11 files changed, 103 insertions, 107 deletions

diff --git a/crates/hir_ty/src/autoderef.rs b/crates/hir_ty/src/autoderef.rs
index 70c56cc45..7ca4af80e 100644
--- a/crates/hir_ty/src/autoderef.rs
+++ b/crates/hir_ty/src/autoderef.rs
@@ -12,10 +12,8 @@ use hir_expand::name::name;
 use log::{info, warn};
 
 use crate::{
-    db::HirDatabase,
-    traits::{InEnvironment, Solution},
-    AliasEq, AliasTy, BoundVar, Canonical, CanonicalVarKinds, DebruijnIndex, Interner, Ty,
-    TyBuilder, TyKind,
+    db::HirDatabase, AliasEq, AliasTy, BoundVar, Canonical, CanonicalVarKinds, DebruijnIndex,
+    InEnvironment, Interner, Solution, Ty, TyBuilder, TyKind,
 };
 
 const AUTODEREF_RECURSION_LIMIT: usize = 10;
diff --git a/crates/hir_ty/src/db.rs b/crates/hir_ty/src/db.rs
index 58e4247c6..4300680d9 100644
--- a/crates/hir_ty/src/db.rs
+++ b/crates/hir_ty/src/db.rs
@@ -123,7 +123,7 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
         &self,
         krate: CrateId,
         goal: crate::Canonical<crate::InEnvironment<crate::DomainGoal>>,
-    ) -> Option<crate::traits::Solution>;
+    ) -> Option<crate::Solution>;
 
     #[salsa::invoke(crate::traits::chalk::program_clauses_for_chalk_env_query)]
     fn program_clauses_for_chalk_env(
diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
index 1b1d4458c..bb885db35 100644
--- a/crates/hir_ty/src/infer.rs
+++ b/crates/hir_ty/src/infer.rs
@@ -37,8 +37,8 @@ use stdx::impl_from;
 use syntax::SmolStr;
 
 use super::{
-    traits::{DomainGoal, Guidance, Solution},
-    InEnvironment, ProjectionTy, TraitEnvironment, TraitRef, Ty, TypeWalk,
+    DomainGoal, Guidance, InEnvironment, ProjectionTy, Solution, TraitEnvironment, TraitRef, Ty,
+    TypeWalk,
 };
 use crate::{
     db::HirDatabase, infer::diagnostics::InferenceDiagnostic, lower::ImplTraitLoweringMode,
diff --git a/crates/hir_ty/src/infer/coerce.rs b/crates/hir_ty/src/infer/coerce.rs
index 028a4d568..32c273afc 100644
--- a/crates/hir_ty/src/infer/coerce.rs
+++ b/crates/hir_ty/src/infer/coerce.rs
@@ -7,7 +7,7 @@
 use chalk_ir::{cast::Cast, Mutability, TyVariableKind};
 use hir_def::lang_item::LangItemTarget;
 
-use crate::{autoderef, traits::Solution, Interner, Ty, TyBuilder, TyKind};
+use crate::{autoderef, Interner, Solution, Ty, TyBuilder, TyKind};
 
 use super::{InEnvironment, InferenceContext};
 
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index a87429a24..ccaae53e9 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -20,10 +20,10 @@ use crate::{
     method_resolution, op,
     primitive::{self, UintTy},
     to_chalk_trait_id,
-    traits::{chalk::from_chalk, FnTrait, InEnvironment},
+    traits::{chalk::from_chalk, FnTrait},
     utils::{generics, variant_data, Generics},
-    AdtId, Binders, CallableDefId, FnPointer, FnSig, Interner, Rawness, Scalar, Substitution,
-    TraitRef, Ty, TyBuilder, TyKind,
+    AdtId, Binders, CallableDefId, FnPointer, FnSig, InEnvironment, Interner, Rawness, Scalar,
+    Substitution, TraitRef, Ty, TyBuilder, TyKind,
 };
 
 use super::{
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index 40abbce42..76609e2df 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -49,7 +49,7 @@ pub use lower::{
     associated_type_shorthand_candidates, callable_item_sig, CallableDefId, ImplTraitLoweringMode,
     TyDefId, TyLoweringContext, ValueTyDefId,
 };
-pub use traits::{AliasEq, DomainGoal, InEnvironment, TraitEnvironment};
+pub use traits::TraitEnvironment;
 pub use types::*;
 pub use walk::TypeWalk;
 
diff --git a/crates/hir_ty/src/method_resolution.rs b/crates/hir_ty/src/method_resolution.rs
index a76586f0c..0e4a620b6 100644
--- a/crates/hir_ty/src/method_resolution.rs
+++ b/crates/hir_ty/src/method_resolution.rs
@@ -800,7 +800,7 @@ pub fn implements_trait_unique(
     let goal = generic_implements_goal(db, env, trait_, ty.clone());
     let solution = db.trait_solve(krate, goal);
 
-    matches!(solution, Some(crate::traits::Solution::Unique(_)))
+    matches!(solution, Some(crate::Solution::Unique(_)))
 }
 
 /// This creates Substs for a trait with the given Self type and type variables
diff --git a/crates/hir_ty/src/traits.rs b/crates/hir_ty/src/traits.rs
index e5e8cff33..66d600bfc 100644
--- a/crates/hir_ty/src/traits.rs
+++ b/crates/hir_ty/src/traits.rs
@@ -8,8 +8,8 @@ use hir_def::{lang_item::LangItemTarget, TraitId};
 use stdx::panic_context;
 
 use crate::{
-    db::HirDatabase, AliasTy, Canonical, DebruijnIndex, HirDisplay, Substitution, Ty, TyKind,
-    TypeWalk, WhereClause,
+    db::HirDatabase, AliasEq, AliasTy, Canonical, DomainGoal, Guidance, HirDisplay, InEnvironment,
+    Solution, SolutionVariables, Ty, TyKind, WhereClause,
 };
 
 use self::chalk::{from_chalk, Interner, ToChalk};
@@ -70,55 +70,6 @@ impl Default for TraitEnvironment {
     }
 }
 
-/// Something (usually a goal), along with an environment.
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
-pub struct InEnvironment<T> {
-    pub environment: chalk_ir::Environment<Interner>,
-    pub goal: T,
-}
-
-impl<T> InEnvironment<T> {
-    pub fn new(environment: chalk_ir::Environment<Interner>, value: T) -> InEnvironment<T> {
-        InEnvironment { environment, goal: value }
-    }
-}
-
-/// Something that needs to be proven (by Chalk) during type checking, e.g. that
-/// a certain type implements a certain trait. Proving the Obligation might
-/// result in additional information about inference variables.
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
-pub enum DomainGoal {
-    Holds(WhereClause),
-}
-
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
-pub struct AliasEq {
-    pub alias: AliasTy,
-    pub ty: Ty,
-}
-
-impl TypeWalk for AliasEq {
-    fn walk(&self, f: &mut impl FnMut(&Ty)) {
-        self.ty.walk(f);
-        match &self.alias {
-            AliasTy::Projection(projection_ty) => projection_ty.walk(f),
-            AliasTy::Opaque(opaque) => opaque.walk(f),
-        }
-    }
-
-    fn walk_mut_binders(
-        &mut self,
-        f: &mut impl FnMut(&mut Ty, DebruijnIndex),
-        binders: DebruijnIndex,
-    ) {
-        self.ty.walk_mut_binders(f, binders);
-        match &mut self.alias {
-            AliasTy::Projection(projection_ty) => projection_ty.walk_mut_binders(f, binders),
-            AliasTy::Opaque(opaque) => opaque.walk_mut_binders(f, binders),
-        }
-    }
-}
-
 /// Solve a trait goal using Chalk.
 pub(crate) fn trait_solve_query(
     db: &dyn HirDatabase,
@@ -246,41 +197,6 @@ fn solution_from_chalk(
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub struct SolutionVariables(pub Canonical<Substitution>);
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-/// A (possible) solution for a proposed goal.
-pub enum Solution {
-    /// The goal indeed holds, and there is a unique value for all existential
-    /// variables.
-    Unique(SolutionVariables),
-
-    /// The goal may be provable in multiple ways, but regardless we may have some guidance
-    /// for type inference. In this case, we don't return any lifetime
-    /// constraints, since we have not "committed" to any particular solution
-    /// yet.
-    Ambig(Guidance),
-}
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-/// When a goal holds ambiguously (e.g., because there are multiple possible
-/// solutions), we issue a set of *guidance* back to type inference.
-pub enum Guidance {
-    /// The existential variables *must* have the given values if the goal is
-    /// ever to hold, but that alone isn't enough to guarantee the goal will
-    /// actually hold.
-    Definite(SolutionVariables),
-
-    /// There are multiple plausible values for the existentials, but the ones
-    /// here are suggested as the preferred choice heuristically. These should
-    /// be used for inference fallback only.
-    Suggested(SolutionVariables),
-
-    /// There's no useful information to feed back to type inference
-    Unknown,
-}
-
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum FnTrait {
     FnOnce,
diff --git a/crates/hir_ty/src/traits/chalk/mapping.rs b/crates/hir_ty/src/traits/chalk/mapping.rs
index 3a5800885..5e4f97a46 100644
--- a/crates/hir_ty/src/traits/chalk/mapping.rs
+++ b/crates/hir_ty/src/traits/chalk/mapping.rs
@@ -10,11 +10,9 @@ use base_db::salsa::InternKey;
 use hir_def::{GenericDefId, TypeAliasId};
 
 use crate::{
-    db::HirDatabase,
-    primitive::UintTy,
-    traits::{Canonical, DomainGoal},
-    AliasTy, CallableDefId, FnPointer, GenericArg, InEnvironment, OpaqueTy, ProjectionTy,
-    QuantifiedWhereClause, Scalar, Substitution, TraitRef, Ty, TypeWalk, WhereClause,
+    db::HirDatabase, primitive::UintTy, AliasTy, CallableDefId, Canonical, DomainGoal, FnPointer,
+    GenericArg, InEnvironment, OpaqueTy, ProjectionTy, QuantifiedWhereClause, Scalar, Substitution,
+    TraitRef, Ty, TypeWalk, WhereClause,
 };
 
 use super::interner::*;
diff --git a/crates/hir_ty/src/types.rs b/crates/hir_ty/src/types.rs
index d00f8e9ab..53662fcdc 100644
--- a/crates/hir_ty/src/types.rs
+++ b/crates/hir_ty/src/types.rs
@@ -11,7 +11,7 @@ use hir_def::LifetimeParamId;
 use smallvec::SmallVec;
 
 use crate::{
-    AliasEq, AssocTypeId, CanonicalVarKinds, ChalkTraitId, ClosureId, FnDefId, FnSig, ForeignDefId,
+    AssocTypeId, CanonicalVarKinds, ChalkTraitId, ClosureId, FnDefId, FnSig, ForeignDefId,
     InferenceVar, Interner, OpaqueTyId, PlaceholderIndex,
 };
 
@@ -352,3 +352,65 @@ pub struct Canonical<T> {
     pub value: T,
     pub binders: CanonicalVarKinds,
 }
+
+/// Something (usually a goal), along with an environment.
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct InEnvironment<T> {
+    pub environment: chalk_ir::Environment<Interner>,
+    pub goal: T,
+}
+
+impl<T> InEnvironment<T> {
+    pub fn new(environment: chalk_ir::Environment<Interner>, value: T) -> InEnvironment<T> {
+        InEnvironment { environment, goal: value }
+    }
+}
+
+/// Something that needs to be proven (by Chalk) during type checking, e.g. that
+/// a certain type implements a certain trait. Proving the Obligation might
+/// result in additional information about inference variables.
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub enum DomainGoal {
+    Holds(WhereClause),
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct AliasEq {
+    pub alias: AliasTy,
+    pub ty: Ty,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct SolutionVariables(pub Canonical<Substitution>);
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+/// A (possible) solution for a proposed goal.
+pub enum Solution {
+    /// The goal indeed holds, and there is a unique value for all existential
+    /// variables.
+    Unique(SolutionVariables),
+
+    /// The goal may be provable in multiple ways, but regardless we may have some guidance
+    /// for type inference. In this case, we don't return any lifetime
+    /// constraints, since we have not "committed" to any particular solution
+    /// yet.
+    Ambig(Guidance),
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+/// When a goal holds ambiguously (e.g., because there are multiple possible
+/// solutions), we issue a set of *guidance* back to type inference.
+pub enum Guidance {
+    /// The existential variables *must* have the given values if the goal is
+    /// ever to hold, but that alone isn't enough to guarantee the goal will
+    /// actually hold.
+    Definite(SolutionVariables),
+
+    /// There are multiple plausible values for the existentials, but the ones
+    /// here are suggested as the preferred choice heuristically. These should
+    /// be used for inference fallback only.
+    Suggested(SolutionVariables),
+
+    /// There's no useful information to feed back to type inference
+    Unknown,
+}
diff --git a/crates/hir_ty/src/walk.rs b/crates/hir_ty/src/walk.rs
index fec5c2f42..bfb3f1041 100644
--- a/crates/hir_ty/src/walk.rs
+++ b/crates/hir_ty/src/walk.rs
@@ -6,8 +6,8 @@ use std::mem;
 use chalk_ir::DebruijnIndex;
 
 use crate::{
-    utils::make_mut_slice, AliasTy, Binders, CallableSig, GenericArg, GenericArgData, Interner,
-    OpaqueTy, ProjectionTy, Substitution, TraitRef, Ty, TyKind, WhereClause,
+    utils::make_mut_slice, AliasEq, AliasTy, Binders, CallableSig, GenericArg, GenericArgData,
+    Interner, OpaqueTy, ProjectionTy, Substitution, TraitRef, Ty, TyKind, WhereClause,
 };
 
 /// This allows walking structures that contain types to do something with those
@@ -357,3 +357,25 @@ impl TypeWalk for CallableSig {
         }
     }
 }
+
+impl TypeWalk for AliasEq {
+    fn walk(&self, f: &mut impl FnMut(&Ty)) {
+        self.ty.walk(f);
+        match &self.alias {
+            AliasTy::Projection(projection_ty) => projection_ty.walk(f),
+            AliasTy::Opaque(opaque) => opaque.walk(f),
+        }
+    }
+
+    fn walk_mut_binders(
+        &mut self,
+        f: &mut impl FnMut(&mut Ty, DebruijnIndex),
+        binders: DebruijnIndex,
+    ) {
+        self.ty.walk_mut_binders(f, binders);
+        match &mut self.alias {
+            AliasTy::Projection(projection_ty) => projection_ty.walk_mut_binders(f, binders),
+            AliasTy::Opaque(opaque) => opaque.walk_mut_binders(f, binders),
+        }
+    }
+}