Auto merge of #46226 - arielb1:special-region-obligation, r=nikomatsakis

avoid type-live-for-region obligations on dummy nodes

Type-live-for-region obligations on DUMMY_NODE_ID cause an ICE, and it
turns out that in the few cases they are needed, these obligations are not
needed anyway because they are verified elsewhere.

Fixes #46069.

Beta-nominating because this is a regression for our new beta.
r? @nikomatsakis

src/test/run-pass/issue-46069.rs

@@ -0,0 +1,32 @@
+// Copyright 2017 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.
+
+use std::iter::{Fuse, Cloned};
+use std::slice::Iter;
+
+struct Foo<'a, T: 'a>(&'a T);
+impl<'a, T: 'a> Copy for Foo<'a, T> {}
+impl<'a, T: 'a> Clone for Foo<'a, T> {
+    fn clone(&self) -> Self { *self }
+}
+
+fn copy_ex() {
+    let s = 2;
+    let k1 = || s;
+    let upvar = Foo(&k1);
+    let k = || upvar;
+    k();
+}
+
+fn main() {
+    let _f = 0 as *mut <Fuse<Cloned<Iter<u8>>> as Iterator>::Item;
+
+    copy_ex();
+}