Disallow associated type constraints on negative bounds

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -701,8 +701,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
         let mut dup_bindings = FxHashMap::default();
         for binding in &assoc_bindings {
-            // TODO: negative polarity can't have associated type bindings!
-
             // Specify type to assert that error was already reported in `Err` case.
             let _: Result<_, ErrorGuaranteed> = self.add_predicates_for_ast_type_binding(
                 hir_id,