Struct Unifier 

pub struct Unifier { /* private fields */ }

Implementations

impl Unifier

pub fn new() -> Self

pub fn fresh(&mut self) -> Ty

pub fn fresh_id(&mut self) -> TyVarId

pub fn fresh_eff_id(&mut self) -> u32

Allocate a fresh effect-row variable for use in polymorphic signatures (e.g. list.map[T, U, E]’s E).

pub fn resolve(&self, t: &Ty) -> Ty

Resolve a type by following substitutions. Recursive; structural.

pub fn resolve_effects(&self, eff: &EffectSet) -> EffectSet

Resolve an effect set by chasing the var substitution chain. Concrete effects accumulate along the chain; the returned set’s var is the terminal unbound var, or None if fully concrete.

pub fn unify_effects( &mut self, a: &EffectSet, b: &EffectSet, ) -> Result<(), UnifyError>

Unify two effect sets. Variables are existentially bound at the signature site; at call sites they bind to the actual closure’s effects.

Cases (after resolving):

• both fully concrete: must be equal
• exactly one carries a var: var := the missing effects (i.e. the other side’s concrete minus this side’s), with the other side’s residual var if any
• both carry a var: bind one to the other (alias)

pub fn unify(&mut self, a: &Ty, b: &Ty) -> Result<(), UnifyError>

Trait Implementations

impl Default for Unifier

fn default() -> Unifier

Returns the “default value” for a type.