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|
//! Implementations of the Chalk `Cast` trait for our types.
use chalk_ir::{
cast::{Cast, CastTo},
interner::HasInterner,
};
use crate::{AliasEq, DomainGoal, GenericArg, GenericArgData, Interner, TraitRef, Ty, WhereClause};
macro_rules! has_interner {
($t:ty) => {
impl HasInterner for $t {
type Interner = crate::Interner;
}
};
}
has_interner!(WhereClause);
has_interner!(DomainGoal);
has_interner!(GenericArg);
has_interner!(Ty);
impl CastTo<WhereClause> for TraitRef {
fn cast_to(self, _interner: &Interner) -> WhereClause {
WhereClause::Implemented(self)
}
}
impl CastTo<WhereClause> for AliasEq {
fn cast_to(self, _interner: &Interner) -> WhereClause {
WhereClause::AliasEq(self)
}
}
impl CastTo<DomainGoal> for WhereClause {
fn cast_to(self, _interner: &Interner) -> DomainGoal {
DomainGoal::Holds(self)
}
}
impl CastTo<GenericArg> for Ty {
fn cast_to(self, interner: &Interner) -> GenericArg {
GenericArg::new(interner, GenericArgData::Ty(self))
}
}
macro_rules! transitive_impl {
($a:ty, $b:ty, $c:ty) => {
impl CastTo<$c> for $a {
fn cast_to(self, interner: &Interner) -> $c {
self.cast::<$b>(interner).cast(interner)
}
}
};
}
// In Chalk, these can be done as blanket impls, but that doesn't work here
// because of coherence
transitive_impl!(TraitRef, WhereClause, DomainGoal);
transitive_impl!(AliasEq, WhereClause, DomainGoal);
macro_rules! reflexive_impl {
($a:ty) => {
impl CastTo<$a> for $a {
fn cast_to(self, _interner: &Interner) -> $a {
self
}
}
};
}
reflexive_impl!(GenericArg);
|
