7 files changed, 201 insertions, 40 deletions

diff --git a/crates/ra_hir/src/ty/autoderef.rs b/crates/ra_hir/src/ty/autoderef.rs
index 2535d4ae7..08f52a53b 100644
--- a/crates/ra_hir/src/ty/autoderef.rs
+++ b/crates/ra_hir/src/ty/autoderef.rs
@@ -7,7 +7,7 @@ use std::iter::successors;
 
 use log::{info, warn};
 
-use super::{traits::Solution, Canonical, Ty};
+use super::{traits::Solution, Canonical, Ty, TypeWalk};
 use crate::{HasGenericParams, HirDatabase, Name, Resolver};
 
 const AUTODEREF_RECURSION_LIMIT: usize = 10;
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index b89a40b4b..ec3b7ffef 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -30,7 +30,7 @@ use super::{
     autoderef, lower, method_resolution, op, primitive,
     traits::{Guidance, Obligation, ProjectionPredicate, Solution},
     ApplicationTy, CallableDef, InEnvironment, ProjectionTy, Substs, TraitEnvironment, TraitRef,
-    Ty, TypableDef, TypeCtor,
+    Ty, TypableDef, TypeCtor, TypeWalk,
 };
 use crate::{
     adt::VariantDef,
diff --git a/crates/ra_hir/src/ty/infer/unify.rs b/crates/ra_hir/src/ty/infer/unify.rs
index e7e8825d1..9a0d2d8f9 100644
--- a/crates/ra_hir/src/ty/infer/unify.rs
+++ b/crates/ra_hir/src/ty/infer/unify.rs
@@ -3,7 +3,7 @@
 use super::{InferenceContext, Obligation};
 use crate::db::HirDatabase;
 use crate::ty::{
-    Canonical, InEnvironment, InferTy, ProjectionPredicate, ProjectionTy, TraitRef, Ty,
+    Canonical, InEnvironment, InferTy, ProjectionPredicate, ProjectionTy, TraitRef, Ty, TypeWalk,
 };
 
 impl<'a, D: HirDatabase> InferenceContext<'a, D> {
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index 47d161277..f6f0137cf 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -8,7 +8,10 @@
 use std::iter;
 use std::sync::Arc;
 
-use super::{FnSig, GenericPredicate, ProjectionTy, Substs, TraitRef, Ty, TypeCtor};
+use super::{
+    FnSig, GenericPredicate, ProjectionPredicate, ProjectionTy, Substs, TraitRef, Ty, TypeCtor,
+    TypeWalk,
+};
 use crate::{
     adt::VariantDef,
     generics::HasGenericParams,
@@ -62,7 +65,9 @@ impl Ty {
                 let self_ty = Ty::Bound(0);
                 let predicates = bounds
                     .iter()
-                    .map(|b| GenericPredicate::from_type_bound(db, resolver, b, self_ty.clone()))
+                    .flat_map(|b| {
+                        GenericPredicate::from_type_bound(db, resolver, b, self_ty.clone())
+                    })
                     .collect::<Vec<_>>();
                 Ty::Dyn(predicates.into())
             }
@@ -70,7 +75,9 @@ impl Ty {
                 let self_ty = Ty::Bound(0);
                 let predicates = bounds
                     .iter()
-                    .map(|b| GenericPredicate::from_type_bound(db, resolver, b, self_ty.clone()))
+                    .flat_map(|b| {
+                        GenericPredicate::from_type_bound(db, resolver, b, self_ty.clone())
+                    })
                     .collect::<Vec<_>>();
                 Ty::Opaque(predicates.into())
             }
@@ -326,15 +333,6 @@ impl TraitRef {
         TraitRef { trait_, substs }
     }
 
-    pub(crate) fn from_where_predicate(
-        db: &impl HirDatabase,
-        resolver: &Resolver,
-        pred: &WherePredicate,
-    ) -> Option<TraitRef> {
-        let self_ty = Ty::from_hir(db, resolver, &pred.type_ref);
-        TraitRef::from_type_bound(db, resolver, &pred.bound, self_ty)
-    }
-
     pub(crate) fn from_type_bound(
         db: &impl HirDatabase,
         resolver: &Resolver,
@@ -349,26 +347,58 @@ impl TraitRef {
 }
 
 impl GenericPredicate {
-    pub(crate) fn from_where_predicate(
-        db: &impl HirDatabase,
-        resolver: &Resolver,
-        where_predicate: &WherePredicate,
-    ) -> GenericPredicate {
-        TraitRef::from_where_predicate(db, &resolver, where_predicate)
-            .map_or(GenericPredicate::Error, GenericPredicate::Implemented)
+    pub(crate) fn from_where_predicate<'a>(
+        db: &'a impl HirDatabase,
+        resolver: &'a Resolver,
+        where_predicate: &'a WherePredicate,
+    ) -> impl Iterator<Item = GenericPredicate> + 'a {
+        let self_ty = Ty::from_hir(db, resolver, &where_predicate.type_ref);
+        GenericPredicate::from_type_bound(db, resolver, &where_predicate.bound, self_ty)
     }
 
-    pub(crate) fn from_type_bound(
-        db: &impl HirDatabase,
-        resolver: &Resolver,
-        bound: &TypeBound,
+    pub(crate) fn from_type_bound<'a>(
+        db: &'a impl HirDatabase,
+        resolver: &'a Resolver,
+        bound: &'a TypeBound,
         self_ty: Ty,
-    ) -> GenericPredicate {
-        TraitRef::from_type_bound(db, &resolver, bound, self_ty)
-            .map_or(GenericPredicate::Error, GenericPredicate::Implemented)
+    ) -> impl Iterator<Item = GenericPredicate> + 'a {
+        let trait_ref = TraitRef::from_type_bound(db, &resolver, bound, self_ty);
+        iter::once(trait_ref.clone().map_or(GenericPredicate::Error, GenericPredicate::Implemented))
+            .chain(
+                trait_ref.into_iter().flat_map(move |tr| {
+                    assoc_type_bindings_from_type_bound(db, resolver, bound, tr)
+                }),
+            )
     }
 }
 
+fn assoc_type_bindings_from_type_bound<'a>(
+    db: &'a impl HirDatabase,
+    resolver: &'a Resolver,
+    bound: &'a TypeBound,
+    trait_ref: TraitRef,
+) -> impl Iterator<Item = GenericPredicate> + 'a {
+    let last_segment = match bound {
+        TypeBound::Path(path) => path.segments.last(),
+        TypeBound::Error => None,
+    };
+    last_segment
+        .into_iter()
+        .flat_map(|segment| segment.args_and_bindings.iter())
+        .flat_map(|args_and_bindings| args_and_bindings.bindings.iter())
+        .map(move |(name, type_ref)| {
+            let associated_ty = match trait_ref.trait_.associated_type_by_name(db, name.clone()) {
+                None => return GenericPredicate::Error,
+                Some(t) => t,
+            };
+            let projection_ty =
+                ProjectionTy { associated_ty, parameters: trait_ref.substs.clone() };
+            let ty = Ty::from_hir(db, resolver, type_ref);
+            let projection_predicate = ProjectionPredicate { projection_ty, ty };
+            GenericPredicate::Projection(projection_predicate)
+        })
+}
+
 /// Build the declared type of an item. This depends on the namespace; e.g. for
 /// `struct Foo(usize)`, we have two types: The type of the struct itself, and
 /// the constructor function `(usize) -> Foo` which lives in the values
@@ -425,7 +455,7 @@ pub(crate) fn trait_env(
 ) -> Arc<super::TraitEnvironment> {
     let predicates = resolver
         .where_predicates_in_scope()
-        .map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred))
+        .flat_map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred))
         .collect::<Vec<_>>();
 
     Arc::new(super::TraitEnvironment { predicates })
@@ -439,7 +469,7 @@ pub(crate) fn generic_predicates_query(
     let resolver = def.resolver(db);
     let predicates = resolver
         .where_predicates_in_scope()
-        .map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred))
+        .flat_map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred))
         .collect::<Vec<_>>();
     predicates.into()
 }
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index d344ab12e..d92d4659b 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -2793,6 +2793,10 @@ fn main() {
 }
 "#),
         @r###"
+    ![0; 17) '{Foo(v...,2,])}': Foo
+    ![1; 4) 'Foo': Foo({unknown}) -> Foo
+    ![1; 16) 'Foo(vec![1,2,])': Foo
+    ![5; 15) 'vec![1,2,]': {unknown}
     [156; 182) '{     ...,2); }': ()
     [166; 167) 'x': Foo
     "###
@@ -3548,6 +3552,97 @@ fn test() {
     );
 }
 
+#[test]
+fn assoc_type_bindings() {
+    assert_snapshot!(
+        infer(r#"
+trait Trait {
+    type Type;
+}
+
+fn get<T: Trait>(t: T) -> <T as Trait>::Type {}
+fn get2<U, T: Trait<Type = U>>(t: T) -> U {}
+fn set<T: Trait<Type = u64>>(t: T) -> T {t}
+
+struct S<T>;
+impl<T> Trait for S<T> { type Type = T; }
+
+fn test<T: Trait<Type = u32>>(x: T, y: impl Trait<Type = i64>) {
+    get(x);
+    get2(x);
+    get(y);
+    get2(y);
+    get(set(S));
+    get2(set(S));
+    get2(S::<str>);
+}
+"#),
+        @r###"
+    [50; 51) 't': T
+    [78; 80) '{}': ()
+    [112; 113) 't': T
+    [123; 125) '{}': ()
+    [155; 156) 't': T
+    [166; 169) '{t}': T
+    [167; 168) 't': T
+    [257; 258) 'x': T
+    [263; 264) 'y': impl Trait<Type = i64>
+    [290; 398) '{     ...r>); }': ()
+    [296; 299) 'get': fn get<T>(T) -> <T as Trait>::Type
+    [296; 302) 'get(x)': {unknown}
+    [300; 301) 'x': T
+    [308; 312) 'get2': fn get2<{unknown}, S<{unknown}>>(T) -> U
+    [308; 315) 'get2(x)': {unknown}
+    [313; 314) 'x': T
+    [321; 324) 'get': fn get<impl Trait<Type = i64>>(T) -> <T as Trait>::Type
+    [321; 327) 'get(y)': {unknown}
+    [325; 326) 'y': impl Trait<Type = i64>
+    [333; 337) 'get2': fn get2<{unknown}, S<{unknown}>>(T) -> U
+    [333; 340) 'get2(y)': {unknown}
+    [338; 339) 'y': impl Trait<Type = i64>
+    [346; 349) 'get': fn get<S<u64>>(T) -> <T as Trait>::Type
+    [346; 357) 'get(set(S))': u64
+    [350; 353) 'set': fn set<S<u64>>(T) -> T
+    [350; 356) 'set(S)': S<u64>
+    [354; 355) 'S': S<u64>
+    [363; 367) 'get2': fn get2<u64, S<u64>>(T) -> U
+    [363; 375) 'get2(set(S))': u64
+    [368; 371) 'set': fn set<S<u64>>(T) -> T
+    [368; 374) 'set(S)': S<u64>
+    [372; 373) 'S': S<u64>
+    [381; 385) 'get2': fn get2<str, S<str>>(T) -> U
+    [381; 395) 'get2(S::<str>)': str
+    [386; 394) 'S::<str>': S<str>
+    "###
+    );
+}
+
+#[test]
+fn projection_eq_within_chalk() {
+    // std::env::set_var("CHALK_DEBUG", "1");
+    assert_snapshot!(
+        infer(r#"
+trait Trait1 {
+    type Type;
+}
+trait Trait2<T> {
+    fn foo(self) -> T;
+}
+impl<T, U> Trait2<T> for U where U: Trait1<Type = T> {}
+
+fn test<T: Trait1<Type = u32>>(x: T) {
+    x.foo();
+}
+"#),
+        @r###"
+    [62; 66) 'self': Self
+    [164; 165) 'x': T
+    [170; 186) '{     ...o(); }': ()
+    [176; 177) 'x': T
+    [176; 183) 'x.foo()': {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();
@@ -3566,7 +3661,6 @@ fn infer(content: &str) -> String {
     let source_file = db.parse(file_id).ok().unwrap();
 
     let mut acc = String::new();
-    // acc.push_str("\n");
 
     let mut infer_def = |inference_result: Arc<InferenceResult>,
                          body_source_map: Arc<BodySourceMap>| {
@@ -3574,7 +3668,9 @@ fn infer(content: &str) -> String {
 
         for (pat, ty) in inference_result.type_of_pat.iter() {
             let syntax_ptr = match body_source_map.pat_syntax(pat) {
-                Some(sp) => sp.either(|it| it.syntax_node_ptr(), |it| it.syntax_node_ptr()),
+                Some(sp) => {
+                    sp.map(|ast| ast.either(|it| it.syntax_node_ptr(), |it| it.syntax_node_ptr()))
+                }
                 None => continue,
             };
             types.push((syntax_ptr, ty));
@@ -3582,22 +3678,34 @@ fn infer(content: &str) -> String {
 
         for (expr, ty) in inference_result.type_of_expr.iter() {
             let syntax_ptr = match body_source_map.expr_syntax(expr) {
-                Some(sp) => sp.either(|it| it.syntax_node_ptr(), |it| it.syntax_node_ptr()),
+                Some(sp) => {
+                    sp.map(|ast| ast.either(|it| it.syntax_node_ptr(), |it| it.syntax_node_ptr()))
+                }
                 None => continue,
             };
             types.push((syntax_ptr, ty));
         }
 
         // sort ranges for consistency
-        types.sort_by_key(|(ptr, _)| (ptr.range().start(), ptr.range().end()));
-        for (syntax_ptr, ty) in &types {
-            let node = syntax_ptr.to_node(source_file.syntax());
+        types.sort_by_key(|(src_ptr, _)| (src_ptr.ast.range().start(), src_ptr.ast.range().end()));
+        for (src_ptr, ty) in &types {
+            let node = src_ptr.ast.to_node(&src_ptr.file_syntax(&db));
+
             let (range, text) = if let Some(self_param) = ast::SelfParam::cast(node.clone()) {
                 (self_param.self_kw_token().text_range(), "self".to_string())
             } else {
-                (syntax_ptr.range(), node.text().to_string().replace("\n", " "))
+                (src_ptr.ast.range(), node.text().to_string().replace("\n", " "))
             };
-            write!(acc, "{} '{}': {}\n", range, ellipsize(text, 15), ty.display(&db)).unwrap();
+            let macro_prefix = if src_ptr.file_id != file_id.into() { "!" } else { "" };
+            write!(
+                acc,
+                "{}{} '{}': {}\n",
+                macro_prefix,
+                range,
+                ellipsize(text, 15),
+                ty.display(&db)
+            )
+            .unwrap();
         }
     };
 
diff --git a/crates/ra_hir/src/ty/traits.rs b/crates/ra_hir/src/ty/traits.rs
index b634f0b79..6e0271a96 100644
--- a/crates/ra_hir/src/ty/traits.rs
+++ b/crates/ra_hir/src/ty/traits.rs
@@ -8,7 +8,7 @@ use ra_db::salsa;
 use ra_prof::profile;
 use rustc_hash::FxHashSet;
 
-use super::{Canonical, GenericPredicate, HirDisplay, ProjectionTy, TraitRef, Ty};
+use super::{Canonical, GenericPredicate, HirDisplay, ProjectionTy, TraitRef, Ty, TypeWalk};
 use crate::{db::HirDatabase, Crate, ImplBlock, Trait};
 
 use self::chalk::{from_chalk, ToChalk};
@@ -124,6 +124,9 @@ impl Obligation {
     pub fn from_predicate(predicate: GenericPredicate) -> Option<Obligation> {
         match predicate {
             GenericPredicate::Implemented(trait_ref) => Some(Obligation::Trait(trait_ref)),
+            GenericPredicate::Projection(projection_pred) => {
+                Some(Obligation::Projection(projection_pred))
+            }
             GenericPredicate::Error => None,
         }
     }
@@ -135,6 +138,18 @@ pub struct ProjectionPredicate {
     pub ty: Ty,
 }
 
+impl TypeWalk for ProjectionPredicate {
+    fn walk(&self, f: &mut impl FnMut(&Ty)) {
+        self.projection_ty.walk(f);
+        self.ty.walk(f);
+    }
+
+    fn walk_mut(&mut self, f: &mut impl FnMut(&mut Ty)) {
+        self.projection_ty.walk_mut(f);
+        self.ty.walk_mut(f);
+    }
+}
+
 /// Solve a trait goal using Chalk.
 pub(crate) fn trait_solve_query(
     db: &impl HirDatabase,
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index 2ebc06135..c201c5e50 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -19,6 +19,7 @@ use crate::{
     ty::display::HirDisplay,
     ty::{
         ApplicationTy, CallableDef, GenericPredicate, ProjectionTy, Substs, TraitRef, Ty, TypeCtor,
+        TypeWalk,
     },
     Crate, HasGenericParams, ImplBlock, ImplItem, Trait, TypeAlias,
 };
@@ -211,6 +212,13 @@ impl ToChalk for GenericPredicate {
             GenericPredicate::Implemented(trait_ref) => {
                 make_binders(chalk_ir::WhereClause::Implemented(trait_ref.to_chalk(db)), 0)
             }
+            GenericPredicate::Projection(projection_pred) => make_binders(
+                chalk_ir::WhereClause::ProjectionEq(chalk_ir::ProjectionEq {
+                    projection: projection_pred.projection_ty.to_chalk(db),
+                    ty: projection_pred.ty.to_chalk(db),
+                }),
+                0,
+            ),
             GenericPredicate::Error => {
                 let impossible_trait_ref = chalk_ir::TraitRef {
                     trait_id: UNKNOWN_TRAIT,