1 files changed, 1 insertions, 1 deletions
diff --git a/string.c b/string.c
index d6fd73115b..c6dec224f1 100644
--- a/string.c
+++ b/string.c
@@ -1594,7 +1594,7 @@ rb_str_init(int argc, VALUE *argv, VALUE str)
                 const size_t osize = RSTRING(str)->as.heap.len + TERM_LEN(str);
                 char *new_ptr = ALLOC_N(char, (size_t)capa + termlen);
                 memcpy(new_ptr, old_ptr, osize < size ? osize : size);
-                FL_UNSET_RAW(str, STR_SHARED);
+                FL_UNSET_RAW(str, STR_SHARED|STR_NOFREE);
                 RSTRING(str)->as.heap.ptr = new_ptr;
 	    }
 	    else if (STR_HEAP_SIZE(str) != (size_t)capa + termlen) {