string.c: check argument type

* string.c (rb_str_quote_unprintable): check if argument is a string.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40920 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 1 deletions

diff --git a/string.c b/string.c
index aef65e74c7..fbd496ea7c 100644
--- a/string.c
+++ b/string.c
@@ -8152,8 +8152,10 @@ rb_str_quote_unprintable(VALUE str)
     rb_encoding *enc;
     const char *ptr;
     long len;
-    rb_encoding *resenc = rb_default_internal_encoding();
+    rb_encoding *resenc;
 
+    Check_Type(str, T_STRING);
+    resenc = rb_default_internal_encoding();
     if (resenc == NULL) resenc = rb_default_external_encoding();
     enc = STR_ENC_GET(str);
     ptr = RSTRING_PTR(str);