[Flight] Improve aborted hanging promise stacks

Author: unstubbable

packages/react-server/src/ReactFlightServer.js

@@ -2291,7 +2291,7 @@ function visitAsyncNode(
         // The technique for debugging the effects of uncached data on the render is to simply uncache it.
         return previousIONode;
       }
-      const awaited = node.awaited;
+      let awaited = node.awaited;
       let match: void | null | PromiseNode | IONode = previousIONode;
       if (awaited !== null) {
         const ioNode = visitAsyncNode(request, task, awaited, visited, cutOff);
@@ -2324,7 +2324,23 @@ function visitAsyncNode(
             // We aborted this render. If this Promise spanned the abort time it was probably the
             // Promise that was aborted. This won't necessarily have I/O associated with it but
             // it's a point of interest.
+
+            // If the awaited node was an await in user space, that will typically have a more
+            // useful stack. Try to find one, before falling back to using the promise node.
+            while (awaited.tag === AWAIT_NODE) {
+              if (
+                awaited.stack !== null &&
+                hasUnfilteredFrame(request, awaited.stack)
+              ) {
+                match = awaited;
+                break;
+              } else {
+                awaited = awaited.awaited;
+              }
+            }
+
             if (
+              match === null &&
               node.stack !== null &&
               hasUnfilteredFrame(request, node.stack)
             ) {