1 files changed, 34 insertions, 8 deletions

diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs
index 6c7bbc448..cc1ac8e3e 100644
--- a/crates/ra_hir_ty/src/lower.rs
+++ b/crates/ra_hir_ty/src/lower.rs
@@ -8,6 +8,8 @@
 use std::iter;
 use std::sync::Arc;
 
+use smallvec::SmallVec;
+
 use hir_def::{
     adt::StructKind,
     builtin_type::BuiltinType,
@@ -360,13 +362,23 @@ impl Ty {
             },
             Some(TypeNs::GenericParam(param_id)) => {
                 let predicates = ctx.db.generic_predicates_for_param(param_id);
-                predicates
+                let mut traits_: Vec<_> = predicates
                     .iter()
                     .filter_map(|pred| match &pred.value {
                         GenericPredicate::Implemented(tr) => Some(tr.trait_),
                         _ => None,
                     })
-                    .collect()
+                    .collect();
+                // Handle `Self::Type` referring to own associated type in trait definitions
+                if let GenericDefId::TraitId(trait_id) = param_id.parent {
+                    let generics = generics(ctx.db.upcast(), trait_id.into());
+                    if generics.params.types[param_id.local_id].provenance
+                        == TypeParamProvenance::TraitSelf
+                    {
+                        traits_.push(trait_id);
+                    }
+                }
+                traits_
             }
             _ => return Ty::Unknown,
         };
@@ -596,21 +608,35 @@ fn assoc_type_bindings_from_type_bound<'a>(
         .into_iter()
         .flat_map(|segment| segment.args_and_bindings.into_iter())
         .flat_map(|args_and_bindings| args_and_bindings.bindings.iter())
-        .map(move |(name, type_ref)| {
+        .flat_map(move |binding| {
             let associated_ty = associated_type_by_name_including_super_traits(
                 ctx.db.upcast(),
                 trait_ref.trait_,
-                &name,
+                &binding.name,
             );
             let associated_ty = match associated_ty {
-                None => return GenericPredicate::Error,
+                None => return SmallVec::<[GenericPredicate; 1]>::new(),
                 Some(t) => t,
             };
             let projection_ty =
                 ProjectionTy { associated_ty, parameters: trait_ref.substs.clone() };
-            let ty = Ty::from_hir(ctx, type_ref);
-            let projection_predicate = ProjectionPredicate { projection_ty, ty };
-            GenericPredicate::Projection(projection_predicate)
+            let mut preds = SmallVec::with_capacity(
+                binding.type_ref.as_ref().map_or(0, |_| 1) + binding.bounds.len(),
+            );
+            if let Some(type_ref) = &binding.type_ref {
+                let ty = Ty::from_hir(ctx, type_ref);
+                let projection_predicate =
+                    ProjectionPredicate { projection_ty: projection_ty.clone(), ty };
+                preds.push(GenericPredicate::Projection(projection_predicate));
+            }
+            for bound in &binding.bounds {
+                preds.extend(GenericPredicate::from_type_bound(
+                    ctx,
+                    bound,
+                    Ty::Projection(projection_ty.clone()),
+                ));
+            }
+            preds
         })
 }