Regression test added for an async ICE.

src/test/run-pass/issues/issue-57084-async-await.rs

@@ -0,0 +1,27 @@
+// This issue reproduces an ICE on compile (E.g. fails on 2018-12-19 nightly).
+// run-pass
+// edition:2018
+#![feature(async_await,futures_api,await_macro,generators)]
+
+pub struct Foo;
+
+impl Foo {
+    async fn with<'a, F, R>(&'a self, f: F) -> R
+    where F: Fn() -> R + 'a,
+    {
+        loop {
+            match f() {
+                _ => yield,
+            }
+        }
+    }
+
+    pub async fn run<'a>(&'a self, data: &'a [u8])
+    {
+        await!(self.with(move || {
+            println!("{:p}", data);
+        }))
+    }
+}
+
+fn main() {}