From 638100dc8bea69cc4093d15f1641ed39a8d27a43 Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Sat, 29 Jun 2019 17:40:00 +0200
Subject: Refactor a bit & introduce Environment struct

---
 crates/ra_hir/src/ty/infer.rs             |  7 ++--
 crates/ra_hir/src/ty/infer/unify.rs       | 20 ++++++++---
 crates/ra_hir/src/ty/method_resolution.rs | 10 +++---
 crates/ra_hir/src/ty/traits.rs            | 31 ++++++++++++-----
 crates/ra_hir/src/ty/traits/chalk.rs      | 56 ++++++++++++++++++++++++++++++-
 5 files changed, 105 insertions(+), 19 deletions(-)

(limited to 'crates/ra_hir/src/ty')

diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index 52a49070a..84edd3d46 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -29,7 +29,8 @@ use test_utils::tested_by;
 use super::{
     autoderef, method_resolution, op, primitive,
     traits::{Guidance, Obligation, ProjectionPredicate, Solution},
-    ApplicationTy, CallableDef, ProjectionTy, Substs, TraitRef, Ty, TypableDef, TypeCtor,
+    ApplicationTy, CallableDef, InEnvironment, ProjectionTy, Substs, TraitRef, Ty, TypableDef,
+    TypeCtor,
 };
 use crate::{
     adt::VariantDef,
@@ -330,7 +331,9 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         for obligation in obligations {
             match &obligation {
                 Obligation::Trait(tr) => {
-                    let canonicalized = self.canonicalizer().canonicalize_trait_ref(tr.clone());
+                    let env = Arc::new(super::Environment); // FIXME add environment
+                    let in_env = InEnvironment::new(env, tr.clone());
+                    let canonicalized = self.canonicalizer().canonicalize_trait_ref(in_env);
                     let solution = self
                         .db
                         .implements(self.resolver.krate().unwrap(), canonicalized.value.clone());
diff --git a/crates/ra_hir/src/ty/infer/unify.rs b/crates/ra_hir/src/ty/infer/unify.rs
index a24e5eb5c..ad2eefcaf 100644
--- a/crates/ra_hir/src/ty/infer/unify.rs
+++ b/crates/ra_hir/src/ty/infer/unify.rs
@@ -2,7 +2,9 @@
 
 use super::InferenceContext;
 use crate::db::HirDatabase;
-use crate::ty::{Canonical, InferTy, ProjectionPredicate, ProjectionTy, TraitRef, Ty};
+use crate::ty::{
+    Canonical, InEnvironment, InferTy, ProjectionPredicate, ProjectionTy, TraitRef, Ty,
+};
 
 impl<'a, D: HirDatabase> InferenceContext<'a, D> {
     pub(super) fn canonicalizer<'b>(&'b mut self) -> Canonicalizer<'a, 'b, D>
@@ -105,14 +107,24 @@ where
         ProjectionPredicate { ty, projection_ty }
     }
 
+    // FIXME: add some point, we need to introduce a `Fold` trait that abstracts
+    // over all the things that can be canonicalized (like Chalk and rustc have)
+
     pub fn canonicalize_ty(mut self, ty: Ty) -> Canonicalized<Ty> {
         let result = self.do_canonicalize_ty(ty);
         self.into_canonicalized(result)
     }
 
-    pub fn canonicalize_trait_ref(mut self, trait_ref: TraitRef) -> Canonicalized<TraitRef> {
-        let result = self.do_canonicalize_trait_ref(trait_ref);
-        self.into_canonicalized(result)
+    pub fn canonicalize_trait_ref(
+        mut self,
+        trait_ref_in_env: InEnvironment<TraitRef>,
+    ) -> Canonicalized<InEnvironment<TraitRef>> {
+        let result = self.do_canonicalize_trait_ref(trait_ref_in_env.value);
+        // FIXME canonicalize env
+        self.into_canonicalized(InEnvironment {
+            value: result,
+            environment: trait_ref_in_env.environment,
+        })
     }
 
     pub fn canonicalize_projection(
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index 76ace66ea..770e1964e 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -7,7 +7,7 @@ use std::sync::Arc;
 use arrayvec::ArrayVec;
 use rustc_hash::FxHashMap;
 
-use super::{autoderef, Canonical, TraitRef};
+use super::{autoderef, Canonical, Environment, InEnvironment, TraitRef};
 use crate::{
     generics::HasGenericParams,
     impl_block::{ImplBlock, ImplId, ImplItem},
@@ -209,7 +209,8 @@ fn iterate_trait_method_candidates<T>(
                 let data = m.data(db);
                 if name.map_or(true, |name| data.name() == name) && data.has_self_param() {
                     if !known_implemented {
-                        let trait_ref = canonical_trait_ref(db, t, ty.clone());
+                        let env = Arc::new(super::Environment); // FIXME add environment
+                        let trait_ref = canonical_trait_ref(db, env, t, ty.clone());
                         if db.implements(krate, trait_ref).is_none() {
                             continue 'traits;
                         }
@@ -279,9 +280,10 @@ impl Ty {
 /// for all other parameters, to query Chalk with it.
 fn canonical_trait_ref(
     db: &impl HirDatabase,
+    env: Arc<Environment>,
     trait_: Trait,
     self_ty: Canonical<Ty>,
-) -> Canonical<TraitRef> {
+) -> Canonical<InEnvironment<TraitRef>> {
     let mut substs = Vec::new();
     let generics = trait_.generic_params(db);
     let num_vars = self_ty.num_vars;
@@ -296,6 +298,6 @@ fn canonical_trait_ref(
     );
     Canonical {
         num_vars: substs.len() - 1 + self_ty.num_vars,
-        value: TraitRef { trait_, substs: substs.into() },
+        value: InEnvironment::new(env, TraitRef { trait_, substs: substs.into() }),
     }
 }
diff --git a/crates/ra_hir/src/ty/traits.rs b/crates/ra_hir/src/ty/traits.rs
index 3e28852b6..718970553 100644
--- a/crates/ra_hir/src/ty/traits.rs
+++ b/crates/ra_hir/src/ty/traits.rs
@@ -67,6 +67,27 @@ fn solve(
     solution
 }
 
+/// A set of clauses that we assume to be true. E.g. if we are inside this function:
+/// ```rust
+/// fn foo<T: Default>(t: T) {}
+/// ```
+/// we assume that `T: Default`.
+#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct Environment;
+
+/// Something (usually a goal), along with an environment.
+#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct InEnvironment<T> {
+    pub environment: Arc<Environment>,
+    pub value: T,
+}
+
+impl<T> InEnvironment<T> {
+    pub fn new(environment: Arc<Environment>, value: T) -> InEnvironment<T> {
+        InEnvironment { environment, 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.
@@ -97,16 +118,10 @@ pub struct ProjectionPredicate {
 pub(crate) fn implements_query(
     db: &impl HirDatabase,
     krate: Crate,
-    trait_ref: Canonical<TraitRef>,
+    trait_ref: Canonical<InEnvironment<TraitRef>>,
 ) -> Option<Solution> {
     let _p = profile("implements_query");
-    let goal: chalk_ir::Goal = trait_ref.value.to_chalk(db).cast();
-    debug!("goal: {:?}", goal);
-    let env = chalk_ir::Environment::new();
-    let in_env = chalk_ir::InEnvironment::new(&env, goal);
-    let parameter = chalk_ir::ParameterKind::Ty(chalk_ir::UniverseIndex::ROOT);
-    let canonical =
-        chalk_ir::Canonical { value: in_env, binders: vec![parameter; trait_ref.num_vars] };
+    let canonical = trait_ref.to_chalk(db).cast();
     // We currently don't deal with universes (I think / hope they're not yet
     // relevant for our use cases?)
     let u_canonical = chalk_ir::UCanonical { canonical, universes: 1 };
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index 4c3744b44..bee35fa62 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -12,7 +12,7 @@ use chalk_rust_ir::{AssociatedTyDatum, ImplDatum, StructDatum, TraitDatum};
 use ra_db::salsa::{InternId, InternKey};
 use test_utils::tested_by;
 
-use super::ChalkContext;
+use super::{Canonical, ChalkContext};
 use crate::{
     db::HirDatabase,
     generics::GenericDef,
@@ -218,6 +218,60 @@ impl ToChalk for ProjectionTy {
     }
 }
 
+impl<T> ToChalk for Canonical<T>
+where
+    T: ToChalk,
+{
+    type Chalk = chalk_ir::Canonical<T::Chalk>;
+
+    fn to_chalk(self, db: &impl HirDatabase) -> chalk_ir::Canonical<T::Chalk> {
+        let parameter = chalk_ir::ParameterKind::Ty(chalk_ir::UniverseIndex::ROOT);
+        let value = self.value.to_chalk(db);
+        let canonical = chalk_ir::Canonical { value, binders: vec![parameter; self.num_vars] };
+        canonical
+    }
+
+    fn from_chalk(db: &impl HirDatabase, canonical: chalk_ir::Canonical<T::Chalk>) -> Canonical<T> {
+        Canonical { num_vars: canonical.binders.len(), value: from_chalk(db, canonical.value) }
+    }
+}
+
+impl ToChalk for Arc<super::Environment> {
+    type Chalk = Arc<chalk_ir::Environment>;
+
+    fn to_chalk(self, _db: &impl HirDatabase) -> Arc<chalk_ir::Environment> {
+        chalk_ir::Environment::new()
+    }
+
+    fn from_chalk(
+        _db: &impl HirDatabase,
+        _env: Arc<chalk_ir::Environment>,
+    ) -> Arc<super::Environment> {
+        Arc::new(super::Environment)
+    }
+}
+
+impl<T: ToChalk> ToChalk for super::InEnvironment<T> {
+    type Chalk = chalk_ir::InEnvironment<T::Chalk>;
+
+    fn to_chalk(self, db: &impl HirDatabase) -> chalk_ir::InEnvironment<T::Chalk> {
+        chalk_ir::InEnvironment {
+            environment: self.environment.to_chalk(db),
+            goal: self.value.to_chalk(db),
+        }
+    }
+
+    fn from_chalk(
+        db: &impl HirDatabase,
+        in_env: chalk_ir::InEnvironment<T::Chalk>,
+    ) -> super::InEnvironment<T> {
+        super::InEnvironment {
+            environment: from_chalk(db, in_env.environment),
+            value: from_chalk(db, in_env.goal),
+        }
+    }
+}
+
 fn make_binders<T>(value: T, num_vars: usize) -> chalk_ir::Binders<T> {
     chalk_ir::Binders {
         value,
-- 
cgit v1.2.3


From b1b12072eddaf989fb08ed7a2e39ec2dbbb83dde Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Sat, 29 Jun 2019 19:14:52 +0200
Subject: Start handling environment in trait resolution

I.e. if we are inside a function with some where clauses, we assume these where
clauses hold.
---
 crates/ra_hir/src/ty/infer.rs             | 11 +++---
 crates/ra_hir/src/ty/lower.rs             | 12 +++++++
 crates/ra_hir/src/ty/method_resolution.rs |  7 ++--
 crates/ra_hir/src/ty/tests.rs             | 60 +++++++++++++++++++++++++++++++
 crates/ra_hir/src/ty/traits.rs            |  8 +++--
 crates/ra_hir/src/ty/traits/chalk.rs      | 19 ++++++++--
 6 files changed, 103 insertions(+), 14 deletions(-)

(limited to 'crates/ra_hir/src/ty')

diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index 84edd3d46..f8839ebd2 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -27,10 +27,10 @@ use ra_prof::profile;
 use test_utils::tested_by;
 
 use super::{
-    autoderef, method_resolution, op, primitive,
+    autoderef, lower, method_resolution, op, primitive,
     traits::{Guidance, Obligation, ProjectionPredicate, Solution},
-    ApplicationTy, CallableDef, InEnvironment, ProjectionTy, Substs, TraitRef, Ty, TypableDef,
-    TypeCtor,
+    ApplicationTy, CallableDef, Environment, InEnvironment, ProjectionTy, Substs, TraitRef, Ty,
+    TypableDef, TypeCtor,
 };
 use crate::{
     adt::VariantDef,
@@ -166,6 +166,7 @@ struct InferenceContext<'a, D: HirDatabase> {
     body: Arc<Body>,
     resolver: Resolver,
     var_unification_table: InPlaceUnificationTable<TypeVarId>,
+    trait_env: Arc<Environment>,
     obligations: Vec<Obligation>,
     method_resolutions: FxHashMap<ExprId, Function>,
     field_resolutions: FxHashMap<ExprId, StructField>,
@@ -189,6 +190,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             var_unification_table: InPlaceUnificationTable::new(),
             obligations: Vec::default(),
             return_ty: Ty::Unknown, // set in collect_fn_signature
+            trait_env: lower::trait_env(db, &resolver),
             db,
             body,
             resolver,
@@ -331,8 +333,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         for obligation in obligations {
             match &obligation {
                 Obligation::Trait(tr) => {
-                    let env = Arc::new(super::Environment); // FIXME add environment
-                    let in_env = InEnvironment::new(env, tr.clone());
+                    let in_env = InEnvironment::new(self.trait_env.clone(), tr.clone());
                     let canonicalized = self.canonicalizer().canonicalize_trait_ref(in_env);
                     let solution = self
                         .db
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index b48ada760..ca47d6e96 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -317,6 +317,18 @@ pub(crate) fn type_for_field(db: &impl HirDatabase, field: StructField) -> Ty {
     Ty::from_hir(db, &resolver, type_ref)
 }
 
+pub(crate) fn trait_env(db: &impl HirDatabase, resolver: &Resolver) -> Arc<super::Environment> {
+    let predicates = resolver
+        .where_predicates_in_scope()
+        .map(|pred| {
+            TraitRef::for_where_predicate(db, &resolver, pred)
+                .map_or(GenericPredicate::Error, GenericPredicate::Implemented)
+        })
+        .collect::<Vec<_>>();
+
+    Arc::new(super::Environment { predicates })
+}
+
 /// Resolve the where clause(s) of an item with generics.
 pub(crate) fn generic_predicates_query(
     db: &impl HirDatabase,
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index 770e1964e..40f5eabf0 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -7,7 +7,7 @@ use std::sync::Arc;
 use arrayvec::ArrayVec;
 use rustc_hash::FxHashMap;
 
-use super::{autoderef, Canonical, Environment, InEnvironment, TraitRef};
+use super::{autoderef, lower, Canonical, Environment, InEnvironment, TraitRef};
 use crate::{
     generics::HasGenericParams,
     impl_block::{ImplBlock, ImplId, ImplItem},
@@ -198,6 +198,8 @@ fn iterate_trait_method_candidates<T>(
     mut callback: impl FnMut(&Ty, Function) -> Option<T>,
 ) -> Option<T> {
     let krate = resolver.krate()?;
+    // FIXME: maybe put the trait_env behind a query (need to figure out good input parameters for that)
+    let env = lower::trait_env(db, resolver);
     'traits: for t in resolver.traits_in_scope(db) {
         let data = t.trait_data(db);
         // we'll be lazy about checking whether the type implements the
@@ -209,8 +211,7 @@ fn iterate_trait_method_candidates<T>(
                 let data = m.data(db);
                 if name.map_or(true, |name| data.name() == name) && data.has_self_param() {
                     if !known_implemented {
-                        let env = Arc::new(super::Environment); // FIXME add environment
-                        let trait_ref = canonical_trait_ref(db, env, t, ty.clone());
+                        let trait_ref = canonical_trait_ref(db, env.clone(), t, ty.clone());
                         if db.implements(krate, trait_ref).is_none() {
                             continue 'traits;
                         }
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index fe5e89f2d..594e82af2 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -2950,6 +2950,66 @@ fn test(o: O<S>) {
     assert_eq!(t, "&str");
 }
 
+#[test]
+fn generic_param_env_1() {
+    let t = type_at(
+        r#"
+//- /main.rs
+trait Clone {}
+trait Trait { fn foo(self) -> u128; }
+struct S;
+impl Clone for S {}
+impl<T> Trait for T where T: Clone {}
+fn test<T: Clone>(t: T) { t.foo()<|>; }
+"#,
+    );
+    assert_eq!(t, "u128");
+}
+
+#[test]
+fn generic_param_env_1_not_met() {
+    let t = type_at(
+        r#"
+//- /main.rs
+trait Clone {}
+trait Trait { fn foo(self) -> u128; }
+struct S;
+impl Clone for S {}
+impl<T> Trait for T where T: Clone {}
+fn test<T>(t: T) { t.foo()<|>; }
+"#,
+    );
+    assert_eq!(t, "{unknown}");
+}
+
+#[test]
+fn generic_param_env_2() {
+    let t = type_at(
+        r#"
+//- /main.rs
+trait Trait { fn foo(self) -> u128; }
+struct S;
+impl Trait for S {}
+fn test<T: Trait>(t: T) { t.foo()<|>; }
+"#,
+    );
+    assert_eq!(t, "u128");
+}
+
+#[test]
+fn generic_param_env_2_not_met() {
+    let t = type_at(
+        r#"
+//- /main.rs
+trait Trait { fn foo(self) -> u128; }
+struct S;
+impl Trait for S {}
+fn test<T>(t: T) { t.foo()<|>; }
+"#,
+    );
+    assert_eq!(t, "{unknown}");
+}
+
 fn type_at_pos(db: &MockDatabase, pos: FilePosition) -> String {
     let file = db.parse(pos.file_id).ok().unwrap();
     let expr = algo::find_node_at_offset::<ast::Expr>(file.syntax(), pos.offset).unwrap();
diff --git a/crates/ra_hir/src/ty/traits.rs b/crates/ra_hir/src/ty/traits.rs
index 718970553..e0c93550a 100644
--- a/crates/ra_hir/src/ty/traits.rs
+++ b/crates/ra_hir/src/ty/traits.rs
@@ -72,11 +72,13 @@ fn solve(
 /// fn foo<T: Default>(t: T) {}
 /// ```
 /// we assume that `T: Default`.
-#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
-pub struct Environment;
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Environment {
+    pub predicates: Vec<GenericPredicate>,
+}
 
 /// Something (usually a goal), along with an environment.
-#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct InEnvironment<T> {
     pub environment: Arc<Environment>,
     pub value: T,
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index bee35fa62..f36ff2fc6 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -239,15 +239,28 @@ where
 impl ToChalk for Arc<super::Environment> {
     type Chalk = Arc<chalk_ir::Environment>;
 
-    fn to_chalk(self, _db: &impl HirDatabase) -> Arc<chalk_ir::Environment> {
-        chalk_ir::Environment::new()
+    fn to_chalk(self, db: &impl HirDatabase) -> Arc<chalk_ir::Environment> {
+        let mut clauses = Vec::new();
+        for pred in &self.predicates {
+            if pred.is_error() {
+                // for env, we just ignore errors
+                continue;
+            }
+            if let GenericPredicate::Implemented(trait_ref) = pred {
+                if blacklisted_trait(db, trait_ref.trait_) {
+                    continue;
+                }
+            }
+            clauses.push(pred.clone().to_chalk(db).cast());
+        }
+        chalk_ir::Environment::new().add_clauses(clauses)
     }
 
     fn from_chalk(
         _db: &impl HirDatabase,
         _env: Arc<chalk_ir::Environment>,
     ) -> Arc<super::Environment> {
-        Arc::new(super::Environment)
+        unimplemented!()
     }
 }
 
-- 
cgit v1.2.3


From 15862fc04183c7f9b3f3af666336a594a6a52cd9 Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Sun, 7 Jul 2019 18:14:56 +0200
Subject: Use environment for associated type normalization as well

---
 crates/ra_hir/src/ty/autoderef.rs    |  6 +++++-
 crates/ra_hir/src/ty/infer.rs        |  3 ++-
 crates/ra_hir/src/ty/infer/unify.rs  | 12 ++++++++----
 crates/ra_hir/src/ty/tests.rs        | 19 +++++++++++++++++++
 crates/ra_hir/src/ty/traits.rs       | 15 ++-------------
 crates/ra_hir/src/ty/traits/chalk.rs | 15 +++++++++++++++
 6 files changed, 51 insertions(+), 19 deletions(-)

(limited to 'crates/ra_hir/src/ty')

diff --git a/crates/ra_hir/src/ty/autoderef.rs b/crates/ra_hir/src/ty/autoderef.rs
index 90c1ae630..214aa7d03 100644
--- a/crates/ra_hir/src/ty/autoderef.rs
+++ b/crates/ra_hir/src/ty/autoderef.rs
@@ -52,6 +52,8 @@ fn deref_by_trait(
 
     // FIXME make the Canonical handling nicer
 
+    let env = super::lower::trait_env(db, resolver);
+
     let projection = super::traits::ProjectionPredicate {
         ty: Ty::Bound(0),
         projection_ty: super::ProjectionTy {
@@ -60,7 +62,9 @@ fn deref_by_trait(
         },
     };
 
-    let canonical = super::Canonical { num_vars: 1 + ty.num_vars, value: projection };
+    let in_env = super::traits::InEnvironment { value: projection, environment: env };
+
+    let canonical = super::Canonical { num_vars: 1 + ty.num_vars, value: in_env };
 
     let solution = db.normalize(krate, canonical)?;
 
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index f8839ebd2..f6cf61ad2 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -356,7 +356,8 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                     };
                 }
                 Obligation::Projection(pr) => {
-                    let canonicalized = self.canonicalizer().canonicalize_projection(pr.clone());
+                    let in_env = InEnvironment::new(self.trait_env.clone(), pr.clone());
+                    let canonicalized = self.canonicalizer().canonicalize_projection(in_env);
                     let solution = self
                         .db
                         .normalize(self.resolver.krate().unwrap(), canonicalized.value.clone());
diff --git a/crates/ra_hir/src/ty/infer/unify.rs b/crates/ra_hir/src/ty/infer/unify.rs
index ad2eefcaf..2ed326cd5 100644
--- a/crates/ra_hir/src/ty/infer/unify.rs
+++ b/crates/ra_hir/src/ty/infer/unify.rs
@@ -129,10 +129,14 @@ where
 
     pub fn canonicalize_projection(
         mut self,
-        projection: ProjectionPredicate,
-    ) -> Canonicalized<ProjectionPredicate> {
-        let result = self.do_canonicalize_projection_predicate(projection);
-        self.into_canonicalized(result)
+        projection: InEnvironment<ProjectionPredicate>,
+    ) -> Canonicalized<InEnvironment<ProjectionPredicate>> {
+        let result = self.do_canonicalize_projection_predicate(projection.value);
+        // FIXME canonicalize env
+        self.into_canonicalized(InEnvironment {
+            value: result,
+            environment: projection.environment,
+        })
     }
 }
 
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index 594e82af2..7340bb9bd 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -3010,6 +3010,25 @@ fn test<T>(t: T) { t.foo()<|>; }
     assert_eq!(t, "{unknown}");
 }
 
+#[test]
+fn generic_param_env_deref() {
+    let t = type_at(
+        r#"
+//- /main.rs
+#[lang = "deref"]
+trait Deref {
+    type Target;
+}
+trait Trait {}
+impl<T> Deref for T where T: Trait {
+    type Target = i128;
+}
+fn test<T: Trait>(t: T) { (*t)<|>; }
+"#,
+    );
+    assert_eq!(t, "i128");
+}
+
 fn type_at_pos(db: &MockDatabase, pos: FilePosition) -> String {
     let file = db.parse(pos.file_id).ok().unwrap();
     let expr = algo::find_node_at_offset::<ast::Expr>(file.syntax(), pos.offset).unwrap();
diff --git a/crates/ra_hir/src/ty/traits.rs b/crates/ra_hir/src/ty/traits.rs
index e0c93550a..01f350bc1 100644
--- a/crates/ra_hir/src/ty/traits.rs
+++ b/crates/ra_hir/src/ty/traits.rs
@@ -134,20 +134,9 @@ pub(crate) fn implements_query(
 pub(crate) fn normalize_query(
     db: &impl HirDatabase,
     krate: Crate,
-    projection: Canonical<ProjectionPredicate>,
+    projection: Canonical<InEnvironment<ProjectionPredicate>>,
 ) -> Option<Solution> {
-    let goal: chalk_ir::Goal = chalk_ir::Normalize {
-        projection: projection.value.projection_ty.to_chalk(db),
-        ty: projection.value.ty.to_chalk(db),
-    }
-    .cast();
-    debug!("goal: {:?}", goal);
-    // FIXME unify with `implements`
-    let env = chalk_ir::Environment::new();
-    let in_env = chalk_ir::InEnvironment::new(&env, goal);
-    let parameter = chalk_ir::ParameterKind::Ty(chalk_ir::UniverseIndex::ROOT);
-    let canonical =
-        chalk_ir::Canonical { value: in_env, binders: vec![parameter; projection.num_vars] };
+    let canonical = projection.to_chalk(db).cast();
     // We currently don't deal with universes (I think / hope they're not yet
     // relevant for our use cases?)
     let u_canonical = chalk_ir::UCanonical { canonical, universes: 1 };
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index f36ff2fc6..32a45731d 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -218,6 +218,21 @@ impl ToChalk for ProjectionTy {
     }
 }
 
+impl ToChalk for super::ProjectionPredicate {
+    type Chalk = chalk_ir::Normalize;
+
+    fn to_chalk(self, db: &impl HirDatabase) -> chalk_ir::Normalize {
+        chalk_ir::Normalize {
+            projection: self.projection_ty.to_chalk(db),
+            ty: self.ty.to_chalk(db),
+        }
+    }
+
+    fn from_chalk(_db: &impl HirDatabase, _normalize: chalk_ir::Normalize) -> Self {
+        unimplemented!()
+    }
+}
+
 impl<T> ToChalk for Canonical<T>
 where
     T: ToChalk,
-- 
cgit v1.2.3


From 9afbf2dff43dee3227358f10162d4c77d192ce7a Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Mon, 8 Jul 2019 21:43:52 +0200
Subject: Unify `normalize` and `implements` to simplify code

---
 crates/ra_hir/src/ty/autoderef.rs         |  6 ++-
 crates/ra_hir/src/ty/infer.rs             | 64 +++++++++----------------------
 crates/ra_hir/src/ty/infer/unify.rs       | 32 ++++++----------
 crates/ra_hir/src/ty/method_resolution.rs | 16 ++++----
 crates/ra_hir/src/ty/traits.rs            | 21 ++--------
 crates/ra_hir/src/ty/traits/chalk.rs      | 17 +++++++-
 6 files changed, 62 insertions(+), 94 deletions(-)

(limited to 'crates/ra_hir/src/ty')

diff --git a/crates/ra_hir/src/ty/autoderef.rs b/crates/ra_hir/src/ty/autoderef.rs
index 214aa7d03..c26513871 100644
--- a/crates/ra_hir/src/ty/autoderef.rs
+++ b/crates/ra_hir/src/ty/autoderef.rs
@@ -62,11 +62,13 @@ fn deref_by_trait(
         },
     };
 
-    let in_env = super::traits::InEnvironment { value: projection, environment: env };
+    let obligation = super::Obligation::Projection(projection);
+
+    let in_env = super::traits::InEnvironment { value: obligation, environment: env };
 
     let canonical = super::Canonical { num_vars: 1 + ty.num_vars, value: in_env };
 
-    let solution = db.normalize(krate, canonical)?;
+    let solution = db.solve(krate, canonical)?;
 
     match &solution {
         Solution::Unique(vars) => {
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index f6cf61ad2..1f74108a4 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -331,53 +331,25 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
     fn resolve_obligations_as_possible(&mut self) {
         let obligations = mem::replace(&mut self.obligations, Vec::new());
         for obligation in obligations {
-            match &obligation {
-                Obligation::Trait(tr) => {
-                    let in_env = InEnvironment::new(self.trait_env.clone(), tr.clone());
-                    let canonicalized = self.canonicalizer().canonicalize_trait_ref(in_env);
-                    let solution = self
-                        .db
-                        .implements(self.resolver.krate().unwrap(), canonicalized.value.clone());
-                    match solution {
-                        Some(Solution::Unique(substs)) => {
-                            canonicalized.apply_solution(self, substs.0);
-                        }
-                        Some(Solution::Ambig(Guidance::Definite(substs))) => {
-                            canonicalized.apply_solution(self, substs.0);
-                            self.obligations.push(obligation);
-                        }
-                        Some(_) => {
-                            // FIXME use this when trying to resolve everything at the end
-                            self.obligations.push(obligation);
-                        }
-                        None => {
-                            // FIXME obligation cannot be fulfilled => diagnostic
-                        }
-                    };
+            let in_env = InEnvironment::new(self.trait_env.clone(), obligation.clone());
+            let canonicalized = self.canonicalizer().canonicalize_obligation(in_env);
+            let solution =
+                self.db.solve(self.resolver.krate().unwrap(), canonicalized.value.clone());
+
+            match solution {
+                Some(Solution::Unique(substs)) => {
+                    canonicalized.apply_solution(self, substs.0);
                 }
-                Obligation::Projection(pr) => {
-                    let in_env = InEnvironment::new(self.trait_env.clone(), pr.clone());
-                    let canonicalized = self.canonicalizer().canonicalize_projection(in_env);
-                    let solution = self
-                        .db
-                        .normalize(self.resolver.krate().unwrap(), canonicalized.value.clone());
-
-                    match solution {
-                        Some(Solution::Unique(substs)) => {
-                            canonicalized.apply_solution(self, substs.0);
-                        }
-                        Some(Solution::Ambig(Guidance::Definite(substs))) => {
-                            canonicalized.apply_solution(self, substs.0);
-                            self.obligations.push(obligation);
-                        }
-                        Some(_) => {
-                            // FIXME use this when trying to resolve everything at the end
-                            self.obligations.push(obligation);
-                        }
-                        None => {
-                            // FIXME obligation cannot be fulfilled => diagnostic
-                        }
-                    };
+                Some(Solution::Ambig(Guidance::Definite(substs))) => {
+                    canonicalized.apply_solution(self, substs.0);
+                    self.obligations.push(obligation);
+                }
+                Some(_) => {
+                    // FIXME use this when trying to resolve everything at the end
+                    self.obligations.push(obligation);
+                }
+                None => {
+                    // FIXME obligation cannot be fulfilled => diagnostic
                 }
             };
         }
diff --git a/crates/ra_hir/src/ty/infer/unify.rs b/crates/ra_hir/src/ty/infer/unify.rs
index 2ed326cd5..e7e8825d1 100644
--- a/crates/ra_hir/src/ty/infer/unify.rs
+++ b/crates/ra_hir/src/ty/infer/unify.rs
@@ -1,6 +1,6 @@
 //! Unification and canonicalization logic.
 
-use super::InferenceContext;
+use super::{InferenceContext, Obligation};
 use crate::db::HirDatabase;
 use crate::ty::{
     Canonical, InEnvironment, InferTy, ProjectionPredicate, ProjectionTy, TraitRef, Ty,
@@ -110,32 +110,24 @@ where
     // FIXME: add some point, we need to introduce a `Fold` trait that abstracts
     // over all the things that can be canonicalized (like Chalk and rustc have)
 
-    pub fn canonicalize_ty(mut self, ty: Ty) -> Canonicalized<Ty> {
+    pub(crate) fn canonicalize_ty(mut self, ty: Ty) -> Canonicalized<Ty> {
         let result = self.do_canonicalize_ty(ty);
         self.into_canonicalized(result)
     }
 
-    pub fn canonicalize_trait_ref(
+    pub(crate) fn canonicalize_obligation(
         mut self,
-        trait_ref_in_env: InEnvironment<TraitRef>,
-    ) -> Canonicalized<InEnvironment<TraitRef>> {
-        let result = self.do_canonicalize_trait_ref(trait_ref_in_env.value);
-        // FIXME canonicalize env
-        self.into_canonicalized(InEnvironment {
-            value: result,
-            environment: trait_ref_in_env.environment,
-        })
-    }
-
-    pub fn canonicalize_projection(
-        mut self,
-        projection: InEnvironment<ProjectionPredicate>,
-    ) -> Canonicalized<InEnvironment<ProjectionPredicate>> {
-        let result = self.do_canonicalize_projection_predicate(projection.value);
-        // FIXME canonicalize env
+        obligation: InEnvironment<Obligation>,
+    ) -> Canonicalized<InEnvironment<Obligation>> {
+        let result = match obligation.value {
+            Obligation::Trait(tr) => Obligation::Trait(self.do_canonicalize_trait_ref(tr)),
+            Obligation::Projection(pr) => {
+                Obligation::Projection(self.do_canonicalize_projection_predicate(pr))
+            }
+        };
         self.into_canonicalized(InEnvironment {
             value: result,
-            environment: projection.environment,
+            environment: obligation.environment,
         })
     }
 }
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index 40f5eabf0..e214bf1af 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -211,8 +211,8 @@ fn iterate_trait_method_candidates<T>(
                 let data = m.data(db);
                 if name.map_or(true, |name| data.name() == name) && data.has_self_param() {
                     if !known_implemented {
-                        let trait_ref = canonical_trait_ref(db, env.clone(), t, ty.clone());
-                        if db.implements(krate, trait_ref).is_none() {
+                        let goal = generic_implements_goal(db, env.clone(), t, ty.clone());
+                        if db.solve(krate, goal).is_none() {
                             continue 'traits;
                         }
                     }
@@ -279,12 +279,12 @@ impl Ty {
 
 /// This creates Substs for a trait with the given Self type and type variables
 /// for all other parameters, to query Chalk with it.
-fn canonical_trait_ref(
+fn generic_implements_goal(
     db: &impl HirDatabase,
     env: Arc<Environment>,
     trait_: Trait,
     self_ty: Canonical<Ty>,
-) -> Canonical<InEnvironment<TraitRef>> {
+) -> Canonical<InEnvironment<super::Obligation>> {
     let mut substs = Vec::new();
     let generics = trait_.generic_params(db);
     let num_vars = self_ty.num_vars;
@@ -297,8 +297,8 @@ fn canonical_trait_ref(
             .enumerate()
             .map(|(i, _p)| Ty::Bound((i + num_vars) as u32)),
     );
-    Canonical {
-        num_vars: substs.len() - 1 + self_ty.num_vars,
-        value: InEnvironment::new(env, TraitRef { trait_, substs: substs.into() }),
-    }
+    let num_vars = substs.len() - 1 + self_ty.num_vars;
+    let trait_ref = TraitRef { trait_, substs: substs.into() };
+    let obligation = super::Obligation::Trait(trait_ref);
+    Canonical { num_vars, value: InEnvironment::new(env, obligation) }
 }
diff --git a/crates/ra_hir/src/ty/traits.rs b/crates/ra_hir/src/ty/traits.rs
index 01f350bc1..d99843319 100644
--- a/crates/ra_hir/src/ty/traits.rs
+++ b/crates/ra_hir/src/ty/traits.rs
@@ -93,7 +93,7 @@ impl<T> InEnvironment<T> {
 /// 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)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum Obligation {
     /// Prove that a certain type implements a trait (the type is the `Self` type
     /// parameter to the `TraitRef`).
@@ -116,11 +116,11 @@ pub struct ProjectionPredicate {
     pub ty: Ty,
 }
 
-/// Check using Chalk whether trait is implemented for given parameters including `Self` type.
-pub(crate) fn implements_query(
+/// Solve a trait goal using Chalk.
+pub(crate) fn solve_query(
     db: &impl HirDatabase,
     krate: Crate,
-    trait_ref: Canonical<InEnvironment<TraitRef>>,
+    trait_ref: Canonical<InEnvironment<Obligation>>,
 ) -> Option<Solution> {
     let _p = profile("implements_query");
     let canonical = trait_ref.to_chalk(db).cast();
@@ -131,19 +131,6 @@ pub(crate) fn implements_query(
     solution.map(|solution| solution_from_chalk(db, solution))
 }
 
-pub(crate) fn normalize_query(
-    db: &impl HirDatabase,
-    krate: Crate,
-    projection: Canonical<InEnvironment<ProjectionPredicate>>,
-) -> Option<Solution> {
-    let canonical = projection.to_chalk(db).cast();
-    // We currently don't deal with universes (I think / hope they're not yet
-    // relevant for our use cases?)
-    let u_canonical = chalk_ir::UCanonical { canonical, universes: 1 };
-    let solution = solve(db, krate, &u_canonical);
-    solution.map(|solution| solution_from_chalk(db, solution))
-}
-
 fn solution_from_chalk(db: &impl HirDatabase, solution: chalk_solve::Solution) -> Solution {
     let convert_subst = |subst: chalk_ir::Canonical<chalk_ir::Substitution>| {
         let value = subst
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index 32a45731d..2df4dd13f 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -12,7 +12,7 @@ use chalk_rust_ir::{AssociatedTyDatum, ImplDatum, StructDatum, TraitDatum};
 use ra_db::salsa::{InternId, InternKey};
 use test_utils::tested_by;
 
-use super::{Canonical, ChalkContext};
+use super::{Canonical, ChalkContext, Obligation};
 use crate::{
     db::HirDatabase,
     generics::GenericDef,
@@ -233,6 +233,21 @@ impl ToChalk for super::ProjectionPredicate {
     }
 }
 
+impl ToChalk for Obligation {
+    type Chalk = chalk_ir::DomainGoal;
+
+    fn to_chalk(self, db: &impl HirDatabase) -> chalk_ir::DomainGoal {
+        match self {
+            Obligation::Trait(tr) => tr.to_chalk(db).cast(),
+            Obligation::Projection(pr) => pr.to_chalk(db).cast(),
+        }
+    }
+
+    fn from_chalk(_db: &impl HirDatabase, _goal: chalk_ir::DomainGoal) -> Self {
+        unimplemented!()
+    }
+}
+
 impl<T> ToChalk for Canonical<T>
 where
     T: ToChalk,
-- 
cgit v1.2.3