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Auto merge of #13112 - lowr:patch/auto-trait-bounds, r=Veykril
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Setup infra for handling auto trait bounds disabled due to perf problems

This patch updates some of the partially-implemented functions of `ChalkContext as RustIrDatabase`, namely `adt_datum()` and `impl_provided_for()`. With those, we can now correctly work with auto trait bounds and distinguish methods based on them.

Resolves #7856 (the second code; the first one is resolved by #13074)

**IMPORTANT**: I don't think we want to merge this until #7637 is resolved. Currently this patch introduces A LOT of unknown types and type mismtaches as shown below. This is because we cannot resolve items like `hashbrown::HashMap` in `std` modules, leading to auto trait bounds on them and their dependents unprovable.

|crate (from `rustc-perf@c52ee6` except for r-a)|e3dc5a588f07d6f1d3a0f33051d4af26190abe9e|HEAD of this branch|
|---|---|---|
|rust-analyzer @ e3dc5a5 |exprs: 417528, ??ty: 907 (0%), ?ty: 114 (0%), !ty: 1|exprs: 417528, ??ty: 1704 (0%), ?ty: 403 (0%), !ty: 20|
|ripgrep|exprs: 62120, ??ty: 2 (0%), ?ty: 0 (0%), !ty: 0|exprs: 62120, ??ty: 132 (0%), ?ty: 58 (0%), !ty: 11|
|webrender/webrender|exprs: 94355, ??ty: 49 (0%), ?ty: 16 (0%), !ty: 2|exprs: 94355, ??ty: 429 (0%), ?ty: 130 (0%), !ty: 7|
|diesel|exprs: 132591, ??ty: 401 (0%), ?ty: 5129 (3%), !ty: 31|exprs: 132591, ??ty: 401 (0%), ?ty: 5129 (3%), !ty: 31|
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@bors
bors committed Feb 19, 2024
2 parents bbb781e + d2b27d0 commit 2223b4f
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Showing 7 changed files with 262 additions and 102 deletions.
2 changes: 1 addition & 1 deletion crates/hir-def/src/data/adt.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@ pub struct StructData {
}

bitflags! {
#[derive(Debug, Clone, PartialEq, Eq)]
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct StructFlags: u8 {
const NO_FLAGS = 0;
/// Indicates whether the struct is `PhantomData`.
Expand Down
293 changes: 199 additions & 94 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 All @@ -10,9 +10,10 @@ use chalk_solve::rust_ir::{self, OpaqueTyDatumBound, WellKnownTrait};

use base_db::CrateId;
use hir_def::{
data::adt::StructFlags,
hir::Movability,
lang_item::{LangItem, LangItemTarget},
AssocItemId, BlockId, GenericDefId, HasModule, ItemContainerId, Lookup, TypeAliasId,
AssocItemId, BlockId, GenericDefId, HasModule, ItemContainerId, Lookup, TypeAliasId, VariantId,
};
use hir_expand::name::name;

Expand All @@ -33,7 +34,7 @@ use crate::{

pub(crate) type AssociatedTyDatum = chalk_solve::rust_ir::AssociatedTyDatum<Interner>;
pub(crate) type TraitDatum = chalk_solve::rust_ir::TraitDatum<Interner>;
pub(crate) type StructDatum = chalk_solve::rust_ir::AdtDatum<Interner>;
pub(crate) type AdtDatum = chalk_solve::rust_ir::AdtDatum<Interner>;
pub(crate) type ImplDatum = chalk_solve::rust_ir::ImplDatum<Interner>;
pub(crate) type OpaqueTyDatum = chalk_solve::rust_ir::OpaqueTyDatum<Interner>;

Expand All @@ -53,8 +54,8 @@ impl chalk_solve::RustIrDatabase<Interner> for ChalkContext<'_> {
fn trait_datum(&self, trait_id: TraitId) -> Arc<TraitDatum> {
self.db.trait_datum(self.krate, trait_id)
}
fn adt_datum(&self, struct_id: AdtId) -> Arc<StructDatum> {
self.db.struct_datum(self.krate, struct_id)
fn adt_datum(&self, struct_id: AdtId) -> Arc<AdtDatum> {
self.db.adt_datum(self.krate, struct_id)
}
fn adt_repr(&self, _struct_id: AdtId) -> Arc<rust_ir::AdtRepr<Interner>> {
// FIXME: keep track of these
Expand Down Expand Up @@ -136,81 +137,92 @@ 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::Error, TyKind::Error)
| (TyKind::Str, TyKind::Str)
| (TyKind::Slice(_), TyKind::Slice(_))
| (TyKind::Never, TyKind::Never)
| (TyKind::Array(_, _), TyKind::Array(_, _)) => 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::FnDef(id_a, _), TyKind::FnDef(id_b, _)) => id_a == id_b,
(TyKind::Ref(id_a, _, _), TyKind::Ref(id_b, _, _))
| (TyKind::Raw(id_a, _), TyKind::Raw(id_b, _)) => id_a == id_b,
(TyKind::Closure(id_a, _), TyKind::Closure(id_b, _)) => id_a == id_b,
(TyKind::Coroutine(id_a, _), TyKind::Coroutine(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,
(_, _) => 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 +501,59 @@ 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 Expand Up @@ -590,7 +655,7 @@ pub(crate) fn trait_datum_query(
coinductive: false, // only relevant for Chalk testing
// FIXME: set these flags correctly
marker: false,
fundamental: false,
fundamental: trait_data.fundamental,
};
let where_clauses = convert_where_clauses(db, trait_.into(), &bound_vars);
let associated_ty_ids = trait_data.associated_types().map(to_assoc_type_id).collect();
Expand Down Expand Up @@ -649,35 +714,75 @@ fn lang_item_from_well_known_trait(trait_: WellKnownTrait) -> LangItem {
}
}

pub(crate) fn struct_datum_query(
pub(crate) fn adt_datum_query(
db: &dyn HirDatabase,
krate: CrateId,
struct_id: AdtId,
) -> Arc<StructDatum> {
debug!("struct_datum {:?}", struct_id);
let chalk_ir::AdtId(adt_id) = struct_id;
chalk_ir::AdtId(adt_id): AdtId,
) -> Arc<AdtDatum> {
debug!("adt_datum {:?}", adt_id);
let generic_params = generics(db.upcast(), adt_id.into());
let upstream = adt_id.module(db.upcast()).krate() != krate;
let where_clauses = {
let generic_params = generics(db.upcast(), adt_id.into());
let bound_vars = generic_params.bound_vars_subst(db, DebruijnIndex::INNERMOST);
convert_where_clauses(db, adt_id.into(), &bound_vars)
let bound_vars_subst = generic_params.bound_vars_subst(db, DebruijnIndex::INNERMOST);
let where_clauses = convert_where_clauses(db, adt_id.into(), &bound_vars_subst);

let (fundamental, phantom_data) = match adt_id {
hir_def::AdtId::StructId(s) => {
let flags = db.struct_data(s).flags;
(
flags.contains(StructFlags::IS_FUNDAMENTAL),
flags.contains(StructFlags::IS_PHANTOM_DATA),
)
}
// FIXME set fundamental flags correctly
hir_def::AdtId::UnionId(_) => (false, false),
hir_def::AdtId::EnumId(_) => (false, false),
};
let flags = rust_ir::AdtFlags {
upstream,
// FIXME set fundamental and phantom_data flags correctly
fundamental: false,
phantom_data: false,
upstream: adt_id.module(db.upcast()).krate() != krate,
fundamental,
phantom_data,
};

#[cfg(FALSE)]
// this slows down rust-analyzer by quite a bit unfortunately, so enabling this is currently not worth it
let variant_id_to_fields = |id: VariantId| {
let variant_data = &id.variant_data(db.upcast());
let fields = if variant_data.fields().is_empty() {
vec![]
} else {
let field_types = db.field_types(id);
variant_data
.fields()
.iter()
.map(|(idx, _)| field_types[idx].clone().substitute(Interner, &bound_vars_subst))
.filter(|it| !it.contains_unknown())
.collect()
};
rust_ir::AdtVariantDatum { fields }
};
// FIXME provide enum variants properly (for auto traits)
let variant = rust_ir::AdtVariantDatum {
fields: Vec::new(), // FIXME add fields (only relevant for auto traits),
let variant_id_to_fields = |_: VariantId| rust_ir::AdtVariantDatum { fields: vec![] };

let (kind, variants) = match adt_id {
hir_def::AdtId::StructId(id) => {
(rust_ir::AdtKind::Struct, vec![variant_id_to_fields(id.into())])
}
hir_def::AdtId::EnumId(id) => {
let variants = db
.enum_data(id)
.variants
.iter()
.map(|&(variant_id, _)| variant_id_to_fields(variant_id.into()))
.collect();
(rust_ir::AdtKind::Enum, variants)
}
hir_def::AdtId::UnionId(id) => {
(rust_ir::AdtKind::Union, vec![variant_id_to_fields(id.into())])
}
};
let struct_datum_bound = rust_ir::AdtDatumBound { variants: vec![variant], where_clauses };
let struct_datum = StructDatum {
// FIXME set ADT kind
kind: rust_ir::AdtKind::Struct,
id: struct_id,

let struct_datum_bound = rust_ir::AdtDatumBound { variants, where_clauses };
let struct_datum = AdtDatum {
kind,
id: chalk_ir::AdtId(adt_id),
binders: make_binders(db, &generic_params, struct_datum_bound),
flags,
};
Expand Down
6 changes: 3 additions & 3 deletions crates/hir-ty/src/db.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -220,12 +220,12 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
trait_id: chalk_db::TraitId,
) -> sync::Arc<chalk_db::TraitDatum>;

#[salsa::invoke(chalk_db::struct_datum_query)]
fn struct_datum(
#[salsa::invoke(chalk_db::adt_datum_query)]
fn adt_datum(
&self,
krate: CrateId,
struct_id: chalk_db::AdtId,
) -> sync::Arc<chalk_db::StructDatum>;
) -> sync::Arc<chalk_db::AdtDatum>;

#[salsa::invoke(chalk_db::impl_datum_query)]
fn impl_datum(
Expand Down
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