add cycle-reporting logic

Fixes #33344

src/test/compile-fail/traits-inductive-overflow-simultaneous.rs

@@ -0,0 +1,30 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Regression test for #33344, initial version. This example allowed
+// arbitrary trait bounds to be synthesized.
+
+trait Tweedledum: IntoIterator {}
+trait Tweedledee: IntoIterator {}
+
+impl<T: Tweedledum> Tweedledee for T {}
+impl<T: Tweedledee> Tweedledum for T {}
+
+trait Combo: IntoIterator {}
+impl<T: Tweedledee + Tweedledum> Combo for T {}
+
+fn is_ee<T: Combo>(t: T) {
+    t.into_iter();
+}
+
+fn main() {
+    is_ee(4);
+    //~^ ERROR overflow evaluating the requirement `_: Tweedle
+}