introduce a region unification table and use it in dropck

Fixes #29844

1 files changed, 33 insertions, 0 deletions

diff --git a/src/test/run-pass/issue-29844.rs b/src/test/run-pass/issue-29844.rs
new file mode 100644
index 00000000000..51df4d60f04
--- /dev/null
+++ b/src/test/run-pass/issue-29844.rs
@@ -0,0 +1,33 @@
+// Copyright 2015 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::sync::Arc;
+
+pub struct DescriptorSet<'a> {
+    pub slots: Vec<AttachInfo<'a, Resources>>
+}
+
+pub trait ResourcesTrait<'r>: Sized {
+    type DescriptorSet: 'r;
+}
+
+pub struct Resources;
+
+impl<'a> ResourcesTrait<'a> for Resources {
+    type DescriptorSet = DescriptorSet<'a>;
+}
+
+pub enum AttachInfo<'a, R: ResourcesTrait<'a>> {
+    NextDescriptorSet(Arc<R::DescriptorSet>)
+}
+
+fn main() {
+    let _x = DescriptorSet {slots: Vec::new()};
+}