Add `impl Trait` and `dyn Trait` types

 - refactor bounds handling in the AST a bit
 - add HIR for bounds
 - add `Ty::Dyn` and `Ty::Opaque` variants and lower `dyn Trait` / `impl Trait`
   syntax to them

1 files changed, 3 insertions, 1 deletions

diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index 6df7094c5..2ebc06135 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -80,7 +80,9 @@ impl ToChalk for Ty {
             // FIXME this is clearly incorrect, but probably not too incorrect
             // and I'm not sure what to actually do with Ty::Unknown
             // maybe an alternative would be `for<T> T`? (meaningless in rust, but expressible in chalk's Ty)
-            Ty::Unknown => {
+            //
+            // FIXME also dyn and impl Trait are currently handled like Unknown because Chalk doesn't have them yet
+            Ty::Unknown | Ty::Dyn(_) | Ty::Opaque(_) => {
                 PlaceholderIndex { ui: UniverseIndex::ROOT, idx: usize::max_value() }.to_ty()
             }
         }