Rollup merge of #62383 - Aaron1011:fix/async-error-span, r=varkor

Improve error span for async type inference error

Fixes #62382

Previously, we would point at the spawn of the 'await' expression,
instead of the actual expression with an unknown type.

2 files changed, 32 insertions, 0 deletions

diff --git a/src/test/ui/async-await/async-error-span.rs b/src/test/ui/async-await/async-error-span.rs
new file mode 100644
index 00000000000..d362348a3fd
--- /dev/null
+++ b/src/test/ui/async-await/async-error-span.rs
@@ -0,0 +1,17 @@
+// edition:2018
+#![feature(async_await)]
+
+// Regression test for issue #62382
+
+use std::future::Future;
+
+fn get_future() -> impl Future<Output = ()> {
+    panic!()
+}
+
+async fn foo() {
+    let a; //~ ERROR type inside `async` object must be known in this context
+    get_future().await;
+}
+
+fn main() {}
diff --git a/src/test/ui/async-await/async-error-span.stderr b/src/test/ui/async-await/async-error-span.stderr
new file mode 100644
index 00000000000..bd8966b9c7d
--- /dev/null
+++ b/src/test/ui/async-await/async-error-span.stderr
@@ -0,0 +1,15 @@
+error[E0698]: type inside `async` object must be known in this context
+  --> $DIR/async-error-span.rs:13:9
+   |
+LL |     let a;
+   |         ^ cannot infer type
+   |
+note: the type is part of the `async` object because of this `await`
+  --> $DIR/async-error-span.rs:14:5
+   |
+LL |     get_future().await;
+   |     ^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0698`.