Merge #3868

3868: Fix Chalk panic r=flodiebold a=flodiebold

Fixes #3865. Basically I forgot to shift 'back' when we got `dyn Trait`s back from Chalk, so after going through Chalk a few times, the panic happened.

And yes, I did run `analysis-stats` now ;)

cc @edwin0cheng 

Co-authored-by: Florian Diebold <[email protected]>

1 files changed, 25 insertions, 0 deletions

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, "()");
+}