diff --git a/src/net/http/h2_bundle.go b/src/net/http/h2_bundle.go
index 678c6eb9d4a37..3d830847022c2 100644
--- a/src/net/http/h2_bundle.go
+++ b/src/net/http/h2_bundle.go
@@ -8985,6 +8985,8 @@ func http2strSliceContains(ss []string, s string) bool {
 
 type http2erringRoundTripper struct{ err error }
 
+func (rt http2erringRoundTripper) RoundTripErr() error { return rt.err }
+
 func (rt http2erringRoundTripper) RoundTrip(*Request) (*Response, error) { return nil, rt.err }
 
 // gzipReader wraps a response body so it can lazily