Enum rustc_type_ir::solve::GoalSource

pub enum GoalSource {
    Misc,
    ImplWhereBound,
    InstantiateHigherRanked,
}

Why a specific goal has to be proven.

This is necessary as we treat nested goals different depending on their source.

Variants

Misc

ImplWhereBound

We’re proving a where-bound of an impl.

FIXME(-Znext-solver=coinductive): Explain how and why this changes whether cycles are coinductive.

This also impacts whether we erase constraints on overflow. Erasing constraints is generally very useful for perf and also results in better error messages by avoiding spurious errors. We do not erase overflow constraints in normalizes-to goals unless they are from an impl where-clause. This is necessary due to backwards compatability, cc trait-system-refactor-initiatitive#70.

InstantiateHigherRanked

Instantiating a higher-ranked goal and re-proving it.

Trait Implementations

impl Clone for GoalSource

fn clone(&self) -> GoalSource

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for GoalSource

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

Formats the value using the given formatter.

impl Hash for GoalSource

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<__CTX> HashStable<__CTX> for GoalSource

fn hash_stable(&self, __hcx: &mut __CTX, __hasher: &mut StableHasher)

impl PartialEq for GoalSource

fn eq(&self, other: &GoalSource) -> 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<I: Interner> TypeFoldable<I> for GoalSource

fn try_fold_with<F: FallibleTypeFolder<I>>( self, _: &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: TypeFolder<I>>(self, _: &mut F) -> Self

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<I: Interner> TypeVisitable<I> for GoalSource

fn visit_with<F: TypeVisitor<I>>(&self, _: &mut F) -> F::Result

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

impl Copy for GoalSource

impl Eq for GoalSource

impl StructuralPartialEq for GoalSource

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: 1 byte

Size for each variant:

• Misc: 0 bytes
• ImplWhereBound: 0 bytes
• InstantiateHigherRanked: 0 bytes