Fix bug: string output port must copy input strings.

diff --git a/src/runtime/stringio.scm b/src/runtime/stringio.scm
index 98afab45d5beea080aebe3c6ec8275f8185cf696..27d00f90d3ab8cb07e8b2508e7c75e4408e05d11 100644 (file)
--- a/src/runtime/stringio.scm
+++ b/src/runtime/stringio.scm
@@ -208,7 +208,7 @@ USA.
 (define (string-out/write-substring port string start end)
   (let ((os (textual-port-state port))
        (n (fix:- end start)))
-    ((ostate-builder os) (string-slice string start end))
+    ((ostate-builder os) (string-copy string start end))
     (update-column-for-substring! os string start end)
     n))