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use crate::interner::HasInterner;
use crate::zip::{Zip, Zipper};
use crate::*;
pub trait CouldMatch<T: ?Sized + HasInterner> {
fn could_match(
&self,
interner: T::Interner,
db: &dyn UnificationDatabase<T::Interner>,
other: &T,
) -> bool;
}
#[allow(unreachable_code, unused_variables)]
impl<T, I> CouldMatch<T> for T
where
T: Zip<I> + ?Sized + HasInterner<Interner = I>,
I: Interner,
{
fn could_match(&self, interner: I, db: &dyn UnificationDatabase<I>, other: &T) -> bool {
return Zip::zip_with(
&mut MatchZipper { interner, db },
Variance::Invariant,
self,
other,
)
.is_ok();
struct MatchZipper<'i, I> {
interner: I,
db: &'i dyn UnificationDatabase<I>,
}
impl<'i, I: Interner> Zipper<I> for MatchZipper<'i, I> {
fn zip_tys(&mut self, variance: Variance, a: &Ty<I>, b: &Ty<I>) -> Fallible<()> {
let interner = self.interner;
let matches = |a: &Substitution<I>, b: &Substitution<I>| {
a.iter(interner)
.zip(b.iter(interner))
.all(|(p_a, p_b)| p_a.could_match(interner, self.db, p_b))
};
let could_match = match (a.kind(interner), b.kind(interner)) {
(TyKind::Adt(id_a, substitution_a), TyKind::Adt(id_b, substitution_b)) => {
id_a == id_b
&& self
.zip_substs(
variance,
Some(self.unification_database().adt_variance(*id_a)),
substitution_a.as_slice(interner),
substitution_b.as_slice(interner),
)
.is_ok()
}
(
TyKind::AssociatedType(assoc_ty_a, substitution_a),
TyKind::AssociatedType(assoc_ty_b, substitution_b),
) => assoc_ty_a == assoc_ty_b && matches(substitution_a, substitution_b),
(TyKind::Scalar(scalar_a), TyKind::Scalar(scalar_b)) => scalar_a == scalar_b,
(TyKind::Str, TyKind::Str) => true,
(
TyKind::Tuple(arity_a, substitution_a),
TyKind::Tuple(arity_b, substitution_b),
) => arity_a == arity_b && matches(substitution_a, substitution_b),
(
TyKind::OpaqueType(opaque_ty_a, substitution_a),
TyKind::OpaqueType(opaque_ty_b, substitution_b),
) => opaque_ty_a == opaque_ty_b && matches(substitution_a, substitution_b),
(TyKind::Slice(ty_a), TyKind::Slice(ty_b)) => {
ty_a.could_match(interner, self.db, ty_b)
}
(
TyKind::FnDef(fn_def_a, substitution_a),
TyKind::FnDef(fn_def_b, substitution_b),
) => {
fn_def_a == fn_def_b
&& self
.zip_substs(
variance,
Some(self.unification_database().fn_def_variance(*fn_def_a)),
substitution_a.as_slice(interner),
substitution_b.as_slice(interner),
)
.is_ok()
}
(
TyKind::Ref(mutability_a, lifetime_a, ty_a),
TyKind::Ref(mutability_b, lifetime_b, ty_b),
) => {
mutability_a == mutability_b
&& lifetime_a.could_match(interner, self.db, lifetime_b)
&& ty_a.could_match(interner, self.db, ty_b)
}
(TyKind::Raw(mutability_a, ty_a), TyKind::Raw(mutability_b, ty_b)) => {
mutability_a == mutability_b && ty_a.could_match(interner, self.db, ty_b)
}
(TyKind::Never, TyKind::Never) => true,
(TyKind::Array(ty_a, const_a), TyKind::Array(ty_b, const_b)) => {
ty_a.could_match(interner, self.db, ty_b)
&& const_a.could_match(interner, self.db, const_b)
}
(
TyKind::Closure(id_a, substitution_a),
TyKind::Closure(id_b, substitution_b),
) => id_a == id_b && matches(substitution_a, substitution_b),
(
TyKind::Generator(generator_a, substitution_a),
TyKind::Generator(generator_b, substitution_b),
) => {
generator_a == generator_b
&& self
.zip_substs(
variance,
None,
substitution_a.as_slice(interner),
substitution_b.as_slice(interner),
)
.is_ok()
}
(
TyKind::GeneratorWitness(generator_a, substitution_a),
TyKind::GeneratorWitness(generator_b, substitution_b),
) => {
generator_a == generator_b
&& self
.zip_substs(
variance,
None,
substitution_a.as_slice(interner),
substitution_b.as_slice(interner),
)
.is_ok()
}
(TyKind::Foreign(foreign_ty_a), TyKind::Foreign(foreign_ty_b)) => {
foreign_ty_a == foreign_ty_b
}
(TyKind::Error, TyKind::Error) => true,
_ => true,
};
if could_match {
Ok(())
} else {
Err(NoSolution)
}
}
fn zip_lifetimes(
&mut self,
variance: Variance,
_: &Lifetime<I>,
_: &Lifetime<I>,
) -> Fallible<()> {
Ok(())
}
fn zip_consts(
&mut self,
variance: Variance,
_: &Const<I>,
_: &Const<I>,
) -> Fallible<()> {
Ok(())
}
fn zip_binders<T>(
&mut self,
variance: Variance,
a: &Binders<T>,
b: &Binders<T>,
) -> Fallible<()>
where
T: HasInterner + Zip<I>,
{
Zip::zip_with(self, variance, &a.value, &b.value)
}
fn interner(&self) -> I {
self.interner
}
fn unification_database(&self) -> &dyn UnificationDatabase<I> {
self.db
}
}
}
}
impl<I: Interner> CouldMatch<DomainGoal<I>> for ProgramClauseData<I> {
fn could_match(
&self,
interner: I,
db: &dyn UnificationDatabase<I>,
other: &DomainGoal<I>,
) -> bool {
self.0.value.consequence.could_match(interner, db, other)
}
}
impl<I: Interner> CouldMatch<DomainGoal<I>> for ProgramClause<I> {
fn could_match(
&self,
interner: I,
db: &dyn UnificationDatabase<I>,
other: &DomainGoal<I>,
) -> bool {
self.data(interner).could_match(interner, db, other)
}
}