Match on coroutine kind, include AsyncGen coroutines for suggestion

Author: metamuffin

compiler/rustc_trait_selection/src/error_reporting/infer/suggest.rs

@@ -167,12 +167,12 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             exp_span, exp_found.expected, exp_found.found,
         );
 
-        let is_async_block = matches!(
-            self.tcx.coroutine_kind(cause.body_id),
-            Some(rustc_hir::CoroutineKind::Desugared(rustc_hir::CoroutineDesugaring::Async, _)),
-        );
-        if !is_async_block {
-            return;
+        match self.tcx.coroutine_kind(cause.body_id) {
+            Some(hir::CoroutineKind::Desugared(
+                hir::CoroutineDesugaring::Async | hir::CoroutineDesugaring::AsyncGen,
+                _,
+            )) => (),
+            _ => return,
         }
 
         if let ObligationCauseCode::CompareImplItem { .. } = cause.code() {