Struct UserTypeProjections

pub struct UserTypeProjections {
    pub contents: Vec<(UserTypeProjection, Span)>,
}

A collection of projections into user types.

They are projections because a binding can occur a part of a parent pattern that has been ascribed a type.

It’s a collection because there can be multiple type ascriptions on the path from the root of the pattern down to the binding itself.

An example:

struct S<'a>((i32, &'a str), String);
let S((_, w): (i32, &'static str), _): S = ...;
//    ------  ^^^^^^^^^^^^^^^^^^^ (1)
//  ---------------------------------  ^ (2)

The highlights labelled (1) show the subpattern (_, w) being ascribed the type (i32, &'static str).

The highlights labelled (2) show the whole pattern being ascribed the type S.

In this example, when we descend to w, we will have built up the following two projected types:

• base: S, projection: (base.0).1
• base: (i32, &'static str), projection: base.1

The first will lead to the constraint w: &'1 str (for some inferred region '1). The second will lead to the constraint w: &'static str.

Fields

contents: Vec<(UserTypeProjection, Span)>

Implementations

impl<'tcx> UserTypeProjections

pub fn none() -> Self

pub fn is_empty(&self) -> bool

pub fn projections_and_spans( &self, ) -> impl Iterator<Item = &(UserTypeProjection, Span)> + ExactSizeIterator

pub fn projections( &self, ) -> impl Iterator<Item = &UserTypeProjection> + ExactSizeIterator

pub fn push_projection(self, user_ty: &UserTypeProjection, span: Span) -> Self

fn map_projections( self, f: impl FnMut(UserTypeProjection) -> UserTypeProjection, ) -> Self

pub fn index(self) -> Self

pub fn subslice(self, from: u64, to: u64) -> Self

pub fn deref(self) -> Self

pub fn leaf(self, field: FieldIdx) -> Self

pub fn variant( self, adt_def: AdtDef<'tcx>, variant_index: VariantIdx, field_index: FieldIdx, ) -> Self

Trait Implementations

impl Clone for UserTypeProjections

fn clone(&self) -> UserTypeProjections

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for UserTypeProjections

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

Formats the value using the given formatter.

impl<__D: TyDecoder> Decodable<__D> for UserTypeProjections

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

impl<__E: TyEncoder> Encodable<__E> for UserTypeProjections

fn encode(&self, __encoder: &mut __E)

impl<'__ctx> HashStable<StableHashingContext<'__ctx>> for UserTypeProjections

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

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

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 UserTypeProjections

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).

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: 24 bytes