment with the given set of predicates.

pub fn without_caller_bounds(self) -> Self

Returns this same environment but with no caller bounds.

pub fn and<T: TypeVisitable<TyCtxt<'tcx>>>( self, value: T, ) -> ParamEnvAnd<'tcx, T>

Creates a pair of param-env and value for use in queries.

Trait Implementations

impl<'tcx> Clone for ParamEnv<'tcx>

fn clone(&self) -> ParamEnv<'tcx>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'tcx> Debug for ParamEnv<'tcx>

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

Formats the value using the given formatter.

impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for ParamEnv<'tcx>

fn decode(d: &mut D) -> Self

impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for ParamEnv<'tcx>

fn encode(&self, e: &mut E)

impl<'tcx> EraseType for ParamEnv<'tcx>

type Result = [u8; 8]

impl<'tcx> Hash for ParamEnv<'tcx>

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, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'tcx, '__ctx> HashStable<StableHashingContext<'__ctx>> for ParamEnv<'tcx>

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

impl<'tcx> Key for ParamEnv<'tcx>

type Cache<V> = DefaultCache<ParamEnv<'tcx>, V>

fn default_span(&self, _: TyCtxt<'_>) -> Span

In the event that a cycle occurs, if no explicit span has been given for a query with key self, what span should we use?

fn key_as_def_id(&self) -> Option<DefId>

If the key is a DefId or DefId–equivalent, return that DefId. Otherwise, return None.

fn def_id_for_ty_in_cycle(&self) -> Option<DefId>

Used to detect when ADT def ids are used as keys in a cycle for better error reporting.

impl<'tcx> ParamEnv<TyCtxt<'tcx>> for ParamEnv<'tcx>

fn caller_bounds(self) -> impl SliceLike<Item = Clause<'tcx>>

impl<'tcx> PartialEq for ParamEnv<'tcx>

fn eq(&self, other: &ParamEnv<'tcx>) -> bool

Tests for self and other values to be equal, and is used by ==.

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

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for ParamEnv<'tcx>

fn try_fold_with<__F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, __folder: &mut __F, ) -> Result<Self, __F::Error>

The entry point for folding. To fold a value t with a folder f call: t.try_fold_with(f).

fn fold_with<F>(self, folder: &mut F) -> Self

where F: TypeFolder<I>,

A convenient alternative to try_fold_with for use with infallible folders. Do not override this method, to ensure coherence with try_fold_with.

impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for ParamEnv<'tcx>

fn visit_with<__V: TypeVisitor<TyCtxt<'tcx>>>( &self, __visitor: &mut __V, ) -> __V::Result

The entry point for visiting. To visit a value t with a visitor v call: t.visit_with(v).

impl<'tcx> Copy for ParamEnv<'tcx>

impl<'tcx> Eq for ParamEnv<'tcx>

impl<'tcx> StructuralPartialEq for ParamEnv<'tcx>

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