Enum chalk_solve::solve::Guidance

pub enum Guidance<I: Interner> {
    Definite(Canonical<Substitution<I>>),
    Suggested(Canonical<Substitution<I>>),
    Unknown,
}

When a goal holds ambiguously (e.g., because there are multiple possible solutions), we issue a set of guidance back to type inference.

Variants

Definite

The existential variables must have the given values if the goal is ever to hold, but that alone isn’t enough to guarantee the goal will actually hold.

Tuple Fields of Definite

0: Canonical<Substitution<I>>

Suggested

There are multiple plausible values for the existentials, but the ones here are suggested as the preferred choice heuristically. These should be used for inference fallback only.

Tuple Fields of Suggested

0: Canonical<Substitution<I>>

Unknown

There’s no useful information to feed back to type inference

Trait Implementations

impl<I: Clone + Interner> Clone for Guidance<I>

fn clone(&self) -> Guidance<I>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<I: Debug + Interner> Debug for Guidance<I>

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

Formats the value using the given formatter.

impl<I: PartialEq + Interner> PartialEq<Guidance<I>> for Guidance<I>

fn eq(&self, other: &Guidance<I>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Guidance<I>) -> bool

This method tests for !=.

impl<I: Eq + Interner> Eq for Guidance<I>

impl<I: Interner> StructuralEq for Guidance<I>

impl<I: Interner> StructuralPartialEq for Guidance<I>