cleanup

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -373,10 +373,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         }
     }
 
-    fn visit_stmt(&mut self, stmt: &'a ast::Stmt) {
-        visit::walk_stmt(self, stmt);
-    }
-
     fn visit_expr(&mut self, e: &'a ast::Expr) {
         match e.kind {
             ast::ExprKind::TryBlock(_) => {

compiler/rustc_feature/src/active.rs

@@ -534,6 +534,8 @@ declare_features! (
     (active, try_blocks, "1.29.0", Some(31436), None),
     /// Allows `impl Trait` to be used inside type aliases (RFC 2515).
     (active, type_alias_impl_trait, "1.38.0", Some(63063), None),
+    /// Allows the use of type ascription in expressions.
+    (active, type_ascription, "1.6.0", Some(23416), None),
     /// Allows creation of instances of a struct by moving fields that have
     /// not changed from prior instances of the same struct (RFC #2528)
     (active, type_changing_struct_update, "1.58.0", Some(86555), None),