close #9655 add testcase (#16683)

tests/ccgbugs/t9655.nim

@@ -0,0 +1,30 @@
+discard """
+  action: "compile"
+"""
+
+import std/[asynchttpserver, asyncdispatch]
+import std/[strformat]
+
+proc main() =
+  let local = "123"
+
+  proc serveIndex(req: Request) {.async, gcsafe.} =
+    await req.respond(Http200, &"{local}")
+
+  proc serve404(req: Request) {.async, gcsafe.} =
+    echo req.url.path
+    await req.respond(Http404, "not found")
+
+  proc serve(req: Request) {.async, gcsafe.} =
+    let handler = case req.url.path:
+      of "/":
+        serveIndex
+      else:
+        serve404
+    await handler(req)
+
+  let server = newAsyncHttpServer()
+  waitFor server.serve(Port(8080), serve, address = "127.0.0.1")
+
+when isMainModule:
+  main()