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Implement RustIrDatabase::impl_provided_for() for ChalkContext
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@lowr @Veykril
lowr authored and Veykril committed Feb 14, 2024
1 parent 000ce5d commit a52accc
Showing 1 changed file with 130 additions and 67 deletions.
197 changes: 130 additions & 67 deletions crates/hir-ty/src/chalk_db.rs
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
//! The implementation of `RustIrDatabase` for Chalk, which provides information
//! about the code that Chalk needs.
use core::ops;
use std::{iter, sync::Arc};
use std::{iter, ops::ControlFlow, sync::Arc};

use tracing::debug;

Expand Down Expand Up @@ -136,81 +136,91 @@ impl chalk_solve::RustIrDatabase<Interner> for ChalkContext<'_> {
_ => self_ty_fp.as_ref().map(std::slice::from_ref).unwrap_or(&[]),
};

let trait_module = trait_.module(self.db.upcast());
let type_module = match self_ty_fp {
Some(TyFingerprint::Adt(adt_id)) => Some(adt_id.module(self.db.upcast())),
Some(TyFingerprint::ForeignType(type_id)) => {
Some(from_foreign_def_id(type_id).module(self.db.upcast()))
}
Some(TyFingerprint::Dyn(trait_id)) => Some(trait_id.module(self.db.upcast())),
_ => None,
};

let mut def_blocks =
[trait_module.containing_block(), type_module.and_then(|it| it.containing_block())];

// Note: Since we're using impls_for_trait, only impls where the trait
// can be resolved should ever reach Chalk. impl_datum relies on that
// and will panic if the trait can't be resolved.
let in_deps = self.db.trait_impls_in_deps(self.krate);
let in_self = self.db.trait_impls_in_crate(self.krate);

let block_impls = iter::successors(self.block, |&block_id| {
cov_mark::hit!(block_local_impls);
self.db.block_def_map(block_id).parent().and_then(|module| module.containing_block())
})
.inspect(|&block_id| {
// make sure we don't search the same block twice
def_blocks.iter_mut().for_each(|block| {
if *block == Some(block_id) {
*block = None;
}
});
})
.filter_map(|block_id| self.db.trait_impls_in_block(block_id));

let id_to_chalk = |id: hir_def::ImplId| id.to_chalk(self.db);

let mut result = vec![];
match fps {
[] => {
debug!("Unrestricted search for {:?} impls...", trait_);
let mut f = |impls: &TraitImpls| {
result.extend(impls.for_trait(trait_).map(id_to_chalk));
};
f(&in_self);
in_deps.iter().map(ops::Deref::deref).for_each(&mut f);
block_impls.for_each(|it| f(&it));
def_blocks
.into_iter()
.flatten()
.filter_map(|it| self.db.trait_impls_in_block(it))
.for_each(|it| f(&it));
}
fps => {
let mut f =
|impls: &TraitImpls| {
result.extend(fps.iter().flat_map(|fp| {
impls.for_trait_and_self_ty(trait_, *fp).map(id_to_chalk)
}));
};
f(&in_self);
in_deps.iter().map(ops::Deref::deref).for_each(&mut f);
block_impls.for_each(|it| f(&it));
def_blocks
.into_iter()
.flatten()
.filter_map(|it| self.db.trait_impls_in_block(it))
.for_each(|it| f(&it));
}
}
if fps.is_empty() {
debug!("Unrestricted search for {:?} impls...", trait_);
self.for_trait_impls(trait_, self_ty_fp, |impls| {
result.extend(impls.for_trait(trait_).map(id_to_chalk));
ControlFlow::Continue(())
})
} else {
self.for_trait_impls(trait_, self_ty_fp, |impls| {
result.extend(
fps.iter().flat_map(move |fp| {
impls.for_trait_and_self_ty(trait_, *fp).map(id_to_chalk)
}),
);
ControlFlow::Continue(())
})
};

debug!("impls_for_trait returned {} impls", result.len());
result
}
fn impl_provided_for(&self, auto_trait_id: TraitId, kind: &chalk_ir::TyKind<Interner>) -> bool {
debug!("impl_provided_for {:?}, {:?}", auto_trait_id, kind);
false // FIXME

let trait_id = from_chalk_trait_id(auto_trait_id);
let self_ty = kind.clone().intern(Interner);
// We cannot filter impls by `TyFingerprint` for the following types:
let self_ty_fp = match kind {
// because we need to find any impl whose Self type is a ref with the same mutability
// (we don't care about the inner type).
TyKind::Ref(..) => None,
// because we need to find any impl whose Self type is a tuple with the same arity.
TyKind::Tuple(..) => None,
_ => TyFingerprint::for_trait_impl(&self_ty),
};

let check_kind = |impl_id| {
let impl_self_ty = self.db.impl_self_ty(impl_id);
// NOTE(skip_binders): it's safe to skip binders here as we don't check substitutions.
let impl_self_kind = impl_self_ty.skip_binders().kind(Interner);

match (kind, impl_self_kind) {
(TyKind::Adt(id_a, _), TyKind::Adt(id_b, _)) => id_a == id_b,
(TyKind::AssociatedType(id_a, _), TyKind::AssociatedType(id_b, _)) => id_a == id_b,
(TyKind::Scalar(scalar_a), TyKind::Scalar(scalar_b)) => scalar_a == scalar_b,
(TyKind::Str, TyKind::Str) => true,
(TyKind::Tuple(arity_a, _), TyKind::Tuple(arity_b, _)) => arity_a == arity_b,
(TyKind::OpaqueType(id_a, _), TyKind::OpaqueType(id_b, _)) => id_a == id_b,
(TyKind::Slice(_), TyKind::Slice(_)) => true,
(TyKind::FnDef(id_a, _), TyKind::FnDef(id_b, _)) => id_a == id_b,
(TyKind::Ref(id_a, _, _), TyKind::Ref(id_b, _, _)) => id_a == id_b,
(TyKind::Raw(id_a, _), TyKind::Raw(id_b, _)) => id_a == id_b,
(TyKind::Never, TyKind::Never) => true,
(TyKind::Array(_, _), TyKind::Array(_, _)) => true,
(TyKind::Closure(id_a, _), TyKind::Closure(id_b, _)) => id_a == id_b,
(TyKind::Coroutine(id_a, _), TyKind::Coroutine(id_b, _)) => id_a == id_b,
(TyKind::CoroutineWitness(id_a, _), TyKind::CoroutineWitness(id_b, _)) => {
id_a == id_b
}
(TyKind::Foreign(id_a), TyKind::Foreign(id_b)) => id_a == id_b,
(TyKind::Error, TyKind::Error) => true,
(_, _) => false,
}
};

if let Some(fp) = self_ty_fp {
self.for_trait_impls(trait_id, self_ty_fp, |impls| {
match impls.for_trait_and_self_ty(trait_id, fp).any(check_kind) {
true => ControlFlow::Break(()),
false => ControlFlow::Continue(()),
}
})
} else {
self.for_trait_impls(trait_id, self_ty_fp, |impls| {
match impls.for_trait(trait_id).any(check_kind) {
true => ControlFlow::Break(()),
false => ControlFlow::Continue(()),
}
})
}
.is_break()
}

fn associated_ty_value(&self, id: AssociatedTyValueId) -> Arc<AssociatedTyValue> {
self.db.associated_ty_value(self.krate, id)
}
Expand Down Expand Up @@ -489,6 +499,59 @@ impl chalk_solve::RustIrDatabase<Interner> for ChalkContext<'_> {
}
}

impl<'a> ChalkContext<'a> {
fn for_trait_impls(
&self,
trait_id: hir_def::TraitId,
self_ty_fp: Option<TyFingerprint>,
mut f: impl FnMut(&TraitImpls) -> ControlFlow<()>,
) -> ControlFlow<()> {
// Note: Since we're using `impls_for_trait` and `impl_provided_for`,
// only impls where the trait can be resolved should ever reach Chalk.
// `impl_datum` relies on that and will panic if the trait can't be resolved.
let in_deps = self.db.trait_impls_in_deps(self.krate);
let in_self = self.db.trait_impls_in_crate(self.krate);
let trait_module = trait_id.module(self.db.upcast());
let type_module = match self_ty_fp {
Some(TyFingerprint::Adt(adt_id)) => Some(adt_id.module(self.db.upcast())),
Some(TyFingerprint::ForeignType(type_id)) => {
Some(from_foreign_def_id(type_id).module(self.db.upcast()))
}
Some(TyFingerprint::Dyn(trait_id)) => Some(trait_id.module(self.db.upcast())),
_ => None,
};

let mut def_blocks =
[trait_module.containing_block(), type_module.and_then(|it| it.containing_block())];

let block_impls = iter::successors(self.block, |&block_id| {
cov_mark::hit!(block_local_impls);
self.db.block_def_map(block_id).parent().and_then(|module| module.containing_block())
})
.inspect(|&block_id| {
// make sure we don't search the same block twice
def_blocks.iter_mut().for_each(|block| {
if *block == Some(block_id) {
*block = None;
}
});
})
.filter_map(|block_id| self.db.trait_impls_in_block(block_id));
f(&in_self)?;
for it in in_deps.iter().map(ops::Deref::deref) {
f(it)?;
}
for it in block_impls {
f(&it)?;
}
for it in def_blocks.into_iter().flatten().filter_map(|it| self.db.trait_impls_in_block(it))
{
f(&it)?;
}
ControlFlow::Continue(())
}
}

impl chalk_ir::UnificationDatabase<Interner> for &dyn HirDatabase {
fn fn_def_variance(
&self,
Expand Down

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