Introduce QuantifiedWhereClause and DynTy analogous to Chalk

This introduces a bunch of new binders in lots of places, which we have
to be careful about, but we had to add them at some point.

1 files changed, 5 insertions, 1 deletions

diff --git a/crates/hir/src/display.rs b/crates/hir/src/display.rs
index 9f6d7be48..c96ebb50a 100644
--- a/crates/hir/src/display.rs
+++ b/crates/hir/src/display.rs
@@ -236,7 +236,11 @@ impl HirDisplay for TypeParam {
         write!(f, "{}", self.name(f.db))?;
         let bounds = f.db.generic_predicates_for_param(self.id);
         let substs = Substitution::type_params(f.db, self.id.parent);
-        let predicates = bounds.iter().cloned().map(|b| b.subst(&substs)).collect::<Vec<_>>();
+        let predicates = bounds
+            .iter()
+            .cloned()
+            .map(|b| hir_ty::Binders::new(0, b.subst(&substs)))
+            .collect::<Vec<_>>();
         if !(predicates.is_empty() || f.omit_verbose_types()) {
             write_bounds_like_dyn_trait_with_prefix(":", &predicates, f)?;
         }