10 files changed, 76 insertions, 37 deletions

diff --git a/crates/hir_ty/src/chalk_db.rs b/crates/hir_ty/src/chalk_db.rs
index 566e4f406..f5b2c5ff0 100644
--- a/crates/hir_ty/src/chalk_db.rs
+++ b/crates/hir_ty/src/chalk_db.rs
@@ -1,4 +1,5 @@
-//! Conversion code from/to Chalk.
+//! The implementation of `RustIrDatabase` for Chalk, which provides information
+//! about the code that Chalk needs.
 use std::sync::Arc;
 
 use log::debug;
@@ -13,7 +14,21 @@ use hir_def::{
 };
 use hir_expand::name::name;
 
-use crate::{AliasEq, AliasTy, BoundVar, CallableDefId, DebruijnIndex, FnDefId, Interner, ProjectionTy, Substitution, TraitRef, TraitRefExt, Ty, TyBuilder, TyExt, TyKind, WhereClause, traits::ChalkContext, db::HirDatabase, display::HirDisplay, from_assoc_type_id, make_only_type_binders, mapping::{convert_where_clauses, generic_predicate_to_inline_bound, TypeAliasAsValue}, method_resolution::{TyFingerprint, ALL_FLOAT_FPS, ALL_INT_FPS}, to_assoc_type_id, to_chalk_trait_id, utils::generics};
+use crate::{
+    db::HirDatabase,
+    display::HirDisplay,
+    from_assoc_type_id, make_only_type_binders,
+    mapping::{
+        convert_where_clauses, from_chalk, generic_predicate_to_inline_bound, ToChalk,
+        TypeAliasAsValue,
+    },
+    method_resolution::{TyFingerprint, ALL_FLOAT_FPS, ALL_INT_FPS},
+    to_assoc_type_id, to_chalk_trait_id,
+    traits::ChalkContext,
+    utils::generics,
+    AliasEq, AliasTy, BoundVar, CallableDefId, DebruijnIndex, FnDefId, Interner, ProjectionTy,
+    Substitution, TraitRef, TraitRefExt, Ty, TyBuilder, TyExt, TyKind, WhereClause,
+};
 
 pub(crate) type AssociatedTyDatum = chalk_solve::rust_ir::AssociatedTyDatum<Interner>;
 pub(crate) type TraitDatum = chalk_solve::rust_ir::TraitDatum<Interner>;
@@ -31,19 +46,6 @@ pub(crate) type AssociatedTyValue = chalk_solve::rust_ir::AssociatedTyValue<Inte
 pub(crate) type FnDefDatum = chalk_solve::rust_ir::FnDefDatum<Interner>;
 pub(crate) type Variances = chalk_ir::Variances<Interner>;
 
-pub(crate) trait ToChalk {
-    type Chalk;
-    fn to_chalk(self, db: &dyn HirDatabase) -> Self::Chalk;
-    fn from_chalk(db: &dyn HirDatabase, chalk: Self::Chalk) -> Self;
-}
-
-pub(crate) fn from_chalk<T, ChalkT>(db: &dyn HirDatabase, chalk: ChalkT) -> T
-where
-    T: ToChalk<Chalk = ChalkT>,
-{
-    T::from_chalk(db, chalk)
-}
-
 impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
     fn associated_ty_data(&self, id: AssocTypeId) -> Arc<AssociatedTyDatum> {
         self.db.associated_ty_data(id)
diff --git a/crates/hir_ty/src/db.rs b/crates/hir_ty/src/db.rs
index ea0580df1..e11fc579e 100644
--- a/crates/hir_ty/src/db.rs
+++ b/crates/hir_ty/src/db.rs
@@ -9,7 +9,12 @@ use hir_def::{
 };
 use la_arena::ArenaMap;
 
-use crate::{Binders, CallableDefId, FnDefId, ImplTraitId, InferenceResult, Interner, PolyFnSig, QuantifiedWhereClause, ReturnTypeImplTraits, TraitRef, Ty, TyDefId, ValueTyDefId, chalk_db, method_resolution::{InherentImpls, TraitImpls}};
+use crate::{
+    chalk_db,
+    method_resolution::{InherentImpls, TraitImpls},
+    Binders, CallableDefId, FnDefId, ImplTraitId, InferenceResult, Interner, PolyFnSig,
+    QuantifiedWhereClause, ReturnTypeImplTraits, TraitRef, Ty, TyDefId, ValueTyDefId,
+};
 use hir_expand::name::Name;
 
 #[salsa::query_group(HirDatabaseStorage)]
@@ -93,10 +98,15 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     fn associated_ty_data(&self, id: chalk_db::AssocTypeId) -> Arc<chalk_db::AssociatedTyDatum>;
 
     #[salsa::invoke(chalk_db::trait_datum_query)]
-    fn trait_datum(&self, krate: CrateId, trait_id: chalk_db::TraitId) -> Arc<chalk_db::TraitDatum>;
+    fn trait_datum(&self, krate: CrateId, trait_id: chalk_db::TraitId)
+        -> Arc<chalk_db::TraitDatum>;
 
     #[salsa::invoke(chalk_db::struct_datum_query)]
-    fn struct_datum(&self, krate: CrateId, struct_id: chalk_db::AdtId) -> Arc<chalk_db::StructDatum>;
+    fn struct_datum(
+        &self,
+        krate: CrateId,
+        struct_id: chalk_db::AdtId,
+    ) -> Arc<chalk_db::StructDatum>;
 
     #[salsa::invoke(chalk_db::impl_datum_query)]
     fn impl_datum(&self, krate: CrateId, impl_id: chalk_db::ImplId) -> Arc<chalk_db::ImplDatum>;
diff --git a/crates/hir_ty/src/display.rs b/crates/hir_ty/src/display.rs
index a0746cd8f..ae3a82780 100644
--- a/crates/hir_ty/src/display.rs
+++ b/crates/hir_ty/src/display.rs
@@ -20,11 +20,11 @@ use hir_expand::name::Name;
 
 use crate::{
     const_from_placeholder_idx, db::HirDatabase, from_assoc_type_id, from_foreign_def_id,
-    from_placeholder_idx, lt_from_placeholder_idx, primitive, subst_prefix, to_assoc_type_id,
-    chalk_db::from_chalk, utils::generics, AdtId, AliasEq, AliasTy, CallableDefId,
-    CallableSig, Const, ConstValue, DomainGoal, GenericArg, ImplTraitId, Interner, Lifetime,
-    LifetimeData, LifetimeOutlives, Mutability, OpaqueTy, ProjectionTy, ProjectionTyExt,
-    QuantifiedWhereClause, Scalar, TraitRef, TraitRefExt, Ty, TyExt, TyKind, WhereClause,
+    from_placeholder_idx, lt_from_placeholder_idx, mapping::from_chalk, primitive, subst_prefix,
+    to_assoc_type_id, utils::generics, AdtId, AliasEq, AliasTy, CallableDefId, CallableSig, Const,
+    ConstValue, DomainGoal, GenericArg, ImplTraitId, Interner, Lifetime, LifetimeData,
+    LifetimeOutlives, Mutability, OpaqueTy, ProjectionTy, ProjectionTyExt, QuantifiedWhereClause,
+    Scalar, TraitRef, TraitRefExt, Ty, TyExt, TyKind, WhereClause,
 };
 
 pub struct HirFormatter<'a> {
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index d42383012..50497eecb 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -17,11 +17,11 @@ use syntax::ast::RangeOp;
 use crate::{
     autoderef, dummy_usize_const,
     lower::lower_to_chalk_mutability,
+    mapping::from_chalk,
     method_resolution, op,
     primitive::{self, UintTy},
     static_lifetime, to_chalk_trait_id,
     traits::FnTrait,
-    chalk_db::from_chalk,
     utils::{generics, Generics},
     AdtId, Binders, CallableDefId, FnPointer, FnSig, FnSubst, InEnvironment, Interner,
     ProjectionTyExt, Rawness, Scalar, Substitution, TraitRef, Ty, TyBuilder, TyExt, TyKind,
diff --git a/crates/hir_ty/src/interner.rs b/crates/hir_ty/src/interner.rs
index 0187767ce..02e26c04e 100644
--- a/crates/hir_ty/src/interner.rs
+++ b/crates/hir_ty/src/interner.rs
@@ -1,7 +1,7 @@
 //! Implementation of the Chalk `Interner` trait, which allows customizing the
 //! representation of the various objects Chalk deals with (types, goals etc.).
 
-use crate::{GenericArg, tls, chalk_db};
+use crate::{chalk_db, tls, GenericArg};
 use base_db::salsa::InternId;
 use chalk_ir::{Goal, GoalData};
 use hir_def::{
@@ -60,15 +60,24 @@ impl chalk_ir::interner::Interner for Interner {
     type Identifier = TypeAliasId;
     type FnAbi = ();
 
-    fn debug_adt_id(type_kind_id: chalk_db::AdtId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+    fn debug_adt_id(
+        type_kind_id: chalk_db::AdtId,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
         tls::with_current_program(|prog| Some(prog?.debug_struct_id(type_kind_id, fmt)))
     }
 
-    fn debug_trait_id(type_kind_id: chalk_db::TraitId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+    fn debug_trait_id(
+        type_kind_id: chalk_db::TraitId,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
         tls::with_current_program(|prog| Some(prog?.debug_trait_id(type_kind_id, fmt)))
     }
 
-    fn debug_assoc_type_id(id: chalk_db::AssocTypeId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+    fn debug_assoc_type_id(
+        id: chalk_db::AssocTypeId,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
         tls::with_current_program(|prog| Some(prog?.debug_assoc_type_id(id, fmt)))
     }
 
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index 0743d3d30..434e2e533 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -51,13 +51,13 @@ pub use autoderef::autoderef;
 pub use builder::TyBuilder;
 pub use chalk_ext::*;
 pub use infer::{could_unify, InferenceResult};
+pub use interner::Interner;
 pub use lower::{
     associated_type_shorthand_candidates, callable_item_sig, CallableDefId, ImplTraitLoweringMode,
     TyDefId, TyLoweringContext, ValueTyDefId,
 };
 pub use traits::TraitEnvironment;
 pub use walk::TypeWalk;
-pub use interner::Interner;
 
 pub use chalk_ir::{
     cast::Cast, AdtId, BoundVar, DebruijnIndex, Mutability, Safety, Scalar, TyVariableKind,
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 0cdded3e1..a035686bc 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -27,14 +27,14 @@ use stdx::impl_from;
 
 use crate::{
     db::HirDatabase,
-    dummy_usize_const, static_lifetime, to_assoc_type_id, to_chalk_trait_id, to_placeholder_idx,
-    chalk_db::ToChalk,
-    Interner,
+    dummy_usize_const,
+    mapping::ToChalk,
+    static_lifetime, to_assoc_type_id, to_chalk_trait_id, to_placeholder_idx,
     utils::{
         all_super_trait_refs, associated_type_by_name_including_super_traits, generics, Generics,
     },
     AliasEq, AliasTy, Binders, BoundVar, CallableSig, DebruijnIndex, DynTy, FnPointer, FnSig,
-    FnSubst, ImplTraitId, OpaqueTy, PolyFnSig, ProjectionTy, QuantifiedWhereClause,
+    FnSubst, ImplTraitId, Interner, OpaqueTy, PolyFnSig, ProjectionTy, QuantifiedWhereClause,
     QuantifiedWhereClauses, ReturnTypeImplTrait, ReturnTypeImplTraits, Substitution,
     TraitEnvironment, TraitRef, TraitRefExt, Ty, TyBuilder, TyKind, WhereClause,
 };
diff --git a/crates/hir_ty/src/mapping.rs b/crates/hir_ty/src/mapping.rs
index 4d3c41b2c..f57115de6 100644
--- a/crates/hir_ty/src/mapping.rs
+++ b/crates/hir_ty/src/mapping.rs
@@ -3,13 +3,29 @@
 //! Chalk (in both directions); plus some helper functions for more specialized
 //! conversions.
 
-use chalk_ir::{DebruijnIndex, cast::Cast, fold::Shift};
+use chalk_ir::{cast::Cast, fold::Shift, DebruijnIndex};
 use chalk_solve::rust_ir;
 
 use base_db::salsa::InternKey;
 use hir_def::{GenericDefId, TypeAliasId};
 
-use crate::{AliasEq, AliasTy, CallableDefId, FnDefId, Interner, ProjectionTyExt, QuantifiedWhereClause, Substitution, Ty, WhereClause, chalk_db::{self, ToChalk}, db::HirDatabase};
+use crate::{
+    chalk_db, db::HirDatabase, AliasEq, AliasTy, CallableDefId, FnDefId, Interner, ProjectionTyExt,
+    QuantifiedWhereClause, Substitution, Ty, WhereClause,
+};
+
+pub(crate) trait ToChalk {
+    type Chalk;
+    fn to_chalk(self, db: &dyn HirDatabase) -> Self::Chalk;
+    fn from_chalk(db: &dyn HirDatabase, chalk: Self::Chalk) -> Self;
+}
+
+pub(crate) fn from_chalk<T, ChalkT>(db: &dyn HirDatabase, chalk: ChalkT) -> T
+where
+    T: ToChalk<Chalk = ChalkT>,
+{
+    T::from_chalk(db, chalk)
+}
 
 impl ToChalk for hir_def::TraitId {
     type Chalk = chalk_db::TraitId;
diff --git a/crates/hir_ty/src/tls.rs b/crates/hir_ty/src/tls.rs
index c319bcf70..92989f11f 100644
--- a/crates/hir_ty/src/tls.rs
+++ b/crates/hir_ty/src/tls.rs
@@ -4,7 +4,9 @@ use std::fmt;
 use chalk_ir::{AliasTy, GenericArg, Goal, Goals, Lifetime, ProgramClauseImplication};
 use itertools::Itertools;
 
-use crate::{db::HirDatabase, from_assoc_type_id, CallableDefId, chalk_db::{from_chalk, self}, Interner};
+use crate::{
+    chalk_db, db::HirDatabase, from_assoc_type_id, mapping::from_chalk, CallableDefId, Interner,
+};
 use hir_def::{AdtId, AssocContainerId, Lookup, TypeAliasId};
 
 pub(crate) use unsafe_tls::{set_current_program, with_current_program};
diff --git a/crates/hir_ty/src/traits.rs b/crates/hir_ty/src/traits.rs
index 5f8666d90..7f77e421d 100644
--- a/crates/hir_ty/src/traits.rs
+++ b/crates/hir_ty/src/traits.rs
@@ -9,7 +9,7 @@ use stdx::panic_context;
 
 use crate::{
     db::HirDatabase, AliasEq, AliasTy, Canonical, DomainGoal, Guidance, HirDisplay, InEnvironment,
-    Solution, TraitRefExt, Ty, TyKind, WhereClause, Interner,
+    Interner, Solution, TraitRefExt, Ty, TyKind, WhereClause,
 };
 
 /// This controls how much 'time' we give the Chalk solver before giving up.