diff --git a/http.go b/http.go
index aaa5ff4ecd..c1c8017a01 100644
--- a/http.go
+++ b/http.go
@@ -328,9 +328,6 @@ func newCloseReader(r io.Reader, closeFunc func() error) io.ReadCloser {
 	if r == nil {
 		panic(`BUG: reader is nil`)
 	}
-	if rv, isOk := r.(io.ReadCloser); isOk {
-		return rv
-	}
 	return &closeReader{Reader: r, closeFunc: closeFunc}
 }