Rework obligation handling

We can't do the easy hack that we did before anymore, where we kept
track of whether any inference variables changed since the last time we
rechecked obligations. Instead, we store the obligations in
canonicalized form; that way we can easily check the inference variables
to see whether they have changed since the goal was canonicalized.

1 files changed, 3 insertions, 3 deletions

diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index f439169ea..6eaccd9b4 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -99,9 +99,9 @@ impl<'a> InferenceContext<'a> {
             environment: trait_env,
         };
         let canonical = self.canonicalize(obligation.clone());
-        if self.db.trait_solve(krate, canonical.value).is_some() {
+        if self.db.trait_solve(krate, canonical.value.cast(&Interner)).is_some() {
             self.push_obligation(obligation.goal);
-            let return_ty = self.normalize_projection_ty(projection);
+            let return_ty = self.table.normalize_projection_ty(projection);
             Some((arg_tys, return_ty))
         } else {
             None
@@ -306,7 +306,7 @@ impl<'a> InferenceContext<'a> {
                     self.resolver.krate(),
                     InEnvironment {
                         goal: canonicalized.value.clone(),
-                        environment: self.trait_env.env.clone(),
+                        environment: self.table.trait_env.env.clone(),
                     },
                 );
                 let (param_tys, ret_ty): (Vec<Ty>, Ty) = derefs