4 files changed, 39 insertions, 3 deletions

diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index a9022dee7..717399b6d 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -1,6 +1,11 @@
 //! The type system. We currently use this to infer types for completion, hover
 //! information and various assists.
 
+#[allow(unused)]
+macro_rules! eprintln {
+    ($($tt:tt)*) => { stdx::eprintln!($($tt)*) };
+}
+
 macro_rules! impl_froms {
     ($e:ident: $($v:ident $(($($sv:ident),*))?),*) => {
         $(
@@ -855,7 +860,8 @@ pub trait TypeWalk {
         );
         self
     }
-    // /// Shifts up debruijn indices of `Ty::Bound` vars by `n`.
+
+    /// Shifts up debruijn indices of `Ty::Bound` vars by `n`.
     fn shift_bound_vars(self, n: DebruijnIndex) -> Self
     where
         Self: Sized,
diff --git a/crates/ra_hir_ty/src/tests/traits.rs b/crates/ra_hir_ty/src/tests/traits.rs
index 081aa943a..22ae6ca90 100644
--- a/crates/ra_hir_ty/src/tests/traits.rs
+++ b/crates/ra_hir_ty/src/tests/traits.rs
@@ -2021,3 +2021,28 @@ fn main() {
     "###
     );
 }
+
+#[test]
+fn dyn_trait_through_chalk() {
+    let t = type_at(
+        r#"
+//- /main.rs
+struct Box<T> {}
+#[lang = "deref"]
+trait Deref {
+    type Target;
+}
+impl<T> Deref for Box<T> {
+    type Target = T;
+}
+trait Trait {
+    fn foo(&self);
+}
+
+fn test(x: Box<dyn Trait>) {
+    x.foo()<|>;
+}
+"#,
+    );
+    assert_eq!(t, "()");
+}
diff --git a/crates/ra_hir_ty/src/traits.rs b/crates/ra_hir_ty/src/traits.rs
index 07854a062..5a1e12ce9 100644
--- a/crates/ra_hir_ty/src/traits.rs
+++ b/crates/ra_hir_ty/src/traits.rs
@@ -148,7 +148,7 @@ pub(crate) fn trait_solve_query(
         Obligation::Trait(it) => db.trait_data(it.trait_).name.to_string(),
         Obligation::Projection(_) => "projection".to_string(),
     });
-    eprintln!("trait_solve_query({})", goal.value.value.display(db));
+    log::info!("trait_solve_query({})", goal.value.value.display(db));
 
     if let Obligation::Projection(pred) = &goal.value.value {
         if let Ty::Bound(_) = &pred.projection_ty.parameters[0] {
diff --git a/crates/ra_hir_ty/src/traits/chalk.rs b/crates/ra_hir_ty/src/traits/chalk.rs
index 53ce362ea..1bc0f0713 100644
--- a/crates/ra_hir_ty/src/traits/chalk.rs
+++ b/crates/ra_hir_ty/src/traits/chalk.rs
@@ -427,7 +427,12 @@ impl ToChalk for GenericPredicate {
         db: &dyn HirDatabase,
         where_clause: chalk_ir::QuantifiedWhereClause<Interner>,
     ) -> GenericPredicate {
-        match where_clause.value {
+        // we don't produce any where clauses with binders and can't currently deal with them
+        match where_clause
+            .value
+            .shifted_out(&Interner)
+            .expect("unexpected bound vars in where clause")
+        {
             chalk_ir::WhereClause::Implemented(tr) => {
                 GenericPredicate::Implemented(from_chalk(db, tr))
             }