1 files changed, 2 insertions, 2 deletions
diff --git a/file.c b/file.c
index f89248b521..1f7b207195 100644
--- a/file.c
+++ b/file.c
@@ -3104,7 +3104,7 @@ rb_file_s_extname(VALUE klass, VALUE fname)
     if (!p)
 	p = name;
     else
-	p++;
+	name = ++p;
 
     e = 0;
     while (*p) {
@@ -3134,7 +3134,7 @@ rb_file_s_extname(VALUE klass, VALUE fname)
 	    break;
 	p = CharNext(p);
     }
-    if (!e || e+1 == p)	/* no dot, or the only dot is first or end? */
+    if (!e || e == name || e+1 == p)	/* no dot, or the only dot is first or end? */
 	return rb_str_new(0, 0);
     extname = rb_str_new(e, p - e);	/* keep the dot, too! */
     rb_enc_copy(extname, fname);