Make ItemContext available for better diagnositcs.

src/test/ui/async-await/try-on-option-in-async.rs

@@ -0,0 +1,27 @@
+#![feature(try_trait, async_closure)]
+// edition:2018
+fn main() {}
+
+async fn an_async_block() -> u32 {
+    async {
+        let x: Option<u32> = None;
+        x?; //~ ERROR the `?` operator
+        22
+    }.await
+}
+
+async fn async_closure_containing_fn() -> u32 {
+    let async_closure = async || {
+        let x: Option<u32> = None;
+        x?; //~ ERROR the `?` operator
+        22_u32
+    };
+
+    async_closure().await
+}
+
+async fn an_async_function() -> u32 {
+    let x: Option<u32> = None;
+    x?; //~ ERROR the `?` operator
+    22
+}