7 files changed, 155 insertions, 98 deletions

diff --git a/crates/ra_hir_ty/src/autoderef.rs b/crates/ra_hir_ty/src/autoderef.rs
index d557962b4..ee48fa537 100644
--- a/crates/ra_hir_ty/src/autoderef.rs
+++ b/crates/ra_hir_ty/src/autoderef.rs
@@ -6,7 +6,7 @@
 use std::iter::successors;
 
 use hir_def::lang_item::LangItemTarget;
-use hir_expand::name;
+use hir_expand::name::name;
 use log::{info, warn};
 use ra_db::CrateId;
 
@@ -52,7 +52,7 @@ fn deref_by_trait(
         LangItemTarget::TraitId(it) => it,
         _ => return None,
     };
-    let target = db.trait_data(deref_trait).associated_type_by_name(&name::TARGET_TYPE)?;
+    let target = db.trait_data(deref_trait).associated_type_by_name(&name![Target])?;
 
     let generic_params = generics(db, target.into());
     if generic_params.len() != 1 {
diff --git a/crates/ra_hir_ty/src/expr.rs b/crates/ra_hir_ty/src/expr.rs
index d2bd64e5c..f752a9f09 100644
--- a/crates/ra_hir_ty/src/expr.rs
+++ b/crates/ra_hir_ty/src/expr.rs
@@ -3,7 +3,7 @@
 use std::sync::Arc;
 
 use hir_def::{
-    path::{known, Path},
+    path::{path, Path},
     resolver::HasResolver,
     AdtId, FunctionId,
 };
@@ -124,7 +124,7 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
             None => return,
         };
 
-        let std_result_path = known::std_result_result();
+        let std_result_path = path![std::result::Result];
 
         let resolver = self.func.resolver(db);
         let std_result_enum = match resolver.resolve_known_enum(db, &std_result_path) {
diff --git a/crates/ra_hir_ty/src/infer.rs b/crates/ra_hir_ty/src/infer.rs
index d16f1eb46..f1b7e9442 100644
--- a/crates/ra_hir_ty/src/infer.rs
+++ b/crates/ra_hir_ty/src/infer.rs
@@ -24,20 +24,20 @@ use hir_def::{
     body::Body,
     data::{ConstData, FunctionData},
     expr::{BindingAnnotation, ExprId, PatId},
-    path::{known, Path},
+    path::{path, Path},
     resolver::{HasResolver, Resolver, TypeNs},
     type_ref::{Mutability, TypeRef},
     AdtId, AssocItemId, DefWithBodyId, FunctionId, StructFieldId, TypeAliasId, VariantId,
 };
-use hir_expand::{diagnostics::DiagnosticSink, name};
+use hir_expand::{diagnostics::DiagnosticSink, name::name};
 use ra_arena::map::ArenaMap;
 use ra_prof::profile;
 
 use super::{
     primitive::{FloatTy, IntTy},
     traits::{Guidance, Obligation, ProjectionPredicate, Solution},
-    ApplicationTy, InEnvironment, ProjectionTy, TraitEnvironment, TraitRef, Ty, TypeCtor, TypeWalk,
-    Uncertain,
+    ApplicationTy, InEnvironment, ProjectionTy, Substs, TraitEnvironment, TraitRef, Ty, TypeCtor,
+    TypeWalk, Uncertain,
 };
 use crate::{db::HirDatabase, infer::diagnostics::InferenceDiagnostic};
 
@@ -338,6 +338,24 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         self.table.resolve_ty_shallow(ty)
     }
 
+    fn resolve_associated_type(&mut self, inner_ty: Ty, assoc_ty: Option<TypeAliasId>) -> Ty {
+        match assoc_ty {
+            Some(res_assoc_ty) => {
+                let ty = self.table.new_type_var();
+                let projection = ProjectionPredicate {
+                    ty: ty.clone(),
+                    projection_ty: ProjectionTy {
+                        associated_ty: res_assoc_ty,
+                        parameters: Substs::single(inner_ty),
+                    },
+                };
+                self.obligations.push(Obligation::Projection(projection));
+                self.resolve_ty_as_possible(ty)
+            }
+            None => Ty::Unknown,
+        }
+    }
+
     /// Recurses through the given type, normalizing associated types mentioned
     /// in it by replacing them by type variables and registering obligations to
     /// resolve later. This should be done once for every type we get from some
@@ -404,61 +422,73 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
     }
 
     fn resolve_into_iter_item(&self) -> Option<TypeAliasId> {
-        let path = known::std_iter_into_iterator();
+        let path = path![std::iter::IntoIterator];
         let trait_ = self.resolver.resolve_known_trait(self.db, &path)?;
-        self.db.trait_data(trait_).associated_type_by_name(&name::ITEM_TYPE)
+        self.db.trait_data(trait_).associated_type_by_name(&name![Item])
     }
 
     fn resolve_ops_try_ok(&self) -> Option<TypeAliasId> {
-        let path = known::std_ops_try();
+        let path = path![std::ops::Try];
+        let trait_ = self.resolver.resolve_known_trait(self.db, &path)?;
+        self.db.trait_data(trait_).associated_type_by_name(&name![Ok])
+    }
+
+    fn resolve_ops_neg_output(&self) -> Option<TypeAliasId> {
+        let path = path![std::ops::Neg];
+        let trait_ = self.resolver.resolve_known_trait(self.db, &path)?;
+        self.db.trait_data(trait_).associated_type_by_name(&name![Output])
+    }
+
+    fn resolve_ops_not_output(&self) -> Option<TypeAliasId> {
+        let path = path![std::ops::Not];
         let trait_ = self.resolver.resolve_known_trait(self.db, &path)?;
-        self.db.trait_data(trait_).associated_type_by_name(&name::OK_TYPE)
+        self.db.trait_data(trait_).associated_type_by_name(&name![Output])
     }
 
     fn resolve_future_future_output(&self) -> Option<TypeAliasId> {
-        let path = known::std_future_future();
+        let path = path![std::future::Future];
         let trait_ = self.resolver.resolve_known_trait(self.db, &path)?;
-        self.db.trait_data(trait_).associated_type_by_name(&name::OUTPUT_TYPE)
+        self.db.trait_data(trait_).associated_type_by_name(&name![Output])
     }
 
     fn resolve_boxed_box(&self) -> Option<AdtId> {
-        let path = known::std_boxed_box();
+        let path = path![std::boxed::Box];
         let struct_ = self.resolver.resolve_known_struct(self.db, &path)?;
         Some(struct_.into())
     }
 
     fn resolve_range_full(&self) -> Option<AdtId> {
-        let path = known::std_ops_range_full();
+        let path = path![std::ops::RangeFull];
         let struct_ = self.resolver.resolve_known_struct(self.db, &path)?;
         Some(struct_.into())
     }
 
     fn resolve_range(&self) -> Option<AdtId> {
-        let path = known::std_ops_range();
+        let path = path![std::ops::Range];
         let struct_ = self.resolver.resolve_known_struct(self.db, &path)?;
         Some(struct_.into())
     }
 
     fn resolve_range_inclusive(&self) -> Option<AdtId> {
-        let path = known::std_ops_range_inclusive();
+        let path = path![std::ops::RangeInclusive];
         let struct_ = self.resolver.resolve_known_struct(self.db, &path)?;
         Some(struct_.into())
     }
 
     fn resolve_range_from(&self) -> Option<AdtId> {
-        let path = known::std_ops_range_from();
+        let path = path![std::ops::RangeFrom];
         let struct_ = self.resolver.resolve_known_struct(self.db, &path)?;
         Some(struct_.into())
     }
 
     fn resolve_range_to(&self) -> Option<AdtId> {
-        let path = known::std_ops_range_to();
+        let path = path![std::ops::RangeTo];
         let struct_ = self.resolver.resolve_known_struct(self.db, &path)?;
         Some(struct_.into())
     }
 
     fn resolve_range_to_inclusive(&self) -> Option<AdtId> {
-        let path = known::std_ops_range_to_inclusive();
+        let path = path![std::ops::RangeToInclusive];
         let struct_ = self.resolver.resolve_known_struct(self.db, &path)?;
         Some(struct_.into())
     }
diff --git a/crates/ra_hir_ty/src/infer/expr.rs b/crates/ra_hir_ty/src/infer/expr.rs
index 2c296987c..2e3cdd53a 100644
--- a/crates/ra_hir_ty/src/infer/expr.rs
+++ b/crates/ra_hir_ty/src/infer/expr.rs
@@ -10,7 +10,7 @@ use hir_def::{
     resolver::resolver_for_expr,
     AdtId, ContainerId, Lookup, StructFieldId,
 };
-use hir_expand::name::{self, Name};
+use hir_expand::name::{name, Name};
 use ra_syntax::ast::RangeOp;
 
 use crate::{
@@ -19,8 +19,8 @@ use crate::{
     method_resolution, op,
     traits::InEnvironment,
     utils::{generics, variant_data, Generics},
-    CallableDef, InferTy, IntTy, Mutability, Obligation, ProjectionPredicate, ProjectionTy, Substs,
-    TraitRef, Ty, TypeCtor, TypeWalk, Uncertain,
+    ApplicationTy, CallableDef, InferTy, IntTy, Mutability, Obligation, Substs, TraitRef, Ty,
+    TypeCtor, TypeWalk, Uncertain,
 };
 
 use super::{BindingMode, Expectation, InferenceContext, InferenceDiagnostic, TypeMismatch};
@@ -95,21 +95,8 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             Expr::For { iterable, body, pat } => {
                 let iterable_ty = self.infer_expr(*iterable, &Expectation::none());
 
-                let pat_ty = match self.resolve_into_iter_item() {
-                    Some(into_iter_item_alias) => {
-                        let pat_ty = self.table.new_type_var();
-                        let projection = ProjectionPredicate {
-                            ty: pat_ty.clone(),
-                            projection_ty: ProjectionTy {
-                                associated_ty: into_iter_item_alias,
-                                parameters: Substs::single(iterable_ty),
-                            },
-                        };
-                        self.obligations.push(Obligation::Projection(projection));
-                        self.resolve_ty_as_possible(pat_ty)
-                    }
-                    None => Ty::Unknown,
-                };
+                let pat_ty =
+                    self.resolve_associated_type(iterable_ty, self.resolve_into_iter_item());
 
                 self.infer_pat(*pat, &pat_ty, BindingMode::default());
                 self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
@@ -284,40 +271,13 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             }
             Expr::Await { expr } => {
                 let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
-                let ty = match self.resolve_future_future_output() {
-                    Some(future_future_output_alias) => {
-                        let ty = self.table.new_type_var();
-                        let projection = ProjectionPredicate {
-                            ty: ty.clone(),
-                            projection_ty: ProjectionTy {
-                                associated_ty: future_future_output_alias,
-                                parameters: Substs::single(inner_ty),
-                            },
-                        };
-                        self.obligations.push(Obligation::Projection(projection));
-                        self.resolve_ty_as_possible(ty)
-                    }
-                    None => Ty::Unknown,
-                };
+                let ty =
+                    self.resolve_associated_type(inner_ty, self.resolve_future_future_output());
                 ty
             }
             Expr::Try { expr } => {
                 let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
-                let ty = match self.resolve_ops_try_ok() {
-                    Some(ops_try_ok_alias) => {
-                        let ty = self.table.new_type_var();
-                        let projection = ProjectionPredicate {
-                            ty: ty.clone(),
-                            projection_ty: ProjectionTy {
-                                associated_ty: ops_try_ok_alias,
-                                parameters: Substs::single(inner_ty),
-                            },
-                        };
-                        self.obligations.push(Obligation::Projection(projection));
-                        self.resolve_ty_as_possible(ty)
-                    }
-                    None => Ty::Unknown,
-                };
+                let ty = self.resolve_associated_type(inner_ty, self.resolve_ops_try_ok());
                 ty
             }
             Expr::Cast { expr, type_ref } => {
@@ -372,31 +332,36 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                     },
                     UnaryOp::Neg => {
                         match &inner_ty {
-                            Ty::Apply(a_ty) => match a_ty.ctor {
-                                TypeCtor::Int(Uncertain::Unknown)
-                                | TypeCtor::Int(Uncertain::Known(IntTy {
-                                    signedness: Signedness::Signed,
-                                    ..
-                                }))
-                                | TypeCtor::Float(..) => inner_ty,
-                                _ => Ty::Unknown,
-                            },
-                            Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => {
-                                inner_ty
-                            }
-                            // FIXME: resolve ops::Neg trait
-                            _ => Ty::Unknown,
+                            // Fast path for builtins
+                            Ty::Apply(ApplicationTy {
+                                ctor:
+                                    TypeCtor::Int(Uncertain::Known(IntTy {
+                                        signedness: Signedness::Signed,
+                                        ..
+                                    })),
+                                ..
+                            })
+                            | Ty::Apply(ApplicationTy {
+                                ctor: TypeCtor::Int(Uncertain::Unknown),
+                                ..
+                            })
+                            | Ty::Apply(ApplicationTy { ctor: TypeCtor::Float(_), .. })
+                            | Ty::Infer(InferTy::IntVar(..))
+                            | Ty::Infer(InferTy::FloatVar(..)) => inner_ty,
+                            // Otherwise we resolve via the std::ops::Neg trait
+                            _ => self
+                                .resolve_associated_type(inner_ty, self.resolve_ops_neg_output()),
                         }
                     }
                     UnaryOp::Not => {
                         match &inner_ty {
-                            Ty::Apply(a_ty) => match a_ty.ctor {
-                                TypeCtor::Bool | TypeCtor::Int(_) => inner_ty,
-                                _ => Ty::Unknown,
-                            },
-                            Ty::Infer(InferTy::IntVar(..)) => inner_ty,
-                            // FIXME: resolve ops::Not trait for inner_ty
-                            _ => Ty::Unknown,
+                            // Fast path for builtins
+                            Ty::Apply(ApplicationTy { ctor: TypeCtor::Bool, .. })
+                            | Ty::Apply(ApplicationTy { ctor: TypeCtor::Int(_), .. })
+                            | Ty::Infer(InferTy::IntVar(..)) => inner_ty,
+                            // Otherwise we resolve via the std::ops::Not trait
+                            _ => self
+                                .resolve_associated_type(inner_ty, self.resolve_ops_not_output()),
                         }
                     }
                 }
@@ -666,7 +631,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         // Parent arguments are unknown, except for the receiver type
         if let Some(parent_generics) = def_generics.as_ref().map(|p| p.iter_parent()) {
             for (_id, param) in parent_generics {
-                if param.name == name::SELF_TYPE {
+                if param.name == name![Self] {
                     substs.push(receiver_ty.clone());
                 } else {
                     substs.push(Ty::Unknown);
diff --git a/crates/ra_hir_ty/src/tests/traits.rs b/crates/ra_hir_ty/src/tests/traits.rs
index 93c5f9a15..6139adb72 100644
--- a/crates/ra_hir_ty/src/tests/traits.rs
+++ b/crates/ra_hir_ty/src/tests/traits.rs
@@ -116,6 +116,70 @@ mod collections {
 }
 
 #[test]
+fn infer_ops_neg() {
+    let (db, pos) = TestDB::with_position(
+        r#"
+//- /main.rs crate:main deps:std
+
+struct Bar;
+struct Foo;
+
+impl std::ops::Neg for Bar {
+    type Output = Foo;
+}
+
+fn test() {
+    let a = Bar;
+    let b = -a;
+    b<|>;
+}
+
+//- /std.rs crate:std
+
+#[prelude_import] use ops::*;
+mod ops {
+    pub trait Neg {
+        type Output;
+    }
+}
+"#,
+    );
+    assert_eq!("Foo", type_at_pos(&db, pos));
+}
+
+#[test]
+fn infer_ops_not() {
+    let (db, pos) = TestDB::with_position(
+        r#"
+//- /main.rs crate:main deps:std
+
+struct Bar;
+struct Foo;
+
+impl std::ops::Not for Bar {
+    type Output = Foo;
+}
+
+fn test() {
+    let a = Bar;
+    let b = !a;
+    b<|>;
+}
+
+//- /std.rs crate:std
+
+#[prelude_import] use ops::*;
+mod ops {
+    pub trait Not {
+        type Output;
+    }
+}
+"#,
+    );
+    assert_eq!("Foo", type_at_pos(&db, pos));
+}
+
+#[test]
 fn infer_from_bound_1() {
     assert_snapshot!(
         infer(r#"
diff --git a/crates/ra_hir_ty/src/traits/builtin.rs b/crates/ra_hir_ty/src/traits/builtin.rs
index 598fd81e3..cd587a338 100644
--- a/crates/ra_hir_ty/src/traits/builtin.rs
+++ b/crates/ra_hir_ty/src/traits/builtin.rs
@@ -1,7 +1,7 @@
 //! This module provides the built-in trait implementations, e.g. to make
 //! closures implement `Fn`.
 use hir_def::{expr::Expr, lang_item::LangItemTarget, TraitId, TypeAliasId};
-use hir_expand::name;
+use hir_expand::name::name;
 use ra_db::CrateId;
 
 use super::{AssocTyValue, Impl};
@@ -79,7 +79,7 @@ fn closure_fn_trait_impl_datum(
     // and don't want to return a valid value only to find out later that FnOnce
     // is broken
     let fn_once_trait = get_fn_trait(db, krate, super::FnTrait::FnOnce)?;
-    let _output = db.trait_data(fn_once_trait).associated_type_by_name(&name::OUTPUT_TYPE)?;
+    let _output = db.trait_data(fn_once_trait).associated_type_by_name(&name![Output])?;
 
     let num_args: u16 = match &db.body(data.def.into())[data.expr] {
         Expr::Lambda { args, .. } => args.len() as u16,
@@ -137,7 +137,7 @@ fn closure_fn_trait_output_assoc_ty_value(
 
     let output_ty_id = db
         .trait_data(fn_once_trait)
-        .associated_type_by_name(&name::OUTPUT_TYPE)
+        .associated_type_by_name(&name![Output])
         .expect("assoc ty value should not exist");
 
     BuiltinImplAssocTyValueData {
diff --git a/crates/ra_hir_ty/src/utils.rs b/crates/ra_hir_ty/src/utils.rs
index aeb211a91..0049d3c6f 100644
--- a/crates/ra_hir_ty/src/utils.rs
+++ b/crates/ra_hir_ty/src/utils.rs
@@ -10,10 +10,8 @@ use hir_def::{
     type_ref::TypeRef,
     ContainerId, GenericDefId, Lookup, TraitId, TypeAliasId, TypeParamId, VariantId,
 };
-use hir_expand::name::{self, Name};
+use hir_expand::name::{name, Name};
 
-// FIXME: this is wrong, b/c it can't express `trait T: PartialEq<()>`.
-// We should return a `TraitREf` here.
 fn direct_super_traits(db: &impl DefDatabase, trait_: TraitId) -> Vec<TraitId> {
     let resolver = trait_.resolver(db);
     // returning the iterator directly doesn't easily work because of
@@ -24,7 +22,7 @@ fn direct_super_traits(db: &impl DefDatabase, trait_: TraitId) -> Vec<TraitId> {
         .where_predicates
         .iter()
         .filter_map(|pred| match &pred.type_ref {
-            TypeRef::Path(p) if p.as_ident() == Some(&name::SELF_TYPE) => pred.bound.as_path(),
+            TypeRef::Path(p) if p.as_ident() == Some(&name![Self]) => pred.bound.as_path(),
             _ => None,
         })
         .filter_map(|path| match resolver.resolve_path_in_type_ns_fully(db, path) {